Synthesis and Characterization of Titanium Vanadate and Vanadium Antimonate and Their Use in Treatment of Some Toxic Waste

Ain Shams University Faculty of Science

Synthesis and characterization of titanium vanadate and vanadium antimonate and their use in treatment of some toxic waste.

Ph.D Thesis Submitted

Chemistry Department Faculty of Science Ain Shams University

Wafaa Mohamed Mohamed Husein M. Sc. (Inorganic Chemistry) Hot Laboratories Center Atomic Energy Authority

2013

Synthesis and characterization of titanium vanadate and vanadium antimonate and their use in treatment of some toxic waste. Ph.D Thesis Submitted To

Chemistry Department Faculty of Science-Ain Shams University

For Degree doctor of philosophy of Science (Chemistry)

By Wafaa Mohamed Mohamed Husein M. Sc. (Chemistry) Hot Laboratories Center Atomic Energy Authority

Supervised By

Prof. Dr. Mohamed F. El-Shahat Prof. Dr. Ibrahim M. El-Naggar Prof. of Analytical and Inorganic Chemistry Prof. of Physical Chemistry Faculty of Science Hot Laboratories Center Ain Shams University Atomic Energy Authority

2013

Approval Sheet for Submission 2009

A Thesis Title

Synthesis and characterization of titanium vanadate and vanadium antimonate and their use in treatment of some toxic waste.

A thesis Submitted By Wafaa Mohamed Mohamed Husein

M.Sc. (Inorganic Chemistry) This thesis has been approved for submission by supervisors

Thesis Advisors: Signature

1- Prof. Dr. Mohamed F. El-Shahat ……………. Prof. of Analytical and Inorganic Chemistry Ain Shams University

2- Prof. Dr. Ibrahim M. El-Naggar ……………. Prof. of Physical Chemistry Atomic Energy Authority

Credit Head of the Department of Chemistry

Prof. Dr./ Hamed Ahmed Yones Derbala

ACKNOWLEDGEMENT

I would like to express my deep thanks to Prof. Dr. Mohamed F. El- Shahat, Professor of Analytical and Inorganic Chemistry, Faculty of Science, Ain Shams University, for sponsoring this work and his continuous encouragement.

I express my sincere gratitude and gratefulness to Prof. Dr. Ibrahim M. El-Naggar, Professor of Physical Chemistry, Hot Labs. Center, Atomic Energy Authority (AEA), for suggesting the point of research, direct supervision guidance, continuous encouragement, valuable comments and discussion, reading the manuscript, his insight on both the professional and personal levels which gave me the greatest helps to accomplish this study.

My deep thanks to Prof. Dr. Essam S. Zakaria, Professor of Physical Chemistry, The Head of Nuclear Fuel Management Division , Hot Labs. Center, Atomic Energy Authority (AEA), for his interest, encouragement and valuable revision of the thesis.

My deepest gratitude to all colleagues and staff members of Radioactive Environmental Pollution Department and Nuclear Fuel Technology Department, Hot Labs. Centre, for their sweet cooperative interactions.

Wafaa Mohamed Mohamed Husein

ّ ِ ْ ِ ﺑﺴﻢ ﷲِ ﱠ ِْاﻟﺮﺣﻤﻦ ﱠِِاﻟﺮﺣﯿﻢ

“اﻟﺒﻘﺮة "32" ﺻﺪق ﷲ اﻟﻌﻈﯿﻢ

ﺟﺎﻣﻌﺔ ﻋﯿﻦ ﺷﻤﺲ ﻛﻠﯿﺔ اﻟﻌﻠﻮم

ﺗﺣﺿﯾر وﺗوﺻﯾف ﺗﯾﺗﺎﻧﺎت واﻧﺗﯾﻣوﻧﺎت اﻟﻔﺎﻧﺎدﯾوم واﺳﺗﺧداﻣﻬﻣﺎ ﻓﻰ ﻣﻌﺎﻟﺟﺔ اﻟﻣﺧﻠﻔﺎت اﻟﺿﺎرة

رﺳﺎﻟﺔ ﻣﻘدﻣﺔ ﻣن

وﻓﺎء ﻣﺣﻣد ﻣﺣﻣد ﺣﺳﯾن ﻣﺎﺟﺳﺗﯾر ﻓﻲ اﻟﻌﻠوم – ﻛﯾﻣﯾﺎء ﻫﯾﺋﺔ اﻟطﺎﻗﺔ اﻟذرﯾﺔ إﻟﻰ ﻗﺳم اﻟﻛﯾﻣﯾﺎء ﻛﻠﯾﺔ اﻟﻌﻠوم - ﺟﺎﻣﻌﺔ ﻋﯾن ﺷﻣس ﻟﻠﺣﺻول ﻋﻠﻰ درﺟﺔ دﻛﺗوراﻩ اﻟﻔﻠﺳﻔﺔ ﻓﻲ اﻟﻌﻠوم (ﻛﯾﻣﯾﺎء) ٢٠١٣

ﺟﺎﻣﻌﺔ ﻋﯿﻦ ﺷﻤﺲ ﻛﻠﯿﺔ اﻟﻌﻠﻮم

ﺗﺣﺿﯾر وﺗوﺻﯾف ﺗﯾﺗﺎﻧﺎت واﻧﺗﯾﻣوﻧﺎت اﻟﻔﺎﻧﺎدﯾوم واﺳﺗﺧداﻣﻬﻣﺎ ﻓﻰ ﻣﻌﺎﻟﺟﺔ اﻟﻣﺧﻠﻔﺎت اﻟﺿﺎرة رﺳﺎﻟﺔ ﻣﻘدﻣﺔ ﻣن وﻓﺎء ﻣﺣﻣد ﻣﺣﻣد ﺣﺳﯾن ﻣﺎﺟﺳﺗﯾر ﻓﻲ اﻟﻌﻠوم – ﻛﯾﻣﯾﺎء ﻫﯾﺋﺔ اﻟطﺎﻗﺔ اﻟذرﯾﺔ إﻟﻰ ﻗﺳم اﻟﻛﯾﻣﯾﺎء - ﻛﻠﯾﺔ اﻟﻌﻠوم - ﺟﺎﻣﻌﺔ ﻋﯾن ﺷﻣس ﻟﻠﺣﺻول ﻋﻠﻰ درﺟﺔ دﻛﺗوراﻩ اﻟﻔﻠﺳﻔﺔ ﻓﻲ اﻟﻌﻠوم (ﻛﯾﻣﯾﺎء) ﺗﺣت إﺷراف

أ.د/ ﻣﺣﻣد ﻓﺗﺣﻰ اﻟﺷﺣﺎت (أﺳﺗﺎذ اﻟﻛﯾﻣﯾﺎء اﻟﺗﺣﻠﯾﻠﯾﺔ و ﻏﯾر اﻟﻌﺿوﯾﺔ- ﺟﺎﻣﻌﺔ ﻋﯾن ﺷﻣس) أ.د./ إﺑراﻫﯾم ﻣﺣﻣد اﻟﻧﺟﺎر (أﺳﺗﺎذ اﻟﻛﯾﻣﯾﺎء اﻟﻔﯾزﯾﺎﺋﯾﺔ- ﻫﯾﺋﺔ اﻟطﺎﻗﺔ اﻟذرﯾﺔ)

ﺗﺣﺿﯾر وﺗوﺻﯾف ﺗﯾﺗﺎﻧﺎت واﻧﺗﯾﻣوﻧﺎت اﻟﻔﺎﻧﺎدﯾوم

واﺳﺗﺧداﻣﻬﻣﺎ ﻓﻰ ﻣﻌﺎﻟﺟﺔ اﻟﻣﺧﻠﻔﺎت اﻟﺿﺎرة

وﻓﺎء ﻣﺣﻣد ﻣﺣﻣد ﺣﺳﯾن

ﻣﺎﺟﺳﺗﯾر ﻓﻰ اﻟﻌﻠوم – ﻛﯾﻣﯾﺎء

اﻟﺳﺎدة اﻟﻣﺷرﻓون: اﻟﺗوﻗﯾﻊ أ.د/ ﻣﺣﻣد ﻓﺗﺣﻰ اﻟﺷﺣﺎت ...... (أﺳﺗﺎذ اﻟﻛﯾﻣﯾﺎء اﻟﺗﺣﻠﯾﻠﯾﺔ و ﻏﯾر اﻟﻌﺿوﯾﺔ - ﺑﻌﻠوم ﻋﯾن ﺷﻣس)

أ.د./ إﺑراﻫﯾم ﻣﺣﻣد اﻟﻧﺟﺎر ......

(أﺳﺗﺎذ اﻟﻛﯾﻣﯾﺎء اﻟﻔﯾزﯾﺎﺋﯾﺔ- ﻫﯾﺋﺔ اﻟطﺎﻗﺔ اﻟذرﯾﺔ)

رﺋﯾس ﻗﺳم اﻟﻛﯾﻣﯾﺎء

أ.د/ ﺣﺎﻣﺪ أﺣﻤﺪ ﯾﻮﻧﺲ درﺑﺎﻟﺔ

رﺳﺎﻟﺔ دﻛﺗوراﻩ إﺳم اﻟطﺎﻟب: وﻓﺎء ﻣﺣﻣد ﻣﺣﻣد ﺣﺳﯾن ﻋﻧوان اﻟرﺳﺎﻟﺔ: ﺗﺣﺿﯾر وﺗوﺻﯾف ﺗﯾﺗﺎﻧﺎت واﻧﺗﯾﻣوﻧﺎت اﻟﻔﺎﻧﺎدﯾوم واﺳﺗﺧداﻣﻬﻣﺎ ﻓﻰ ﻣﻌﺎﻟﺟﺔ اﻟﻣﺧﻠﻔﺎت اﻟﺿﺎرة

إﺳم اﻟدرﺟﺔ: درﺟﺔ دﻛﺗوراﻩ اﻟﻔﻠﺳﻔﺔ ﻓﻰ اﻟﻌﻠوم (اﻟﻛﯾﻣﯾﺎء)

ﻟﺟﻧﺔ اﻹﺷراف: أ.د/ ﻣﺣﻣد ﻓﺗﺣﻰ اﻟﺷﺣﺎت (أﺳﺗﺎذ اﻟﻛﯾﻣﯾﺎء اﻟﺗﺣﻠﯾﻠﯾﺔ و ﻏﯾر اﻟﻌﺿوﯾﺔ- ﺟﺎﻣﻌﺔ ﻋﯾن ﺷﻣس) أ.د./ إﺑراﻫﯾم ﻣﺣﻣد اﻟﻧﺟﺎر (أﺳﺗﺎذ اﻟﻛﯾﻣﯾﺎء اﻟﻔﯾزﯾﺎﺋﯾﺔ- ﻫﯾﺋﺔ اﻟطﺎﻗﺔ اﻟذرﯾﺔ) ﻟﺟﻧﺔ اﻟﺗﺣﻛﯾم واﻟﻣﻧﺎﻗﺷﺔ: ١- ٢- ٣- ٤-

ﺗﺎرﯾﺦ اﻟﺑﺣث / / ٢٠١٣ اﻟدراﺳﺎت اﻟﻌﻠﯾﺎ

ﺧﺗم اﻹﺟﺎزة أﺟﯾزت اﻟرﺳﺎﻟﺔ ﺑﺗﺎرﯾﺦ / / ٢٠١٣

ﻣواﻓﻘﺔ ﻣﺟﻠس اﻟﻛﻠﯾﺔ / / ٢٠١٣ ﻣواﻓﻘﺔ ﻣﺟﺎس اﻟﺟﺎﻣﻌﺔ / / ٢٠١٣

ﺷﻛر وﺗﻘدﯾر

أﺗﻘــدم ﺑﺄﺳــﻣﻰ آﯾــﺎت اﻟــﺷﻛر واﻟﺗﻘــدﯾر إﻟــﻰ أﺳــﺎﺗذﺗﻰ اﻷﻓﺎﺿــل اﻟــذﯾن ﻗــﺎﻣو ﺑﺎﻹﺷــراف ﻋﻠــﻰ

ﻫذﻩ اﻟرﺳﺎﻟﺔ وﻫم:

ﻛﻣﺎ أﺗﻘدم ﺑﺧﺎﻟص اﻟﺷﻛر إﻟﻰ ﺟﻣﯾﻊ أﻋﺿﺎء ﻗﺳم ﺗﻠـوث اﻟﺑﯾﺋـﺔ ﺑﺎﻹﺷـﻌﺎع وﻗـﺳم ﺗﻛﻧوﻟوﺟﯾـﺎ اﻟوﻗود اﻟﻧووي ﺑﻣرﻛز اﻟﻣﻌﺎﻣـل اﻟﺣـﺎرة - ﻫﯾﺋـﺔ اﻟطﺎﻗـﺔ اﻟذرﯾـﺔ وﻛـل ﻣـن ﻗـﺎم ﺑﻣـﺳﺎﻋدﺗﻰ ﻓـﻰ إﺗﻣﺎم ﻫذﻩ اﻟرﺳﺎﻟﺔ. وﻛذﻟك أﺗﻘدم ﺑﺎﻟﺷﻛر إﻟﻰ ﺟﻣﯾﻊ أﻓراد ﻋﺎﺋﻠﺗﻰ.

وﷲ اﻟﺣﻣد واﻟﺷﻛر ﻣن ﻗﺑل وﻣن ﺑﻌد واﻟذى ﺑدون ﺗوﻓﯾﻘﻪ ﻣﺎ ﺗم ﻫذا اﻟﻌﻣل.

ﺟﺎﻣﻌﺔ ﻋﯿﻦ ﺷﻤﺲ ﻛﻠﯿﺔ اﻟﻌﻠﻮم

ﺻﻔﺣﺔ اﻟﻌﻧوان

ﻋﻧوان اﻟرﺳﺎﻟﺔ: " ﺗﺣﺿﯾر وﺗوﺻﯾف ﺗﯾﺗﺎﻧﺎت واﻧﺗﯾﻣوﻧﺎت اﻟﻔﺎﻧﺎدﯾوم واﺳﺗﺧداﻣﻬﻣﺎ ﻓﻰ ﻣﻌﺎﻟﺟﺔ اﻟﻣﺧﻠﻔﺎت اﻟﺿﺎرة" ." إﺳم اﻟطﺎﻟب: وﻓﺎء ﻣﺣﻣد ﻣﺣﻣد ﺣﺳﯾن ﻣﻛﺎن اﻟﻌﻣل: ﻣرﻛز اﻟﻣﻌﺎﻣل اﻟﺣﺎرة – ﻫﯾﺋﺔ اﻟطﺎﻗﺔ اﻟذرﯾﺔ اﻟدرﺟﺔ اﻟﻌﻠﻣﯾﺔ: دﻛﺗوراﻩ اﻟﻔﻠﺳﻔﺔ ﻓﻰ اﻟﻌﻠوم (ﻛﯾﻣﯾﺎء) اﻟﻘﺳم اﻟﺗﺎﺑﻊ ﻟﻪ: ﻗﺳم اﻟﻛﯾﻣﯾﺎء إﺳم اﻟﻛﻠﯾﺔ: ﻛﻠﯾﺔ اﻟﻌﻠوم اﻟﺟﺎﻣﻌﺔ: ﺟﺎﻣﻌﺔ ﻋﯾن ﺷﻣس ﺳﻧﺔ اﻟﺗﺧرج: ٢٠٠١م ﺳﻧﺔ اﻟﻣﻧﺢ: ٢٠١٣م

W.M. EL-KENANY اﻟﻤﻠﺨﺺ اﻟﻌﺮﺑﻲ ARABIC SUMMARY

اﻟﻣﻠﺧص اﻟﻌرﺑﻲ

ﻗـــد ﺗـــم ﻧـــﺷر اﻟﻌدﯾـــد ﻣـــن اﻷﺑﺣـــﺎث واﻟﺗﻘﻧﯾـــﺎت ﻋﻠـــﻰ اﺳـــﺗﺧدام ﻛـــل ﻣـــن اﻟﻣﺑـــﺎدﻻت اﻻﯾوﻧﯾـــﺔ ﻏﯾـــر اﻟﻌـــﺿوﯾﺔ ﻓـــﻲ ﻣﻌﺎﻟﺟـــﺔ اﻟﻣﯾـــﺎﻩ اﻟﻣﻠوﺛـــﺔ ﺑﺎﻟﻌﻧﺎﺻـــر اﻟـــﺿﺎرة، ﺳـــواء ﻛﺎﻧـــت ﻋﻧﺎﺻـــر ﺛﻘﯾﻠـــﺔ ﻣـــن اﻟﻧﻔﺎﯾـــﺎت اﻟﺻﻧﺎﻋﯾﺔ أو ﻋﻧﺎﺻر ﻣﺷﻌﺔ ﻣن اﻟﻧﻔﺎﯾﺎت اﻟﻧﺎﺗﺟﺔ ﻋن اﻟﻌﻣل ﻓﻲ اﻟﻣﺟﺎل اﻟﻧووي. ﺗﻬدف ﻫـذﻩ اﻟرﺳـﺎﻟﺔ إﻟـﻰ ﺗﺣـﺿﯾروﺗوﺻﯾف ﺗﯾﺗﺎﻧـﺎت واﻧﺗﯾﻣوﻧـﺎت اﻟﻔﺎﻧـﺎدﯾوم ﻛﻣﺑـﺎدل ﻛـﺎﺗﯾوﻧﻲ، وﻫﻣـﺎ ﻣﺑﺎدﻻن ﻏﯾر ﻋﺿوﯾﺎن واﺳﺗﺧداﻣﻬﻣﺎ ﻓﻲ ازاﻟﺔ اﻟﻌﻧﺎﺻر اﻟـﺿﺎرة ﻣـن اﻟﻧﻔﺎﯾـﺎت اﻟـﺻﻧﺎﻋﯾﺔ اﻟـﺳﺎﺋﻠﺔ اﻟﻧﺎﺗﺟـﺔ ﻋن ﺻرف اﻟﻧﻔﺎﯾﺎت اﻟﺻﻧﺎﻋﯾﺔ. اﻟرﺳﺎﻟﺔ ﺗﺣﺗوى ﻋﻠﻰ ﺛﻼﺛﺔ أﺑواب رﺋﯾﺳﯾﺔ ﻫﻲ :

اﻟﺑﺎب اﻷول(اﻟﻣﻘدﻣﺔ): ﺗﺣﺗـوي اﻟﻣﻘدﻣـﺔ ﻋﻠـﻰ ﻣـﺳﺣﺎ ﺷــﺎﻣﻼ ﯾﻐطـﻲ ﻋﻣﻠﯾـﺔ اﻟﺗﺑـﺎدل اﻷﯾــوﻧﻲ وﻧﺑـذة ﺗﺎرﯾﺧﯾـﺔ ﻋـن اﻟﻣﺑــﺎدﻻت اﻟﻌﺿوﯾﺔ وﻏﯾر اﻟﻌﺿوﯾﺔ، ﻛﻣـﺎ أﻧﻬـﺎ اﺷـﺗﻣﻠت ﻋﻠـﻰ اﻧـواع اﻟﻣﺑـﺎدﻻت اﻷﯾوﻧﯾـﺔ ﻏﯾـر اﻟﻌـﺿوﯾﺔ وﺧواﺻـﻬﺎ ﻛﻣﺎ ﺗﺣﺗوى اﯾﺿﺎ ﻋﻠﻰ ﻣﺳﺢ اﺳﺗرﺟﺎﻋﻰ ﻋﻠﻰ ﻣﺑﺎدﻻت اﻻﻧﺗﯾﻣوﻧﺎت واﻟﻔﺎﻧﺎدات اﻟﺑﺎب اﻟﺛﺎﻧﻲ(اﻟﻌﻣﻠﻲ): وﯾﺷﺗﻣل ﻋﻠﻰ وﺻف ﻟﻠﻣواد اﻟﻛﯾﻣﯾﺎﺋﯾـﺔ اﻟﻣـﺳﺗﺧدﻣﺔ ودرﺟـﺔ ﻧﻘﺎوﺗﻬـﺎ وطرﯾﻘـﺔ اﻟﺗﺣـﺿﯾر اﻟﻣـﺳﺗﺧدﻣﺔ ﻓـــﻲ ﻫـــذﻩ اﻟرﺳـــﺎﻟﺔ وﻛـــذﻟك أﺟﻬـــزة اﻟﻘﯾـــﺎس اﻟﻣﺧﺗﻠﻔـــﺔ واﻟﺗﺣﺎﻟﯾـــل اﻟﺗـــﻲ أﺟرﯾـــت ﻋﻠـــﻰ اﻟﻣﺑـــﺎدﻟﯾن اﻷﯾـــوﻧﯾﯾن اﻟﻣﺳﺗﺧدﻣﯾن ﻓﻲ ﻫذﻩ اﻟرﺳﺎﻟﺔ.

اﻟﺑﺎب اﻟﺛﺎﻟث(اﻟﻧﺗﺎﺋﺞ وﻣﻧﺎﻗﺷﺎﺗﻬﺎ): وﯾﺗﺿﻣن ﻫذا اﻟﺑﺎب اﻟﻧﺗﺎﺋﺞ اﻟﺗﻲ ﺗم اﻟﺣﺻول ﻋﻠﯾﻬﺎ وﻣﻧﺎﻗﺷﺗﻬﺎ ﺛم ﺗﺣﻠﯾﻠﻬﺎ، ﻛﻣﺎ ﺗم ﻋرض ﻣﺳﺗﻔﯾض ﻟﺗﺣﺿﯾر ﻣﺑﺎدل ﺗﯾﺗﺎﻧﺎت واﻧﺗﯾﻣوﻧﺎت اﻟﻔﺎﻧدﯾوم، وﺗم ﺗوﺻﯾف اﻟﻣواد اﻟﻣﺣﺿرة ﺑﺎﺳﺗﺧدﻟم ﺑﻌض اﻟطرق اﻟﺗﺣﻠﯾﻠﯾﺔ ﻣﺛل :اﻻﺷﻌﺔ ﺗﺣت اﻟﺣﻣراء (FTIR) واﺷﻌﺔ اﻛس اﻟوﻣﯾﺿﯾﺔ (XRF) واﻟﺗﺣﻠﯾل اﻟﺣرارى اﻟﺗﻔﺎﺿﻠﻰ(TGA-DTA) واﻟﻣﯾﻛروﺳﻛوب اﻻﻟﻛﺗروﻧﻰ اﻟﻣﺎﺳﺢ (SEM).

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W.M. EL-KENANY اﻟﻤﻠﺨﺺ اﻟﻌﺮﺑﻲ ARABIC SUMMARY

وﻗد ﺑﯾﻧت اﻟﺗﺣﺎﻟﯾل أن اﻟﺻﯾﻐﺔ اﻟﻛﯾﻣﯾﺎﺋﯾﺔ اﻟﻣﻘﺗرﺣﺔ ﻟﻠﻣﺑﺎدﻟﯾن ﺗﯾﺗﺎﻧﺎت اﻟﻔﺎﻧﺎدﯾوم واﻧﺗﯾﻣوﻧﺎت اﻟﻔﺎﻧﺎدﯾوم ﻫﻰ: Ti2V2O9 . 2.5H2O

Sb6V8O35. 9.35 H2O

ﻛﻣﺎ أﻣﻛن ﻋﻣل ﺗﺟرﺑﺔ ﻣﻧﺣﻧﻰ اﻷس اﻟﻬﯾدروﺟﯾﻧﻲ اﻟﻣﻌﯾﺎري (pH titration curve) ﻋﻠﻰ اﻟﻣﺑﺎدﻟﯾن ﺗﯾﺗﺎﻧﺎت واﻧﺗﯾﻣوﻧﺎت اﻟﻔﺎﻧﺎدﯾوم وﻗد ﺗﺑﯾن أن اﻟﻣﻧﺣﻧﻰ ﯾﺣﺗوي ﻋﻠﻰ ﻧﻘطﺔ اﻧﺣراف واﺣدة، ﻣﻣﺎ ﯾدل ﻋﻠﻰ أن ﻫذﯾن اﻟﻣﺑﺎدﻟﯾن اﻷﯾوﻧﯾﯾن ﯾﺣﺗوﯾﺎن ﻋﻠﻰ ﻣﺟﻣوﻋﺔ واﺣدة ﻓﻌﺎﻟﺔ وأﻧﻬﻣﺎ ذو ﺧواص ﺣﺎﻣﺿﯾﺔ. أﺷﺗﻣل ﻫذا اﻟﺑﺎب أﯾﺿﺎ ﻋﻠﻰ ﻧﺗﺎﺋﺞ اﻟﺗﺣﺎﻟﯾل اﻟﺗﻲ أﺟرﯾت ﻋﻠﻰ ﻋﯾﻧﺎت ﺗﯾﺗﺎﻧﺎت واﻧﺗﯾﻣوﻧﺎت اﻟﻔﺎﻧﺎدﯾوم وﻗد أﺛﺑﺗت اﻟﺗﺣﺎﻟﯾل أن اﻧﺗﯾﻣوﻧﺎت اﻟﻔﺎﻧﺎدﯾوم اﻟﻣﺣﺿرة ﻋدﯾﻣﺔ اﻟذوﺑﺎن ﻓﻲ اﻟﻣﺣﺎﻟﯾل اﻟﻣﺎﺋﯾﺔ وﺷﺣﯾﺣﺔ اﻟذوﺑﺎن ﻓﻰ اﻟﻣﺣﺎﻟﯾل اﻟﺣﻣﺿﯾﺔ ﻟﻛل ﻣن ﺣﻣض اﻟﻧﯾﺗرﯾك وﺣﻣض اﻟﻬﯾدروﻛﻠورﯾك ﺣﺗﻰ ﺗرﻛﯾز ٢ ﻣوﻻرى ﺑﯾﻧﻣﺎ ﺗﯾﺗﺎﻧﺎت اﻟﻔﺎﻧﺎدﯾوم ﺗﻛون ﺗﺎﻣﺔ اﻟذوﺑﺎن ﻋﻧد ﺗرﻛﯾز٤ ﻣوﻻرى ﻣن ﺣﻣﺿﻰ اﻟﻧﯾﺗرﯾك واﻟﻬﯾدروﻛﻠورﯾك ، ﻛﻣﺎ ﺗﺑﯾن أن اﻟﺛﺑﺎت اﻟﻛﯾﻣﯾﺎﺋﻲ ﻟﻣﺑﺎدﻟﯾن ﺗﯾﺗﺎﻧﺎت اﻟﻔﺎﻧﺎدﯾوم و اﻧﺗﯾﻣوﻧﺎت اﻟﻔﺎﻧﺎدﯾوم أﻋﻠﻰ ﻣن اﻟﺛﺑﺎت اﻟﻛﯾﻣﯾﺎﺋﻲ ﻟﻠﻛﺛﯾر ﻣن اﻟﻣﺑﺎدﻻت ﻏﯾر اﻟﻌﺿوﯾﺔ اﻻﺧرى .ﻛﻣﺎ ان اﻟﺛﺑﺎت اﻟﻛﯾﻣﯾﺎﺋﻰ ﻻﻧﺗﯾﻣوﻧﺎت اﻟﻔﺎﻧﺎدﯾوم اﻛﺑر ﻣن اﻟﺛﺑﺎت اﻟﻛﯾﻣﯾﺎﺋﻰ ﻟﺗﯾﺗﺎﻧﺎت اﻟﻔﺎﻧﺎدﯾوم وﻫذﻩ إﺣدى ﺛﻣﺎر ﻫذﻩ اﻟدراﺳﺔ. أظﻬرت اﻟﻧﺗﺎﺋﺞ أن ﻣرﻛب ﺗﯾﺗﺎﻧﺎت اﻟﻔﺎﻧﺎدﯾوم ﻫو ﻣرﻛب ﻏﯾر ﺑﻠوري وأن ﺧواﺻﻪ ﻏﯾر اﻟﺑﻠورﯾﺔ ﻻ o o ﺗﺗﺎﺛر ﺑزﯾﺎدة درﺟﺔ اﻟﺗﺳﺧﯾن ﻣن ٥٠ م ﺣﺗﻰ ٦٠٠ م. اﻣﺎ ﻣرﻛب اﻧﺗﯾﻣوﻧﺎت اﻟﻔﺎﻧﺎدﯾوم ﻓﻬو اﯾﺿﺎ ﻏﯾر o o ﺑﻠﻠورى وﻟﻛن اﻟﺧواص اﻟﺑﻠﻠورﯾﺔ ﺗﺗﺣﺳن ﺑزﯾﺎدة درﺟﺔ اﻟﺗﺟﻔﯾف ﻣن ٥٠ م ﺣﺗﻰ ٦٠٠ م ﻛﻣﺎ ﺗﺑﯾن ﻣن اﻟﺗﺣﻠﯾل اﻟﺣراري ﻟﻠﻣواد اﻟﻣﺣﺿرة أﻧﻬﺎ ﺗﻣﺗﻠك ﺛﺑﺎﺗﺎ ﺣرارﯾﺎ ﻋﺎﻟﯾﺎ ﺟدا ﻣﻘﺎرﻧﺔ ﺑﺑﻌض اﻟﻣﺑﺎدﻻت اﻷﺧرى، ﺣﯾث ﺗﺑﯾن أن ﺗﯾﺗﺎﻧﺎت اﻟﻔﺎﻧﺎدﯾوم اﻟﻣﺣﺿرة ﺗﻔﻘد ١٢.٥٢% ﻣن وزﻧﻬﺎ ﻓﻘط إذا ﺗم o o ﺗﺟﻔﯾﻔﻬﺎ ﻋﻧد ٤٠٠ م وﺗﻔﻘد ١٥.٦٦% ﻓﻘط ﻣن وزﻧﻬﺎ إذا ﺗم ﺗﺟﻔﯾﻔﻬﺎ ﻋﻧد ٨٠٠ م، ﺑﯾﻧﻣﺎ ﺗﻔﻘد o اﻧﺗﯾﻣوﻧﺎت اﻟﻔﺎﻧﺎدﯾوم ١٤.٢٢% ﻓﻘط ﻣن وزﻧﻬﺎ إذا ﺗم ﺗﺟﻔﯾﻔﻬﺎ ﻋﻧد ٤٠٠ م وﺗﻔﻘد ١٩% ﻓﻘط ﻣن o وزﻧﻬﺎ إذا ﺗم ﺗﺟﻔﯾﻔﻬﺎ ﻋﻧد ٨٠٠ م. ﻗد ﺗم دراﺳـﺔ ﻣﻌﺎﻣـل ﺗوزﯾـﻊ اﻟﻌﻧﺎﺻـر اﻟﻣﺧﺗﻠﻔـﺔ ﻣـﻊ أرﻗـﺎم ﻣﺧﺗﻠﻔـﺔ ﻣـن اﻷس اﻟﻬﯾـدروﺟﯾﻧﻲ (pH) ﻋﻠــﻰ اﻟﻣﺑــﺎدﻟﯾن ﺗﯾﺗﺎﻧــﺎت واﻧﺗﯾﻣوﻧــﺎت اﻟﻔﺎﻧــﺎدﯾوم ﻣــﻊ ﻋﻧﺎﺻــر اﻟــﺳﯾزﯾوم واﻟﻛــﺎدﻣﯾوم واﻟﻧﺣــﺎس اﻟﻛوﺑﺎﻟــت ،ووﺟـد ان اﻟﻌﻼﻗـﺔ ﺑـﯾن ﻣﻌﺎﻣـل اﻟﺗوزﯾـﻊ (Kd) ﻣـﻊ اﻷس اﻟﻬﯾـدروﺟﯾﻧﻲ (pH) ﺗﻌطـﻰ ً ﺧطـﺎ ًﻣـﺳﺗﻘﯾﻣﺎ ﻛﻣـﺎ

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W.M. EL-KENANY اﻟﻤﻠﺨﺺ اﻟﻌﺮﺑﻲ ARABIC SUMMARY

وﺟد أن ﻣﯾل ﻫذا اﻟﺧط ﯾﺧﺗﻠف ﻋن ﺗﻛﺎﻓؤ اﻟﻌﻧـﺻر وﻗـد ﺗﺑـﯾن أن اﻻﺧﺗﯾﺎرﯾـﺔ ﻟﻠﻌﻧﺎﺻـر اﻟﻣدروﺳـﺔ ﻟﻣﺑـﺎدل ﺗﯾﺗﺎﻧﺎت اﻟﻔﺎﻧﺎدﯾوم ﻛﺎﻟﺗﺎﻟﻲ : اﻟﻛﺎدﻣﯾوم < اﻟﻛوﺑﺎﻟت < اﻟﻧﺣﺎس << اﻟﺳﯾزﯾوم ﺑﯿﻨﻤﺎ ﺗﻜﻮن اﺧﺘﯿﺎرﯾﺔ اﻧﺘﯿﻤﻮﻧﺎت اﻟﻔﺎﻧﺪﯾﻮم ﻟﻠﻌﻨﺎﺻﺮ اﻟﻤﺪروﺳﺔ ھﻰ: اﻟﻛﺎدﻣﯾوم < اﻟﺳﯾزﯾوم< اﻟﻛوﺑﺎﻟت < اﻟﻧﺣﺎس

ﻛذﻟك ﺗم دراﺳﺔ ﻣﻌﺎﻣل اﻟﺗوزﯾﻊ ﺗﯾﺗﺎﻧﺎت واﻧﺗﯾﻣوﻧﺎت اﻟﻔﺎﻧﺎدﯾوم ﻟﻠﻌﻧﺎﺻر ﻋﻧد درﺟﺎت ﺣرارة اﻟﺗﻔﺎﻋل o اﻟﻣﺧﺗﻠﻔﺔ ﻣن ( ٢٥، ٤٥ ، ٦٠ م ) ووﺟد أن ﻣﻌﺎﻣل اﻟﺗوزﯾﻊ Kd ﯾزﯾد ﺑزﯾﺎدة درﺟﺔ اﻟﺣرارة. وﻗــد ﺗﻣــت ًأﯾــﺿﺎ دراﺳــﺔ ﺳــﻌﺔ ﺗﯾﺗﺎﻧــﺎت واﻧﺗﯾﻣوﻧــﺎت اﻟﻔﺎﻧــﺎدﯾوم ﻟﻠﻌﻧﺎﺻــر ﻣﺣــل اﻟدراﺳــﺔ ﻋﻧــد ﺗرﻛﯾــز ﺛﺎﺑت ﻣن أﯾون اﻟﻬﯾدروﺟﯾن و ﻋﻧد ﺗرﻛﯾز (M ٠.٠٥ )، ﻛﻣﺎ ﺗم أﯾـﺿﺎ دراﺳـﺔ ﺳـﻌﺔ ﺗﯾﺗﺎﻧـﺎت واﻧﺗﯾﻣوﻧـﺎت o اﻟﻔﺎﻧﺎدﯾوم ﻋﻧد درﺟﺎت ﺗﺟﻔﯾف ﻣﺧﺗﻠﻔﺔ ( ٥٠، ٢٠٠، ٤٠٠ م) وﻗـد ﺗﺑـﯾن أن اﻟـﺳﻌﺔ ﺗﻘـل ﻛﻠﻣـﺎ ازدادت o o درﺟﺎت اﻟﺗﺟﻔﯾف ﻣن ٥٠ م ﺣﺗﻰ ٤٠٠ م. وﻛــذﻟك ﺗــم دراﺳــﺔ ﻛﯾﻧﺎﺗﯾﻛﯾــﺔ اﻟﺗﺑــﺎدل ﺑــﯾن ﻣﺑــﺎدل ﺗﯾﺗﺎﻧــﺎت اﻟﻔﺎﻧــﺎدﯾوم وﻛــل ﻣــن أﯾوﻧــﺎت اﻟــﺳﯾزﯾوم و اﻟﻧﺣﺎس واﻟﻛوﺑﺎﻟت واﻟﻛﺎدﻣﯾوم وذﻟك ﺑﻌد ﺗﻬﯾﺋﺔ اﻟظـروف اﻟﻣﻼﺋﻣـﺔ ﻟدراﺳـﺔ آﻟﯾـﺔ اﻻﻧﺗـﺷﺎر داﺧـل اﻟﺣﺑﯾﺑـﺎت ﻛوﺳﯾﻠﺔ ﺗﺟﺎرب ﻣﻧﻔﺻﻠﺔ ﻣﺣددة، وﻗد وﺟد أن: - ﺳرﻋﺔ اﻟﺗﺑﺎدل ﺗزداد ﻛﻠﻣﺎ ّﻗل ﻗطر ﺣﺑﯾﺑﺎت ﻣﺑﺎدل ﺗﯾﺗﺎﻧﺎت اﻟﻔﺎﻧﺎدﯾوم. o o - ﺳرﻋﺔ اﻟﺗﺑﺎدل ﺗﻘل ﻛﻠﻣﺎ زادت درﺟﺔ اﻟﺗﺟﻔﯾف ﻣن ٥٠ م ﺣﺗﻰ ٤٠٠ م. - ﺳرﻋﺔ اﻟﺗﺑﺎدل ﻻ ﺗﻌﺗﻣد ﻋﻠﻰ ﺗرﻛﯾز ﻣﺣﺎﻟﯾل اﻷﯾوﻧﺎت ﻣﺣل اﻟدراﺳﺔ. - ﺳـــرﻋﺔ اﻟﺗﺑـــﺎدل ﺗـــزداد ﻛﻠﻣـــﺎ زادت درﺟـــﺔ اﻟﺣـــرارة اﻟﺗـــﻲ ﯾﺟـــرى ﻋﻧـــدﻫﺎ اﻟﺗﻔﺎﻋـــل، وﻓـــﻰ ﻫـــذا اﻟﺟـــزء ﻣـــن اﻟرﺳـﺎﻟﺔ ﺗـم ﺣـﺳﺎب طﺎﻗــﺔ اﻟﺗﻧـﺷﯾط وﻣﻌﺎﻣـل اﻻﻧﺗــﺷﺎر، ٕواﻧﺗروﺑﯾـﺎ اﻟﺗﺑـﺎدل اﻷﯾــوﻧﻲ ﻟﻠﻌﻧﺎﺻـر ﻣﺣـل اﻟدراﺳــﺔ وذﻟك ﺑﺗطﺑﯾق ﻣﻌﺎدﻟﺔ أرﻫﯾﻧﯾوس. ﺗم ﺗطﺑﯾـق ﻣﻌـﺎدﻻت اﻟﻣﻧﺣﻧﯾـﺎت ﻣﺗـﺳﺎوﯾﺔ اﻟﺣـرارة ﻋﻠـﻰ اﻣﺗـﺻﺎص ﺟﻣﯾـﻊ اﻟﻌﻧﺎﺻـر اﻟﻣدروﺳـﺔ ﻓـﻲ o وﺳـــط اﻟﻛﻠورﯾـــد و ﺗﻣـــت ﻫـــذﻩ اﻟدراﺳـــﺔ ﻋﻧـــد درﺟـــﺎت ﺣـــرارة ﻣﺧﺗﻠﻔـــﺔ ( ٢٥، ٤٥ ، ٦٠ م )، ﻓوﺟـــد أن إﻣﺗزاز ﺟﻣﯾﻊ اﻟﻌﻧﺎﺻر ﻋﻠﻰ اﻟﻣﺑﺎدﻟﯾن ﺗﯾﺗﺎﻧﺎت واﻧﺗﯾﻣوﻧﺎت اﻟﻔﺎﻧﺎدﯾوم ﯾﺗﺑﻌـﺎن ﻣﻧﺣﻧﯾـﺎت ﻻﻧﺟﻣـﺎﯾر، أي أﻧـﻪ إﻣﺗزاز ﻣن ﻧوع ﻛﯾﻣﯾﺎﺋﻲ. أﺧﯾرا ﺟرت دراﺳﺔ اﺣﺗﻣﺎﻟﯾﺔ اﺳﺗﺧدام اﻟﻣﺑﺎدﻟﯾن ﺗﯾﺗﺎﻧﺎت واﻧﺗﯾﻣوﻧﺎت اﻟﻔﺎﻧﺎدﯾوم ﻓﻲ ازاﻟﺔ ﺑﻌض اﻟﻌﻧﺎﺻر اﻟﺿﺎرة ﻋﻧد درﺟﺔ اﻟﺣﺎﻣﻀﯿﺔ اﻟﻄﺒﯿﻌﯿﺔ ﺑﺎﺳﺗﺧدام أﻋﻣدة ﻛروﻣﺎﺗوﺟراﻓﯾﺔ ﻣﻣﺗﻠﺋﺔ ﺑﺎﻟﻣﺑﺎدﻟﯾن ﺗﯾﺗﺎﻧﺎت واﻧﺗﯾﻣوﻧﺎت اﻟﻔﺎﻧﺎدﯾوم ، وﻗد ﺗﺑﯾن ﻣن ﻫذﻩ اﻟدراﺳﺔ إﻣﻛﺎﻧﯾﺔ ازاﻟﺔ ﻋﻧﺎﺻر اﻟﺳﯾزﯾوم و اﻟﻧﺣﺎس

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W.M. EL-KENANY اﻟﻤﻠﺨﺺ اﻟﻌﺮﺑﻲ ARABIC SUMMARY

واﻟﻛوﺑﻠت واﻟﻛﺎدﻣﯾوم ﻣن ﺗﯾﺗﺎﻧﺎت اﻟﻔﺎﻧﺎدﯾوم ﻋﻧد ﺗرﻛﯾزات (٠.١ و٠.٥ ﻣوﻻرى) ﻣن ﺣﻣض اﻟﻧﯾﺗرﯾك، واﯾﺿﺎ اﻣﻛﺎﻧﯾﺔ ازاﻟﺔ ﻋﻧﺎﺻر اﻟﺳﯾزﯾوم و اﻟﻧﺣﺎس واﻟﻛوﺑﻠت واﻟﻛﺎدﻣﯾوم ﻣن اﻧﺗﯾﻣوﻧﺎت اﻟﻔﺎﻧﺎدﯾوم ﻋﻧد ﺗرﻛﯾزات (٠.١ و٠.٥ و ١و ٢ ﻣوﻻرى) ﻣن ﺣﻣض اﻟﻧﯾﺗرﯾك. وﻣﻣــﺎ ﺳــﺑق ﯾﺗــﺿﺢ ﻟﻧــﺎ أن ﻣـــﺎدﺗﻰ ﺗﯾﺗﺎﻧــﺎت واﻧﺗﯾﻣوﻧــﺎت اﻟﻔﺎﻧــﺎدﯾوم ﻣـــن اﻟﻣــواد اﻟواﻋــدة ﻓــﻲ إزاﻟـــﺔ ﺑﻌض اﻟﻌﻧﺎﺻر اﻟﺿﺎرة.

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CONTENTS

List of Tables…………………………………………………………………... VI List of Figures………………………………………………………………….. IX List of Publications…………………………………………………………….. XXI Plan of Work…………………………………………………………...... XXII Abstract………………………………………………………………...... XXIV

CHAPTER-1 INTRODUCTION

INTRODUCTION ……………………..…………..…... 1

1.1.Histrotical back ground …………………………...... 2 1.2. Ion exchange……………………………………...... 4 1.3.Classification of ion exchange materials:………………….. 4 1.3.1.Organic ion exchanger……………………………...... 5 1.3.2.Inorganic ion exchanger……………………………… 5 1.3.3.Composites ion exchangers[Hybrid exchanger]………… 9 1.4. Antimonate as inorganic ion exchanger…………………… 9 1.5.Vanadates as Inorganic ion exchanger…………………….. 16 1.6.Quantitative description of selectivity of ion exchangers….. 21 1.7.Ion-exchange properties of inorganic ion exchangers…… 22 1.7.1 Chemical stability……………………………………… 22 1.7.2. Radiation stability …………………………………….. 24 Thermal stability…………………………….. 25.٣ .1.7 1.7.4. Internal order and homogeneity in inorganic sorbets: 25 1.8.Selectivities of ion exchangers……………………………. 26

I 1.8.1.Ion sieve Effect…………………………………………. 26 1.8.2.Steric effect……………………………………………… 27 1.9. Ion exchange capacity…………………………………..... 27 1.10.Ion exchange and sorption………………………………. 28 1.11.Distribution studies:…………………………………….. 30 1.12. Ion exchange kinetics ………………………………….. 32 1.12.1. Film diffusion………………………………………….. 33 1.12.2. Particle diffusion……………………………………. 34 1.12.3. Adsorption as a chemical phenomenon …………………. 35 1.13.Sorption isotherms… …………………………………….. 35 1.13.1.Langmuir isotherm……………………………………..... 36 1.13.2.Freundlich isotherm……………………………………… 36 1.13.3 Dubinin-Raduskevich ( D-R) isotherm…………………. 37

CHAPTER-2 EXPERIMENTAL

2.1.Materials …………………………………………………. 38 2.1.1. Reagents ………………………………………………… 38

2.2. Preparation of vanadium antimonate…………………... 38 2.2.1. Preparation of reagents …………………………………. 38 2.2.2. Preparation vanadium antimonate 38 2.3.Preparation of titanium vanadate……………………….. 39 2.3.1.Preparation of reagents ……………………………..…. 39 39 2.3.2.Preparation of titanium vanadate

II 2.4.Equipment ………………………………………………. 39

2.4.1. Water thermostat shaker……………………………….. 39 2.4.2. pH-meter ……………………………………………….. 40 2.4.3. Differential thermal (DTA) and thermogravimetric (TG) 40 analyses ……………………………………………………….. 2.4.4. Infrared spectral analysis …………………………….…. 40 2.4.5. X-ray diffraction patterns …………………………….…. 40 2.4.6. Atomic absorption spectrophotometer …………………. 40 2.4.7. Elemental analysis……………………………………….. 40

2.5.Chemical stability ………………………………. 41 2.6. Capacity vanadium antimonate and titanium vanadate for the 41 studied hazardous metal ions……………... 2.7.Distribution studies ………………………...... 42 2.8.Kinetic measurements ……………………...... 43 2.9.Sorption isotherms ……………………………………… 43 2.10.Column operations ………………………... 43

CHAPTER-3 RESULTS and DISCUSSION

3.1. Preparation and characterization of the prepared 47 materials……………………………………………………… 3.1.1. Chemical stability………………………….…………….. 48 3.1.2. Infrared spectra of the prepared samples ……..…………. 50 3.1.3. X-ray diffraction patterns.…………………...... 53

III 3.1.4. Thermal analysis (TG-DTA): ………………………... 56 3.1.5. Elemental analysis (X-ray flourescence): ……………. 60 3.1.6. pH Titration …………………………………………… 61 3.1.7.Scanning electron microscope analysis...... 64

3.2.Distribution studies …………………...... 67 3.3.Capacity measurements ………………………………… 94 3.4. Kinetics studies…………………………...... 102 3.5.Sorption isotherm…………………………………………. 134 3.5.1. Langmuir isotherm …………………………………….... 134 3.5.2. Freundlich isotherm ……………………………………... 148 3.5.3. Dubinin-Radushkevich (D-R) isotherm ………………… 160 3.5.4. Temkin isotherm…………………………………………. 173

3.6.Column Operations ……………………………….. 185

CONCLUSION….………………………………….…………...... 192

SUMMARY……………………………………………………………………. 195

REFERENCES………………………………………………………...... 201

ARABIC SUMMARY…………………………………………………………

IV LIST of TABLES

Table (1) Solubility of the prepared titanium vanadate at different acid 49 concentration ……………………………………………….. Table (2) Solubility of the prepared vanadium antimonate at different 49 acid concentration.………………………………………….. Table (3) The weight loss percent of titanium vanadate dried at 59 different drying temperatures……………………………

Table (4) The weight loss percent of vanadium antimonate dried at 59 different drying temperatures……………………......

+ 2+ 2+ Table (5) Kd values and separation factors (α) of Cs , Cu , Co and 68 Cd2+ as a function of pH on titanium vanadate……………..

+ 2+ 2+ Table (6) Kd values and separation factors (α) of Cs , Cu , Co and 69 Cd2+ as a function of pH on vanadium antimonate……………

+ 2+, 2+ 2+ Table (7) Kd values of Cs ,Cu Co and Cd ions on titanium 74 vanadate at natural pH …………...... + 2+, 2+ 2+ Table (8) Kd values of Cs ,Cu Co and Cd ions on vanadium 74 antimonate at natural pH ………………......

+ 2+ 2+ 2+ Table (9) Comparison of Kd, values of Cs , Co , Cu , and Cd ions 76 for various cationic ion exchangers in DMW.……………..

2+ 2+ 2+ + Table (10) Comparison of Kd, values of Cu , Co , Cd and Cs , ions 77 for various cation ion exchangers in DMW. ………………..

V Table (11) Thermodynamic parameters for adsorption of Cs+, Cu2+, Co2+ 92 and Cd2+ ions on titanium vanadate………………………… Table (12) Thermodynamic parameters for adsorption of Cs+, Cu2+, Co2+ 92 and Cd2+ ions on vanadium antimonate ……………..

Table (13) Ion-exchange capacity of various exchanging ions on 98 inorganic cation-exchanger titanium vanadate at natural media…………………………………………………….

Table (14) Ion-exchange capacity of various exchanging ions on 98 inorganic cation-exchanger vanadium antimonate at natural media………………………………………………………….

Table (15) Capacities of Cs+ ,Co2+ ,Cu2+ and Cd2+ ions on 100 titanium vanadate at different drying temperatures…......

Table (16) Capacities of Cs+ ,Co2+ ,Cu2+ and Cd2+ ions on vanadium 102 antimonate at different drying temperatures…………………

Table (17) Values of the diffusion coefficient of Cs+, Co2+, Cu2+ and 115 Cd2+ ions on different particle diameters of titanium vanadate at 25±1 ◦C…………………………………………

Table (18) Values of the diffusion coefficient of Cs+, Co2+, Cu2+, and 116 Cd2+ on titanium vanadate dried at different drying temperatures at 25±1 ◦C……………………………………..

Table (19) Values of the diffusion coefficient of Cs+ ,Co2+, Cu2+, and 129 Cd2+ on titanium vanadate dried at 50oC at different reaction temperatures, relative errors about ±3% (Weast, 1974)………

VI Table (20) Thermodynamic parameters for the diffusion of Cs+, Co2+, Cu2+ and 131 Cd2+on titanium vanadate dried at 50oC at different reaction temperatures, relative errors about ±3% (Weast, 1974).

Table (21) Comparison of activation energy values of Co2+, Cu2+, Cd2+ 132 and Cs+ ions for various ion exchangers…………

Table (22) Langmuir isotherm parameter for the sorption of Cs+ ,Co2+, 146 Cu2+ and Cd2+ ions on titanium vanadate at different reaction temperatures………………………………………………….

Table (23) Langmuir isotherm parameter for the sorption of Cs+, 147 Co2+,Cu2+ and Cd2+on vanadium antimonate at different reaction temperatures ……………………………………….

Table(24) Freundlich isotherm parameter for the sorption of Cs+, Co2+, 158 Cu2+and Cd2+ on titanium vanadate at different reaction

temperatures……………………………………….

Freundlich isotherm parameter for the sorption of Cs+, Co2+, Table(25) 2+ 2+ 159 Cu and Cd on vanadium antimonate at different reaction temperatures………………………………………..

+ 2+ 2+ Table (26) D-R isotherm parameter for the sorption of Cs , Co , Cu 171 and Cd2+on titanium vanadate at different reaction temperatures…………………………………………………

VII

Table (27) D-R isotherm parameter for the sorption of Cs+, Co2+, 172 Cu2+ and Cd2+on titanium vanadate at different reaction

temperatures………………………………………………

+ 2+ 182 Table(28) Temkin isotherm parameter for the sorption of Cs , Co , 2+ 2+ Cu and Cd on titanium vanadate at different reaction

temperatures……………………………………………………..

+ 183 Table (29) Temkin isotherm parameter for the sorption of Cs , Co2+,Cu2+ and Cd2+ on vanadium antimonate at different reaction temperatures……………………..

VIII LIST of FIGURES

Fig. (1) Infrared pattern of titanium vanadate at different 51 drying temperatures……………………………………. Fig. (2) Infrared pattern of vanadium antimonate at different 52 drying temperatures …………………………………… Fig. (3) X-ray diffraction pattern of titanium vanadate at 54 different drying temperatures ……...... Fig. (4) X-ray diffraction pattern of vanadium antimonate at 5 5 different drying temperatures………………………….. Fig. (5) TG-DTA Pattern of titanium vanadate …………...... 57

Fig. (6) TG-DTA pattern of vanadium antimonate. ………….. 58

Fig. (7) The pH titration curve of titanium vanadate………… 62

Fig. (8) The pH titration curve of vanadium antimonate…...... 63

Fig. (9) Scanning electron microscope of titanium vanadate….. 65

Fig. (10) Scanning electron microscope of vanadium 66 antimonate…………………. 2+ 2+ Fig. (11) Plots of K d against pH for the exchange of Cd ,Co 70 ,Cs+ and Cu2+ on titanium vanadate at 25oC.

2+, 2+ Fig. (12) Plots of log K d against pH for the exchange of Cd Co , 71 Cs+ and Cd2+ ions on vanadium antimonate at 25 oC.

+ Fig. (13) Plots of log Kd against different concentrations of Cs 80 Cu2+ ,Co2+ and Cd2+ ions on titanium vanadate at 50oC.

+ Fig. (14) Plots of log Kd against different concentrations of Cs 81 Cu2+ ,Co2+ and Cd2+ ions on vanadium antimonate at 50oC………………………………………………..

2+ Fig. (15) Plots of log Kd against pH for the exchange of Co ions 82 on titanium vanadate at different reaction temperatures….

+ Fig. (16) Plots of log Kd against pH for the exchange of Cs ions on 83 titanium vanadate at different reaction temperatures….....

2+ Fig. (17) Plots of log Kd against pH for the exchange of Cu ions 84 on titanium vanadate at different reaction temperatures….

2+ Fig. (18) Plots of log Kd against pH for the exchange of Cd ions 85 on titanium vanadate at different reaction temperatures….

2+ Fig. (19) Plots of log Kd against pH for the exchange of Cu 86 ions on vanadium antimonate at different reaction temperatures…………………………………………..

X + Fig. (20) Plots of log Kd against pH for the exchange of Cs ions on 87 vanadium antimonate at different reaction temperatures……………………………………………..

2+ Fig. (21) Plots of log Kd against pH for the exchange of Co 88 ions on vanadium antimonate at different reaction temperatures…………………………………………… .

2+ Fig. (22) Plots of log Kd against pH for the exchange of Cd 89 ions on vanadium antimonate at different reaction temperatures…………………………………………….

Fig. (23) The relation between log Kd and 1/T for the exchange of 90 Cd2+ , Co2+ Cs+and Cu2+ ions on titanium vanadate. ………………………………………………. Fig. (24) The relation between log Kd and 1/T for the exchange 91 of Cd2+ , Co2+ Cs+and Cu2+ ions on vanadium antimonate. Fig. (25) Plots of capacity against pH for exchange of Cs+, 95 Co2, Cu2+, Cd2 + on titanium vanadate ………... Fig. (26) Plots of capacity against pH for exchange of Cs+, 96 Co2, Cu2+, Cd2 + on vanadium antimonate. ………...... Fig. (27) Plots of F against time for exchange of Cs+ ion at 105 different concentrations on titanium vanadate at 25±1oC… Fig. (28) Plots of F against time for exchange of Co2+ ion at 1 06 different concentrations on titanium vanadate at 25±1oC. Fig. (29) Plots of F against time for exchange of Cu2+ ion at 1 07 different concentrations on titanium vanadate at 25±1oC ………………………...

XI Fig. (30) Plots of F against time for exchange of Cd2+ ion at 108 different concentrations on titanium vanadate at 25±1oC…

Fig. (31) Plots of F and Bt against time for exchange of Cs+ ion on 109 titanium vanadate at different particle diameters at 25±1oC.………………………... Fig. (32) Plots of F and Bt against time for exchange of Cu2+ ion on 110 titanium vanadate at different particle diameters at 25±1oC………………………... Fig. (33) Plots of F and Bt against time for exchange of Co2+ ion on 111 titanium vanadate at different particle diameters at 25±1oC………………………... Fig. (34) Plots of F and Bt against time for exchange of Cd2+ ion on 112 titanium vanadate at different particle diameters at 25±1oC……………………………………………….. Fig. (35) Plots of B against 1/r2 for the exchange of Cs+, Co2+, 113 Cu2+ and Cd2+ ions on titanium vanadate at 25±1oC Fig. (36) Plots of F and Bt against time for exchange of Cs+ ion on 117 titanium vanadate at different drying temperature at 25±1 oC.………………………………... Fig. (37) Plots of F and Bt against time for exchange of Cu2+ ion on 118 titanium vanadate at different drying temperature at 25±1 oC.……….. 2+ Fig. (38) Plots of F and Bt against time for exchange of Co ion on 119

titanium vanadate at different drying temperature at 25±1 oC……………………………………………………. 2+ Fig. (39) Plots of F and Bt against time for exchange of Cd ion on 120

titanium vanadate at different drying temperature at 25±1 oC.……………………………..

XII Fig. (40) Plots of F and Bt against time for exchange of Cs+ ion on 122 titanium vanadate at different reaction temperatures

Fig. (41) Plots of F and Bt against time for exchange of Cu2+ ion on 123 titanium vanadate at different reaction temperatures……..

2+ Fig. (42) Plots of F and Bt against time for exchange of Co ion on 124 titanium vanadate at different reaction temperatures……...

Fig. (43) Plots of F and Bt against time for exchange of Cd2+ ion on 125 titanium vanadate at different reaction temperatures……… Fig. (44) Arrhenius plots for exchange of Cs+, Co2+, Cu2+ and 1 26 Cd2+on titanium vanadate ……………………………..

+ Fig. (45) Langmuir adsorption isotherm for adsorption of Cs ion 138 on titanium vanadate at different reaction temperatures

2+ Fig. (46) Langmuir adsorption isotherm for adsorption of Cu ion 139 on titanium vanadate at different reaction temperatures.

Fig. (47) Langmuir adsorption isotherm for adsorption of Co2+ ion 140 on titanium vanadate at different reaction temperatures.…………………………….. Fig. (48) Langmuir adsorption isotherm for adsorption of Cd2+ ion 141 on titanium vanadate at different reaction temperatures

Fig. (49) 142 Langmuir adsorption isotherm for adsorption of Cs+ ion

on vanadium antimonate at different reaction temperatures.………………………………………………

XIII 2+ Fig. (50) Langmuir adsorption isotherm for adsorption of Cu ion 143 on vanadium antimonate at different reaction temperatures………………………………………….. 2+ Fig. (51) Langmuir adsorption isotherm for adsorption of Co ion 144 on vanadium antimonate at different reaction temperatures…………………………….. 2+ Fig. (52) Langmuir adsorption isotherm for adsorption of Cd ion 145 on vanadium antimonate at different reaction temperatures………………………………………… + Fig. (53) Freundlich adsorption isotherm for adsorption of Cs ion 149 on titanium vanadate at different reaction temperatures…….. …………………………….. Fig. (54) Freundlich adsorption isotherm for adsorption of Cu2+ ion 150 on titanium vanadate at different reaction temperatures………………………………………… Fig. (55) Freundlich adsorption isotherm for adsorption of Co2+ ion 151 on titanium vanadate at different reaction temperatures…………………………………………. 2+ Fig. (56) Freundlich adsorption isotherm for adsorption of Cd ion 152 on titanium vanadate at different reaction temperatures…………… ……………………………. + Fig. (57) Freundlich adsorption isotherm for adsorption of Cs ion 153 on vanadium antimonate at different reaction temperatures……………………………………….. ..

2+ Fig. (58) Freundlich adsorption isotherm for adsorption of Cu ion 154 on vanadium antimonate at different reaction temperatures.…………………………….

XIV

Fig. (59) Freundlich adsorption isotherm for adsorption of Co2+ ion 155 on vanadium antimonate at different reaction temperatures.

Fig. (60) Freundlich adsorption isotherm for adsorption of Cd2+ ion 156 on vanadium antimonate at different reaction temperatures . Fig. (61) Linearized D-R isotherms for adsorption of Cs+ ion on 162 titanium vanadate at different reaction temperatures ……………………………. Fig. (62) Linearized D-R isotherms for adsorption of Cu2+ ion on 163 titanium vanadate at different reaction temperatures ……………………………………… Fig. (63) Linearized D-R isotherms for adsorption of Co2+ ion on 164 titanium vanadate at different reaction temperatures……... ……………………………………… Fig. (64) Linearized D-R isotherms for adsorption of Cd2+ ion on 165 titanium vanadate at different reaction temperatures.……………………………………… Fig. (65) Linearized D-R isotherms for adsorption of Cs+ ion on 166 vanadium antimonate at different reaction temperatures ……………………………………… Fig. (66) Linearized D-R isotherms for adsorption of Cu2+ ion on 167 vanadium antimonate at different reaction temperatures.

Fig. (67) Linearized D-R isotherms for adsorption of Co2+ ion on 168 vanadium antimonate at different reaction temperatures.

XV Fig. (68) Linearized D-R isotherms for adsorption of Cd2+ ion on 169 vanadium antimonate at different reaction temperatures….

+ Fig. (69) Linearized Temkin isotherms for adsorption of Cs ion 174 on titanium vanadate at different reaction temperatures…..

Fig. (70) Linearized Temkin isotherms for adsorption of Cu2+ 175 ion on titanium vanadate at different reaction temperatures...... Fig. (71) Linearized Temkin isotherms for adsorption of Co 2+ ion 176 on titanium vanadate at different reaction temperatures...... Fig. (72) Linearized Temkin isotherms for adsorption of Cd 2+ ion 177 on titanium vanadate at different reaction temperatures ……………………………………………………….. Fig. (73) Linearized Temkin isotherms for adsorption of Cs+ ion 178 on vanadium antimonate at different reaction temperatures.…………………………………………….. Fig. (74) Linearized Temkin isotherms for adsorption of Cu2+ ion 179 on vanadium antimonate at different reaction temperatures……………………………………………….

Fig. (75) Linearized Temkin isotherms for adsorption of Co2+ ion 180 on vanadium antimonate at different reaction temperatures……………………………………………... Fig. (76) Linearized Temkin isotherms for adsorption of Cd2+ ion 181 on vanadium antimonate at different reaction temperatures……………………………………………... XVI Fig. (77) Break-through curves of mixture of Co2+, Cu2+, Cd2+ and 187 Cs+ ions on titanium vanadate at natural pH and 25±1˚C..

Fig. (78) Break-through curves of mixture of Co2+, Cu2+, Cd2+ and 188 Cs+ ions on vanadium antimonate at natural pH and 25±1˚C………………………………………………….

Fig. (79) Elution curves of mixture of Co2+, Cu2+, , Cd2+and Cs+ 190

ions with 0.01, 0.1and 0.5 M HNO3 from titanium vanadate (1 cm diameter x 1.2 cm length and 4-5 drops/min. flow rate)…………………………………….

Fig. (80) Elution curves of mixture of Co2+, Cu2+, , Cd2+and Cs+ 191

ions with 0.01, 0.1, 0.5, 1and 2 M HNO3 from vanadium antimonate (1 cm diameter x 1.2 cm length and 4-5 drops/min. flow rate)………………………………………

XVII

Synthesis and characterization of titanium vanadate and vanadium antimonate and their use in treatment of some toxic waste

List of Publications

1. El-Naggar, I.M., Zakaria .E.S., El-Kenany. W.M., El-Shahat M.F., “Synthesis and Equilibrium Studies of Titanium Vanadate and Its Use in the Removal of Some Hazardous Elements”, 2013, vol. 55, no. 5

XVIII PLAN OF WORK

Synthesis and characterization of titanium vanadate and vanadium antimonate and their use in treatment of some toxic waste

Recently, the main methods used for the treatment of radioactive waste are chemical precipitation , absorption and ion exchange . Choice of certain techniques is governed by the radiochemical composition of the waste that will treat, as well as, the economic aspects. Although the organic ion exchangers have wide applicability, a few limitations of the organic resins have been reported. One of several limitations of the organic resins is the poor thermal stability .The mechanical strength and removal capacity of organic ion exchange resins tend to decrease under high temperature and strong radiation condition. The potential usefulness of the inorganic ion exchangers have been proved in various nuclear ,non nuclear applications, especially in the isolation and fixation of fission products and hazardous elements .Inorganic ion exchangers have received attention for these purposes because of their strong chemical affinity , high retention capacity and high radiation resistance for ionizing radiation for nuclides. The main aim of this work was directed to find the optimum conditions for removal of some toxic elements using titanium vanadate and vanadium antimonate cation – exchanger. Therefore, the following items will be involved in this study: 1. Preparation of titanium vanadate and vanadium antimonate. 2. Characterization of the prepared ion exchanger using IR spectra, X – ray diffraction patterns, surface area measurements and DTA and TG analyses. XIX 3. Chemical stability, capacity and equilibrium measurements will be determined on these materials at different conditions, (heating temperature, reaction temperature and different pH's). 4. Determination of the ion exchange mechanism (Kinetics) and the selectivity behavior of the investigated metal ions on the prepared ion exchanger. 5. Ion exchange isotherms and it's application for the removal of the studied ions. 6. Break through curves for removal of some toxic elements on the prepared exchangers under certain conditions.

XX Synthesis and characterization of titanium vanadate and vanadium antimonate and their use in treatment of some toxic waste

Wafaa.M.El-kenany

ABSTRACT

Ion exchangers are insoluble solid materials, which carry exchangeable cations or anions. When the ion exchanger is in contact with an electrolyte solution, these ions are exchanged with an equivalent amount of other ions of the same sign .Synthetic inorganic ion exchangers possess good ion-exchange capacity, high chemical and radiation stabilities, reproducibility and selectivity for heavy metals. These materials were characterized using X-ray (XRD and XRF), IR, TGA-DTA and total elemental analysis studies. On the basis of distribution studies, titanium vanadate was highly selective for Cs(I) while vanadium antimonate was selective for Cu2+ ions . Thermodynamic parameters (i.e. ΔGo, ΔSo and ΔHo) have also been calculated for the adsorption of Cs+, Cd2+, Cu2+ and Co2+ ions on titanium vanadate and vanadium antimonate showing that the overall adsorption process is spontaneous and endothermic. The mechanism of diffusion of Co2+, Cu2+, Cd2+ and Cs+ in the H -form of titanium vanadate and vanadium antimonate cation exchanger was studied as a function of particle size, concentration of the exchanging ions, reaction temperature, drying temperature. The exchange rate was controlled by particle diffusion mechanism as a limited batch technique and is confirmed from straight lines of B versus 1/r2 plots. The values of diffusion coefficients, activation energy and entropy of activation were calculated and their significance was discussed. The data obtained have been compared with that reported for other organic and inorganic exchangers.

XXI Exchange isotherms for H+/Co2+, H+/Cu2+, H+/Cd2+ and H+/Cs+ were determined at 25, 45 and 60±1oC. These isotherms showed that Co2+,Cu2+, Cd2+ and Cs+ are chemically adsorbed. Moreover, the values of thermodynamic parameters were determined and the overall adsorption processes were found spontaneous and endothermic. Finally, removal of the above mentioned cations on titanium vanadate and vanadium antimonate in column was performed.

Keywords: Removal, Hazardous Metal Ions, Ion Exchange, Titanium Vanadate and Vanadium Antimonate, Synthesis, Characterization, Distribution Studies, Diffusion, Sorption Isotherm.

XXII INTRODUCTION W.M.EL-KENANY

1. INTRODUCTION

People have used metals for many centuries and in our day the mass usage of metals is accepted as an inalienable fact .The hydrometallurgical industry produces many types of waste streams. The toxic nature of heavy metal ions, even at trace levels in natural waters, has been a public health problem [Moore and Ramamoorthy., 1984]. To solve this problem, industrial waters must be treated to remove the toxic metal ions before they can be discharged into the sewerage. Separation is basically a pre-treatment method which, usually precedes any qualitative analysis. Separation involves both classical and modern techniques. The general methods of separation include distillation, extraction, precipitation, crystallization, dialysis, diffusion etc. The most modern and versatile techniques used for the purpose of separations are chromatography, electrophoresis and ion exchange chromatography. Ion exchange chromatography has emerged as a most versatile and standard analytical tool. The most important technologies for toxic ion removal or to reduce the exchange phytoextraction, ultrafiltration ,reverse osmosis, and electrodialysis and sorption [Yu et al., 2000] [Adria-Cerezo et al., 2000] .Nevertheless, many of these approaches can be marginally cost effective or difficult to implement in estrategy that is simple, and compatible with local resources and constraints. The effective concentration of metal ion in aqueous water are chemical precipitation, ion recovery of these metals is possible only if the separation process is selective enough. Selective ion-exchangers can be used for reducing the amount of metal wastes; they can be used for purification of process liquids for re-use and for the treatment of final waste waters. [ Karppinen and Yli -Pentti ., 2000],[Cortina et al.,

- 1 - INTRODUCTION W.M.EL-KENANY

1996]. [Soylak., 1997) ,[Seco et al., 1999] and [Brown et al.,2000] .By ion exchange either all ions can be removed from a solution or substances are separated Therefore, selective removal of ionic contamination and complete deionization can be distinguished. The choice between both depends mainly on the composition of the solution and on the extent of decontamination required. Used up galvanic baths and waste solutions from various production generally contain large quantities of various ions which are hazardous for the environment. Frequently only one kind of ions must be removed from industrial wastewaters due either to its toxicity or its substantial value. Selectivity is achieved by new types of ion exchangers with specific affinity to definite metal ions or groups of metals. It should be emphasized that in most cases ion exchange enables replacing the undesirable ion by another one which is neutral within environment [Dia-Prosim.,1975; Bolto and Pawłowski., 1987;Warshawsky and Erlich-Rogozinski., 1977; Dorfner., 1991; Hubicki et al., 1999]

1.1.Histrotical back ground Ion exchange is basically a process of nature occurring throughout the ages from even before the dawn of human civilization. The phenomenon of ion exchange is not of a recent origin. The earliest of the references were found in Holy Bible, which says ‘Moses’ succeeded in preparing drinking water from brackish water by an ion exchange method . Aristotle stated that the sea water loses part of its salt content when percolated through certain sands. In 1623, Francis Bacon and Hales described a method for removing salts by filtration and desalination from sea water. In 1790, Lowritz purified sugar beet juice by passing it through charcoal. In the beginning of 19th century, chemists were quite aware about ion exchange and were busy in new researches. Gazzari (1819) discovered that clay retained dissolved fertilize particle. In 1826,

- 2 - INTRODUCTION W.M.EL-KENANY

Sprengel stated that the humus frees certain acids from soils. Fuchs 1833 pointed out that the lime frees potassium and sodium from some clay. By middle of 19 the century sufficient experimental observations and information had been collected but principle on ion exchange had not yet been discovered. Thompson and Roy .,1845, and Way 1850 laid the foundation of ion exchange by base exchange in soil. They observed that when soils are treated with ammonium salts, ammonium ions are taken up by the soil and an equivalent amount of calcium and magnesium ions are released. During 1850-55 the agrochemist Way demonstrated the following mechanism to be one of the ion exchange method involving the complex silicates present in the soil. As described by Way the process observed by the Thompson could be formulated:

Ca-Soil + (NH4)2SO4 ↔ NH4-Soil + CaSO4 The ion exchange process is reversible and aluminosilicates (zeolites) are responsible for the exchange in soil, established by [Eichorn.,1850] . The first synthetic aluminum based ion exchanger was prepared by Rumpler in 1903 to purify the beet syrup .According to [Lamberg.,1870] and [Wiegner., 1912] the materials responsible for the phenomenon were mainly clays, zeolites, gluconites and humic acids.

Lamberg also obtained analcite (Na2O.Al2O3.4SiO2.2H2O) by leaching the mineral leucite (K2O.Al2O3.4SiO2) with solution of sodium chloride and found that, this transformation could be reversed by treating analcite with a solution potassium chloride ,there by exchanging Na+ again by K+ . The first application of synthetic zeolite for collection and separation of ammonia from urine was made by [Follin and Bell., 1917.] [ Gans., 1905] succeeded in utilizing the synthetic aluminium silicates ion exchangers for industrial purposes like softening of water and also for treating sugar solutions. Due to the limitations in the applications of neutral and synthetic silicates in various industrial applications and in an

- 3 - INTRODUCTION W.M.EL-KENANY

attempt to meet the demands of the industries, [Adam and Holms 1935 ] laid the foundation of organic exchangers when they observed that the crushed phonograph records exhibit ion exchange properties. This lead to investigators to develop synthetic ion exchange resins. These resins were developed and improved by the former I.G. Farben industries in Germany followed by the manufacturers in U.S.A. and U.K, which proved very effective for separations recoveries , the ionization catalysis, etc

1.2. Ion Exchange Ion exchangers generally are insoluble solids that have cations or anions available for exchange. In a typical ion exchange reaction, the solid with the exchangeable cations R is contacted with a + solution containing cations M , and the exchange process may be expressed as in equation 1,

R – H + M+ ↔ R – M+ + H+ (1)

As opposed to sorption, ion exchange is a stoichiometric reaction, and each ion removed from the exchanger is replaced by an equivalent amount of another ion to retain charge neutrality. Selectivity is a characteristic of each ion exchange material and is determined by several factors, such as the nature of the exchanging ion, its charge, size and hydration, the structure and the net charge of the framework of the exchanger, and the concentration of the surrounding solution (degree of loading). 1.3.Classification of ion exchange materials: 1-Organic ion exchanger (organic resins) 2-Inorganic ion exchanger 3-Composite ion exchanger

- 4 - INTRODUCTION W.M.EL-KENANY

1.3.1-Organic ion exchanger Organic ion exchanger is classified into a-Natural organic ion exchanger A large number of organic materials exhibit ion exchange properties; these include polysaccharides (such as cellulose, algic acid, straw and peat), proteins (such as casein, keratin and collagen) and carbonaceous materials (such as charcoal , lignites and coal). b-Synthetic organic ion exchanger The framework, or matrix, of the resins is a flexible random network of hydrocarbon chains. This matrix carries fixed ionic charges at various locations. The resins are made insoluble by cross-linking the various hydrocarbon chains. The degree of cross-linking determines the mesh width of the matrix, swelling ability, movement of mobile ions, hardness and mechanical durability. Highly cross-linked resins are harder, more resistant to mechanical degradation, less porous and swell less in solvents.(such as acrylic , phenolic and acrylic acid).

1.3.2-Inorganic ion exchanger a-Natural inorganic ion exchanger Natural zeolites:

Natural zeolites such as clinoptilolite, chabazite and mordenite have been extensively studied for applications in nuclear waste treatment, and zeolites were the first materials to be used in large-scale processes to treat these wastes. They have also been used a water softeners in detergents (exchange of Ca2+ and Mg2+) for many decades. used as water softeners in detergents (exchange of Ca2+ and Mg2+) for many decades. Their ion exchange properties have been thoroughly investigated and the regular structures are well suited for many ion exchange modeling purposes.(Moller., 2002).

- 5 - INTRODUCTION W.M.EL-KENANY b-Synthetic inorganic ion exchanger:

In the last decades a good deal of interest has grown in synthetic inorganic ion exchangers [Amphlett., 1964]. This is mainly because of their greater power to with stand higher radiation doses [El- Naggar et al., 1995] and temperatures than the commonly used organic- based resins. In addition to this, they sometimes exhibit highly specific properties which might permit improved separations under ordinary conditions.

In this concern, these materials may be divided into the main following groups [Qureshi and Varshney, 1991; Vesely, and Pekarek, 1972].

1) Synthetic zeolites 2) Polybasic acid salts 3) Hydrous oxides 4) Metal ferrocynides 5) Insoluble ion exchange materials 6) Hetropolyacids

1) Synthetic zeolites Zeolites are crystalline aluminosilicate based materials and can be prepared as micro-crystalline powders, pellets or beads. Zeolites are crystalline hydrated aluminosilicates, built from [SiO4]4- and [AlO4]5- tetrahedra connected by oxygen bridges. The rigid three-dimensional structure, with cavities and tunnels of 4-7 Å in size, often acts as an ’ion sieve’ and it structurally separates ions according to size (Moller., 2002) The main advantages of synthetic zeolites when compared with naturally occurring zeolites are that, they can be engineered with a wide

- 6 - INTRODUCTION W.M.EL-KENANY variety of chemical properties and pore sizes and they are stable at high temperatures. 2)Polybasic acid salts:

Acidic salts of multivalent metals formed by mixing acidic oxides of metals belonging to IV, V and VI groups of the periodic table. Acid salts of the quadrivalent metals are most studied groups of this class. They are extremely insoluble. Their composition is non stochiometric and depends on the condition under which they are precipitated. The materials which have been so far synthesized includes the phosphates, arsenates, molybdates, tungstates, antimonates, silicates, vanadates, and tellurates of zirconium, titanium, thorium, tin, cerium chromium, iron, niobium, tantalum etc. 3) Hydrous oxides The ion exchangers of this class show an amphoteric behavior depending upon the pH of the solution equilibria (Nikol’skii .,1934). The process can be described by the following M . OH → M+ + OH- (I)

M . OH → MO- + H+ (II)

Reactions (I) produce anion-exchange properties and are favored by low pH. Reactions (II) result in cation-exchange characteristics that are favored by high pH. An approximate order of decreasing acidity of oxides in the series MO3 > M2O5 > MO2 >M2O3 > MO represents decreasing cation-exchange character for these ion-exchanging materials.

In practical use, Sb2O5, WO3, or MoO3 exhibit strong cation exchange character only; on the other hand, hydrous forms of MgO or Bi2O3 exhibit an exclusively anion exchange character. Oxides of quadrivalent elements are mostly amphoteric exchangers.

- 7 - INTRODUCTION W.M.EL-KENANY

4)Metal Ferrocyanides

Insoluble metal ferrocyanides can also be used as inorganic ion exchangers. They are also known as scavengers for alkali metals. They are easily prepared and useful in the separation of radioactive wastes and fissionable materials (Kuamura et al., 1970) 5)Insoluble ion exchange materials Various insoluble ion exchanging materials are also of interest. A large number of such compounds have been prepared. These materials have been prepared by precipitation from metal salt solution with Na2S or

H2S The ion exchange properties of insoluble sulphides (e.g. Ag2S, SnS,

CuS, PbS, FeS, NiS, As2S3 Sb2S3) have been investigated. The sulphides are selective towards cations forming insoluble sulphides. Three kinds of exchange may be distinguished: (1) exchange in the surface layer, (2) exchange throughout the crystals and formation of mixed crystals, and (3) exchange with formation of a new phase . The exchange reaction occurs through metathetical reactions in which the metal of sulphide is displaced by appropriate ion from the solution. 6)Heteropolyacids Heteropolyacid salts can be used as inorganic ion exchangers. This group of exchangers is derived from 12-heteropolyacids of general formula HnXY12O40.nH2O where X may be P, As, Si, B or Ce and Y may be one of the elements such as Mo, W or V. The heteropoly compounds especially those of 12-molybdo compounds are quite strong oxidizing agents. The exchangers of this type are stable in moderately concentrated acid. However they dissolve in the solution of alkali. The heteropolyacids exhibit high affinity to heavy alkali metals, thorium and silver. The size of univalent ions of these elements is suitable for their retention in the crystal lattice of heteropolyacids.

- 8 - INTRODUCTION W.M.EL-KENANY

1.3.3)Composites ion exchangers[Hybrid exchanger] The ‘organic-inorganic’hybrid materials prepared via the sol- gel technique have attracted significant attention for numerous applications. The combination of organic and inorganic precursors yields hybrid materials that have mechanical properties not present in the pure materials. Organic-inorganic composite ion exchange materials show the improvement in its granulometric properties that makes them more suitable for the application in column operations. The binding of organic polymer also introduces the better mechanical properties in the end product, i.e. composite ion exchange materials [Philipp and Schmidt. ,1984]. 1.4.Antimonate as inorganic ion exchanger: Antimonate of multivalent metal ions form a series important group of inorganic ion exchanger. These metal antimonates show excellent ion exchange property when compared to phosphate ,molybdate , tungstate of different metal ions (Siviah et al 2007),(Vesely and Pekarek., 1972). The potentiometric ion-exchange titrations of niobium antimonate have been performed for the systems Li+/H+ , Na+/H +,K+/H+ + + and NH4 /H . Samples at each step of exchange have been characterised by X-ray diffraction analysis. It is concluded that the alkali metal ion exchange in niobium antimonate occurs without phase transition and the exchanger shows a trifunctional acid behavior. The ion exchange capacity of the material is 3.69 meq.g-1. At pH 7 the proton exchange by + + + + -1 Li , Na , K and NH4 is 1.05, 1.70, 1.25 and 1.60 meq.g ~respectively. Thus the exchanger produces a wide range of acidities as is found in noncrystalline or semicrystalline ion exchange materials. The column ion-exchange capacity for the univalent metal ions has been determined

- 9 - INTRODUCTION W.M.EL-KENANY and compared with those of a batch experiment. The low ion exchange capacity observed in column operation has been interpreted in terms of slow kinetics of the ion exchange process (Gupta et al ., 1978). The sorption of 134Cs, 60Co and 152+154Eu by crystals of unmodified and phosphoric acid modified silico-antimonates (SiSb). Equilibrium and selectivity sequence for co-exiting metal ions under strongly acidic conditions of HClO4, H2SO4, HNO3 and HCl were investigated. The results showed that the silico-antimonate either in the high Sb5+ content or in the phosphate form possesses acidic characters and shows cation-exchange properties more efficient in acidic media. Kinetic studies indicated that pseudo-second-order model gave better fitting parameters comparing to that of pseudo-first-order one. The thermodynamic parameters of the sorption processes revealed spontaneous and endothermic nature. High negativity of ∆G◦ values for the modified SiSb confirms the positive role of phosphoric acid impregnation in the sorption process. The break-through capacities of the studied ions were further calculated from a column investigation (Ali., 2009). Chemically synthesized cero-antimonate and titanium cero- antimonate prepared by sol-gel technique was conducted for the synthesis of a novel ion exchanger. The prepared materials has been characterized by X-ray diffraction, X-ray fluorescence, Fourier transform Infrared Spectroscopy (FT-IR) and Thermogravemetric analyses. The structures and empirical formula's was identified and found to CeSb4O12·6.19H2O and TiCeSb4O14·12.22H2O, for cero-antiomate and titanium cero- antimonate, respectively. The data obtained from X-ray diffraction was analyzed to define the crystallographic feature of cero-antimonate and titanium cero-antimonate and found both the composites were belong to

- 10 - INTRODUCTION W.M.EL-KENANY cubic system with lattice constant 5.15 and 5.149 Å, respectively. The crystallite size and strain of cero-antimonate and titanium cero antimonate were determined. By using ChemDraw Ultra program the modeling structures of cero-antimonate and titanium cero-antimonate were conducted. Finally, application of the prepared materials for the removal of heavy metals from industrial waste water in terms of capacity measurements was performed (Abou-Mesalam., 2011).

Uranium antimonate (USb) has been prepared and characterized by various analytical techniques such as TG-DTA, EDX,XRF, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and FT-IR spectroscopy. The precipitation reaction of potassium pyroantimonate

(KSb(OH)6) with uranyl nitrate results in the formation of amorphous USb with U/Sb mole ratio of 0.35, which crystallises at temperature above 900 ◦C, leading to the formation of USb3O10. The amorphous form and heat treated uranium antimonate exhibits ion exchange with some fission products like137Cs+, 90Sr2+ and 154Eu3+ due to the presence of surface hydroxyl groups and the distribution coefficient (Kd, mL/g) decreases with heat treatment. Thermal analysis of USb indicated the loss of surface hydroxyl groups due to the condensation reaction is responsible for the decrease in Kd values after heat treatment. Based on the analytical and sorption data on uranium antimonate a molecular formula of HUO2Sb3O4(OH)10·4.7 H2O has been arrived ( Sivaiah et al., 2007). Column chromatographic technique has been utilized to study the column performance of uranyl ion separation on tin(IV) antimonite hydrous oxide matrix .Different flow rates were applied, at 0.6 ionic strength and pH 3, to evaluate the effect of different flow rate on column

- 11 - INTRODUCTION W.M.EL-KENANY breakthrough behaviour. Van Demeeter equation was used to emphasize the optimum column conditions. High equivalent to theoretical plate, breakthrough capacity (Q0.5) were also calculated [ Aly ., 2010].

The applicability of uranium antimonate (USb) for the efficient removal of strontium from aqueous acidic solutions by adsorption has been investigated. The adsorption data analysis was carried out using the Freundlich and Langmuir isotherms for the uptake of Sr in the initial concentrations range 1.14 × 10–4 to 1.14 × 10–2 mol L–1 on USb from nitric acid medium. The adsorption process is heterogeneous in nature as evident from the fractional value (0.48) of β. The sorption capacity b was found to be 18.81 mg g–1 from 0.5 mol.L-1 nitric acid medium. Equilibrium adsorption values at different temperatures have been utilized to evaluate the change in enthalpy, entropy and free energy. The adsorption of strontium on USb was found to be endothermic [Kumar., and Sudarsan .,2009]. Uranium antimonate (USb) has been prepared by the precipitation reaction between uranyl nitrate and potassium pyroantimonate and it has been characterized by X-ray diffraction (XRD), thermal analysis, energy disperse X-ray florescence, and pH titration. Ion exchange of europium on USb as a function of time, temperature, concentration of nitric acid and europium has been studied. The distribution coefficient of europium on USb was found to decrease from ~105 ml g−1 at 0.05M nitric acid to 22 ml g−1 at 2M nitric acid. Uptake of europium was fitt to a particle diffusion equation and the diffusion coefficient (Di) was calculated from the slope of Bt–t plots. The energy (Ea) and entropy (∆S*) of activation for the sorption of europium were found to be 17 kJ mol−1 and −67.9 J mol−1 K−1, respectively. Sorption data obtained at various concentrations of europium were fitted

- 12 - INTRODUCTION W.M.EL-KENANY into a Langmuir adsorption isotherm and the enthalpy change accompanied by the sorption of europium was determined by the temperature variation method [Siviah et al., 2004]. Various antimonate compounds are well known as important inorganic ion exchangers, since they resist radiation and chemical degradation and also exhibit selectivities towards different cations. Ceric, silicon, titanium and ferric antimonates were prepared as inorganic ion exchangers. Characterization of these materials has been described using different techniques, including thermal analysis, surface area measurements , X-ray diffraction and IR-spectroscopy. In batch distribution experiments the influence of HNO3 molarity and Mo concentration for Mo sorption on different matrices is described in terms of their retention capacities and distribution coefficients .The selectivities of these exchangers towards molybdenum are in the order: CeSb>SiSb>FeSb>TiSb [El-Naggar et al., 2003]. Cerium(IV) antimonte had been prepared by the dropwise addition of 0.6 M antimony pentachloride and 0.6 M cerium .ammonium nitrate solutions by n molar ratio of Ce/Sb 0.75. Exchange isotherms for H+/ Co2+ , H+/Cs+, H+/Zn2+,H+/Sr2+ and H+/Eu3+ have been determined at 25, 40 and 60°C. Besides it was proved that europium is physically adsorbed while zinc, strontium, cobalt and cesium are chemically adsorbed. Moreover, the heat of adsorption of zinc, strontium, cobalt and cesium on cerium (IV) antimonate had been calculated and indicated that cerium (IV) antimonate is of endothermic behaviour towards these ions. Also the distribution coefficients of these ions were determined and it was found that the selectivity in the order: Eu3+ > Sr3+ > Cs+ > Na+ [Aly et al., 1998].

- 13 - INTRODUCTION W.M.EL-KENANY

Several metal antimonates MSbO (M = Si, Ti, Mn, Sn) have been studied for the removal of several key radionuclides (60Co, 90Sr and 137Cs) from nuclear waste solutions. Special emphasis was the removal of radionuclides from acidic effluents and from effluents of high Ca content.Synthesis and initial screening test indicated that increasing the degree of substitution of other metals (M) for Sb increases the uptake of divalent cations (Sr, Co) in acidic media. Some of the synthesized compounds also showed considerable tolerance for Ca ions in Sr removal. Column tests with granular silicon antimonate gave very good decontamination factors (DF) for 85Sr (DF up to 10000) and 134Cs (DF up to 600) in nitric acid solution (0.1 M) and for 57Co (up to 5000) 85Sr (up to 3000) in neutral simulated pond water. Precoat tests with manganese antimonite powder gave high decontamination factors for 57Co (DF up to 600) in simulated NPP floor drain water. In general, the performance of the metal antimonates was considerably better than that of commercial materials (zeolite, titanate, and silicotitanate) that were tested in parallel for reference [Harjula et al., 2001]. Radiochemical study of the kinetics of ion-exchange of Rb+ and Cs+with H+ on zirconium antimonate. The slow step which determines the rate of exchange of these ions is diffusion through the particle. Values for the diffusion coefficients, energy of activation, and entropy of activation have been calculated. The data obtained have been compared with those reported for other organic and inorganic exchangers [Mathew and Tandon., 1977]. Tin(IV) antimonate (SnSb), cerium(IV) antimonate (CeSb), silicon(IV) antimonate(SiSb) ant titanium(IV) antimonate (TiSb) were prepared under various conditions. The ion-exchange properties and the thermal stability of these materials were examined in order to elucidate

- 14 - INTRODUCTION W.M.EL-KENANY their applicability to the processing of radioactive liquid wastes. Capacity, equilibrium measurements, adsorption isotherms and the selectivity patterns for Cs+, Sr 2+,Co2+ and Eu 3+ ions on these sorbents at different conditions were determined. The effect of high concentrations of salts and complexing agent as interfering ions in the feed solutions on the distribution coefficient of the metals, mentioned above, was tested as a function of [HNO3.] Based on the results obtained, practical separation experiments on column were performed (Aly and El-Naggar., 1998). Ion exchange properties of titanium antimonates have been investigated with the main objective being selective removal of radionuclides from acidic nuclear waste solutions and in the presence of strongly interfering calcium. Five samples with Ti : Sb ratios between 0.21–4.9 were synthesized by hydrolysis in distilled water under reflux. Products of either a mopungite, rutile or pyrochlore phase crystallized depending on the Ti : Sb ratio, the order of metal prehydrolysis and the synthesis temperature (20oC, reflux at 100 oC or hydrothermal treatment at 200 oC). The acidity of the exchanger and 85Sr selectivity in acid increases with increasing antimony content, while Sr2+/Na+exchange is favored as the acidity decreases. The tolerance for Ca2+ in strontium uptake has a reverse trend and the 85Sr/Ca2+ selectivity coefficients

(kSr/Ca) increase with the Ti : Sb ratio from 1.2 to 130 in 0.01 M

Ca(NO3)2. In addition to the Ti : Sb ratio, the crystal phase directs the radionuclide affinity through the ion sieve effect. The pyrochlore structure favors strontium while the rutile phase seems to prefer cesium in acid (Moller et al .,2003). A novel inorganic cation exchanger cerium zirconium antimonate (CeZrSb) was synthesized by co precipitation method. Zirconium substitution of cerium in the solid solution has proved to be

- 15 - INTRODUCTION W.M.EL-KENANY beneficial in increasing the oxygen storage capability. Chemical composition of the compound was determined from EDS and structural studies were carried out using TGA, XRD and FTIR. UV-VIS Diffuse Reflectance spectroscopic studies were conducted to obtain information on surface coordination and different oxidation states of metal ions and to study their properties. The material synthesized showed very good cation exchange properties and the distribution studies showed that the selectivity towards various metal ions was in the order Pb2+ > Cu2+ > Mn2+ > Co2+ > Cd2+ > Y3+ > Ni2+ >Hg2+ > Zn2+ > Th3+ > Mg2+. Its selectivity for lead helps the removal of it from other cations. Cu2+ ion exchange changes the color of the material from yellow to green and Mn2+ ions which get oxidized in the matrix of the material changes the color to dark brown / black. Thus the material can be used as an environment friendly solid indicator for the detection of trace amounts of Mn2+ ions in solution. The electron exchange property of cerium ions enable it to be used widely in various catalytic and functional systems. UV-Vis DR Spectroscopy was used for characterizing the synthesized material and its Mn and Cu ion exchanged forms. The decrease in rate of catalytic degradation of methyl orange dye with its Mn exchanged form is correlated with its UV VIS DR spectra [ Preetha and Janardanan .,, 2012]. 1.5.Vanadates as inorganic ion exchanger Ceric vanadate synthesized and characterized an inorganic ion-exchanger,. The exchanger is stable towards thermal, chemical and radiation doses within the appreciable working range. The molecular formula of the ceric vanadate has been formulated as

4CeO2.5V2O5.12H2O.Multi elemental uptake studies by the newly synthesized exchanger have been carried out using “tracer packet”

- 16 - INTRODUCTION W.M.EL-KENANY technique. It has been found that the exchanger is highly suitable in removing Tl, Pb, Bi and Po. However, the uptake of Cu and As by the exchanger is moderate while that of Hg, Zn, Ga, Ge, and Se has been found negligible [ Maji et al., 2007]. Two inorganic ion exchangers, zirconium vanadate and ceric vanadate were synthesized and applied to confine and separate 152Eu and 134Cs from a synthetic mixture. The percentages of adsorption of the two radionuclides were studied for the two ion exchangers at varying pH conditions. At pH 3, zirconium vanadate adsorbs both Eu and Cs and a column chromatographic separation was achieved using 0.1M EDTA as the eluant. The ceric vanadate ion exchanger showed an increased trend in adsorption for both the radionuclides with increase of pH value from 1 to 6. At pH 1, a column chromatographic separation of these radionuclides from a mixture was achieved, because at this pH only 134Cs was adsorbed to ceric vanadate bed in the column [Lahiri et al., 2005]. Thermally stable, and highly strontium-specific inorganic ion exchanger, titanium(1V) vanadate, has been prepared by mixing 0.5 M solution of titanic chloride and sodium vanadate at pH 0- 1. Its ion exchange capacity is 0.65 meq.g-1 at 400 "C. Separation factors of Sr2+ with respect to Ba2+, Ca2+, and Mg2+ are 8,11.8, and 33.3, respectively. Binary mixtures of Sr2+ with Ba2+, Ca2+, and Mg2+ have been separated. Calcium and magnesium are eluted with 0.001 M HNO,. Barium and strontium are eluted with 0.01 and 0.1 M HNO3 respectively. A new parameter ∆C/∆T is proposed for the study of structural changes in inorganic ion exchangers [Qureshi et al., 1972]. A new inorganic ion exchanger, zirconium vanadate, has been synthesized and characterized. Elemental analysis suggests that the probable formula of the compound is ZrO2, V2O5, 2H2O. The exchanger

- 17 - INTRODUCTION W.M.EL-KENANY is highly stable in thermal, radiation and chemical environments. Radiochemical separation schemes for the 134Cs and 133Ba pair and also for separating the short-lived daughter 137Ba from its parent 137Cs using this newly synthesized ion exchanger have been developed [Roy et al ., 2002]. Multielemental uptake studies on the inorganic ion exchanger zirconium vanadate [Roy et al., 2003].

Nano-powder zirconium vanadate was chemically synthesized using homogeneous precipitation technique. The synthesis conditions such as reactant concentrations and precipitating agent concentration were changed to optimize the ion exchange properties of the produced ion exchanger. 0.4M sodium vanadate added to 0.1M zirconium oxy chloride in presence of 1.5g urea & 0.04M HCl were the optimum conditions that produce zirconium vanadate with maximum ion exchange capacity equal 1.26 meq/g.The granulometry, morphology, composition and structure of that exchanger with the maximum capacity were studied using SEM, XRD, TGA-DSC, and FTIR. Composition of the polycrystalline zirconium vanadate can be written as Zr(OH)2 (HVO2)2

.2H2O. Ion exchange capacity (IEC) and thermal stability studies were also carried out to understand the cation exchange behavior of the materials. Organic inorganic hybrid materials enable the integration of useful organic and inorganic characteristics within a molecular-scale composite. So the effect of the binding polymer mixture of polyvinyl alcohol and alginate on the physicochemical properties of prepared zirconium vanadate ion exchanger was studied [Abdel-Latif and El- Kady., 2008]. Amorphous titanium vanadate has been prepared with

TiO2/V2O5 ratio 4:1 . The product was characterized using powder X-ray diffraction , Fourier-Transform infrared spectra , thermal analysis , X-ray

- 18 - INTRODUCTION W.M.EL-KENANY fluorescence and particle size analysis . The ion exchange capacities of the prepared exchanger have been investigated for Cs+ ,Co2+ and Sr2+ ions separation . Loss in loading was found for the samples that heated at o 400 C . The Kd values were measured for the elements at different pH + 2+ 2+ values , where Cs shows higher Kd values than Co and Sr . Nitric acid can be used to elute Cs+ and Co2+ ions from their columns [Ibrahim., 2006]. A newly designed inorganic ion exchanger, based on aluminum vanadate, has been synthesized and characterized by elemental analysis, spectroscopic tools and powdered X-ray diffraction. The insoluble poorly polycrystalline material is highly stable towards thermal and radiation doses and in various chemical environments. The data of exchange capacities of the solid material for the different alkali and alkaline metal ions determined by batch technique show that the compound can be employed as an ion exchanger. The successful radiochemical separations of the no carrier added daughter nuclides; 137mBa and 115mIn from their respective parents present in equilibrium mixtures have been carried out using this material. Elution of 137mBa and 115mIn were performed using 0.0426 mol L-1 ascorbic acid solution and 4.0 molL-1 HCl, respectively, after sorption of the equilibrated mixtures 137Cs-137mBa at 0.01mol.L-1 HCl medium and 115Cd-115mIn at pH 7.0, respectively. In another column operation, it has been observed that the separation of gold and silver is possible with the help of the eluents, 0.01% alcoholic solution of Rhodamine-B for gold and 0.5% thiourea -1 solution in 0.1molL HClO4 for silver, respectively, after the sorption of no carrier added onto this material at pH 2.0, at a no carrier added level [Dhara et al., 2009].

- 19 - INTRODUCTION W.M.EL-KENANY

Nano polyoxometallate cation exchangers, tin potassium vanadate (TPV), and zirconium potassium vanadate (ZPV), with stereoregular particulate structures have been chemically synthesized using a homogeneous precipitation technique under a variety of conditions. The experimental parameters such as mixing, volume ratio, order of mixing and pH were established for the synthesis of the materials and fairly compromised to optimize the ion exchange properties of the produced ion exchangers. Structural characterizations of the materials were performed using XRF, XRD, thermal analysis, surface area and porosity measurements, and infra-red spectroscopy. The results were correlated to the lattice parameters, unit cell parameters, and space group of the exchangers. Scanning electron microscopy and atomic force microscopy revealed their sereoregularity in space. Compositions and molecular formulae of both the amorphous and crystalline materials have been investigated. Ion exchange properties and distribution coefficients, 2+ 2+ 2+ +6 Kd , for some heavy metals namely, Co , Cu , Ni , and Cr were measured at different pH values. TPV and ZPV selectivities have been examined by achieving some important and analytically difficult binary and multi-component separations. The results indicated that TPV is practically utilized for best separation of Co2+/Cu2+, Ni2+/Co2+, Cr6+/Co2+, Ni2+/Cu2+, Cr6+/Cu2+, Ni2+/Cr6+, Ni2+/(Co2+, Cu2+), and Ni2+/(Co2+, Cu2+, Cr6+), while ZPV could be efficiently used for separation of Cu2+/Co2+, Ni2+/Co2+, Cr6+/Co2+, Cu2+/Ni2+, Cr6+/Cu2+, Cr6+/Ni2+, and Cr6+/(Co2+, Cu2+, Ni2+) [Ibrahim et al., 2011]. Samples of stannic vanadate have been synthesized by varying the mixing ratio of the reagents and pH of the mixture. The most stable sample has been synthesized by mixing 0.25 M solutions of stannic chloride and sodium metavanadate in the ratio of 2:3 at pH 2.5. The

- 20 - INTRODUCTION W.M.EL-KENANY material behaves as a weak cation exchanger. This sample has been critically studied for its ion-exchange, chemical, and thermal behaviour. The analytical utility of the material has been demonstrated by achieving some binary separations of metal ions on its column. Arsenate has also been quantitatively removed from a mixture of tungstate, phosphate, and antimonate [Qureshi et al .,1977]. Zirconium vanadate cation exchanger has been synthesized. the product was characterized by powdered X-ray diffraction ,X- ray fluorescence, thermal analysis and infrared spectrometry. The data of capacities for the samples dried at different heating temperatures and the distribution coefficients showed that the selectivity decreases in the order Co2+ > Cs+ > Eu3+ > Zn2+. The thermodynamic parameters were evaluated for the studied cations at different reaction temperatures. Besides, the effects of drying temperatures of the matrix have a profound effect on the ion exchange capacities [Shady et al., 2010-a]. The kinetics and mechanism of diffusion of Eu3+, Co 2+, Zn 2+ and Cs+ in the H+ form of zirconium vanadate as a cation exchanger have been studied. the data proved that the rate of diffusion is a function of particle sizes of the matrix and reaction temperature of the medium. the diffusion coefficients have been determined using Reichenberg's equation, and the particle diffusion route has been favored. in this concern, the activation energies, entropies and free energies or activation were evaluated and their significance was discussed [[Shady et al., 2010-b]. A new zirconium vanadate (Zr–V) ion-exchanger was synthesized and characterized for fast and selective separation procedure of 90Y from 89Sr. The method was based on 90Y(III) sorption from aqueous HCl solution containing 89Sr(II) onto Zr–V gel exchanger. The kinetics of Y(III) sorption from HCl solution by Zr–V exchanger was subjected to Weber–Morris, Lagergren, Bhattacharya and Venkobachar, and Bt models. Initially, the uptake of Y(III) onto the exchanger was fast followed by kinetically first-order sorption with an overall rate constant,

- 21 - INTRODUCTION W.M.EL-KENANY

−4 −1 K Lager = (3.55 ± 0.03) × 10 min . Film and intraparticle transport are the two steps that might influence Y(III) sorption. The negative values of ΔG of 90Y retention dictate that, the process is a spontaneous. The negative values of ΔH and ΔS reflect the exothermic nature of 90Y(II) sorption and the random uptake of 90Y(III) onto Zr–V sorbent. Zr–V exchanger offers unique advantages of 90Y(III) retention over conventional solid sorbents in rapid and effective separation of traces of 90Y(III) from Sr. The exchanger was successfully packed in column for an effective separation of 90Y [El-Shahawi et al .,2013]. 1.6.Quantitative description of selectivity of ion exchangers The framework of inorganic ion exchangers possesses positive or negative charges which are compensated by ions of opposite charge called counter-ions. In the ion-exchange process these counter- ions is replaced by ions of the same charge in electrolyte solutions in contact with the ion exchanger preserving the electroneutrality of the exchanger framework. The interstices in the framework are known as pores. The channels or cavities in the framework depend on their inter- connections. Certain materials are capable of exchanging both cations and anions. These are known as amphoteric ion exchangers .The selectivity sequences on inorganic ion exchangers have been reported by various laboratories. That selectivity depends on the following factors: 1. Acid strength of the substances; cation, amphoteric and anion-ex change reaction 2. Concentration of the exchanging ions 3. Crystallinity of the materials 4. Solution media and ionic strength Generally, amorphous materials exhibit selectivity sequence that are similar to those reached with organic ion-exchange resins. This result

- 22 - INTRODUCTION W.M.EL-KENANY is attributed to the fact that both materials have relatively open and elastic structures. The concentration dependence of Distribution coefficients

(Di), values is generally much larger for ions with large ionic crystal raditih an it is for ions with small ionic crystal radii. However Di values depend on the loading of metal ions in inorganic ion exchangers. Ion- exchange ideality is usually maintained up to relatively high concentrations of the metal ions, but the Di values increase with decreasing concentration of metal ions. A typical example of such concentration dependence for Cs+ and Mg2+ ions in equilibrium with cubic antimonic acid (Abe and Uno., 1979) Generally, an unique Di, value is obtained with relative higher concentration for organic ion exchange resins than that for inorganic ion-exchangers. Only when the concentration of the metal ion under investigation is very small (< l0-7 - -3 mol. dm ) can a unique response of Di, to solution concentration level be

Di, expected. This ist he case with organic ion exchangers well. However, it is often difficult to make valid comparisons between data from different laboratories. To circumvent this problem , the initial concentration must be provided along with the total volume of the solution, the weight of exchanger used and the temperature. 1.7.Ion-exchange properties of inorganic ion exchangers 1.7.1 Chemical stability Chemical stability of synthetic ion exchangers plays an important role in their analytical applications. Exchangers which have a high solubility in water , as well as acidic media not be very useful for separation studies .It is ,therefore, advisable to have a rough guide of the solubility of an ion exchanger [Qureshi and varshney.,1991] Qureshi and Thakur made an effort in this direction and proposed a series for the solubility of synthetic inorganic ion exchangers. The

- 23 - INTRODUCTION W.M.EL-KENANY following sequence of the solubility has been found : molybdate , arsenate, selenites antimonates , phosphates , tungstates .Only 3 of 16 pairs of exchangers tested didn,t follow this trend [Qureshi and Thakur., 1979] .Thus , the above series suggests that ,in general ,tungstates. Only 3 of the 16 pairs of exchangers tested did not follow this trend .Thus , the above series suggests that , in general , tungstates are the least stable , of inorganic ion exchangers tested. 1.7.2 Radiation stability: It is generally believed that inorganic ion exchangers are resistant to radiation Varshney et al.,1984 synthesized some ion exchange materials based on Si, P , As which show promising ion exchange behavior and high thermal and chemical stability. Their radiation stability was studied by varying the total of radiation from 108 to 3x108 rad obtained from a Co-60 source and observing the effect on their ion exchange properties [Varshney et al.,1984-a]. Zirconium (IV) arsenosilicate [Varshney et al .,1983-a] , Zirconium (IV), arsenophosphate [Varshney et al., 1983-b], tin (IV) arsenosilicate [Varshney et al., 1984-b ] ,thorium (IV) phosphosilicate [Varshney et al., 1984-c] and antimony (V) silicate [Varshney et al., 1983-c] were selected for such study . The studies revealed that the materials are highly resistant to radiation as far as their ion exchange capacity and elution behavior are concerned, except thorium(IV) phosphosilicate which shows a slight variation in these properties with an increase in the absorbed dose . Also, no appreciable change has been observed in its infrared spectra, indicating no significant structural changes. An interesting feature is observed in the distribution behavior of these materials on irradiation . the Kd values obtained in different media for four alkaline earths generally increase with total dose observed

- 24 - INTRODUCTION W.M.EL-KENANY in zirconium arsenosilicate . A study on stannic ferrocyanide zirconium ferrocyanide, ceric antimonate . titanic antimonate, ceric tungstate and zirconium arsenophosphate [Gill and Tandon., 1973] . Organic ion exchangers , especially copolymers ,are resistant to abrasion and are thus useful for use in packed columns. In contrast , inorganic ion exchange sorbents exhibit poor hydrodynamic properties and are difficult to prepare in the form of particles with an acceptable- size distribution .By using the sol-gel method, supports or embedding materials for the preparation of dimensionally more homogeneous grains, these drawbacks can be eliminated to a certain degree . But the abrasion resistance remains very low and the mechanical strength of the particles is unsatisfactory. For these reasons, the use of a number of inorganic sorbents for column separations is dubious (Gill and Tandon., 1973) 1.7.3. Thermal stability Knowledge of the thermal behaviour of the synthetic inorganic ion exchanger is therefore of basic importance for understanding their behaviour either as ion exchangers or as catalysts . TG must played an important role in characterizing these material as well as IR – spectra.. Amorphous titanium antimonate was synthesized and the crystalinity of the materials was improved with increasing the drying temperature. The capacity and the distribution coefficients for both uranium and thorium ions were investigated under different conditions [El-Naggar et al., 1997]. Generally, heating causes a change in the structure , stereochemistry and in the acid strength of inorganic ion exchangers. 1.7.4. Internal order and homogeneity in inorganic sorbets: The structural arrangement of the sorbent is important for its sorption properties . Organic resins essentially have an elastic structure

- 25 - INTRODUCTION W.M.EL-KENANY even for high degrees of cross linking , and the hydration number of the exchanging ions may be nearly as large as that for the ions in the aqueous solution .However, inorganic ion exchange sorbents have relatively rigid structures which undergo only slight swelling or shrinkage on immersion in an aqueous solution ,resulting in ion – sieve or steric effects . when highly hydrated cations are sorbed on the weakly hydrated sites of the inner phase without loses of water, the number of degree of freedom may decrease in the system .however when the ingoing cations are less + + hydrated ions, e.g., Cs and Rb . The internal solid phase of synthetic organic ion exchangers is relatively homogeneous with defined arrangement of the ion exchanging sites, usually with defined ion exchange properties .Inorganic ion exchange sorbents are usually heterogeneous and contain ion exchange sites with various exchange properties .so, the ion exchange mechanism can vary widely ( El-Aryan., 2006) . 1.8.Selectivities of ion exchangers The solvent content of organic ion exchangers depends on the exchanging ion. Inorganic ion exchangers with their much more rigid three dimensional frameworks undergo much less shrinkage or expansion in parallel situations. These inorganic ion exchangers will show different properties from organic ion-exchange resins by experiencing ion sieve and steric effects. 1.8.1.Ion sieve effect In order to replace protons in the acid form of inorganic ion exchangers, the cation present in the external solution must diffuse through the windows connecting the cavities. The water molecules of the hydrated ions are exchanged frequently with bulk water molecules in the solution. When the size of the window is smaller than the diameter of the

- 26 - INTRODUCTION W.M.EL-KENANY hydrated counter ions, a part or all of the water molecules of their hydration shell must be lost to allow the cation to pass through the window. If the cations can pass the inorganic ion exchanger pores only after having lost water molecules coordinated to them in solution, the distinct kinetic effect observed varies with the hydration energies of the various ions. If the counter ions have larger crystal ionic radii than this opening of the window, ion sieve effects can prevail 1.8.2.Steric effect If there is not enough available space for ingoing large ions within the cavities in the exchangers, their exchange becomes increasingly difficult in the course of the ion-exchange reaction. 1.9. Ion exchange capacity The term ‘ion exchange capacity’ is intended to describe the total available exchange capacity of an ion exchange resin, as described by the number of functional groups on it. This value is constant for a given ion exchange material and is generally given as milliequivalents per gram (meq/g), based on the dry weight of material in a given form (such as H+ or Cl–). For organic ion exchange resins it can be given as milliequivalents per millilitre (meq/mL), based on the wet fully swollen volume of a settled bed of resin. The numbers quoted in the literature vary widely for different resins. This number can be used to compare different resins or to calculate the total amount of resin to be added during a batch exchange process. For the characterization of ion exchangers two capacity parameters are commonly used: the total static exchange capacity (which is determined under static conditions) and the dynamic exchange capacity (which is determined by passing a solution through a bed of the exchanger). The exchange capacity depends on the

- 27 - INTRODUCTION W.M.EL-KENANY number of functional group per gram of exchanger. The extent of the use of the total exchange capacity depends on the level of ionization of the functional groups of the exchanger and on the chemical and physical conditions of the process. The operating or breakthrough capacity of a column type ion exchange system depends on its design and operating parameters, the concentration of the ions being removed and the effects of interference from other ions. In a column system this generally refers to the volume of the solution that can be treated before a sharp increase in the effluent concentration of the species being removed is observed. At this point the ion exchange medium is considered to be spent and must be replaced or regenerated. The operating or breakthrough capacity is the number of most interest in the design of a column type ion exchange system and is generally given as the number of bed volumes (the ratio of the volume of liquid processed before the breakthrough point to the volume of the settled bed of the exchanger). Some important parameters that affect the breakthrough capacity are the: —Nature of the functional group on the exchanger, —Degree of cross-linking, —Concentration of the solution, —Ionic valence, —Ionic size, —Temperature. 1.10.Ion exchange and sorption Sorption is a separation process involving two phases between which certain components can become differentially distributed. There are three types of sorption, classified according to the type of bonding involved: (a) Physical sorption. There is no exchange of electrons in physical sorption, rather intermolecular attractions occur between ‘valency happy’

- 28 - INTRODUCTION W.M.EL-KENANY sites and are therefore independent of the electronic properties of the molecules involved. The heat of adsorption, or activation energy, is low and therefore this type of adsorption is stable only at temperatures below about 150°C. (b) Chemical sorption. Chemical adsorption, or chemisorption, involves an exchange of electrons between specific surface sites and solute molecules,which results in the formation of a chemical bond. Chemisorption is typified by a much stronger adsorption energy than physical adsorption. Such a bond is therefore more stable at higher temperatures. (c) Electrostatic sorption (ion exchange). This is a term reserved for coulombic attractive forces between ions and charged functional groups and is more commonly classified as ion exchange. In addition to being ion exchangers, ion exchange materials can also act as sorbents. When they are contacted with an electrolyte solution the dissolved ions are concentrated on both the surface and in the pores of the ion exchange media. In a solution of weak electrolytes or non-electrolytes, sorption by ion exchangers is similar to that of non-ionic adsorbents. In a solution of strong electrolytes a sorption equilibrium results, owing to the electrostatic attraction between the ions in solution and the fixed ionic groups on the ion exchange media. Sorption equilibrium is normally represented by ‘sorption isotherm’ curves. Many forces and interactions have been found by experimentation to affect the sorption of non- electrolytes. Solutes may form complexes or chelates with the counter ions of the exchanger. Temperature variations may not only affect the state of the solute but also the condition of the exchanger. The molecular size of the solute and the degree of cross-linking of the exchanger will also affect the sorption kinetics

- 29 - INTRODUCTION W.M.EL-KENANY

1.11.Distribution studies:

The batch distribution coefficient (Kd) is an equilibrium measure of the overall ability of the solid phase ion exchange material to remove an ion from solution under the particular experimental conditions that exist during the contact. The batch Kd is an indicator of the selectivity, capacity, and affinity of an ion for the ion exchange material in the presence of a complex matrix of competing ions. The addition of a small quantity of ion exchange material into a small volume of supernatant solution is rapid and cost effective method for comparing a wide variety of such materials. However, this method dose not normally provides information about ion exchange kinetics but is useful for measuring ion exchange under the particular conditions of the test.

Accurate comparison of Kd results requires identical experimental conditions (volume: mass ratio, equilibrium solution composition, material pretreatment, etc.) because all of these factors are known to affect Kd.

In the batch Kd tests, a known quantity of ion exchange material is placed in contact with a known volume of waste. The material is allowed to contact the solution at constant temperature for sufficient time to reach equilibrium, after which the solid ion exchange material and liquid supernatant are separated. The concentration of the species of interest is determined in the solution and in the solid phase. In practice, it is easier to measure the concentration of the particular ion of interest in the solid instead of in solution. Therefore, the equation for the determination of the batch distribution can be written as follows;

The Kd value was calculated using the formula (2):

- 30 - INTRODUCTION W.M.EL-KENANY

I–F V

Kd = X ml / g (2) F A Where, I is the initial activity of the cation, F is the final activity of the cation after equilibrium, A is the weight of the exchanger in grams and V is the volume of the cation solution in ml. When the ion exchange proceeds by the reaction; — ― nH+ + Mn+ Mn+ + nH+

In sufficiently diluted solution, where activity coefficient may be neglected, the selectivity coefficient can be defined by the following equation; [Helfferch, 1962]. ― n+ + n M [M ] [ H ] KH = ― (3) [ H+ ]n [Mn+] where , [Mn+] and [H+] denote to the concentration of Mn+ and H+ ions in the solid phase, [H+] and [Mn+] their concentrations in the solution. As

Kd is given by Concentration of the cation in exchanger Kd = (4)

Concentration of the cation in solution

― [Mn+]

Kd = (5) [Mn+]

― + n M [H ] Kd = KH (6) + n [H ]

- 31 - INTRODUCTION W.M.EL-KENANY

H ― + n + log Kd = log KM [H ] – n log [H ] (7)

― ― ― M n+ + n+ + + when [M ] << [H ] and [M ] << [H ], [H ] KH is considered as constant, thus equation (7) can be reduced to :

+ log Kd = C – n log [H ] = C + npH (8)

when log Kd values of n valent metal ions are plotted against log [H+] a straight line having slope –n should be obtained

1.12. Ion exchange kinetics

Since, the speed at which an ion-exchange reaction will take place is of considerable practical as well as theoretical importance. It is important to examine the factors that influence the kinetics of ion exchange. The exchange of a reaction between ions in solution and solid material is usually established via the following steps: a- Diffusion of ions through the solid/liquid interface. b- Diffusion of ions in the solid phase. c- Interaction which may be electrostatic or even chemical between the ions and solid phase. d- Diffusion of displaced ions from the interior of the solid phase to the sorbent surface. e- Diffusion of the displaced ions through the solution. The rate of ion-exchange is governed by the slow step (rate- determining step) in the ion exchange reaction. The slow step may be:

- 32 - INTRODUCTION W.M.EL-KENANY

a- Film diffusion, i.e diffusion of ions through a liquid film encompassing the solid particle where a concentration gradient persists. b- Particle diffusion, i.e diffusion of ions through the adsorbent particle. c- Chemical reaction occuring at the particle surface or inside the particle.

1.12.1 Film diffusion The simplifying assumption of film state that: i) Interdiffusion within a film is treated as quasistationary ii) The film is treated as a planer layer. iii) Film interdiffusion coefficient, D, is constant. Under such conditions the rate law for film diffusion controlled ion exchange in finite solution volume has been derived (Qureshi et al ., 1969).

F(t)=1- exp [-3D(VC + VC)t/(rδCV)] (9)

where, F(t) is the fractional attainment of equilibrium, i.e.

Qt Amount of exchange after time t F = = (10) Q∞ Amount of exchange after infinite time r and δ are the particle radius and film thickness, respectively. C and V are the aqueous phase counter ion concentration and solution volume, respectively; symbols with bars represent the solid phase. The equation is applied only when the sorbed ion is a microcomponent of the exchange and the solution. Film diffusion control is usually favored by small particle size, low concentration, high capacity and week agitation of solution [Boyed et al., 1947].

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1.12.2. Particle diffusion According to Boyd et al [Boyed et al., 1947] if the sorbed ion is a microcomponent of the exchanger, the following particle diffusion equation can be applied for single exchanger of pair of ions

Qt 1 ∞ 1 = F(t) = 1 - ∑ exp (– n2 Bt) (11) 2 n-1 2 Q∞ П n

Where, 2 2 B = П Di / r (12)

Qt is the amount exchanged at time t,

Qω is the amount exchanged at infinite time,

Di is the internal diffusion coefficient, n is an integer number and r is the particle radius . According to above equation if Bt is plotted against times a straight line passing through the origin is obtained in case of particle diffusion, Bt is a mathematical function of F(t) and the values of Bt corresponding to each value of F(t) were calculated and tabulated by Reichenberg

[Reichenberg, 1953]. The value of Di can then be calculated from the slope of a plot of Bt Vs.t. The validity of the above mentioned equation of Boyed et al [Boyed et al., 1947] can be taken as an evidence for particle diffusion control. Particle diffusion control is usually favored by a relatively large particle size of the exchanger and vigorous shaking. Another equation of particle diffusion is derived by Kresrman and Kitchner [Kresrman and Kitchener, 1949].

6 Qo Qt F(t)= . (13) R Qo-Qe п Where,

- 34 - INTRODUCTION W.M.EL-KENANY

Qo is the initial amount of counter ions in solution

Qe is the amount sorbed at equilibrium

Qt is the amount sorbed after time (t) This equation is only applicable at low values of F when the amount of srbed ion is vigorously kept equivalent to the amount of displaced ion in the sorbent. 1.12.3. Adsorption as a chemical phenomenon

For the exchange reaction

K1 + + R — B + A R — A + B (14) K2 The rate equation is: Ln (1– F) = -St (15) Where, + + S = K1 [A ] + K2 [B ] (16) and:

K1 and K2 are the rate of forward and backward reaction, respectively. This equation implies that when the rate of reaction is chemically controlled, δ is independent of r and δ, but depends on the concentration of ions in the solution. This equation is applicable if the sorbed ion and counter ion concentration δ are kept constant and the exchange sites are sparsely occupied.

1.13. Sorption isotherms An adsorption isotherm describes the relationship between the amount of metal adsorbed and the metal ion concentration remaining in solution. There are many equations for analyzing experimental adsorption equilibrium data. The equation parameters and the underlying

- 35 - INTRODUCTION W.M.EL-KENANY thermodynamic assumptions of these equilibrium models often provide some insight into both the adsorption mechanism and the surface properties and affinity of the sorbent. The following four models were tested. 1.13.1.Langmuir Isotherm

The Langmuir isotherm is based on the following assumptions [Langmuir. , 1918] 1 – metals ions are chemically adsorbed at a fixed number of well-defined sites. 2 – Each site can only hold one ion . 3 – All sites are energetically equivalent . 4- There is no interaction between the ions. The Langmuir equation is formulated as

Ce Ce 1 = + (17) qe Q bQ

where Ce (mg /l) and qe (mg/g )are the equilibrium concentrations in the

Liquid and solid phase, respectively, Q is a Langmuir constant related to the energy of adsorption and affinity of the sorbent. 1.13.2.Freundlich isotherm Freundlich expression is an exponential equation and therefore assumes that the concentration of adsorbate on the adsorbent surface increases with the adsorbate concentration. Theoretically, using this expression, an infinite amount of adsorption can occur (Freundlich, 1906). The equation is widely applied in heterogeneous systems

log qe = log Kf + 1/n log Ce (18)

- 36 - INTRODUCTION W.M.EL-KENANY

where KF (l/g) and n are equilibrium constants characteristic of the system, indicating the adsorption capacity and adsorption intensity, respectively. 1.13.3. Dubinin-Raduskevich ( D-R) isotherm:

The sorption D-R isotherm model is applicable at low concentration ranges and can be used to describe sorption on both homogeneous and heterogeneous surfaces. This is postulated within an adsorption “space” close to sorbent surface. If the surface is heterogeneous and an approximation to a Langmuir isotherm is chosen as a local isotherm for all sites that are energetically equivalent then the quantity K⁄ can be related to the mean sorption energy, ε, which is the free energy of the transfer of 1mol of the studied ions from infinity to the surface of the sorbent. It can be represented by the general expression:

/ 2 ln qe = lnqm − K ε (19) where qm is the maximum sorption capacity and ε is a constant related to energy and ( is the Polanyi potential) :

ε = RT ln /1+Ce (20) where R is a gas constant in kJ mol−1 and T is the temperature in Kelvin. 2 −1 2 / −1 If ln qe is plotted against ε (mol.K ) and k , qm (meq. g ) will be obtained from the slope and intercept, respectively. The sorption energy can also be worked out using the following relationship

E=1/√-2 K/ (21)

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2. EXPERIMENTAL

2.1. Materials 2.1.1. Reagents The most reagents used for the synthesis of the materials were obtained from BDH (England) and Loba Chemie (India). All other reagents and chemicals were of analytical reagent grade purity and used without further purification. In all experiments, bidistilled water was used for solvation, preparation, dilution, analytical purposes and for final washing of the inorganic ion exchanger where distilled water was employed for washing all glassware.

2.2. Preparation of vanadium antimonate: 2.2.1. Preparation of reagents

0.5 M of antimony pentachloride solution SbCl5 (which prepared by dissolving antimony powder with aqua regia) and 0.5

M of sodium monovanadate (NaVO3) solution and ammonia solution (33%) . 2.2.2. Preparation vanadium antimonate : Vanadium antimonate was synthesized by reaction of sodium monovanadate (NaVO3) with antimony pentachloride

(SbCl5) (which prepared by dissolving antimony powder with aqua regia) , with molar ratio V to Sb equal 1:1 . The reaction carried out in a water bath thermostat at 60oC with continuous stirring with dropwising of ammonia solution , a yellow gelatinous precipitate was formed. The precipitate was left over night for settling. The precipitate separated by centrifugation at 3000 rpm and washed - with 0.1M HNO3 to remove the excess Cl ions and impurities.

Rewash the precipitate with distilled water to remove NO3

- 38 - EXPERIMENTAL W.M.EL-KENANY

ions..Dry the precipitate in drying oven at 50o±C . A pale yellow precipitate was formed. The obtained material was grained , sieved and stored at room temperature.

2.2.3.Preparation of titanium vanadate: Preparation of reagents :

0.5 M of sodium monovanadate (NaVO3) solution , 0.5 M of titanium tetrachloride solution and ammonia solution. Preparation of titanium vanadate: Titanium vanadate was prepared as reported ealier [Ibrahim.,2006] by mixing 0.5M of Sodium monovanadate

( NaVO3 ) with 0.5M of titanium tetrachloride solution with the volume ratio 1:1.The reaction carried out in water bath at 60oC with a continous stirring . The ammonia solution was dropwised. A gelatinous yellow precipitate was formed . The precipitate was washed with 0.1M HNO3 solution , then washed by distilled water and dried at 50o ±1oC, A shiny dark brown precipitate was formed.The obtained material was grained , sieved and stored at room temperature.

2.3. Equipment The following equipment were utilized in this work: 2.3.1. Water thermostat shaker

Equilibration studies were performed using a water thermostat shaker of type Julabo SW-20C/2, Germany. 2.3.2. pH-meter

The pH-values of solutions were measured using bench pH meter, model 601A, USA.

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2.3.3. Differential thermal (DTA) and thermogravimetry (TG) analyses Measurements of differential thermal (DTA) and thermogravimetric (TG) analyses were carried out using a Shimadzu DTG-60 thermal analyzer obtained from Shimadzu Kyoto "Japan". The sample measured for ambient temperature up o to 1000 C in N2 atmosphere, with the heating rate of 10 deg/min and using alumina powder as a reference material.

2.3.4. Infrared spectral analysis The IR spectra of vanadium antimonate and titanium vanadate were measured by the KBr disc method by mixing of the solid with potassium bromide in ratio 1:4 and ground to a very fine powder. A transparent disc was formed in a moisture free atmosphere. The IR spectra were recorded using a IR nicolet - IS 10, made in USA in the range 400-4000 cm-1.

2.3.5. X-ray diffraction patterns Measurements of X-ray diffraction patterns were carried out using a Shimadzu X-ray diffractometer obtained from Shimadzu

Kyoto "Japan", model XD-Dl, with a nickel filter and a Cu Kα-X- radiation tube (λ = 1.5418 Å).

2.3.6. Atomic absorption spectrophotometer An atomic absorption spectrophotometer model AA-6701 F- Shimadzu, Kyoto "Japan" was used in the distribution coefficient measurements and also in column chromatography measurements. 2.3.9. Elemental analysis Chemical composition of the inorganic ion exchangers vanadium antimonate and titanium vanadate samples was

- 40 - EXPERIMENTAL W.M.EL-KENANY

performed by X-ray fluorescence (XRF) of solid samples with Philips XRF detector, Holland.

2.4. Chemical stability The chemical stabilities of the vanadium antimonate and titanium vanadate were studied in water, acid (HNO3 and HCl) at different concentrations [0.001, 0.1, 0.5, 1 2, 4M] by mixing 0.1 gm of each of the prepared samples of vanadium antimonate and titanium vanadate and 50 ml of the desired solution with intermittent shaking for about one week at 25±1oC. The filtrate was tested gravimetrically.

2.5. Capacity of vanadium antimonate and titanium vanadate for the studied hazardous metal ions

The capacities of vanadium antimonate and titanium vanadate samples were determined by batch experiment technique. 0.1 g of the solid material was equilibrated with 10 ml of ionic strength about 0.1 [ Cs+ ,Cu2+ ,Co2+ and Cd 2+ ] chloride solution with V/m ratio equal 100 ml/g for vanadium antimonate and titanium vanadate ion exchanger. The mixture was shaked in a shaker thermostat at 25 ± 1oC. After overnight standing the solid was separated and the concentration of the metal ions was measured instrumentally (using AA-6701 F) The capacity value was calculated by the following formula;

uptake ٪ Capacity in meq/g = × Co × Z × V/m (22) 100

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2.6. Distribution studies

+ 2+ 2+ The distribution coefficients (Kd) of, Cs , , Cd , Cu and Co2+ on vanadium antimonate and titanium vanadate were determined by batch equilibration as a function of hydrochloric acid concentration. 0.1 g of the prepared ion exchangers was shaken with 10 ml at a V/m ratio of 100 ml/g of 10-3 M of the above mentioned metal ion solutions. The mixture was placed overnight (time within an equilibrium was attained) in a shaker thermostat adjusted at 25 ±1oC. After equilibrium, the solutions were separated by centrifugation and the concentration of metal ions in the exchanger and in the solution was deduced from the concentration relative to the initial concentration in the solution. The pH values were measured before and after equilibration by using a pH meter of the bench, model 601A, USA. The concentration of Cs+, Co2+, Cu2+ and Cd2+ ions were measured using (AA-6701 F).. All tests were repeated two or three times and the total experimental error were about ± 3%.

The distribution coefficients (Kd) and separation factor values were evaluated;

Ao − Af V Kd = ———— × —— (ml/g) (23) Af m Where,

Ao: is the concentrations of the ions in solution before equilibration.

Af : is the concentrations of the ions in solution after equilibration . V : is the volume of the solution (ml) . m : is the weight of the exchanger (g).

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2.7. Kinetic measurements

The radius of the particle of the sieved fractions was determined by measuring the diameter of 100 particles with an optical microscope. The particles were assumed to be spherical and a mean equivalent radius was calculated, kinetic experiments were performed under particle diffusion control condition and a limited batch technique. Kinetic measurements were carried out at different operative conditions of concentration of metal ions and different particle diameters (0.115 – 0.375 mm) of titanium vanadate sample with V/m equals 100 ml/g. This was performed using aqueous solution which contains the cation solutions metals. All the kinetic experiments were done in a shaker thermostat adjusted at 25, 45 and 60±1oC. After each time interval the shaker is stopped and the solution is separated at once from the solid and the extent of sorption was determined. The sorption rate of the elements was followed in batch experiments with the solution to solid ratio permitting to obtain % uptake of ions <50%. Under these conditions, the only reaction taking place is the ion exchange between the metal ions in solution and the counter ions (co-ions), on the exchanger. Besides, the rate of exchange is governed by the diffusion of the metal ions. Also, the condition of that uptake <50% of ions is necessary to obtain a purely particle diffusion controlled exchange and hence a constant internal diffusion coefficient.

2.8. Sorption isotherms Sorption isotherm is done by a gradual increase in the concentration of sorbate ions in solution and measuring the amount

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sorbed at each equilibrium concentration. The degree of sorption should therefore be a function of the concentration of the sorbate ions only. Sorption isotherm for some hazardous metal ions was determined over the concentration range 5x10-4 to 5x10-2 M at constant V/m ratio of 100 ml/g. The experiments were carried out at 25, 45 and 60±1oC, in shaker thermostat. After equilibration the respective mixture was filtered and analyzed instrumentally for the all studied metal ions. The adsorption results were analyzed by the Langmuir adsorption isotherm as follows;

Ce Ce 1 = + (17) qe Q bQ

where Ce is the equilibrium concentration of the adsorbate ions, qe is the amount of ions sorbed per gram of sorbent (mol/g) at equilibrium time, Q and b are Langmuir constants related to maximum adsorption capacity (monolayer capacity) (meq/g) and heat of adsorption, respectively., if the Langmuir isotherm is valid, a straight line relationship should be obtained when qe is plotted against Ce , with slope Q and intercept b. According to Freundlich sorption isotherm, the following equation is valid;

log qe = log Kf + 1/n log Ce (18)

where qe is the amount adsorbed at equilibrium (mol/g), Ce is the equilibrium concentration of the adsorbate metal ions, Kf and n are

- 44 - EXPERIMENTAL W.M.EL-KENANY

Freundlich constants, Therefore, if the Freundlich isotherm is obeyed, a straight line relation ship should be obtained between log qe and log Ce According to Dubinin-Radushkevich (D-R) isotherm sorption isotherm, the following equation is valid;

/ 2 ln qe = ln qm - K ε (19)

wher ε (the polanyi potential) = RT ln (1+1/Ce), qe is the amount of ions sorbed per gram of sorbent (mol/g), qm is the adsorption capacity of the sorbent (meq/g), Ce is the equilibrium concentration / of the metal ions in solution, K is a constant related to the adsorption energy (mol2 kJ-2), R is the gas constant (kJ K-1mol-1), and T is the temperature (K), if the Dubinin-Radushkevich (D-R) isotherm is obeyed, a straight line relation ship should be obtained 2 between log qe and ε .

2.9. Column Operations Chromatographic column breakthrough investigations were conducted as follows, 1.0 gm of vanadium antimonate and titanium vanadate was packed in a glass column (1cm diameter and 1.2 cm heights) to give a bed heights of 1.2 cm3 volume. 500 ml of the desired neutral solutions containing 10-3 M of metal chloride [M 2+ 2+ 2+ + (Cl)x where M =, Co , Cu , , Cd ,and Cs ] were passed through the column beds at a flow rate of 4-5 drops/min, equal fractions were collected and the concentrations were continuously measured using atomic absorption spectrophotometer . The values of breakthrough capacity were calculated using the formula;

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Co Breakthrough capacity = V(50%) × —— (meq/g) (24) m where;

V(50%) : is the effluent volume at 50% breakthrough (ml).

Co : is the concentration of feed solution. m : is the amount of the column bed per gram .

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3. RESULTS AND DISCUSSION

3.1. Preparation and characterization of the prepared materials As a result of the method of the precipitation, granular type of titanium vanadate cation-exchanger was obtained. The H+-form of titanium vanadate was prepared as mentioned before in the experimental. Titanium vanadate was hard granules in nature and suitable to use in column operations and shiny dark brown in color. The color of the prepared material was not changed with increasing the drying temperatures from 50oC to 850oC. As a result of the method of the precipitation, a powder type of vanadium antimonate cation-exchanger was obtained. The H+- form of vanadium antimonate was prepared as mentioned before in the experimental. Vanadium antimonate was a powder material and yellow in colour . The colour of the prepared material was not changed when vanadium antimonate heated from 50 to 200oC but the color of the prepared material was changed from yellow to dark black when the material heated from 50 to 400oC and there is no change in colour occur when vanadium antimonate heated from 400 to 850oC.

The prepared samples were characterized using different analytical techniques such as solubility, I.R spectra, X-ray diffraction patterns and thermal analysis [TG and DTA] , X-ray fluorescence and scanning electron microscope analyses.

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3.1.1. Chemical stability

The solubility of the prepared titanium vanadate and vanadium antimonate was studied in water, acid (HNO3 and HCl) at different concentrations [ 0.01,0.1 ,0.5,1,2 and 4 M], by mixing 100 mg of each of the prepared samples of titanium vanadate or vanadium antimonate and 50 ml of the desired solution with intermittent shaking for about one week at 25±1oC as given in Tables (1,2). Table (1) shows the solubility of the prepared titanium vanadate ion exchangers in different concentrations of HCl and

HNO3 acids and H2O. Its clear that titanium vanadate is stable in water and partially soluble in (HCl and HNO3 ) up to 1M of both acids. Titanium vanadate is more stable in HCl acid than HNO3 acid and the solubility of the prepared material increases with the increase of acid concentration .At 2M of both acids the material is completely dissolved.

Table (2) shows the solubility of the prepared vanadium antimonate ion exchangers at different concentrations of HCl and

HNO3 acids and H2O.Its clear that vanadium antimonate is stable in water and acidic media (HCl ,HNO3 ) up to 1M of both acids . The vanadium antimonate is more stable in HCl acid than HNO3 nitric acid but the solubility of the prepared material increases with increasing the acid concentration.Vanadium antimonate still stable up to 4M of both acids. It is noticed that the chemical stability of vanadium antimonate is higher than titanium vanadate. In general titanium vanadate and vanadium antimonate are high chemically stable inorganic ion exchangers.

- 48 - RESULTS AND DISCUSSION W.M.EL-KENANY

Table (1) : Solubility percent of the prepared titanium vanadate at different acid concentration.

HCl H2O HNO3 Solvent concentration, 0.01 0.1 0.5 1 2 4 0.01 0.1 0.5 1 2 4 M Titanium U.D 2.5 20 40 75 95 C.D vanadate 1.6 12.5 34.79 59.0 96.3 C.D

C.D: Completely Dissolution U. D: Under Detection

Table (2) : Solubility percent of the prepared vanadium antimonate at different acid concentration.

HCl H2O HNO3 Solvent concentration, 0.01 0.1 0.5 1 2 4 0.01 0.1 0.5 1 2 4 M Vanadium U.D 1.86 20.9 36.8 39 42.9 49.1 ٥٣.٨ ٥٠.٢ 6.٣٣ ٢٩.٦ ١١.٧ antimonate 0.95

U.D: Under Detection

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3.1.2. Infrared spectra of the prepared samples

Infrared spectra of titanium vanadate was presented in Figure (1) and showed that , abroad band at (3406) cm-1 which corresonding to the presence of free water and hydroxyle group [Nakamato., 1981],[Davis., 1963] .The second peak which presented at (1612) cm-1 resulting from the bending deformation vibration of free water [Abdel-Latif and El-Kady., 2008]. The band at (970) cm-1 is due to presence of vanadate [Qureshi et al., 1972 ], [Miller and Wilkins., 1952] . The sharp band at 522 cm-1 is due to presence of titanium oxygen bond [Qureshi et al., 1977],[ Wirguin and Yaron., 1966]. It was noticed that the intenisities of the first and the second peak decrease with increasing the heating temperature due to loss of water [Nyquist and Kagel., 1997] .The intenisity of the M-O band increases with increasing the heating temperature of the prepared sample. The FTIR spectra of vanadium antimonate is presented in Fig (2).A broad band which appear at ≈ 2800 to 3500 cm-1 is assigned to stretching vibration mode of interstitial water molecules and OH groups [Socrates., 1980],[Nakamato., 1981].The second peak which presented at 1630 cm-1 resulting from the bending deformation vibration mode of water molecules [Rao., 1963] . The peak which presented at 1401 cm-1 related to the deformation vibration of Sb-OH group [ Siviah et al., 2007], [Abdel –Badei et al., 1992]. The band 991 cm-1 is corresponding to presence of vanadate [ Qureshi et al., 1972], [Abdel-Latif and El- Kady., 2008] . The band at 760 cm-1 assigned to Sb -O bond [Siviah et al.,2007], [Alonso et al., 1985]

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600

400

200 Transmittance

Wave number cm-1

Fig (1) : Infrared pattern of titanium vanadate at different drying temperatures.

- 51 - RESULTS AND DISCUSSION W.M.EL-KENANY

600

400

200

Transmittance

-1 Wave number cm Fig (2) : Infrared pattern of vanadium antimonate at different drying temperatures.

- 52 - RESULTS AND DISCUSSION W.M.EL-KENANY

It was noticed that the intenisities of the first and the second peak decrease with increasing the heating temperature due to loss of water molecules [EL-Naggar et al., 2003-a] but the intenisity of the M-O band increases with increasing the heating tempereatures of the prepared sample. A new band appear in sample heated at 400oC presented at ≈ 663 cm-1 which may be assigned to Sb-O-Sb bond [Siviah et al., 2007] ,[Ok et al., 2004].

3.1.3. X-ray diffraction patterns The X-ray diffraction patterns (XRD) of the synthesized materials were recorded using Shimadzu XD-Dl spectrometer with

Cu Kα radiation tube (λ = 1.5418 Å). The operating conditions were 30 kV and 30 mA. The patterns and the intensity with d-spacing value tables were used for the calculation of the crystal size of the samples. The prepared titanium vanadate and vanadium antimonate was annealed at different temperatures (50, 200, 400 and 600 oC) and grained to a very fine powder to be suitable for powder XRD measurement. The samples were mounted on a sample holder plate without using back tape. Identifying the crystalline phases that are formed in consequence of the thermal annealing was a very difficult task, due to the presence of large number of elements in the material under study X-ray analysis is showed in Fig (3) which reveal that titanium vanadate is amorphus (non crystalline) materials [ Naushad., 2009], [Ibrahim., 2006 ] and no change occur to the prepared sample when heated up to 600oC [Qureshi et al., 1972]. X-ray analysis is shown in Fig (4) which appears that vanadium antimonate is amorphus material. We noticed that the crystallinity of the prepared matrix increased with increasing the

- 53 - RESULTS AND DISCUSSION W.M.EL-KENANY

Fig(3): X-ray diffraction pattern of titanium vanadate at different drying temperatures.

- 54 - RESULTS AND DISCUSSION W.M.EL-KENANY

Fig (4): X-ray diffraction pattern of vanadium antimonate at different drying temperatures.

- 55 - RESULTS AND DISCUSSION W.M.EL-KENANY

drying temperatures. This change in the crystallinity is may be assigned to dehydration and formation of hydrous metal oxide. This change in the crystallinity after thermal treatment is reported by others [Siviah et al .,2007], [El-Naggar et al., 2003].

3.1.4. Thermal analysis (TG-DTA):

Differential thermal analysis and thermogravimetry were used to study phase transformation and weight loss during heat treatment TGA - DTA analysis is shown in Fig (5,6). Figure (5) show the thermal analysis of titanium vanadate it appears that there is an endothermic peak present at ≈ 133 oC which resulting from the removal of external water in titanium vanadate [Duval., 1963]. another endothermic peak at ≈ 673oC which corresponding to formation of metal oxide. An exothermic peak present at ≈ 477. 09 oC which may be caused by phase transition [El-Naggar et al., 2003], [Abdel-Latif and El-Kady., 2008]. From Figure (6) it is clear that thermogravimetric pattern contain an endothermic peak present at ≈ 136.8 oC which resulting from the removal of external water in vanadium antimonate [Duval., 1963]. Another exothermic peak at ≈ 456.9 oC which corresponding to decomposition of residual surface hydroxyl groups vanadium antimonate [Siviah et-al ., 2007]. Table (3) represents the weight loss of titanium vanadate at different drying temperatures .it is noticed that the percentage of weight loss Titanium vanadate are 10.8 ,12.52 ,15.43 and 15.66% when heated at 200, 400 ,600 and 800oC respectively. Table (4) represents the percent of weight loss of the prepared material at different drying

- 56 - RESULTS AND DISCUSSION W.M.EL-KENANY

Fig(5):TG-DTA Pattern of titanium vanadate.

- 57 - RESULTS AND DISCUSSION W.M.EL-KENANY

Fig (6): TG-DTA pattern of vanadium antimonate.

- 58 - RESULTS AND DISCUSSION W.M.EL-KENANY

Table (3): The weight loss percent of titanium vanadate dried at different drying temperatures.

Titanium vanadate % weight loss

Drying Temperatures 200°C 10.8 400°C 12.52 600 °C 15.43 800°C 15.66

Table (4): The percent of weight loss of vanadium antimonate dried at different drying temperatures.

Vanadium antimonate % weight loss

Drying Temperatures 200°C 7.9 400°C 14.22 600 °C 17.85 800°C 19.0

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temperatures. Vanadium antimonate loss 7.9, 14.22, 17.85 and 19.0 % when heated at 200, 400, 600 and 800 oC respectively. 3.1.5. Elemental analysis (X-ray flourescence): Elemental analysis data give indication that titanium vanadate contain about 42.79% of TiO2 and 44.92% of V2O5 .From elemental analysis the chemical formula may be ( Ti2V2O9).n , H2O.by using of Alberti s equation [Alberti et al .,1966]. 18n = X (M + 18n) / 100 (25) in which (M+18n) is the molecular weight of the material , n is the nomber of water molecules , X is the percent of weight loss 11.7% of the exchanger by heating up to ≈ 230 oC and the calculations gives ≈ 2.5 for the external water molecules (n) per molecule of cation exchanger , So the tentative formula of the exchanger can be written as following;

Ti2V2O9 . 2.5H2O

Elemental analysis show that vanadium antimonate contain about 51.25% and 33.49% of Sb2O3 and V2O5 respectively. From elemental analysis the chemical formula may be Sb6V8O35. n H2O. By using of Al berti,s equation [Alberti et al., 1966]. 18n = X (M + 18n) / 100 (25) in which n is the number of water molecules , X is the percent of weight loss 9.02% of the exchanger by heating up to ≈ 230 oC and the calculations gives ≈ 9.35 for the external water molecules (n) per molecule of cation exchanger , So the tentative formula of the exchanger can be written

Sb6V8O35. 9.35 H2O

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3.1.6 pH titration.

Titanium vanadate and vanadium antimonate (0.2 g) were placed in a column fitted with glass wool at its bottom. A glass bottle containing 20 mL of 0.001 M HCl was placed below the column, and for determination of pH, a glass electrode was placed in the solution, then 100 mL of 0.01 M (NaOH) was poured into the column. Titration was carried out by passing the alkali metal hydroxide at a drop rate of about 10 drop/min, and continued to a pH of about 10 [Nilchi et al., 2006]. The results are shown in Figures (7 and 8).

Figures (7,8) show the pH titration curve of titanium vanadate and vanadium antimonate .In these Figures, the X axis represents the number of millimoles of 0.01M of NaOH passed through per gram of titanium vanadate and Y-axis shows the pH values of effluents , passed through the column. In Figure (7) the pH titration curve shows only one inflection point indicating that the titanium vanadate behaves as mono functional ion exchanger [Qureshi et al., 1972] . This behaviour is simillar to zirconium vanadate [Roy et al., 2004], aluminium vanadate [Dhara et al., 2009]. In Figure (8) the pH titration curve shows only one inflection point indicating that the Vanadium antimonate behaves as mono functional ion exchanger. This behaviour is simillar to uranium antimonate [Siviah et al., 2004].

- 61 - RESULTS AND DISCUSSION W.M.EL-KENANY

1 0 9

8 7

6 p H 5

0 0 1 0 2 0 3 0 4 0 5 0 6 0 No.m moles of 0.01M NaOH

Fig (7 ) : The pH titration curve of titanium vanadate.

- 62 - RESULTS AND DISCUSSION W.M.EL-KENANY

9 8

6 pH 5

4 3

1 0 0 10 20 30 40 50 No.m moles of 0.01M NaOH

Fig (8): The pH titration curve of vanadium antimonate

- 63 - RESULTS AND DISCUSSION W.M.EL-KENANY

3.1.7.Scanning electron microscope analysis:

Figures (9,10) show the surface properties of the titanium vanadate and vanadium antimonate obtained at 15.0, 20 kV at the magnifications of 1000×,1300x using scanning electron microscopy. The results reveal that the particles of titanium vanadate and vanadium antimonate have irregular forms. Lack of clearly defined morphology speaks for its low crystallinity and this sequence can be confirmed by results obtained from X-ray diffraction patterns as shown "in Figures 3,4".

- 64 - RESULTS AND DISCUSSION W.M.EL-KENANY

Fig(9):Scanning electron microscope of titanium vanadate

- 65 - RESULTS AND DISCUSSION W.M.EL-KENANY

Fig(10):Scanning electron microscope of vanadium antimonate.

- 66 - RESULTS AND DISCUSSION W.M.EL-KENANY

3.2. Distribution Studies The potential use of titanium vanadate and vanadium antimonate in separation involving , Co2+, Cu2+, , Cd2+ and Cs+ ions was studied. In order to investigate its selectivity for metal ions, distribution coefficient (Kd) was determined at different pH for each of Co2+, Cu2+ , Cd2+and Cs+ ions. The preliminary studies indicate that, the time of equilibrium for the exchange of Co2+, Cu2+, Cd2+ and Cs+ ions with titanium vanadate and vanadium antimonate was attained within 24 h. (sufficient to attain equilibrium). The distribution coefficient of the investigated metal ions in demineralized water cannot give us any indications about the selectivity of titanium vanadate and vanadium antimonate for any of the cations studied (Co2+, Cu2+ ,Cd2+and Cs+). In order to investigate its selectivity for the studied metal cations, the distribution coefficients (Kd) were determined at different pH values. The results of Kd values are shown in Fig. (11,12) and Tables (5,6) for titanium vanadate and vanadium antimonate at different conditions. Figures (11,12) and Tables (5,6) represent the effect of the pH + 2+ 2+ 2+ on the distribution coefficient (Kd) for Cs , Co ,Cu and Cd ions on titanium vanadate ion exchanger .The values of Kd increase with increasing the pH . This increase in the Kd values with the increase in the pH is due to that titanium vanadate and vanadium antimonate are cationic exchangers [Qureshi et al., 1972], [Aly and El-Naggar., 1998] and their cation behaviour become more pronounced by increase in the pH ,as the pH increases , so the ion exchangers are greately enhanced.

- 67 - RESULTS AND DISCUSSION W.M.EL-KENANY

+ 2+ Table (5): Kd values and separation factors (α) of Cs , Cu , Co2+ and Cd2+ as a function of pH on titanium vanadate.

-1 Kd(ml g ) pH

Cs+ Cu2+ Co2+ Cd2+ 40.73 3.63 2.08 7.94 1.6 (11.22) ( 19. 49 ) ( 5.13 ) ( 1.74 ) ( 0.46 ) ( 0.26 ) 89. 12 7.58 5.24 11.48 2.1 ( 11.76 ) (17.00) ( 7.76 ) ( 1.45 ) ( 0.66 ) ( 0.46 ) 436.51 30.19 28.18 20.41 3 ( 14.45 ) ( 15.49 ) ( 21.38 ) ( 1.07 ) ( 1.48 ) ( 1.38 ) 2398 128.82 186.20 42.65 ( 18.61 ) (12.87) ( 56.22 ) 4 ( 0.69 ) ( 3.02 ) ( 4.39 )

- 68 - RESULTS AND DISCUSSION W.M.EL-KENANY

+ 2+ Table (6): Kd values and separation factors (α) of Cs , Cu , Co2+ and Cd2+ as a function of pH on vanadium antimonate.

-1 pH Kd ( ml.g ) Cu2+ Co2+ Cs+ Cd2+ 1.6 151.35 79.43 120.22 26.3 ( 1.9 ) ( 1.25 ) ( 5.75) (0.66 ) ( 3.02) ( 4.57 ) 2.1 199.52 117.48 158.48 37.15 ( 1.69 ) ( 1.25 ) ( 5.37 ) ( 0.74) ( 3.16 ) ( 4.26 ) 3 346.73 173.78 281.83 74.13 ( 1.9 ) ( 1.23 ) ( 4.67) ( 0.61) ( 2.34 ) ( 3.8 ) 4 616.59 630.95 489.77 158.48 (0 .97 ) ( 1.25 ) ( 3.89 ) ( 1.28 ) ( 3.98 ) ( 3.09)

- 69 - RESULTS AND DISCUSSION W.M.EL-KENANY

3.5

3.0

2.5

d 2.0

LogK 1.5

1.0 Cu 2+

Cd 2+

0.5 Cs+

Co 2+ 0.0 0 1 2 pH 3 4 5

2+ 2+ Fig (11): Plots of K d against pH for the exchange of Cd ,Co ,Cs+ and Cu2+ on titanium vanadate at 25oC.

- 70 - RESULTS AND DISCUSSION W.M.EL-KENANY

K Log 2

Cu 2+ Co 2+ Cd 2+ Cs+ 1 1 2 pH 3 4

2+ Fig (12): Plots of log Kd against pH for the exchange of Cu , Co2+, Cs+ and Cd2+ ions on vanadium antimonate at 25 oC.

- 71 - RESULTS AND DISCUSSION W.M.EL-KENANY

, It s clear that the linear relationship between Log Kd and pH was observed for Cs+, Co2+, Cu2+ and Cd2+ ions with slopes ( 0.76, 0.82 , 0.65, 0.31 ) , (0.25, 0.37 ,0.25, 0.32) on titanium vanadate and vanadium antimonate respectively. These slopes does not equal to the valence of the studied metal ions . So the exchange reaction of Cs+, Cu2+,Co2+ and Cd2+ ions on titanium vanadate and vanadium antimonate is a non ideal ion exchange reaction. These findings cannot be explained only in terms of electrostatic interaction between the hydrated cations and the anionic sites in the exchanger. It may therefore be considered that the dependence of

Kd for cations cannot be understood by a purely columbic interaction with the anionic sites.

+ Figure ( 11 ) show that the Kd values of Cs ions is higher than Cu2+,Co2+ and Cd2+ ions. The selectivity sequence for titanium vanadate toward Cs+,Cu2+, Co2+ and Cd2+ ions is Cs+ > Cu2+ > Co2+ 2+ 2+ > Cd .But figure (12) show that the Kd values of Cu ions is higher than Co2+, Cs+ and Cd2+ ions. The selectivity sequence for vanadium antimonate toward Cs+, Cu2+, Co2+ and Cd2+ ions is Cu2+ > Co2+ > Cs+ > Cd2+, The ions with smaller ionic radii are easily exchanged and move faster than that the ions with greater + ionic radii while the Kd values of Cs ions are greater than the other studied metal ions and this is may be resulting from that the hydration energy of Cs+ jion is very small as compared to the hydration energy of the other studied metal ions [El-Naggar et al., 2010-a], and this result is presented in Tables (7,8).

The Kd values and separation factors (α =KdA/KdB) where A and B are any neighboring pair ions ) of Cs+, Cu2+, Co2+ and Cd2+

- 72 - RESULTS AND DISCUSSION W.M.EL-KENANY

ions in different pH on titanium vanadate and vanadium antimonate are summarized in Tables (5,6). From Table (5) it is clear that the separation factors between Cs+ and another studied metal ions are larger on titanium vanadate. It,s evident from the above studies of the separation factors on titanium vanadate , some selective separation is feasible for various metal ions such separation of Cs+ - Cu2+, Cs+ - Co2+ and Cs+ - Cd2+ may be taken on titanium vanadate at pH,s 1.6, 2.1, 3.00 and 4.00- but the separation between Cu2+ - Cd2+ and Co2+- Cd2+ may be achieved of at pH 4.0. From Table (6) the separation factors between Cu2+, Co2+, Cs+ and cadmium metal ions are larger on vanadium antimonate. It,s evident from the above studies of the separation factors on vanadium antimonate , some selective separation is feasible for various metal ions such separation of Cu2+- Cd2+, Co2+ - Cd2+ and Cs+ - Cd2+ may be taken on vanadium antimonate at pH,s 1.6, 2.1, 3.00 and 4.00. From these results titanium vanadate and vanadium antimonate can be used for recovery of hazardous ions from waste.

- 73 - RESULTS AND DISCUSSION W.M.EL-KENANY

+ 2+, 2+ 2+ Table (7 ) : Kd values of Cs ,Cu Co and Cd ions on titanium vanadate at natural pH.

Exchanging Distribution Ionic radii Hydration ions coefficient ( Kd) ( A ) energy ml.g-1 kJ.mol-1 Cs+ 2630 1.67 263 Cu2+ 223.87 0.72 2100 Co2+ 173.78 0.72 2054 Cd2+ 61.66 0.97 1806

2+ 2+ + 2+ Table (8): Kd values of Cu , Co , Cs and Cd ions on vanadium antimonate at natural pH.

Exchanging Distribution Ionic radii Hydration ions coefficient ( Kd ) ( A ) energy ml.g-1 kJ.mol-1 Cu2+ 794.33 0.72 2054 Co2+ 676.08 0.72 2100 Cs+ 489.79 1.67 263 Cd2+ 218.78 0.97 1806

- 74 - RESULTS AND DISCUSSION W.M.EL-KENANY

Tables (9 and 10) show the distribution coefficient values of titanium vanadate and vanadium antimonate for the studied metal ions as compared to another inorganic and composite ion exchangers respectively.

From Table (9), titanium vanadate ion exchanger gives higher distribution coefficient values than other ion exchangers, e.g. (Cs+) on potassium titanium trisilicate III [Bortun et al., 2000], (Cs+ ,Cu2+) on silicotitanate [El-Naggar et al ., 2008], (Cu2+ and Co2+) on cerium zirconium antimonate 114 [Preetha and Janardanan., 2012], (Cs+) on zirconium vanadate [Lahiri et al., 2005], (Cs+) on ceric vanadate [Lahiri et al., 2005], (Cs+, Co2+ ) on silico titanate [El-Naggar et al., 2008], (Cu2+ and Co2+) on Cellulose acetate -zr molybdophosphate [Nabi and Naushad 2008], (Cu2+ and Co2+) on Polyaniline zr titanium phosphate [Khan and Paquiza., 2011], (Cs+) on copper hexacyanoferrate–polyacrylonitrile composite [Nilchi et al., 2011], (Cs+ and Cu2+) on thorium tungstophosphate [Yavari et al., 2006], (Cs+, Cd2+, Cu2+ and Co2+) on magneso- silicate and (Cs+, Cu2+ and Co2+ ) magnesium alumino-silicate [El- Naggar and Abou-Mesalam., 2007] and (Cs+) on iron-silicate [Ali et al., 2008]. While the prepared titanium vanadate gives lower distribution coefficient values than other ion exchangers, e.g. (Cs+ , Cu2+, Co2+ ,Cd2+) polyacrylamide Sn(IV) molybdophosphate [El- Naggar et al., 2010-a] (Cs+) on potassium titanium trisilicateI [Bortun. et al., 2000] (Cd2+) on cerium zirconium antimonate 114 [Preetha and Janardanan.,2012], (Cd2+) on Polyaniline zr titanium phosphate [Khan and Paquiza., 2011], (Cd2+) on Cellulose acetate -zr molybdophosphate [Nabi and Naushad., 2008], Cd2+ on magnesium auminosilicate [El-Naggar and Abou-

- 75 - RESULTS AND DISCUSSION W.M.EL-KENANY

Table (9): Comparison of Kd, values of Cs+ , Co2+, Cu2+, and Cd2+ ions for various cationic ion exchangers in DMW.

-1 Inorganic ion exchanger Kd (ml g ) References Cs+ Cu2+ Co2+ Cd2+ Titanium vanadate a 2630 223.87 173.78 61.66 Cerium zirconium antimonate-114 - 212 115 83 [Preetha and Janardanan ., 2012] Poly aniline zr titanium phosphate 162 115 159 [Khan and Paquiza., 2011]

Cellulose acetate –zr molybdo phosphate 98 110 166 [Nabi and Naushad., 2008]

Zirconium tungstoiodo phosphate - 7900 3600 4500 [Siddiqi and Khan., 2007]

Potassium titanium trisilicate I 40000 [Bortun. et al., 2000] Potassium titanium trisilicate III 20 [Bortun. et al., 2000] Silico antimonate - 1100 155 [Abou-Mesalam, 2002] Zirconium vanadate 46.9 - - - [Lahiri et al., 2005] Ceric vanadate 91.1 - - - [Lahiri et al., 2005] Silico titanate 38.9 - 12.02 - [El-Naggar et al., 2008] copper hexacyanoferrate– 1673 [Nichi et al., 2011] polyacrylonitrile Thorium tungstophosphate 32 18 - [Yavari et al., 2006] magneso-silicate 58.95 13.66 39.43 24.68 [El-Naggar and Abou- Mesalam, 2007] Magnesium alumino-silicate 77.46 34.12 98.01 73.31 [El-Naggar and Abou- Mesalam, 2007] Iron-silicate 602.56 - - - [Ali et al., 2008] Polyacrylamide Sn(IV) 3090.290 957.1900 346.73 1096.470 [El-Naggar et al ., 2010-a] molybdophosphate

- 76 - RESULTS AND DISCUSSION W.M.EL-KENANY

Table (10): Comparison of Kd, values of Cu2+, Co2+, Cd2+ and Cs+, ions for various cation ion exchangers in DMW.

-1 ion exchanger Kd (ml g ) References

Cs+ Cd2+ Cu2+ Co2+ Vanadium antimonate a 489.79 218.78 794.33 676.08 Zr molybdo tungsto vanado silicate 407.25 - - T.A [Zonoz et al., 2009] Bismuth iodo phosphate - 7 5.59 11.51 [Chand et al., 2011] Tin (IV) phosphate - 311 666.7 330 [Vareshney et al., ., 2007] Zr p s - 7.14 - [Zhang et al., 2009] Zr p - 8.03 - - [Zhang et al., 2009] Zr antimono tungstate - - 17.50 7.54 [Sharma and Neetu., 2011] Titanium molybdo phosphate -11 3323 104 104 1918 [Yavari et al., 2009] Titanium molybdo phosphate -21 104 104 4569 112 [Yavari et al., 2009] Titanium molybdo phosphate -31 4651 85.9 1954 24 [Yavari et al., 2009] Zr(IV) tungsto molybdate - 298 84 1217 [Nabi et al., 2007] Poly-o-toluidine Zr(IV) phosphate - 157 200 67 [Khan and Akhtar, 2008] (Poly methyl metha acrylate - 1100 2100 750 [Siddiqui et al., 2007] zirconium phosphate) Tamarind iminodiacetic acid (TIDAA) - 7.59×103 9.78×103 - [Sharma and Singh, 2005] Poly acrylamide- Zirconium - 27.7 70 - [Nabi and Shalla 2009] phosphate Sodium bis (2-ethyle 3774.41 2104.91 [iqbal et al., 2011] hexyle)sulfosuccinate tin phosphate Poly aniline cerium molybdate 1673 1157 400 [Alam et al., 2010]

(a): the material under study

- 77 - RESULTS AND DISCUSSION W.M.EL-KENANY

Mesalam.,2007] ,(Cu2+ ,Co2+) on silico antimonate [Abou- Mesalam., 2002], (Cu2+ ,Co2+ Cd2+) on Zirconium tungstoiodo phosphate [Siddiqi and Khan., 2007].

From Table (10), vanadium antimonate ion exchanger gives higher distribution coefficient values than other ion exchangers, e.g. (Cs+) on Zr molybdo tungsto vanado silicate [Zonoz et al., 2009], (Co2+ Cd2+ , Cu2+) Bismuth iodo phosphate [Chand et al., 2011], (Cu2+ and Co2+) on Tin (IV) phosphate [Varshney et al., 2007], (Cd2+) on Zr p s , Zr p [Zhang et al., 2009], (Cu2+ ,Co2+) on Zr antimono tungstate [Sharma and Neetu .,2011], (Cd2+,Cu2+ , Co2+ ) on Poly-o-toluidine Zr(IV) phosphate [Khan and Akhtar., 2008], (Cu2+) on Zr(IV) tungstomolybdate [Nabi et al., 2007] , (Cu2+ and Cd2+) Tamarind iminodiacetic acid (TIDAA) [Sharma and Singh., 2005], (Cu2+ and Cd2+) on Poly acrylamide- Zirconium phosphate [Nabi and Shella., 2009], (Co2+) on Poly aniline cerium molybdate [Alam et al., 2010], (Cd2+ and Cu2+) on titanium molybdophosphate-11 [Yavari et al., 2009], (Cs+, Cd2+, and Co2+) on titanium molybdophosphate-21 and (Co2+,Cd2+) titanium molybdophosphate-31 [Yavari et al., 2009] While the prepared vanadium antimonate gives lower distribution coefficient values than other ion exchangers, e.g. (Cd2+) on tin (IV) phosphate [Varshney et al., 2007] (Cd2+ and Co2+) on Zr(IV) tungstomolybdate [Nabi et al., 2007] , (Cu2+, Co2+ ,Cd2+) on Poly methyl metha acrylate zirconium phosphate [Siddiqui et al., 2007], 2+ 2+ (Cu , Cd ) on Sodium bis (2-ethyle hexyle)sulfosuccinate tin phosphate [Iqbal et al., 2011] , (Cu2+ ,Cd2+) on Polyaniline cerium molybdate [Alam et al., 2010],(Cs+ ,Co2+) on titanium

- 78 - RESULTS AND DISCUSSION W.M.EL-KENANY

molybdophosphate-11, (Cu2+) on titanium molybdophosphate-21 and (Cs+,Cu2+) titanium molybdophosphate-31 [Yavari et al., 2009].

The effect of metal ion concentration on Kd was studied on titanium vanadate and vanadium antimonate with the investigated + 2+ 2+ 2+ ions (Cs ,Cu ,Co and Cd ) . Figures (13,14 ) show that Kd values increase with decreasing the concentration of metal ion . In other words ,the Kd values increase as dilution of metal ions in solution proceeds [Erdem et al., 2004], [Metwally .,2008].

Figures (15-18),(19-22) show that Kd values increase with increasing the reaction temperatures of titanium vanadate and vanadium antimonate from 25oC to 60 ±1oC which reveal that all these systems are endothermic reaction.This trend may be attributed to the mobility of Cs+, Co2+, Cu2+ and Cd2+ ions increase with increasing the reaction temperatures ,so the exchange process increase and then the Kd values also increase [El-Naggar et al., 2009].

Figures (23,24) : show the linear relation between log Kd and 1/T according to Van,t Hoff equation :

ln Kd = ∆S*/T - ∆H*/RT (26) Where ∆S* is the entropy change of adsorption, ∆ H* is the enthalpy change of adsorption, R is the gas constant and T is the absolute temperature. It was found that the distribution coefficients of Cs+, Cu2+ Co2+ and Cd2+ ions increased with increasing the reaction temperature from 298 to 333 K (i.e) Distribution coefficients decreased with increasing 1/T ) as shown in Figure

- 79 - RESULTS AND DISCUSSION W.M.EL-KENANY

4.5

+ 4.0 Cs Cu2+ 3.5 Co2+

Cd2+ 3.0

d 2.5

Log K Log 2.0

1.5

1.0

0.5

0.0 0.00 0.01 0.02 0.03 0.04 0.05 Conc (M) + Fig (13 ) : Plots of log Kd against different concentrations of Cs Cu2+ ,Co2+ and Cd2+ ions on titanium vanadate at 50oC

- 80 - RESULTS AND DISCUSSION W.M.EL-KENANY

3.5

Cu2+ 3.0 Co2+

Cs+ 2+ 2.5 Cd

2.0 d

Log K Log 1.5

1.0

0.5

0.00 0.01 0.02 0.03 0.04 0.05 Conc(M)

+ Fig (14 ) : Plots of log Kd against different concentrations of Cs Cu2+ ,Co2+ and Cd2+ ions on vanadium antimonate at 50oC

- 81 - RESULTS AND DISCUSSION W.M.EL-KENANY

Log K Log 1 o 25 C 45oC

o 60 C

0 1 2 pH 3 4

2+ Fig (15 ) : Plots of log Kd against pH for the exchange of Co ions on titanium vanadate at different reaction temperatures.

- 82 - RESULTS AND DISCUSSION W.M.EL-KENANY

LogK

o 2 25 C o 45 C o 60 C

1 1 2 pH 3 4 5

+ Fig (16 ) : Plots of log Kd against pH for the exchange of Cs ions on titanium vanadate at different reaction temperatures.

- 83 - RESULTS AND DISCUSSION W.M.EL-KENANY

3.0

2.5

2.0

1.5d

Log K Log 1.0 25oC

45oC

0.5 60oC

0.0

1 2 pH 3 4 5

2+ Fig (17 ) : Plots of log Kd against pH for the exchange of Cu ions on titanium vanadate at different reaction temperatures.

- 84 - RESULTS AND DISCUSSION W.M.EL-KENANY

3.0

2.5

2.0

d 1.5

Log K Log 1.0 o 25 C o 45 C 0.5 o 60 C

0.0 1 2 pH 3 4 5

2+ Fig (18) : Plots of log Kd against pH for the exchange of Cd ions on titanium vanadate at different reaction temperatures.

- 85 - RESULTS AND DISCUSSION W.M.EL-KENANY

Log K Log

o 2 5 C 4 5 oC

6 0 oC

2 1 2 p H 3 4

2+ Fig (19): Plots of log Kd against pH for the exchange of Cu ions on vanadium antimonate at different reaction temperatures.

- 86 - RESULTS AND DISCUSSION W.M.EL-KENANY

Log K Log

25oC

45oC

60oC

2 1 2 pH 3 4

+ Fig (20): Plots of log Kd against pH for the exchange of Cs ions on vanadium antimonate at different reaction temperatures.

- 87 - RESULTS AND DISCUSSION W.M.EL-KENANY

3.0

2.5

d 2.0

Log K Log

o 1.5 25 C

45oC

60oC

1.0 1 2 pH 3 4

2+ Fig (21): Plots of log Kd against pH for the exchange of Co ions on vanadium antimonate at different reaction temperature

- 88 - RESULTS AND DISCUSSION W.M.EL-KENANY

3.0

2.5

d 2.0

Log K Log

1.5 25oC 45oC 60oC

1.0 1 2 3 4 5 pH 2+ Fig (22): Plots of log Kd against pH for the exchange of Cd ions on vanadium antimonate at different reaction temperatures.

- 89 - RESULTS AND DISCUSSION W.M.EL-KENANY

Log K Log 2 C u 2 + C o 2 + C d 2 + C s +

1 2 .9 3 .0 3 .1 3 .2 3 .3 3 .4 o -3 1 /T K * 1 0

Fig (23) : The relation between log Kd and 1/T for the exchange of Cd2+ , Co2+ Cs+and Cu2+ ions on titanium vanadate.

- 90 - RESULTS AND DISCUSSION W.M.EL-KENANY

Log K Log 2

Cu2+ Co2+ Cd2+ Cs+ 1 2.9 3.0 3.1 3.2 3.3 3.4 o -3 1/T K *10

Fig (24): The relation between log Kd and 1/T for the exchange of Cd2+ , Co2+ Cs+and Cu2+ ions on vanadium antimonate.

- 91 - RESULTS AND DISCUSSION W.M.EL-KENANY

Table (11) : Thermodynamic parameters for adsorption of Cs+, Cu2+, Co2+ and Cd2+ ions on titanium vanadate.

Metal ions Temp ∆G* ∆H* ∆S* (K) kJmo1-1 kJ mol-1 Jmol-1K-1 Cs+ 298 -19.-49 142.41 318 -21.89 22.95 141.00 333 -24.52 142.58 Cu2+ 298 -13.40 106.5 318 -15.33 18. 34 105.88 333 -16.99 106.1 Co2+ 298 -12.74 89.32 318 -14.59 13.88 89.52 333 -16.25 90.49 Cd2+ 298 -10.20 116.34 318 -12.39 24.47 115.9 333 -14.25 116.27

Table (12): Thermodynamic parameters for adsorption of Cs+, Cu2+, Co2+ and Cd2+ ions on vanadium antimonate.

Metal ions Temp ∆G* ∆H* ∆S* (K) kJ mo1-1 kJ mol-1 Jmol-1K-1

Cu2+ 298 -16.-52 142.41 318 -19.03 24.81 141.00 333 -21.40 142.58 Co2+ 298 -16.12 106.5 318 -18.55 23. 24 105.88 333 -20.76 106.1 Cs+ 298 -15.03 97.24 318 -17.52 13.95 98.98 333 -18.74 98.16 Cd2+ 298 -10.20 116.34 318 -12.39 18.13 115.9 333 -14.25 116.27

- 92 - RESULTS AND DISCUSSION W.M.EL-KENANY

(23-24 ). This increase in the extent of adsorption with the increase in temperature was attributed to accleration of some originally slow adsorption steps and creation of some new active sites on the adsorbent surface [Clark., 1970], [Mishra., 1996] from the slopes. and intercepts of these straight lines which represented in Figure (23,24) the enthalpy change of adsorption ( ∆H* ) and entropy change of adsorption ( ∆S* ) were evaluated and listed in Tables (11,12) for titanium vanadate and vanadium antimonate ion exchanger . The free energy change ( ∆G* ) was calculated ∆ G* = ∆H -T∆S* (27)

∆ G* = RT ln Kd (28) The positive values of ( ∆H*) indicate the endothermic nature of the adsorption process, the negative values of free energy change ( ∆G* ) for the exchange of Cs+,Cu2+,Co2+ and Cd2+ ions indicate that the adsorption process is a spontaneous process and the adsorption of metal ions is more pereferable than the H+ ion [El-Naggar et al., 2008]. It was found that the negativity of ∆G* increase in order Cs+ > Cu2+ > Co2+ > Cd2+ and then the order agrees with the selectivity sequence of titanium vanadate toward Cs+, Cu2+, Co2+ and Cd2+ ions and also the negativity of ∆G* increase in order Cu2+ > Co2+ > Cs+ > Cd2+ and then the order agrees with the selectivity sequence of vanadium antimonate toward Cs+, Cu2+, Co2+ and Cd2+ ions.

From Table (11,12) the values of ∆s* are postive and that refer to disorder ( randomness ) of sorption process of Cs+,Cu2+, Co2+ and Cd2+ ions on titanium vanadate ion exchanger and this results agree with [El-Naggar et al., 2008].

- 93 - RESULTS AND DISCUSSION W.M.EL-KENANY

3.3.Capacity measurements: The capacities of titanium vanadate and vanadium antimonate samples were determined by batch experiment technique. 0.1 g of the solid material was equilibrated with 10 ml of ionic strength about 0.1 (Cs+, Co2+, Cu2+ and Cd2+) chloride solution with V/m ratio equal 100 ml/g for all titanium vanadate and vanadium antimonate samples . The mixture was shaked in a shaker thermostat at 25 ± 1oC. After overnight standing the solid was separated and the concentration of the metal ions was measured instrumentally (using atomic absorption spectrometer). The capacity value was calculated by the following formula;

Capacity = % uptake / 100 x Co x V/m x Z (meq./g) (22)

where Co is the initial concentration of the ions in solution, V is the solution volume, m is the sorbent mass and Z is the valence of the exchanged ions.

The ion exchange capacities of titanium vanadate and vanadium antimonate samples for Co2+, Cu2+, Cd2+ and Cs+ ions has been determined as a function of pH with constant ionic strength (0.1). From Figures (25,26), it was found that, the capacity of the studied metal ions increases by increasing the pH, this is may be attributed to increasing the pH of the solution the [H]+ in solution is decrease and it is facilitate the release of H+ from the exchanger in solution, So the % uptake values increase and the capacity increase [Abdel-Galil ., 2010].

- 94 - RESULTS AND DISCUSSION W.M.EL-KENANY

2.5 Cs+ Co2+ Cu2+ 2.0 Cd2+

1.5

Capacity meq/g Capacity

1.0

0.5

0.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5

Fig. (25): plots of capacity against pH for exchange of Cs+, Co2+, Cu2+, Cd2 + on titanium vanadate.

- 95 - RESULTS AND DISCUSSION W.M.EL-KENANY

1.5

2+ Cu 2+ Co + Cs 2+ Cd 1.0

Capacity meq/g Capacity 0.5

0.0 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 pH

Fig. (26): Plots of capacity against pH for exchange of Cs+, Co2, Cu2+, Cd2 + on vanadium antimonate.

- 96 - RESULTS AND DISCUSSION W.M.EL-KENANY

From Table (13,14) it is clear that, the ion-exchange capacity of the cation-exchangers titanium vanadate and vanadium antimonate for the studied metal ions increases according to the decrease in the hydrated ionic radii and hydration energy and have the following sequence for titanium vanadate and vanadium antimonate respectively ; Cs+ > Cu2+ > Co2+ > Cd2+ Cu2+ > Co2+ > Cs+ > Cd2+

Titanium vanadate cation exchanger gives higher ion exchange capacity than other inorganic and composite ion exchangers, e.g. (Cs+ 1.18 meqg-1) on cerium iodotungstate [Dhara et al., 2009-a], (Cs+ 0.13 meqg-1) on ceric vanadate [Lahiri et al., 2005] , ( Cs+ 2.4 meqg-1 ) on zirconium vanadate [Abdel-Latif and El-kady., 2008] and also vanadium antimonate gives higher ion exchange capacity than (Cs+ 1.19, Co2+ 1.15,Cu2+ 1.09 meqg-1) on polyacrylamide Sn(IV) molybdophosphate [El-Naggar et al., 2010-a], ,(Co2+ 0.24),(Cu2+ 0.25, Cd2+ 0.55 mmol.g-1 on cero- antimonate , (Cu2+ 0.41 mmol.g-1 Cd2+ 0.82 mmol.g-1) on titanium cero-antimonate [ Abou-Mesalam., 2011]. (Cs+ 0.45 meqg-1 and Co2+ 0.62 meqg-1) on iron-silicate [Ali et al., 2008], (Cs+ 0.46 meqg-1 and Co2+ 1.02 meqg-1) on tin silicate [Abou-Mesalam and El-Naggar, 2009], (Cs+ 0.57 meqg-1, Cd+2 0.82 meqg-1, Cu2+ 0.60 meqg-1 on magneso-silicate [El-Naggar and Abou-Mesalam, 2007] , (Cs+ 0.77 meqg-1, Co2+ 1.00 meqg-1, Cu2+ 0.88 meqg-1) on magnesium alumino-silicate [El-Naggar and Abou-Mesalam., 2007], , (Cs+ 0.59 meqg-1, Co2+ 0.31 meqg-1) on silico titanate [El- Naggar et al., 2008], (Cs+ 0.55, 0.029 meqg-1) on OMS ,TMS , (0.77 , 0.03 ) on OMAS and TMAS [Abou- Mesalam and El- Naggar., 2008],

- 97 - RESULTS AND DISCUSSION W.M.EL-KENANY

Table (13): Ion-exchange capacity of various exchanging ions on a inorganic cation-exchanger titanium vanadate at natural media

Exchanging Ionic Hydration ion-exchange ions radii (Å) energy capacity kJ.mol-1 (meq.g−1)

Cd2+ 0.97 1806 0.177 Cs+ 1.67 263 2.56 Co2+ 0.72 2054 0.231 Cu2+ 0.72 2100 0.76

Table (14): Ion-exchange capacity of various exchanging ions on a inorganic cation-exchanger vanadium antimonate at natural media

Exchanging Ionic Hydration ion-exchange ions radii (Å) energy capacity kJ.mol-1 (meq.g−1)

Cd2+ 0.97 1806 0.42 Cs+ 1.67 263 1.18 Co2+ 0.72 2054 1.30 Cu2+ 0.72 2100 1.42

- 98 - RESULTS AND DISCUSSION W.M.EL-KENANY

(Cs+ 0.975 meqg-1, Co2+ 0.718 meqg-1 meqg-1) on titanium(IV) antimonate [Abou-Mesalam and Shady, 2004], (Cs+ 0.75 meqg-1) on tin(IV) antimonate [El-Naggar et al., 1996], (Cs+ 0.75 meqg-1) on lithium zirconium silicate (LiZrSi) [El-Naggar and Abou- Mesalam, 2005], (Co2+0.89 meqg-1) on zirconium titanate [Zakaria et al., 2004-a] and (Cu2+ 0.44 meqg-1) on silico antimonate [Abou-Mesalam., 2003] while the ion exchange capacity of Cd2+ on titanium vanadate and vanadium antimonate is lower than that of Cd2+ (1.41 meqg-1) on polyacrylamide Sn(IV) molybdophosphate [El-Naggar et al., 2010- a], Cd+2 0.79 meqg- 1on silico antimonate [Abou-Mesalam., 2003], (Cd2+ 0.82 , 2.06 meqg-1 on magneso-silicate and magnesium alumino-silicate [El- Naggar and Abou-Mesalam., 2007] ,(Cu2+ 1.33 mmol/g) on zirconium oxide [Abou –Mesalam., 2011-a]. Tables (15,16), It was found that the ion exchange capacity of titanium vanadate and vanadium antimonate decreased with increasing the heating temperatures from 50oC to 400oC. This may be due to the loss of free water and chemical bond water which may act as exchangable active site [El-Naggar et al., 1998], [Abou-Mesalam and El-Naggar., 2008], [Abou-Mesalam., 2011]. This trend agrees with the ion exchange capacities of K+ ion on stannic vanadate (sample 4) at different drying temperatures [Qureshi et al., 1977].

- 99 - RESULTS AND DISCUSSION W.M.EL-KENANY

Table (15): Capacities of Cs+ ,Co2+ ,Cu2+ and Cd2+ ions on titanium vanadate at different drying temperatures.

Temperatures -1 Capacity meq.g

Cation 50 200 400

1.45 Cs+ 2.56 1.98

0.76 0.57 0.24 Cu2+

2+ Co 0.23 0.15 0.09

2+ Cd 0.17 0.11 0.05

- 100 - RESULTS AND DISCUSSION W.M.EL-KENANY

Table (16 ): Capacities of Cs+ ,Co2+ ,Cu2+ and Cd2+ ions on vanadium antimonate at different drying temperatures.

Temperatures -1 Capacity meq.g

Cation 50 200 400

0.87 Cs+ 1.12 1.08

1.42 1.26 1.14 Cu2+

2+ Co 1.30 1.12 0.94

2+ Cd 0.42 0.25 0.11

- 101 - RESULTS AND DISCUSSION W.M.EL-KENANY

3.4. Kinetics Studies It has been mentioned in the first chapter (Introduction), that rate of ion exchange is governed by the slow step (rate determining step) in the ion exchange reaction. The slow step may be diffusion in the liquid surrounding the particle of the exchanger (film diffusion control) or diffusion inside the exchanger particles itself (particle diffusion mechanism) and/or the ion exchange process itself when the exchanging ions form strong complexes with the functional groups of the exchanger (chemical control) [Rudolf and Clearfield, 1989; Inezed, 1957; El-Naggar., 1984]. The conditions of this thesis were set to study the particle diffusion mechanism only. As a limited batch technique was used. As the rate determining step is diffusion through the spherical particle of the exchanger which immersed in a well stirred solution of approximately an infinite volume. The equation developed by Boyed is applied as follows [Boyed., 1947]:

2 2 2 6 ∞ 1 -n л Di/r F= 1- — ∑ — e (11) л2 n=1 n2

where Di is the self diffusion coefficient of the exchanging ions inside the exchanger particles, F is the fractional attainment of the equilibrium, n is an integer number and r is the particle radius of the exchanger. This equation was improved by Reichenberg [Reichenberg., 1953] and is used if the rate determining step is diffusion through the spherical particles of the exchanger or for infinite batch conditions where the ionic composition of the exchange surface remains constant during the exchange process. Then the above equation may be written in the form;

- 102 - RESULTS AND DISCUSSION W.M.EL-KENANY

6 ∞ 1 - n2Bt F= 1- — ∑ — exp (29) л2 n=1 n2 where

2 2 Bt= л Di/r (12) where F is a function of Bt and Reichenberg had tabulated the values of Bt corresponding to each value of fractional exchange. When the fractional attainment of equilibrium (F) is less than 0.4 the above equation (Equation 29) can be approximate to a simpler form as follows:

6 1/2 F (t) = — (Dit/л) (30) r

This holds a fairly good approximation. Therefore, a plot of F(t) against the square root of the contact time must give a straight line passing through the origin in the region in which F(t) is less than 0.4 . The radius of the particle of the sieved fractions was determined by measuring the diameter of 100 particles with an optical microscope. The particles were assumed to be spherical and a mean equivalent radius was calculated. The reaction takes place between the metal ions and the counter ions in the exchanger and the rates are controlled by particle diffusion mechanism only. Kinetics experiments were performed by using batch factor of V/m equals 100 ml g−1, and 5x10−3 M for cesium, cobalt , copper and cadmium chloride solution in a shaker thermostat adjusted at the desired temperatures. After the adjusted interval period, the solid

- 103 - RESULTS AND DISCUSSION W.M.EL-KENANY

was separated immediately from the solution and the extent of sorption was determined as follows:

%sorption = [(Ai − Af)/Ai] × 100

where Ai and Af are the initial and final concentrations of the metal ions in solution. The study of the effect of concentration on the rate of exchange of Cs+, Co2+, Cu2+ and Cd2+ ions on titanium vanadate at 25±1oC and 0.375 ±0.02 mm mish size showed at concentrations (5x10-3, 10-2 and 5x10-2 M). From the data presented in Figs.(27- 30), at the concentrations studied. The rate of exchange is independent of the metal ion concentration. So, this is the evident that the conditions set in this thesis are particle diffusion mechanism for all metal ions studied and the film diffusion can be excluded at this concentration condition 5x10-3 M (generally used in this work) [El-Naggar et al., 1992 ; El-Naggar and Aly., 1992]. Similar finding were obtained by [Shady et al., 2012] ,[El- Shorbagy and El-Sadek., 2012], El-Naggar et al., 2007-a; El- Naggar et al., 2007-b; [El-Naggar et al., 2010-b]; [Zakaria et al., 2004-b]; [Zakaria., 2005], ,[Jinasa et al., 2006]. The effect of particle diameters of titanium vanadate on the rate of exchange of Cs+, Co2+, Cu2+ and Cd2+ ions was studied and the data are given in Figs.(31-34) as relation between F and Bt against time. Figures (31-34) show that straight lines passing through the origin are obtained for Bt and t relations for Cs+, Co2+, Cu2+ and Cd2+ ions on titanium vanadate which is a further proof of a particle diffusion mechanism. The same trend was reported by others

- 104 - RESULTS AND DISCUSSION W.M.EL-KENANY

1.0

0.8

0.6

0.4

-2 0.2 5*10 -2 10 5*10-3

0.0 0 30 60 90 120 150 180 210 240 270 Time (min)

Fig. (27): Plots of F against time for exchange of Cs+ ion at different concentrations on titanium vanadate at 25±1oC.

- 105 - RESULTS AND DISCUSSION W.M.EL-KENANY

1.0

0.8

0.6

0.4

0.2 -2 5*10 10-2

5*10-3

0.0 0 30 60 90 120 150 180 210 240 270 Time (min)

Fig. (28): Plots of F against time for exchange of Co2+ ion at different concentrations on titanium vanadate at 25±1oC.

- 106 - RESULTS AND DISCUSSION W.M.EL-KENANY

1.0

0.8

0.6

0.4

5*10-2 0.2 10-2 -3 5*10

0.0 0 30 60 90 120 150 180 210 240 270 Time (min)

Fig(29): Plots of F against time for exchange of Cu2+ ion at different concentrations on titanium vanadate at 25±1oC.

- 107 - RESULTS AND DISCUSSION W.M.EL-KENANY

1.0

0.8

0.6 F

0.4

10-2 0.2 5*10-3 10-3

0.0 0 30 60 90 120 150 180 210 240 270 Time (min) Fig(30): Plots of F against time for exchange of Cd2+ ion at different concentrations on titanium vanadate at 25±1oC.

- 108 - RESULTS AND DISCUSSION W.M.EL-KENANY

1.0 4

F Bt

0.5 2

0.375mm 0.185mm 0.115mm

0.0 0 0 50 100 150 200 250 Time (min)

Fig. (31): Plots of F and Bt against time for exchange of Cs+ ion on titanium vanadate at different particle diameters at 25±1oC

- 109 - RESULTS AND DISCUSSION W.M.EL-KENANY

1.0

1.5 0.8

0.6 1.0

F Bt

0.4

0.5

0.2 0.375mm 0.185mm 0.115mm

0.0 0.0 0 50 100 150 200 250 Time (min)

Fig. (32): Plots of F and Bt against time for exchange of Cu2+ ion on titanium vanadate at different particle diameters at 25±1oC

- 110 - RESULTS AND DISCUSSION W.M.EL-KENANY

1.0 1.5

0.8

1.0 0.6 Bt F

0.4

0.5

0.2 0.375mm 0.185mm 0.115mm

0.0 0.0 0 50 100 150 200 250 Time (min)

Fig. (33): Plots of F and Bt against time for exchange of Co2+ ion on titanium vanadate at different particle diameters at 25±1oC

- 111 - RESULTS AND DISCUSSION W.M.EL-KENANY

0.8

1.5

0.6

F 1.0

Bt 0.4

0.5 0.2 0.375mm 0.185mm 0.115mm 0.0 0.0 0 50 100 150 200 250 Time (min)

Fig. (34): Plots of F and Bt against time for exchange of Cd2+ ion on titanium vanadate at different particle diameters at 25±1oC

- 112 - RESULTS AND DISCUSSION W.M.EL-KENANY

0.013 + Cs Cu2+ 0.012 2+ Co 2+ 0.011 Cd

0.010

0.009

0.008

0.007

0.006

0.005

0.004 0 2 4 6 8 10 12 14 16 18 20 2 -2 1/r x10

Fig. (35): Plots of B against 1/r2 for the exchange of Cs+, Co2+, Cu2+ and Cd2+ ions on titanium vanadate at 25±1oC.

- 113 - RESULTS AND DISCUSSION W.M.EL-KENANY

[Amphlett, 1964]; [AlO-thman et al., 2012]; [El-Naggar et al., 1999; El-Naggar et al., 2007-b; El-Naggar et al., 2010-b; Zakaria 2005; Abou-Mesalam and El-Naggar, 2003; Shady et al., 2006],[Mishra et al., 1996]. It is clear that the exchange of Cs+, Co2+, Cu2+ and Cd2+ ions on titanium vanadate increases with decreasing the particle size which is in agreement with the fundamental theory of particle diffusion mechanism as shown in Figs (29-32). This can also be taken as a further proof of particle diffusion mechanism [Vinter et al., 1970; Reichenberg, 1953; El- Naggar and Al-Absy, 1992; Abe, 1987]. From Figs. (29-32), the + 2+ 2+ average values of diffusion coefficients (Di) of Cs , Co , Cu and Cd2+on titanium vanadate of different particle diameters were calculated and given in Table (17). It is clear that, the diffusion coefficients calculated for larger particle sizes are slightly higher. This difference was also observed by others [Amphlett, 1964; Boyed, 1953], who assumed that large particles are formed from agglomerated small particle units, and, therefore, a quicker diffusion took place through the channels between these units [Amphlett, 1964]. Similar finding were obtained by [El-Naggar et al., 2007-a; El-Naggar et al., 2010-b]. A plots of B(the slopes of straight lines (Bt vs.t plots)) versus 1/r2 for the exchange of Cs+, Co2+, Cu2+ and Cd2+on titanium vanadate are given in Fig.(35). Straight lines are obtained for all the studied metal ions. Figure (35) shows that the reciprocal proportionality between the rate of exchange and square of particle size is considered as a further proof of a particle diffusion control. This result agrees with that reported by El-Naggar et al [Abou-Mesalam and El-Naggar, 2003; El-Naggar et al ., 2007-b ; El-Naggar and Aly, 1992 ; El- Naggar and Al-Absy, 1992; El-Naggar et al., 2011].

- 114 - RESULTS AND DISCUSSION W.M.EL-KENANY

Table (17): Values of the diffusion coefficient of Cs+, Co2+, Cu2+and Cd2+ ions on different particle diameters of titanium vanadate at 25±1 ◦C.

8 2 −1 Particle Di (×10 cm s ) diameters + 2+ 2+ 2+ (±0.02 mm) Cs Cd Co Cu 0.115 0.283 .0110 0.129 0.143

0.185 0.607 0.2671 0.292 0.308

0.375 1.992 1.007 1.053 1.122

Finally, we can conclude that to verify the particle diffusion mechanism of the metal ions Cs+, Co2+, Cu2+ and Cd2+on titanium vanadate exchanger under the conditions set in the present work, the following experimental results were obtained: (i) the rate of exchange of different metal ions on titanium antimonate is independent of metal concentrations in solutions up to 5x10−2 M (show Figs. (27-30), (ii) straight line relationships passing through the origin were obtained between the function Bt and t for the metal ions under study, (iii) the exchange rate of Cs+, Co2+, Cu2+ and Cd2+ were found to increase with the decrease in the particle size of the prepared titanium vanadate exchanger (show Figs. 31-34 and Table 17), and (iv) the plots of B the slopes of straight lines (Bt versus t plots) versus 1/r2 for Cs+, Co2+, Cu2+ and Cd2+on titanium vanadate gave straight lines (show Fig. 35). All these results provide a good base supporting the particle diffusion mechanism under our experimental conditions. Similar findings were previously reported [El-Naggar et al., 2007-a; El-Naggar et al.,

- 115 - RESULTS AND DISCUSSION W.M.EL-KENANY

2007-b; Varshney and Tayal, 2000; Khan et al., 2004; Khan et al., 2003; Mikhail et al., 1995; Mishra et al., 1996]. The effect of drying temperature of titanium vanadate (50, 200 and 400◦C) on the rate of exchange of the investigated metal ions was studied as a relation between F and Bt against time. The rate of exchange was found to decrease by increasing the drying temperature from 50 to 400◦C (show Figs. 36-39). It is clear that there is an appreciable decrease of self- diffusion coefficients of Cs+, Co2+, Cu2+, and Cd2+ with increasing the drying temperature of titanium vanadate from 50 to 400◦C as + 2+ shown in Table 18. The decrease in the Di values for, Cs , Co , Cu2+, and Cd2+ with the increase in the drying temperature of the ion exchanger from 50 to 400◦C may be attributed to the decrease in the surface area and porosity of the dried exchanger. The lower porosity means less free water inside the exchanger particles which hinders the diffusion of the metal ions [Misak and El-Naggar., 1989] ,[El-Naggar et al., 2011], [Shady et al., 2012], ,[El- Shorbagy and El-Sadek., 2012].

Table (18): Values of the diffusion coefficient of Cs+, Co2+, Cu2+, and Cd2+ on titanium vanadate dried at different drying temperatures at 25±1 ◦C.

8 2 −1 Drying Di (×10 cm s ) temperature Cs+ Cd2+ Co2+ Cu2+ (◦C) 50 1.99 1.007 1.05 1.12 200 1.78 0.896 0.934 1.007 400 1.52 0.722 0.822 0.882

- 116 - RESULTS AND DISCUSSION W.M.EL-KENANY

1.0

0.8

0.6 Bt F

0.4

o 0.2 50 C 200oC o 400 C 0.0 0 0 50 100 150 200 250 Time (min)

Fig. (36): Plots of F and Bt against time for exchange of Cs+ ion on titanium vanadate at different drying temperature at 25±1 oC.

- 117 - RESULTS AND DISCUSSION W.M.EL-KENANY

0.8

1.0

0.6

F Bt

0.4 0.5

0.2 o 50 C 200oC 400oC

0.0 0.0 0 50 100 150 200 250 Time (min)

Fig. (37): Plots of F and Bt against time for exchange of Cu2+ ion on titanium vanadate at different drying temperature at 25±1 oC.

- 118 - RESULTS AND DISCUSSION W.M.EL-KENANY

0.8

1.0

0.6

F Bt

0.4 0.5

0.2 50oC o 200 C 400oC 0.0 0.0 0 50 100 150 200 250 Time (min)

Fig. (38): Plots of F and Bt against time for exchange of Co2+ ion on titanium vanadate at different drying temperature at 25±1 oC.

- 119 - RESULTS AND DISCUSSION W.M.EL-KENANY

0.8

1.0

0.6

Bt F

0.4

0.5

0.2 o 50 C 200oC 400oC

0.0 0.0 0 50 100 150 200 250 Time (min)

Fig. (39): Plots of F and Bt against time for exchange of Cd2+ ion on titanium vanadate at different drying temperature at 25±1 oC.

- 120 - RESULTS AND DISCUSSION W.M.EL-KENANY

Similar findings were already reported for other ion exchange materials [Shady et al., 2012; El-Naggar et al., 2010-b]. The relations between Bt and F against time for the exchange of Cs+, Co2+, Cu2+ and Cd2+on titanium vanadate at 25, 45 and 60±1◦C were investigated and given in Figs.(40-43). These relations gave straight lines passing through the origin in all cases studied. Figures (40-43) also showed that, the rate of exchange reaction increased with increase in the reaction temperature from 25 to 60±1 ◦C [El-Naggar et al., 2011]. This trend is probably because of a higher diffusion rate of ions through the thermally enlarged interstitial positions of the ion exchange matrix [Khan and Khan., 2007] or may be due to the mobility of these ions increases with increasing the temperature [Patel and Chudasama., 2010],[Mathew and Tandon., 1975],. This agrees with the reported results for the rate of exchange of (Pb2+,Cd2+ and Zn2+) on acrylic acid-acrylonitrile potassium titanate [El-Shorbagy and El- Sadek., 2012], (Cu2+ and Zn2+) on polypyrrole/polyantimonic acid [Khan et al., 2004], (Cu2+ and Zn2+) on poly-o-toluidine Th(IV) phosphate [Khan and Khan, 2007], Mg (II), Ca (II), Sr (II) and Ba (II) on zirconium titanium phosphate [Jinasa et al .,2006], (Cd2+, Cu2+ ,Pb2+ and Zn2+) on nylon6,6 Zr(IV) phosphate composite [Al-Othman et al .,2012].,(Mg2+ ,Ca2+ ,Sr2+ and Ba2+ )on zirconium diethylene triamine pentamethylene phosphonate [Patel and Chudasama., 2010].

The diffusion coefficients values (Di) of the investigated metal ions were calculated from the slopes of the previous relations at 25, 45 and 60±1 ◦C using Eq. (32). The results are summarized in

- 121 - RESULTS AND DISCUSSION W.M.EL-KENANY

o 1.0 25 C o 45 C o 60 C 0.8

F Bt 0.6 2

0.4

0.2

0.0 0 0 50 100 150 200 250 Time (min)

Fig. (40): Plots of F and Bt against time for exchange of Cs+ ion on titanium vanadate at different reaction temperatures.

- 122 - RESULTS AND DISCUSSION W.M.EL-KENANY

1.0

o 25 C o 45 C o 0.8 60 C 1.5

0.6

F 1.0 Bt

0.4

0.5

0.2

0.0 0.0 0 50 100 150 200 250 Time(min) Fig. (41): Plots of F and Bt against time for exchange of Cu2+ ion on titanium vanadate at different reaction temperatures.

- 123 - RESULTS AND DISCUSSION W.M.EL-KENANY

1.0 25oC 1.5 45oC 0.8 60oC

0.6 1.0 Bt F

0.4

0.5

0.2

0.0 0.0 0 50 100 150 200 250 Time(min)

Fig. (42): Plots of F and Bt against time for exchange of Co2+ ion on titanium vanadate at different reaction temperatures.

- 124 - RESULTS AND DISCUSSION W.M.EL-KENANY

o 0.8 25 C 45oC 1.2 60oC

0.6

0.8 F Bt

0.4

0.4 0.2

0.0 0.0 0 50 100 150 200 250

Time(min)

Fig. (43): Plots of F and Bt against time for exchange of Cd2+ ion on titanium vanadate at different reaction temperatures.

- 125 - RESULTS AND DISCUSSION W.M.EL-KENANY

-7.5 + Cs 2+ Cu Co2+ -7.6 Cd2+

-7.7

Di Log -7.8

-7.9

-8.0

2.95 3.00 3.05 3.10 3.15 3.20 3.25 3.30 3.35 1/T x103

Fig. (44): Arrhenius plots for exchange of Cs+, Co2+, Cu2+ and Cd2+on titanium vanadate.

- 126 - RESULTS AND DISCUSSION W.M.EL-KENANY

Table (19). From this table it is clear that the values of diffusion coefficient of the investigated metal ions take the order

Cs+ > Cu2+ > Co2+ > Cd2+ This sequence is in accordance with the ionic radii of the exchanged ions which take the order (Cu2+= Co2+ < Cd2+). The ion with smaller ionic radius is easily exchanged and moves faster than + that the ion with greater ionic radius). The Di values of Cs is greater than the Di values of the other studied metal ions because the hydration energy of Cs+ is low as compared to the hydration energy of the other exchanging metal ions (show Table 19). The energy of activation (Ea) and the pre-exponential constant (Do) were determined by applying the Arrhenius equation:

(-Ea/RT) Di = Do exp (31)

where Ea is the activation energy, Do is a pre-exponential constant and R is the gas constant. The entropy of activation (ΔS*) can be

calculated from Do by substituting in the equation proposed by Barrer et al (Barrer et al., 1963):

2 (ΔS*/R) Do = 2.72 (KTd /h) exp (32)

Where K is the Boltzmann constant, T the absolute temperature, d the average distance between two successive positions in the process of diffusion which was taken as 0.5 mm and h is the Planck’s constant. The above equations were used for calculation of the values of Do, Di, Ea and ΔS* for the exchanged systems and the obtained results are given in Table (19).

- 127 - RESULTS AND DISCUSSION W.M.EL-KENANY

+ When log Di is plotted against 1/T for the exchange of Cs , Co2+, Cu2+ and Cd2+, on titanium vanadate, straight lines were obtained (Figure 44). From the slope of these lines and applying

Arrhenius equation, the energy of activation (Ea) and the pre- exponential constant (Do) were calculated. On the other hand, the entropy of activation (ΔS*) can be calculated from Do using Eq. (32).

It is of interest to compare the values of Di obtained for Cs+, Co2+, Cu2+ and Cd2+, on titanium vanadate with those previously reported using other ion exchangers. Thus, for strongly + acidic cationic styrene resin (001X7), Di for l-Tryptophan H exchange is calculated to be 6.43 × 10−9 cm2s-1 at concentration 6 g/ l [Xie et al., 2011 ]. For similar resin, on Dowex 50-8.6x, Di values for Rb+ and Cs+ ions were reported to be 13.8x10-7 and 13.7x10-7 cm2s-1, respectively. For a weakly cationic resin IRC-50, Conway et al. (Conway et al., 1957) reported the value 9x10-9 2 -1 + + cm s for Na /H exchange. For zeolites, the values of Di are much smaller and are found in the order 10-12 – 10-16 cm2s-1 (Groshkov et al., 1962). The values of Di obtained for Cs+, Co2+, and Cd2+on SnV is 5.16 x10-9 , 4.37 x10-9 ,4.68 x10-9 with [Shady et al., 2012] ,The Di values given by (Shady and El-Gammal., 2005) for Na+/H+and Cs+/H+ exchange system on titanium(IV) antimonate were 0.72 × 10-12 m2s-1 and 0.98 × 10-12m2s-1, respectively. The Di values given by [El-Naggar et al., 2007- a] for Cs+/H+, Co2+/H+, and Eu3+/H+ exchange system on SiTi were 4.03 × 10-7, 2.98 × 10-7, and 4.25× 10-7 cm2s-1, respectively. and zirconium silicate [El-Naggar et al., 2007-b] were 12.8x10-7 and 16x10-9 cm2 s−1 for Cs+/H+, 7.18x10-7 and 14.5x10-9 cm2 s−1 for Co2+/H+ and 11.5x10-7 and 10.2x10-9 for Eu3+/H+, respectively. For hydrous tin(IV) oxide [Qureshi and

- 128 - RESULTS AND DISCUSSION W.M.EL-KENANY

Ahmed., 1988] Also, the diffusion coefficient (Di) for Cs+/*Cs+ and Na+/*Na+ exchanges on hydrous zirconium oxide was found to be 6.7×10-9and 11.4x10-9cm2s-1 [Misak and El-Naggar., 1989]. −8 −9 −8 The Di values were found to be 2.63×10 , 2.6×10 , 3.23×10 and 2.82×10−8 cm2 s−1 for Cs+/H+, Na+/H+,Co2+/H+ and Sr2+/H+ exchanges on silico(IV)titanate [El-Naggar et al., 1998-a],

respectively. Furthermore, the Di values of all the metal ions exchanged on titanium vanadate take the order:

Cs+ > Cu+2 > Co2+ > Cd2+

Table (19): Values of the diffusion coefficient of Cs+ ,Co2+, Cu2+, and Cd2+ on titanium vanadate dried at 50oC at different reaction temperatures, relative errors about ±3% (Weast., 1974).

Exchange Ionic Hydration Reaction Di

system radii (A°) energy temperature (×108 cm2 s−1) (oK) 298 1.99 Cs+/H+ 1.67 263 318 2.68 333 3.33 298 1.007 Cd2+/H+ 0.97 1806 318 1.15 338 1.27 298 1.12 Cu2+/H+ 0.72 2100 318 1.43 338 1.68 298 1.05 Co2+/H+ 0.72 2054 318 1.31 338 1.49

- 129 - RESULTS AND DISCUSSION W.M.EL-KENANY

The activation energy of cations diffusion process (show Table 20) reflects the ease with which cations can pass through the exchanger particles. The activation energy for the investigated metal ions (heating at 50 ◦C) has the order:

Cs+/H+ (13.37) > Cu2+/H+ (10.57) > Co2+/H+ (9.17) > Cd2+/H+ (6.19)

This sequence of Ea of the studied metal ions is in accordance with the ionic radii of the exchanged ions which take the order (Cu2+< Co2+ < Cd2+). The ion with smaller ionic radius is easily exchanged and moves faster than that the ion with greater ionic + radius). The Ea values of Cs and is greater than the Ea values of the other studied metal ions because the hydration energy of Cs+ is very low as compared to the hydration energy of the other exchanging metal ions. The relatively small activation energies + 2+ 2+ 2+ values Ea obtained, Table (20), for Cs , Co , Cu and Cd on titanium vanadate, indicated that the rate of exchange is particle diffusion [El-Baouti et al 1996], [El-Naggar et al., 1992],[Al- Othman et al., 2011,2012]. In other words, these values of activation energy are relatively small as compared to those reported for other organic and inorganic exchangers which confirm the particle diffusion mechanism. Table (21) shows the activation energies values (Ea) for the studied metal ions as compared to the other ion exchange materials. The negative ΔS* values obtained for all systems studied are given in Table (20). The entropy change normally depends on the extent of hydration of the exchangeable and exchanging ions a long with any change in water structure around ions that may occur when they pass through the channels of exchanger particles.

- 130 - RESULTS AND DISCUSSION W.M.EL-KENANY

Table (20): Thermodynamic parameters for the diffusion of Cs+, Co2+, Cu2+ and Cd2+on titanium vanadate dried at 50oC at different reaction temperatures, relative errors about ±3% (Weast., 1974).

8 2 −1 2 −1 Exchange Reaction Di (×10 cm s ) Do (cm s ) −1 * Ionic radii (A°) Hydration temperature Ea (kJ mol ) Δs system energy (oK) (J mol−1 K−1)

298 -70.40 -3 Cs+/H+ 1.67 1.99 4.98 x10 263 318 13.37 -73.89 2.68 3.07 x10-3 333 -76.07 3.33 2.25 x10-3 298 3.20 x10 -6 -131.53 Cd2+/H+ 0.97 1.007 1806 6.19 318 2.56 x10-6 -132.85 1.15 333 1.27 2.22 x10-6 -133.66 298 2.08 x10-4. -96.83 2+ + 1.12 Cu /H 0.72 318 1.43 x10-4 10.57 -99.39 2100 1.43 333 1.11 x10-4 -101.12 1.68 298 5.30 x10-5 -108.19 2+ + 1.05 Co /H 0.72 318 3.88 x10-5 9.17 -110.23 2054 1.31 333 3.07 x10-5 -111.80 1.49

- 131 - RESULTS AND DISCUSSION W.M.EL-KENANY

Table (21): Comparison of activation energy values of Co2+, Cu2+, Cd2+ and Cs+ ions for various ion exchangers. −1 Inorganic ion exchanger Ea (kJ mol ) References Cs+ Cd2+ Cu2+ Co2+ Titanium vanadate (a) 13.37 6.19 10.57 9.17 Tin vanadate 3.39 4.91 - 3.98 [Shady et al., 2012] polyaniline Ce(IV) 123.05 88.12 - [Al-Othman et al., 2012] molybdate Cerium(IV) tungstate - - - 20.85 [El-Kamash et al., 2007] nylon 6,6 Zr(IV) phosphate - 85.36 8.47 90.99 [Al-Othman et al., 2011] TiK vanadate 6.31 3.5 - 3.16 [El-Shorbagy et al., 2012] Polyaniline Sn(IV) - - 15.73 - [Khan et al., 2003] tungstoarsenate Silico(IV)titanate 11.87 - - 12.90 [El-Naggar et al., 2007-a] Zirconium silicate 15.4 - - 13.6 [El-Naggar et al., 2007-b] Polypyrrole/polyantimonic acid - - 9.23 - [Khan et al., 2004] Polyacrylamide Sn(IV) 26.080- 17.736 10.774 10.327 [El-Naggar et al., 2011] molybdophosphate Antimonic acid - 14.6 - - [El-Naggar et al., 2010-b] acrylic acid-acrylonitrile K- - 11.6 - [El-Shorbagy and El-Sadek.,2012] titanate Zirconium molybdate - - - - [Shady et al., 2006] Tin(IV) antimonate - - - 19.15 [El-Naggar et al., 1994] Crystalline sodium titanate 8.58 [Zakaria et al., 2004-b] Amorphous sodium titanate 10.21 [Zakaria et al., 2004-b] (a): the material under study

- 132 - RESULTS AND DISCUSSION W.M.EL-KENANY

The negative values obtained for the entropy of activation suggest that no significant structural change occurs in titanium vanadate. Also the lower values of ΔS* for Cs+, Co2+, Cu2+ and Cd2+ on titanium vanadate support the higher stability and hence the less steric difference of the system. These results are parallel to those reported for other ion exchangers [El-Kamash et al., 2007; Niwas et al., 1999; Patel and Chudasama, 2010 , El-Shorbagy et al 2012 , El-Shorbagy and El-Sadek., 2012].

Thus, from the above results and the negative values of ΔS* reported in Table (20), it is anticipated that the Cs+, Co2+, Cu2+, and, Cd2+ ions exchange with H+ into the exchanger is in the unhydrated form.

- 133 - RESULTS AND DISCUSSION W.M.EL-KENANY

3.5. Sorption Isotherms

Sorption equilibrium is usually described by an isotherm equation whose parameters express the surface properties and affinity of the sorbent, at a fixed temperature and pH. An adsorption isotherm describes the relationship between the amount of adsorbate on the adsorbent and the concentration of dissolved adsorbate in the liquid at equilibrium [Peric et al .,2004], Nilchi et al .,2011]. The Langmuir, Freundlich , Dubinin–Radushkevich (D– R), and Temkin isotherms are common kinds of several isotherm equations that were tested to fit the obtained sorption data.

3.5.1. Langmuir isotherm

The Langmuir adsorption model assumes that molecules are adsorbed at a fixed number of well-defined sites, each of which can only hold one molecule and no trans- migration of adsorbate in the plane of the surface. These sites are also assumed to be energetically equivalent and distant to each other, so that there are no interactions between molecules adsorbed to adjacent sites [ Unlü, and Ersoz., 2006] [Hameed et al., 2007]. The linear form of the Langmuir isotherm is represented by the following equation [Langmuir., 1918; Altin et al., 1998]

- 134 - RESULTS AND DISCUSSION W.M.EL-KENANY

Ce Ce 1 = + (17) qe Q bQ

Where Q(mmol/g) is the maximum adsorption at monolayer, Ce (mmol/L) is the equilibrium concentration of metal ions, qe (mmol/g) is the adsorption amount of metal ions per unit weight of adsorbent at equilibrium, and b (L/mmol) is the Langmuir constant related to the affinity of binding sites, which is a measure of the energy of adsorption. With the slope and intercept of the linearized plot of Ce/qe versus

Ce, and b can be calculated .

The results fit quite well the linear form of Langmuir adsorption isotherm over the entire range of Cs+ Co2+, Cu2+ and Cd2+ on titanium vanadate and vanadium antimonate in the concentration range from 5x10-4 to 5x10 M-2 at different reaction o temperatures (25, 45 and 60±1 C), when Ce/qe is plotted against Ce , a straight line with slope 1/Q and intercept 1/bQ is obtained (Figs. which shows that the adsorption of the studied metal ions ,(4٥-5٢ on titanium vanadate and vanadium antimonate follows Langmuir isotherm model and these results agreed with adsorption of uranium on zeolites A and P (Hossein et al., 2008) , adsorption of Cu2+ ,Zn2+ and Cd2+ on Amberlite (IR-120) (Lee et al., 2007) , Removal of Ca(II) and Mg(II) using amberlite (IRC748) (Yu et al., 2009), removal of Ni(II) using sodium iron titanate and Iron-doped sodium nonatitanate (Akieh et al .,2008)

-٤٥ .From the slope of the linear plots of Ce/qe vs. Ce, (Figs the value of Q, the saturation capacity of titanium vanadate , (٥٢ and vanadium antimonate for Cs+, Co2+, Cu2+, and Cd2+ ions at the investigated temperatures (25, 45 and 60 ±1oC, respectively) . The

- 135 - RESULTS AND DISCUSSION W.M.EL-KENANY

Langmuir constants Q and b with temperature are calculated and summarized in Table (22,23). Table (22,23) shows that the capacity of sorption Q is increased at higher temperatures. This increase in sorption capacity with temperature may be attributed to the active surfaces available for sorption have increased with temperature [Abd El-Rahman et al., 2006], and this increase in sorption capacity with temperature for all studied adsorption isotherms models (Table 22,23) and also because of increasing kinetics energy of the sorbent metal ions, which increases the frequency of collisions between the adsorbent and metal ions and thus enhances adsorption of metals on the surface of the adsorbent [Argun et al., 2007]. The observed increase in the Q sorption capacity in Tables 22 and 23 indicates the endothermic nature of the adsorption process [Anirudhan and Suchithra., 2010], [El-Naggar et al., 2012].

The essential characteristics of the Langmuir equation can be expressed in terms of a dimensionless constant called equilibrium parameter or separation factor, RL, [Weber and Chakkravorti, 1974] which can be calculated by the following equation defined as: (Hall et al., 1966).

RL= 1/ (1+bCo) (33) -2 Where Co is the highest initial solute concentration (5*10 ' M), b is the Langmuirs adsorption constant (L/mg). The RL value implies the adsorption to be unfavorable (RL > 1), linear (RL = 1), favorable (0 < RL<1) or irreversible (RL = 0) [Mohan and Chander., 2006],[Sari et al., 2009],[Wang et al., 2007]. The values of RL for the studied elements are summarized in Tables

(22,23) and were found to be 0 < RL<1 confirmed that the prepared

- 136 - RESULTS AND DISCUSSION W.M.EL-KENANY

titanium vanadate and vanadium antimonate is favorable for adsorption Co2+, Cu2+, , Cd2+, Cs+, + under condition used in this study [Hameed et al., 2007]. The very low, separation factor values RL indicate that the metal ions preferred to remain bound to the sorbent surface (Sharma and Neetu., 2011).The values of RL in the case of Fe(III) and Hg(II) sorption onto ZrSbW-III is (0.013,

Sharma and Neetu., 2011). The value of RL was found to) (٠.٠٥٧ 2+ be 0.598 (0 < RL<1) in case of the adsorption of Cu on purolite C100-MB [Hamdaoui., 2009] and it was found to be 0.111, 0.04 in case of the adsorption of Cs+ and Sr2+ on zeolite, respectively [El-

Kamash., 2008], RL values for adsorption of of As (III) , As(V) on laterite soil was 0.843 and 0.039 respectively (Maji et al., 2007-a) and these results agree with our finding. Conformation of the experimental data with Langmuir isotherm indicate the monolayer coverage of sorption surfaces and assumes that sorption occurs on a structurally homogeneous adsorbent and all sorption sites are energetically identical. From the above discussion all the studied elements (Co2+, Cu2+, Cd2+and Cs+) are chemically adsorbed.

- 137 - RESULTS AND DISCUSSION W.M.EL-KENANY

0.035

0.030

o 25 C o 0.025 45 C o 60 C

0.020

e /q e 0.015 C

0.010

0.005

0.000

0.00 0.01 0.02 0.03 0.04 0.05 C e

+Langmuir adsorption isotherm for adsorption of Cs :(Fig. (4٥ ion on titanium vanadate at different reaction temperatures.

- 138 - RESULTS AND DISCUSSION W.M.EL-KENANY

0.20

o 25 C 45oC 0.15 o 60 C

0.10

e /q e C

0.05

0.00

0.00 0.01 0.02 0.03 0.04 0.05 C e

Langmuir adsorption isotherm for adsorption of Cu2+ :(Fig. (4٦ ion on titanium vanadate at different reaction temperatures.

- 139 - RESULTS AND DISCUSSION W.M.EL-KENANY

0.5

25oC o 0.4 45 C

o 60 C

0.3

e /q e 0.2 C

0.1

0.0

0.00 0.01 0.02 0.03 0.04 0.05

C e

Langmuir adsorption isotherm for adsorption of Co2+ :(Fig. (4٧ ion on titanium vanadate at different reaction temperatures.

- 140 - RESULTS AND DISCUSSION W.M.EL-KENANY

0.6 o 25 C 45oC 0.5 o 60 C

0.4

e 0.3 /q e C 0.2

0.1

0.0

0.00 0.01 0.02 0.03 0.04 0.05

Langmuir adsorption isotherm for adsorption of Cd2+ :(Fig. (4٨ ion on titanium vanadate at different reaction temperatures.

- 141 - RESULTS AND DISCUSSION W.M.EL-KENANY

0.10

0.08 o 25 C 45oC o 60 C 0.06

e /q e 0.04 C

0.02

0.00

0.00 0.01 0.02 0.03 0.04 0.05

C e

+Langmuir adsorption isotherm for adsorption of Cs :(Fig. (4٩ ion on vanadium antimonate at different reaction temperatures.

- 142 - RESULTS AND DISCUSSION W.M.EL-KENANY

0.07

0.06 o 25 C 45oC 0.05 60oC

0.04

e /q e 0.03 C

0.02

0.01

0.00

0.00 0.01 0.02 0.03 0.04 0.05

C e

Langmuir adsorption isotherm for adsorption of :(٥٠) .Fig Cu2+ ion on vanadium antimonate at different reaction temperatures.

- 143 - RESULTS AND DISCUSSION W.M.EL-KENANY

0.08

0.07 25oC 0.06 45oC o 60 C 0.05

0.04

e /q e C 0.03

0.02

0.01

0.00

-0.01 0.00 0.01 0.02 0.03 0.04 0.05 C e Langmuir adsorption isotherm for adsorption of Co2+ :(٥١) .Fig ion on vanadium antimonate at different reaction temperatures.

- 144 - RESULTS AND DISCUSSION W.M.EL-KENANY

0.30

25oC 0.25 45oC o 60 C 0.20

0.15 e /q e

0.10

0.05

0.00

0.00 0.01 0.02 0.03 0.04 0.05 C e Langmuir adsorption isotherm for adsorption of Cd2+ :(Fig. (5٢ ion on vanadium antimonate at different reaction temperatures.

- 145 - RESULTS AND DISCUSSION W.M.EL-KENANY

Table (22): Langmuir isotherm parameter for the sorption of Cs+, Co2+,Cu2+ and Cd2+on titanium vanadate at different reaction temperatures.

Langmuir isotherm dimensionless Reaction Q (saturation b (L/mol) Cation R2 separation factor, temperature capacity) o R ( K) (meq/g) L

298 1.43 780.89 0.99949 0.024972

Cs+ 318 2.01 729.48 0.9993 0.026685

333 2.49 1042.83 0.99954 0.018818

298 0.23 988.8241 0.99959 0.019825

Cu2+ 318 0.38 712.7833 0.99894 0.027293

333 0.66 540.8208 0.99716 0.035662

298 0.115219 3999.581 0.99924 0.004976

Co2+ 318 0.159817 5128.828 0.99945 0.003884

333 0.240603 16338.41 0.99951 0.001223

298 0.090325 908.2182 0.9998 0.021547 Cd2+ 318 0.125782 970.7289 0.99919 0.020187 333 0.160045 897.7371 0.99888 0.021793

- 146 - RESULTS AND DISCUSSION W.M.EL-KENANY

Table (23): Langmuir isotherm parameter for the sorption of Cs+, Co2+, Cu2+ and Cd2+on vanadium antimonate at different reaction temperatures.

Langmuir isotherm

dimensionless Reaction Q b Cation R2 separation temperature (saturation (L/mol) o factor, ( K) capacity) (meq/g) RL

298 0.559466 1314.279 0.9995 0.014989

318 0.99984 Cs+ 0.706839 2571.567 0.007717 333 0.89958 2138.083 0.99993 0.009267 298 0.721142 0.99825 654.0991 0.029669 Cu2+ 318 0.874669 0.99824 714.5563 0.027227 333 1.261655 0.99738 471.7917 0.030592 298 0.660471 1469.971 0.99985 0.013423 318 0.99997 Co2+ 0.852813 1856.245 0.01066 333 0.99979

1.228713 1330.722 0.014807 298 0.200902 3318.373 0.99964 0.005991 2+ Cd 318 0.316316 3439.325 0.99982 0.005781 333 0.401999 5154.998 0.99991

0.003865

- 147 - RESULTS AND DISCUSSION W.M.EL-KENANY

3.5.2. Freundlich isotherm

The Freundlich isotherm [Freundlich, 1906] is the earlist known relationship describing the sorption equation. This isotherm valid for physical adsorption and usually for an adsorbent with very heterogeneous surface [Benes and Majer, 1980] and is expressed by the following equation:

1/n qe = KfCe (34)

The equation may be linerized by taking the logarithm of both sides:

log qe = log Kf + 1/n log Ce (18)

where where Kf is related to adsorption capacity and n is related to intensity of adsorption. The Freundlich isotherm described as a fairly satisfactory empirical isotherm used for non-ideal adsorption is related to heterogeneous process as well as multilayer adsorption.

The constants Kf and n of the Freundlich model are, respectively, obtained from the intercept and the slope of the linear plot of log qe versus log Ce according to Eq. (4). The constant Kf can be defined as an adsorption coefficient which represents the quantity of adsorbed metal ion for a unit equilibrium concentration (i.e.,Ce =

1). Higher values of Kf indicate higher affinity for metal ions.The slope 1/ n is a measure of the adsorption intensity or surface heterogeneity [Gopal et al., 2007] ,[Chabani et al., 2006]. Figures show a straight line with a slope of 1/n and an intercept of (٦٠-5٣) log Kf when log qe is plotted against log Ce. The corresponding

- 148 - RESULTS AND DISCUSSION W.M.EL-KENANY

0.4

25oC 0.2 45oC o 60 C 0.0

e -0.2

q Log

-0.4

-0.6

-0.8

-5.0 -4.5 -4.0 -3.5 -3.0 -2.5 -2.0 -1.5 -1.0 Log Ce

+Freundlich adsorption isotherm for adsorption of Cs :(Fig. (5٣ ion on titanium vanadate at different reaction temperatures.

- 149 - RESULTS AND DISCUSSION W.M.EL-KENANY

o 25 C o 45 C 60oC

-0.5

q Log

-1.0

-5.5 -5.0 -4.5 -4.0 -3.5 -3.0 -2.5 -2.0 -1.5 -1.0

Log C e

Freundlich adsorption isotherm for adsorption of :(Fig. (5٤ Cu2+ ion on titanium vanadate at different reaction temperatures.

- 150 - RESULTS AND DISCUSSION W.M.EL-KENANY

-0.5

o -0.6 25 C 45oC

-0.7 o 60 C

-0.8

-0.9

e -1.0

q Log

-1.1

-1.2

-1.3

-1.4

-5.0 -4.5 -4.0 -3.5 -3.0 -2.5 -2.0 -1.5 -1.0

Log Ce

Freundlich adsorption isotherm for adsorption of :(Fig. (5٥ Co2+ ion on titanium vanadate at different reaction temperatures.

- 151 - RESULTS AND DISCUSSION W.M.EL-KENANY

-0.5 25oC o 45 C

o 60 C

e -1.0

Log q Log

-1.5

-4.0 -3.5 -3.0 -2.5 -2.0 -1.5 -1.0 Log C e

Freundlich adsorption isotherm for adsorption of :(Fig. (5٦ Cd2+ ion on titanium vanadate at different reaction temperatures.

- 152 - RESULTS AND DISCUSSION W.M.EL-KENANY

0.0

-0.2 25oC

45oC

60oC -0.4

-0.6 Log q Log

-0.8

-1.0

-1.2 -5.0 -4.5 -4.0 -3.5 -3.0 -2.5 -2.0 -1.5 -1.0 log C e +Freundlich adsorption isotherm for adsorption of Cs :(Fig. (5٧ ion on vanadium antimonate at different reaction temperatures.

- 153 - RESULTS AND DISCUSSION W.M.EL-KENANY

0.2

o 25 C 0.0 o 45 C o -0.2 60 C

-0.4

-0.6

-0.8 Log q Log

-1.0

-1.2

-1.4

-1.6 -5.5 -5.0 -4.5 -4.0 -3.5 -3.0 -2.5 -2.0 -1.5 -1.0

Log C e

Freundlich adsorption isotherm for adsorption of :(Fig. (5٨ Cu2+ ion on vanadium antimonate at different reaction temperatures.

- 154 - RESULTS AND DISCUSSION W.M.EL-KENANY

0.2

0.0

25OC O -0.2 45 C

60OC

e -0.4

q Log -0.6

-0.8

-1.0

-1.2 -5.0 -4.5 -4.0 -3.5 -3.0 -2.5 -2.0 -1.5 -1.0 Log C Freundlich adsorption isotherm for adsorption of :(Fig. (5٩ Co2+ ion on vanadium antimonate at different reaction temperatures.

- 155 - RESULTS AND DISCUSSION W.M.EL-KENANY

-0.3

-0.4 25oC -0.5 45oC 60oC -0.6

-0.7 e

-0.8 q Log

-0.9

-1.0

-1.1

-1.2 -4.5 -4.0 -3.5 -3.0 -2.5 -2.0 -1.5 -1.0

Log Ce

Freundlich adsorption isotherm for adsorption of :(٦٠) .Fig Cd2+ ion on vanadium antimonate at different reaction temperatures.

- 156 - RESULTS AND DISCUSSION W.M.EL-KENANY

Freundlich isotherm constants Kf and 1/n together with the correlation coefficients (R) are also listed in Table (24,25). Values of Kf derived from the Freundlich equation are an indicator of the adsorption capacity. The adsorption capacities towards Cs+, Co2+, Cu2+ and Cd2+, ions on titanium vanadate and vanadium antimonate , increased with increasing temperatures. The slope 1/n ranging between 0 and 1 is a measure of adsorption intensity or surface heterogeneity, becoming more heterogeneous as its value gets closer to zero [Gregory et al., 2005,. Hussain et al., 2006] .The numerical values of 1/n for the studied metal ions were found to be less than the one (1/n ˂ 1) (Table 24,25). According to the statistical theory of adsorption [Clark., 1970], when the value of 1/n in the adsorption isotherm is less than unity, it implies heterogeneous surface structure with minimum interaction between the adsorbed atoms [Abou-Mesalam et al., 2003], so in this study the value of 1/n for the studied metal ions is less than one (1/n ˂ 1), it implies heterogeneous surface structure and favorable Freundlich adsorption processes [Saltalı et al .,2007],[ Karadag et al., 2006].

- 157 - RESULTS AND DISCUSSION W.M.EL-KENANY

Table (24): Freundlich isotherm parameter for the sorption of Cs+, Co2+, Cu2+ and Cd2+ on titanium vanadate at different reaction temperatures.

Freundlich isotherm

Reaction 1/n Kf 2 Cation R temperature o (mol/g) ( K) (L/mol)1/n

298 0.31726 4.65 0.97162

318 0.35066 7.43 0.97568 Cs+ 333 0.34594 9.54 0.97191 298 0.2759 0.65 0.97263

Cu2+ 318 0.32103 1.23 0.98396 333 0.32988 1.95 0.9811502 298 0.18701 0.279 0. 84325 318 0.22098 0.447 0.88294 Co2+ 333 0.24349 0.703 0.93154

298 0.24004 0.213 0.965579

Cd2+ 318 0.27006 0.405 0.89704

333 0.274180 0.573 0.87059

- 158 - RESULTS AND DISCUSSION W.M.EL-KENANY

Table (25): Freundlich isotherm parameter for the sorption of Cs+, Co2+, Cu2+ and Cd2+ on vanadium antimonate at different reaction temperatures.

Freundlich isotherm

Cation Reaction temperature 1/n Kf 2 o R ( K) (mol/g)

(L/mol)1/n

298 0.3082 1.92 0.92646

+ 318 0.33179 2.90 0.93122 Cs 333 0.34319 3.85 0.93831 298 0.38355 2.96 0.97857

Cu2+ 318 0.3746 3.45 0.9847

333 0.2823 4.30 0.94012 298 0.31546 2.364 0.94333 318 0.33588 3.444 0.95095 Co2+ 333 0.36051 5.325 0.96061

298 0.18733 0.437 0.87266

Cd2+ 318 0.23823 0.829 0.8846 333 0.2682 1.28 0.90285

- 159 - RESULTS AND DISCUSSION W.M.EL-KENANY

3.5.3.Dubinin–Radushkevich (D–R) isotherm Another popular isotherm model, which is more general than the Langmuir and Freundlich models, is Dubinin–Radushkevich (D–R) isotherm. The Dubinin- Radushkevich (D-R) isotherm is more general than the Langmuir isotherm because it does not assume a homogenous surface or constant adsorption potential. It was applied to distinguish between the physical and chemical adsorption. The linear forms of D– R isotherm can be expressed as follows [Metwally et al .,2008].

/ 2 ln qe = lnqm − K ε (19)

The regression parameters and correlation coefficients (R2) presented in Table (26,27), Figs. (61-68) indicate that the adsorption data best fitted the Langmuir adsorption isotherm for the studied metal ions Figures (61-68) show a straight line with a slope of K/ and an 2 intercept of ln qm when ln qe is plotted against ε . The regression parameters and correlation coefficients (R2) are also listed in Table

(26,27). Values of qm derived from the Dubinin-Radushkevich equation are an indicator of the adsorption capacity. The adsorption capacities towards Cs+, Co2+, Cu2+ and Cd2+ ions on titanium vanadate and vanadium antimonate increased with increasing temperatures. The correlation coefficient R2 represented from Langmuir isotherm for the studied metal ions is greater than the correlation coefficient R2 represented from Freundlich adsorption isotherm and Dubinin-Radushkevich (D-R) isotherm (Table 26,27), and this result confirmed that the adsorption of the studied metal ions (Cs+,

- 160 - RESULTS AND DISCUSSION W.M.EL-KENANY

Co2+, Cu2+ and Cd2+ ions) on titanium vanadate and vanadium antimonate is favorable for the Langmuir isotherm more than Freundlich isotherm and Dubinin-Radushkevich (D-R) isotherm. The mean sorption energy E (kJ/mol), defined as the free energy change when one mole of ion is transferred to the surface of the solid from infinity in the solution, is calculated according to the following equation The mean adsorption energy (E, kJ mol-1) can be obtained from the K/ values of the D-R isotherm [Nilchi et al., 2011] using the following equation:

E =1/√2 K/ (35)

It is known that the magnitude of E can be used to estimate the type of adsorption .If this values is in the range of 8-16 kJ mol-1 ,the adsorption type can be explained by chemical ion exchange and if E ˂ 8 then the adsorption type is physisorption [ Bhakat et al., 2006], [Maity et al., 2005].(Shah et al., 2009) and above 40 kJ mol-1 showing chemisorption mechanism (Ozacar., 2008),(Abasi et al., 2011). From Table (26,27) the adsorption energies were between 8 and 16 kJmol-1, suggestion that the sorption process was dominated by ion-exchange (i.e. chemical ion exchange reaction) [Argun et al., 2007] at all studied temperatures and this result confirmed that the adsorption of the studied metal ions (Cs+,Co2+, Cu2+ and Cd2+ ions) on titanium vanadate and vanadium antimonate is favorable for the Langmuir isotherm more than the other adsorption modules (Freundlich isotherm and D-R isotherm).The value of E is 12.9 kJ /mol for adsorption 2,4,6 trichlorophenol onto microporous ZnCl2 activated coir pith carbon (Subha and Namasivayam.,2008), The value of E was found to be 11.4 kJmol-

- 161 - RESULTS AND DISCUSSION W.M.EL-KENANY

1 and 12.5 kJmol-1 for Cs+ and Sr2+ ions sorbed on zeolite, respectively [El-Kamash., 2008] and also E = 9.7 kJ mol -1 for the adsorption of Sr2+ on rice-straw based carbons [Yakout and El-Sherif., 2010]

- 162 - RESULTS AND DISCUSSION W.M.EL-KENANY

1.0 o 25 C 45oC 0.5 60oC

0.0

ln q ln -0.5

-1.0

-1.5

-2.0 0 1 2 3 4 5 6 7 8 9 x 108 ε٢ Linearized D-R isotherms for adsorption of Cs+ ion :(٦١) .Fig on titanium vanadate at different reaction temperatures.

- 163 - RESULTS AND DISCUSSION W.M.EL-KENANY

-0.5 25oC o 45 C -1.0 60oC

-1.5

ln q ln -2.0

-2.5

-3.0

0 1 2 3 4 5 6 7 8 9 10 11 2 8 ε x10

Fig. (62): Linearized D-R isotherms for adsorption of Cu2+ ion on titanium vanadate at different reaction temperatures.

- 164 - RESULTS AND DISCUSSION W.M.EL-KENANY

-1.5 o 25 C 45oC

60oC

-2.0

ln q ln

-2.5

-3.0

0 1 2 3 4 5 6 7 8 9 8 x 10 ٢ ε Fig. (63): Linearized D-R isotherms for adsorption of Co2+ ion on titanium vanadate at different reaction temperatures.

- 165 - RESULTS AND DISCUSSION W.M.EL-KENANY

-1.0 o 25 C 45oC 60oC -1.5

-2.0

ln q ln

-2.5

-3.0

-3.5

1 2 3 4 5 6 8 x10 ٢ ε

Fig. (64): Linearized D-R isotherms for adsorption of Cd2+ ion on titanium vanadate at different reaction temperatures.

- 166 - RESULTS AND DISCUSSION W.M.EL-KENANY

0.0 25oC o 45 C

o 60 C -0.5

-1.0

ln q ln -1.5

-2.0

-2.5

0 1 2 3 4 5 6 7 8 9 8 x 10 ٢ ε

Fig. (65): Linearized D-R isotherms for adsorption of Cs+ ion on vanadium antimonate at different reaction temperatures

- 167 - RESULTS AND DISCUSSION W.M.EL-KENANY

0 25oC o 45 C 60oC

-1

ln q ln

-2

-3

0 2 4 6 8 10 12

8 ٢ ε x10 Fig. (66): Linearized D-R isotherms for adsorption of Cu2+ ion on vanadium antimonate at different reaction temperatures

- 168 - RESULTS AND DISCUSSION W.M.EL-KENANY

0.5

25oC 0.0 o 45 C

o 60 C -0.5

-1.0

ln q ln

-1.5

-2.0

-2.5

0 1 2 3 4 5 6 7 8 9 8 ٢ ε x10

Fig. (67): Linearized D-R isotherms for adsorption of Co2+ ion on vanadium antimonate at different reaction temperatures

- 169 - RESULTS AND DISCUSSION W.M.EL-KENANY

25oC

o -1.0 45 C 60oC

-1.5

ln q ln

-2.0

-2.5

0 1 2 3 4 5 6 7 8 ٢ ε x 10 Fig. (68): Linearized D-R isotherms for adsorption of Cd2+ ion on vanadium antimonate at different reaction temperatures

- 170 - RESULTS AND DISCUSSION W.M.EL-KENANY

Table (26): D-R isotherm parameter for the sorption of Cs+, Co2+, Cu2+ and Cd2+on titanium vanadate at different reaction temperatures.

D-R isotherm

q K/ (mol2 E R2 Cation Reaction m kJ-2) (KJmol- temperature 1 (meq/g) ) (K) 9 *10

298 1.93 4.04742 11.114 0.99718

Cs+ 318 2.75 3.81763 11.444 0.99853

333 3.46 3.26989 12.365 0.99795 298 0.309 3.59426 11.794 0.99373

Cu2+ 318 0.493 3.45062 12.037 0.99332 333 0.67 2.81495 13.327 0.9922 298 0.176 2.62382 11.271 0.90658

Co2+ 318 0.253 2.60048 13.866 0.93764 333 0.353 2.36386 14.543 0.96515 298 0.118 3.48718 11.974 0.9918

Cd2+ 318 0.210 3.45606 12.028 0.94886 333 0.293 3.1234 12.65 0.93025

- 171 - RESULTS AND DISCUSSION W.M.EL-KENANY

,+D-R isotherm parameter for the sorption of Cs :(Table (2٧ Co2+, Cu2+ and Cd2+on vanadium antimonate at different reaction temperatures.

D-R isotherm

q K/ E R2 Cation Reaction m (mol2 kJ-2) (KJmol1) temperature (meq/g) (K) *109

298 0.856 4.08392 11.09 0.96364

Cs+ 318 1.148 3.66162 11.68 0.96403

333 1.467 3.37737 12.16 0.97091 298 0.95 4.51979 10.52 0.99024

Cu2+ 318 1.07 3.63265 11.73 0.98818 333 1.31 3.08378 12.73 0.98216 298 1.007 4.05017 11.11 0.97683

Co2+ 318 1.358 3.67186 11.66 0.98431 333 1.899 3.46167 12.10 0.98989 298 0.276 2.68167 13.654 0.92328

Cd2+ 318 0.459 2.93922 13.042 0.93659 333 0.646 2.91909 13.087 0.95183

- 172 - RESULTS AND DISCUSSION W.M.EL-KENANY

3.5.4.Temkin isotherm

The Temkin model considered the effects of some indirect adsorbate / adsorbate interactions on adsorption isotherm (Hameed and Rahman .,2008). it assumes that decrease in adsorption energy is linear with the coverage of adsorbate /adsorbent interaction. The linear form of temkin isotherm is written as follows (Salarirad and Behnamfard .,2011):

qe = qm lnKo + qm ln Ce ( 36)

qm = RT/b

Where qe is the mount of metal ion adsorbed per of specific amount adsorbent (meql/g), Ce is equilibrium concentration (mg/L), b is related to heat of adsorption (kJ/mol) , R is the universal gas constant , T is the absolute temperatures (K), b , KT are temkin constants which can be determined from the slope and intercept of linear relation between qe and ln Ce is equilibrium concentration.

From our results the relationship between qe and ln Ce gives straight line relationship for Cs+,Cu2+ ,Co2+ and Cd2+ on titanium vanadate and vanadium antimonate which are presented in figures(69-76) with high R2 values (Tables 28-29). So our results fitted with temkin model.

- 173 - RESULTS AND DISCUSSION W.M.EL-KENANY

2.5

25oC

45oC

2.0 o 60 C

1.5

e q

1.0

0.5

0.0 -11 -10 -9 -8 -7 -6 -5 -4 -3 lnC e

Fig. (69): Linearized Temkin isotherms for adsorption of Cs+ ion on titanium vanadate at different reaction temperatures.

- 174 - RESULTS AND DISCUSSION W.M.EL-KENANY

0.7

0.6 25oC 45oC 0.5 60oC

0.4

e q 0.3

0.2

0.1

0.0 -12 -11 -10 -9 -8 -7 -6 -5 -4 -3 -2

ln Ce

Fig. (70): Linearized Temkin isotherms for adsorption of Cu2+ ion on titanium vanadate at different reaction temperatures.

- 175 - RESULTS AND DISCUSSION W.M.EL-KENANY

0.26

0.24 o 25 C 0.22 45oC

60oC 0.20

0.18

0.16

e q 0.14

0.12

0.10

0.08

0.06

0.04

-11 -10 -9 -8 -7 -6 -5 -4 -3 -2

ln Ce

Fig. (71): Linearized Temkin isotherms for adsorption of Co2+ ion on titanium vanadate at different reaction temperatures.

- 176 - RESULTS AND DISCUSSION W.M.EL-KENANY

0.22

0.20 25oC o 0.18 45 C 60oC 0.16

0.14

q 0.12

0.10

0.08

0.06

0.04

0.02 -9 -8 -7 -6 -5 -4 -3

ln Ce

Fig. (72): Linearized Temkin isotherms for adsorption of Cd2+ ion on titanium vanadate at different reaction temperatures.

- 177 - RESULTS AND DISCUSSION W.M.EL-KENANY

1.0

25oC 0.9 45oC

0.8 60oC

0.7

0.6

0.5 e q

0.4

0.3

0.2

0.1

0.0 -11 -10 -9 -8 -7 -6 -5 -4 -3

ln Ce

Fig. (73): Linearized Temkin isotherms for adsorption of Cs+ ion on vanadium antimonate at different reaction temperatures.

- 178 - RESULTS AND DISCUSSION W.M.EL-KENANY

1.3

1.2 o 25 C 1.1 o 45 C 1.0 o 60 C 0.9

0.8 0.7

e 0.6 q

0.5

0.4

0.3

0.2

0.1 0.0 -13 -12 -11 -10 -9 -8 -7 -6 -5 -4 -3 ln C e Fig. (74): Linearized Temkin isotherms for adsorption of Cu2+ ion on vanadium antimonate at different reaction temperatures.

- 179 - RESULTS AND DISCUSSION W.M.EL-KENANY

1.3

1.2

1.1 o 25 C 1.0 45oC o 0.9 60 C

0.8

0.7 e

q 0.6 0.5

0.4

0.3

0.2

0.1

0.0 -11 -10 -9 -8 -7 -6 -5 -4 -3 Ln C e

Fig. (75): Linearized Temkin isotherms for adsorption of Co2+ ion on vanadium antimonate at different reaction temperatures.

- 180 - RESULTS AND DISCUSSION W.M.EL-KENANY

0.45

o 0.40 25 C 45oC o 0.35 60 C

0.30

e q 0.25

0.20

0.15

0.10

0.05 -10 -9 -8 -7 -6 -5 -4 -3

ln Ce

Fig. (76): Linearized Temkin isotherms for adsorption of Cd2+ ion on vanadium antimonate at different reaction temperatures.

- 181 - RESULTS AND DISCUSSION W.M.EL-KENANY

Table (28): Temkin isotherm parameter for the sorption of Cs+, Co2+, Cu2+ and Cd2+ on titanium vanadate at different reaction temperatures.

Temkin isotherm 2 KT b R Cation Reaction (l/g) ( kJ/mol ) temperature (K)

298 38.356 13.128 0.99773

Cs+ 318 33.339 10.056 0.99296

333 56.667 9.033 0.99182 298 46.671 4.51979 0.99024

Cu2+ 318 37.66 3.63265 0.98818 333 64.134 3.08378 0.98216

298 410.284 4.05017 0.97683

Co2+ 318 212.212 3.67186 0.98431

333 198.866 3.46167 0.98989 298 36.66 2.68167 0.92328

Cd2+ 318 42.845 2.93922 0.93659

333 63.318 2.91909 0.95183

- 182 - RESULTS AND DISCUSSION W.M.EL-KENANY

Table (29): Temkin isotherm parameter for the sorption of Cs+, Co2+, Cu2+and Cd2+ on vanadium antimonate at different reaction temperatures.

Temkin isotherm 2 KT b R Cation Reaction (l/g) ( kJ/mol ) temperature (K)

298 46.324 31.314 0.9304

Cs+ 318 50.667 25.297 0.93358

333 58.733 21.825 0.95022

298 35.380 0.98353 27.434 Cu2+ 318 55.350 26.288 0.97302

333 82.793 21.970 0.94099

298 49.943 0.95983 26.921 Co2+ 318 54.028 22.172 0.97092

333 56.395 17.173 0.98982

298 102.083 246.57 0.8396

Cd2+ 318 64.046 102.343 0.86184 333 47.857 78.474 0.8898

- 183 - RESULTS AND DISCUSSION W.M.EL-KENANY

From the above studies, the results suggest that the adsorption of the studied metal ions (Cs+, Co2+, Cu2+ and Cd2+ ) on titanium vanadate and vanadium antimonate is favorable for the Langmuir isotherm more than Freundlich , D-R and Temkin isotherm for the following reasons: 1- The correlation coefficient R2 represented from Langmuir isotherm for the studied metal ions is greater than the correlation coefficient R2 represented from Freundlich , D-R and Temkin isotherm (Tables 22,23).

The dimensionless separation factor, RL represented from Eq.

was found to be 0

2- From Table (26,27) the adsorption energies (E) were between 8 and 16 kJmol-1, suggestion that the sorption process was dominated by ion-exchange (Argun et al., 2007).

Conformation of the experimental data with Langmuir isotherm indicate the monolayer coverage of sorption surfaces and assumes that sorption occurs on a structurally homogeneous adsorbent and all sorption sites are energetically identical. From the above discussion all the studied elements (Cs+, Co2+, Cu2+ and Cd2+) are chemically adsorbed.

- 184 - RESULTS AND DISCUSSION W.M.EL-KENANY

3.6.Column study

The main theory which explains separation by column chromatography is plate theory. According to this theory, the column is considered to be divided into a number of equal units called theoretical plates. These units, although entirely hypothetical, give rise to a very useful way for the practical measurements of column efficiency. Investigation were conducted to explore suitable conditions for quantitative loading and sorption of Cs+, Co2+, Cu2+, and Cd2+ ions in neutral media by chromatographic column procedures at room temperatures (25 oC). As far as the break-through capacity of the column used (Figs. 77,78) shows curves for Co2+, Cu2+, Cd2+, and Cs+ ions (10-3 M for each) from titanium vanadate and vanadium antimonate column in the feed solutions. Each break-through curve depicts the percent concentrations of the respective metal ion in the effluent to the feed solution (C/Co %) Vs. effluent volume (V ml) as shown in Figs. (77,78). The corresponding uptake for the investigated cations per gram of solid is calculated using the following formula; Co (Q0.5 (breakthrough capacity) = V(50%) × —— (meq/g) (2٤ m where Q0.5 means the break-through capacity in g , Co is the initial metal concentration in mg/ml, V is the volume to break-through in cm3 and m is the weight of the dry resin in grams. From the results presented in Figs. (77,78), it is found that the selectivity of the ions towards titanium vanadate is in the order:

Cs+ > Cu2+ > Co2+ > Cd2+ And the selectivity sequence of the investigated ions on vanadium antimonate is Cu2+ > Co2+ > Cs+ > Cd2+

- 185 - RESULTS AND DISCUSSION W.M.EL-KENANY

this selectivity order is accordance with that obtained from batch technique. The break-through capacity for all the metal ions studied are calculated from Figs. (77,78), and it was found to be 0.30, 0.06, 0.05, 0.0049 meq./g for, Cs+, Cu2+,Co2+ and Cd2+ ions on titanium vanadate and 0.085, 0.18, 0.095 and 0.064 for vanadium antimonate respectively, the break-through capacity for all the metal ions is low as compared to the ion exchange capacity for the same metal ions obtained from batch technique due to the interference between ions. Titanium vanadate cation exchanger gives higher break-through capacity than polyacrylamide Sn(IV) molybdophosphate e.g. Cs+ (0.22 meqg-1) [Abdel-Galil., 2010] , also titanium vanadate and vanadium antimonate higher than other inorganic ion exchangers, e.g. Cs+ (0.06 meqg-1) on CeSb [El- Naggar et al., 2003], while the break-through capacity of titanium vanadate is lower than that of Cs+ (0.32 meqg-1), (0.35 meqg-1) on FeSb and SiSb, respectively [El-Naggar et al., 2003] , Cu2+ (2.5 meqg-1), Cd2+ (1.55 meqg-1) on magnesium silicate, respectively [Kotp., 2008], Cs+ (0.35 meq g-1), Co2+ (0.33 meqg-1) on iron(III) silicate [Ibrahim., 2006-a], Cs+ Co2+ (0.82 and 0.18 mmol.g- 1) respectively on zirconium selenomolybdate [El-Said., 2013] and (Co2+ 0.073 meqg-1) on zirconium molybedate [El-Gammal and Shady., 2006], (Co2+ 0.23 meqg-1) on zirconium silicate [El- Gammal and Shady., 2006]. The break-through capacity for Cd2+ and Cu2+ ions on poly (acrylamide – acrylic acid) –silicon titanate was found to be 11, 9.6 mg/g for Cd2+ and Cu2+ ions[Abdel-Aziz., 2005], respectively. The break-through capacity for Cd2+, Cu2+ ions on silico titanate and silico antimonate and it was found to be Cd2+ (10.8 and 66 mg/g) and Cu2+ (20.8 and 11 mg/g), respectively [Abou-Mesalam., 2002]. The break-through capacity of titanium vanadate and vanadium antimonate is low compared to the other

- 186 - RESULTS AND DISCUSSION W.M.EL-KENANY

1.0

i /C

C 0.5

Cd2+ Cs+ 2+ Cu Co2+

0.0 0 100 200 300 400 Effluent volume (ml)

Fig. (77): Break-through curves of mixture of Co2+, Cu2+, Cd2+ and Cs+ ions on titanium vanadate at natural pH and 25±1˚C.

- 187 - RESULTS AND DISCUSSION W.M.EL-KENANY

1.0

0.8

0.6

i /C t

0.4

2+ Co 2+ 0.2 Cu 2+ Cs 2+ Cd 0.0 0 50 100 150 200 250 300 350 Volume of effluent (ml)

Fig. (78): Break-through curves of mixture of Co2+, Cu2+, Cd2+ and Cs+ ions on vanadium antimonate at natural pH and 25±1˚C.

- 188 - RESULTS AND DISCUSSION W.M.EL-KENANY

ion exchanger may be due to interference between the metal ions under study The elution profiles for the investigated cations Cs+, Co2+, Cu2+, and Cd2+ ions are given in Figs. (79,80) for titanium vanadate and vanadium antimonate, and the elution of these metal ions are studied in nitric acid solutions [0.01-0.5 M ] for titanium vanadate ,[0.01-2M] for vanadium antimonate. Figure (79) shows that, at

0.01 M HNO3 there is no peak appear for any elements but at 0.1 M as a second eluent sharp peaks for Cs+, Cu2+, Co2+ and Cd2+ ions. At 0.5 M small peaks for Cu2+ and Cs+ only. Cesium and Copper ions can be separated at 0.5M of HNO3 Figure (80) represent the elution behavior of vanadium antimonate. At 0.01 M HNO3, no peak appear for any element but + 2+ 2+ 2+ at 0.1 M HNO3, sharp peak for Cs ,Co ,Cu and Cd ions and at 1M ,sharp peak for Cu2+ and Co2+ ions and small peak for Cs+ and Cd2+ ions .At 2M sharp peak for Cu2+ and Co2+ ions and small peak for Cs+ ion. From the presented results, it is clear that the different ions can be removed from titanium vanadate column by 0.1, 0.5 M

HNO3 and vanadium antimonate column by 0.1, 0.5, 1 and 2 M

HNO3 so we can expect using the column in the regeneration process.

- 189 - RESULTS AND DISCUSSION W.M.EL-KENANY

0.1M 1.0 Cu2+ + Cs Cd2+ 0.8 Co2+

0.6 i /C t 0.01M C

0.4 0.5M

0.2

0.0 0 50 100 150 200 250 300 350 400 volume of eluent (ml)

Fig. (79): Elution curves of mixture of Co2+, Cu2+, , Cd2+and + Cs ions with 0.01, 0.1and 0.5 M HNO3 from titanium vanadate (1 cm diameter x 1.2 cm length and 4-5 drops/min. flow rate).

- 190 - RESULTS AND DISCUSSION W.M.EL-KENANY

0.1M 2+ 0.5M Cu 1.0 Cd2+ Co2+ Cs+ 0.8 1M

0.01M 2M

0.6 i /C t

0.4

0.2

0.0 0 100 200 300 400 500 600 700 volume of eluent (ml)

Fig. (80): Elution curves of mixture of Co2+, Cu2+, , Cd2+and + Cs ions with 0.01, 0.1, 0.5, 1and 2 M HNO3 from vanadium antimonate

- 191 - CONCLUSION W.M.EL-KENANY

CONCLUSION

1. Titanium vanadate and vanadium antimonate were prepared and characterized with X-ray diffraction (XRD),thermal ,Infra-red (IR), X-ray fluorescence (XRF) and scanning electron microscope analyses. Titanium vanadate is a shiny dark brown hard granules in nature and suitable to use in column operations but vanadium antimonate is Yellow powder in color. The tentative molecular formula for titanium vanadate and vanadium antimonate can be written as: Ti2 V2O9 . 2.5H2O

Sb6V8O35. 9.35 H2O

2. The prepared materials are amorphous materials 3. The pH titration curve shows only one inflection point indicating that the titanium vanadate and vanadium antimonate behaves as monofunctional. 4. Titanium vanadate and vanadium antimonate are high chemically stable materials 5. The prepared titanium vanadate and vanadium antimonate possess high thermal stability compared with other inorganic ion exchanger Titanium vanadate losses about 12.52 ,15.66 % of its weight on heating up to 400 and 600 oC, while, vanadium antimonate losses about 14.22 ,19 % of its weight on heating up to 400 and 600 oC. 6. The ion-exchange capacity of titanium vanadate and vanadium antimonate cation exchanger for the studied metal ions increases according to the decrease in the hydrated ionic radii and hydration energy and have the following sequence;

- 192 - CONCLUSION W.M.EL-KENANY

Cs+ > Cu2+ > Co2+ > Cd2+ Cu2+ > Co2+ > Cs+ > Cd2+

7. By applying Kd we conclude that: All cations reveal increasing adsorption with pH increasing up studied pH value. The selectivity order of the investigated cations on titanium vanadate in the same conditions has the following sequence; Cs+ >> Cu2+ > Co2+ > Cd2+ But the selectivity sequence of the investigated cations on vanadium antimonate is Cu2+ > Co2+ > Cs+ > Cd2+ 8. The changes in thermodynamic parameters, enthalpy change (ΔHo), entropy change (ΔSo) and free energy change (ΔGo) were studied for Co2+, Cu2+, Cd2+ and Cs+ ions on titanium vanadate and vanadium antimonate at 25, 45 and 60±1oC. The positive values of (ΔHo) indicate the endothermic nature of the adsorption process, while the positive values of ΔSo for Cs+, Cu2+, Cd2+ and Co2+ indicate the increased randomness at solid-solution interface during the adsorption of these cations on titanium vanadate and vanadium antimonate. The negative values of the free energy change (ΔGo) for the investigated metal ions indicate that the adsorption process is spontaneous and indicate the preferable adsorption of these cations on titanium vanadate and vanadium antimonate as compared to H+ ion. 9. The exchange kinetics of Cs+, Co2+, Cu2+ and Cd2+, on the prepared titanium vanadate were studied as a function of particle radius, drying temperature of titanium vanadate, reaction temperature. 10. The rate of exchange is independent of the metal ion concentration, and this is evident that the conditions set in this

- 193 - CONCLUSION W.M.EL-KENANY

work are particle diffusion mechanism for the investigated metal ions. 11. The rate of exchange increases with decrease in the particle size and drying temperature of the exchange materials. However, the rate increases with increase in the reaction temperature .

12. The diffusion coefficient values (Di) of the investigated metal ions on titanium vanadate (heated at 50◦C) follow the order; Cs+ > Cu2+ > Co2+ > Cd2+ + 2+ 2+ 2+ 13. The Di values of, Cs , Co , Cu and Cd ions on titanium vanadate at 25◦C decrease with increasing the drying temperatures from 50 to 400◦C. 14. Negative values of entropy of activation (ΔS*) were obtained and this anticipated that the investigated metal ions are exchanged with H+ of titanium vanadate in the unhydrated form. 15. The removal efficiencies for the studied metal ions decreased as the initial concentration of this metal ions increased from 5x 10-4 M to ~ 5x10-2 M. The results suggest that the adsorption of the studied metal ions (Cs+,Co2+, Cu2+and Cd2+ ions) on titanium vanadate is favorable for the Langmuir isotherm more than Freundlich , D-R and Temkin isotherm . Conformation of the experimental data with Langmuir isotherm indicate the monolayer coverage of sorption surfaces and assumes that sorption occurs on a structurally homogeneous adsorbent and all sorption sites are energetically identical. From the above discussion all the studied elements (Cs+, Co2+, Cu2+ and Cd2+) are chemically adsorbed. 16. Different ions can be removed from titanium vanadate column by using 0.01, 0.1, 0.5 M HNO3 as eluents and and also the studied metal ions can be removed from vanadium antimonate by using using 0.01, 0.1, 0.5,1 ,2 M HNO3 and the adsorbed ions are completely removed, so we can expect using the column in the regeneration process.

- 194 - SUMMARY W.M.EL-KENANY

SUMMARY

There has been substantial research on the inorganic ion exchangers commonly known as ion exchange media for the remediation of wastewater from hazardous metal containing. This work had been done in an attempt to synthesis, characterization of titanium vanadate and vanadium antimonate and using these materials in treatment of toxic waste. The work carried out in this thesis is summarized in to three main parts; namely, introduction, experimental and finally results and discussion. First chapter

The first chapter is the introduction which includes the history of ion exchange process ,classification of ion exchanger ,types of inorganic ion exchanger, literature survey which includes antimonate and vanadate families. Second chapter The second chapter is the experimental which includes the chemicals used and their purity, the method of preparation of titanium vanadate and vanadium antimonate as well as the instrumentation, the analytical techniques and the procedures used in this thesis. Third chapter The third chapter deals with the results and discussion and is divided into main sections namely; preparation and characterization of adsorbent materials, distribution studies, kinetic studies, sorption isotherms and column operations in the first section from third chapter is the preparation and characterization, brief account on the

- ١٩٥ -

SUMMARY W.M.EL-KENANY

method of preparation of titanium vanadate , vanadium antimonate and characterization by Infra-Red analysis (IR), thermal analysis (TGA-DTA), X-ray fluorescence (XRF) and scanning electron microscope (SEM) analyses . The tentative formula of the prepared materials titanium vanadate and vanadium antimonate respectively may be :

Ti2V2O9 . 2.5H2O

Sb6V8O35. 9.35 H2O

The XRD patterns of the prepared materials were determined at different drying temperatures and the results showed that, the prepared titanium vanadate heated at 50±1oC is amorphus, and no change occur to the prepared material with the increase of heating temperatures from 50oC to 600 ±1oC . Vanadium antimonate is also amorphous material but its crystalinity improved with increasing the drying temperatures from 50oC to 600±1oC.

The pH titration curves show only one inflection point indicating that titanium vanadate and vanadium antimonate behave as monofunctional. The solubility of the prepared materials was determined in H2O and acidic solution, the prepared titanium vanadate and vanadium antimonate are stable in water but titanium vanadate is sparingly soluble in acid solutions up to 2 M HNO3 and

HCl, and completely soluble at 4M of HCl and HNO3 while the vanadium antimonate is sparingly soluble up to 4M . The chemical stability of the prepared titanium vanadate and vanadium antimonate is more than other inorganic ion exchangers. . Also the

- ١٩٦ -

SUMMARY W.M.EL-KENANY

I.R of the prepared materials was determined at different drying temperatures, 50, 200, 400, 600 and 850oC. Effect of heating temperature on the prepared exchangers was studied by thermal analysis and the results indicate that vanadium antimonate and titanium vanadate have high thermal stabilities .Titanium vanadate lost only 12.52 ,15.66 % of its weight on heating at 400 and 600 oC±1oC respectively . Vanadium antimonate o o 19% of its weight by heating at 400 and 600 C±1 C , ١٤.٢٢ only respectively . These results indicate that the prepared material has a good thermal and chemical stability compared to other inorganic ion exchangers. The second section from the third chapter is the distribution studies, the ion exchange properties have been studied using four cations (Cs+, Co2+, Cu2+ and Cd2+) which represent the main different categories of the nuclear and industrial waste solution. The distribution coefficient of the studied cations (Cs+, Co2+, Cu2+ and Cd2+) was investigated on titanium vanadate and vanadium antimonate at different pH values at 25oC±1oC. The obtained results showed the Kd values increase with increasing the + 2+ pH of the solution. From the plots of log Kd vs. pH, (Cs , Co , Cu2+ and Cd2+) ions were found to deviate from the ideal ion exchange reaction mechanism. The selectivity order of the investigated cations on titanium vanadate in the same conditions has the following sequence;

Cs+ >> Cu2 + > Co2+ > Cd2+ The selectivity sequence of the investigated cations on vanadium antimonate is Cu2 + > Co2+ > Cs+ > Cd2+

- ١٩٧ -

SUMMARY W.M.EL-KENANY

The distribution coefficient values of titanium vanadate and vanadium antimonate for the studied metal ions were compared to the other ion exchange materials. The effect of reaction temperature on the adsorption of Cs+, Co2+, Cu2+ and Cd2+ ions on titanium vanadate and vanadium antimonate sample was carried out in the temperature range 25- o + 2+ 2+ 60±1 C, the distribution coefficient (Kd) of Cs , Co , Cu and Cd2+ on titanium vanadate and vanadium antimonate increased with increasing temperature from 25oC to 60oC and the thermodynamic parameters (ΔHo, ΔSo and ΔGo) for the adsorption of Cs +, Co2+, Cu2+ and Cd2+ ions on titanium vanadate and vanadium antimonate were calculated. The ion-exchange capacity of titanium vanadate and vanadium antimonate cation-exchangers for the studied metal ions increases according to the decrease in the hydrated ionic radii and hydration energy and have the following sequence; Cs+ > Cu2+ > Co2+ > Cd2+ Titanium vanadate and vanadium antimonate cation exchangers give higher ion exchange capacity than other inorganic ion exchangers. The ion exchange capacities of titanium vanadate and vanadium antimonate for Cs+, Co2+, Cu2+ and Cd2+ ions has been determined at different drying temperatures. The obtained results showed that, the capacity of the studied metal ions decreases by increasing the drying temperatures from 50oC to 400oC. The third section from the third chapter is the kinetic studies, the kinetics of exchange of Cs+, Co2+, Cu2+ and Cd2+ ions on titanium vanadate are studied as a function of particle radius, heating temperatures, reaction temperatures (all experiments were

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SUMMARY W.M.EL-KENANY

carried out under particle diffusion control as a limited batch techniques only). The results showed that, the rate of exchange of different metal ions on titanium vanadate is independent of metal concentrations in solutions up to 5x10−2 M. The rate increases with decreasing the particle size. Also, the rate increases with decreasing the heating temperature of the exchange materials, while it increases with increasing the reaction temperature. The values of * the effective diffusion coefficients (Di), entropy of activation (ΔS ) + 2+ 2+ 2+ and energy of activation (Ea) for Cs ,, Co , Cu and Cd ions on titanium vanadate have been determined and are compared with the values reported in literature.. The results were found that the values of diffusion coefficient (Di) inside titanium vanadate sample follow the order; Cs+ > Cu2+ > Co2+ > Cd2+

The average values of diffusion coefficients (Di) of Cs+, Co2+, Cu2+ and Cd2+ ions on titanium vanadate of different particle diameters were calculated. The obtained results showed the diffusion coefficients calculated for larger particle sizes are slightly higher. Also, the average values of diffusion coefficients (Di) of Cs+, Co2+, Cu2+ and Cd2+ on titanium vanadate dried at (50, 200 and 400◦C) were calculated. The obtained results showed that there is an appreciable decrease of self-diffusion of Cs+, Co2+, Cu2+ and Cd2+ with an increase in the drying temperature of titanium ◦ vanadate from 50 to 400 C. On contrast, the values of Di increase with increasing the reaction temperatures from 25 to 60oC. The activation energy for the investigated metal ions (heating at 50 ◦C) was calculated and has the order: Cs+> Cu2+ > Co2+ > Cd2+

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SUMMARY W.M.EL-KENANY

Negative values of entropy of activation (ΔS*) were obtained for Cs+, Co2+, Cu2+ and Cd2+ ions on titanium vanadate sample at all operative conditions. The fourth section from third chapter is the sorption isotherm, the effect of concentration on the sorption of Cs+, Co2+, Cu2+ and Cd2+ ions on titanium vanadate and vanadium antimonate has been studied at different reaction temperatures (25, 45 and 60oC) using concentration range 5x10-4 – 5x10-2 M. The results proved that the sorption of these ions is endothermic process and the sorption capacities of the studied metal ions increased with increasing the reaction temperature for all studied adsorption isotherms models (Langmuir, Freundlich , D-R and Temkin isotherm). Also, the results suggest that the adsorption of the studied metal ions (Cs+, Co2+, Cu2+ and Cd2+) on titanium vanadate and vanadium antimonate is favorable for the Langmuir isotherm more than Freundlich , D-R and Temkin isotherm. Conformation of the experimental data with Langmuir isotherm indicate the monolayer coverage of sorption surfaces and assumes that sorption occurs on a structurally homogeneous adsorbent and all sorption sites are energetically identical. From the above discussion all the studied elements Cs+, Co2+, Cu2+ and Cd2+ ions on titanium vanadate and vanadium antimonate are chemically adsorbed. The column investigations were studied on titanium vanadate and vanadium antimonate and it was found that Cs+ ,Cu2+ ,Co2+ and Cd2+ ions can be removed from titanium vanadate column by (0.1,

0.5 M HNO3), and also can be removed from vanadium antimonate column by (0.1 , 0.5 ,1 and 2M HNO3), respectively.

Also application studies were extended to the removal of some hazardous metal ions from industrial wastewater solutions.

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REFERENCES W.M.EL-KENANY

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