DOCSLIB.ORG

Hydroxyapatite Degradation and Biocompatibility

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Hydroxyapatite Degradation and Biocompatibility HYDROXYAPATITE DEGRADATION AND BIOCOMPATIBILITY DISSERTATION Presented in Partial Fulfillment of the Requirements for the Degree of Philosophy in the Graduate School of The Ohio State University By Haibo Wang, B.S. * * * * * The Ohio State University 2004 Dissertation Committee: Approved by Professor John Lannutti, Adviser Professor Henk Verweij _____________________________ Adviser Professor Derek Hansford Materials Science and Engineering ABSTRACT Hydroxyapatite (HA) is widely used as a bioactive ceramics since it forms a chemical bonding to bone. The disadvantage of this material is its poor mechanical properties. HA can be degraded in body, which is the reason for its bioactivity, but too fast degradation rate could cause negative effects, such as macrophage present, particle generation, and even implant clinical failure. HA degradation rate will be greatly changed under many conditions: purity, HA form (i.e. bulk form, porous form, coating, or HA/polymer composites), microstructure, implant site, body conditions, etc. Although much work has been done in HA properties and application areas, the HA degradation behavior and mechanism under these different conditions are still not clear. In this research, three aspects of HA degradation have been studied: 1) Two very common impurities—Tri-Calcium Phosphate (TCP) and Calcium Oxide and their influences on HA degradation in vitro and in vivo, 2) influence of HA/polymer composite form on HA degradation, 3) HA material particle generation and related mechanism. From the in vitro and in vivo tests on bulk HA disks with various Ca/P ratios, HA degradation can clearly be found. The degradation level is different in different Ca/P ratio samples as well as in different test environments. In same test environment, non- stoichiometric HA samples have higher degradation rate than stoichiometric HA. HA/PMMA composite design successfully intensifies HA degradation both in vitro and ii in vivo. Grain boundary damage can be found on in vivo test samples, which has not been clearly seen on bulk HA degraded surface. HA particle generation is found in in vitro and in vivo HA/PMMA composite surface and in vivo bulk HA surface. Sintering temperature and time does affect HA grain size, and this affect HA degradation rate. Intergranular fracture is found in a several micron zone close to the Ca/P ratio 1.62 and 1.67 sample degraded surfaces. At Ca/P ratio greater than 1.667, after HA degradation in water, solution pH increases because of CaO presence. iii Dedicated to my wife iv ACKNOWLEDGMENTS I want to thank my adviser, Dr. John J. Lannutti, for his intellectual guidance, encouragement and incredible patience which made this thesis possible. I thank Dr. David Anderson from Veterinary Clinical Sciences, who give us the opportunity to do in vivo tests. I also thank Dr. Amr Moursi and Phillip Winnard for their help on osteoblastic cell culture and the in vitro test. Special thanks go to Dr. Henk Verweij and Dr. Derek Hansford for serving on my defense committee and providing valuable suggestions to the completion of this work. I am especially grateful to Dr. Jong-Kook Lee-the visiting professor from Chosun Univerisity, Kwangju, Korea, who joined this research and during the one year on his staying with us, he gave us important contribution on the literature review. I wish to thank all the members of our research group for providing a joyful working site, especially Kathy Lu, Nan Guo, Shiling Ruan, J. Dawson White, Wenxia Li, Taryn Sproule, Jin Nam, Heather Power, Zhijun Zhao, Alex Tsai, Andrew Kohm, and Kathy Elias. I thank my grandparents, my mother for their constant love and support to me. Finally, my loving appreciation goes to my wife Ying, who encouraged me and unconditionally supported me. v VITA 1972 ……………………………………… Wanshan, GuiZhou Province, China. 1995 ……………………………………… B.S. Mechanical Engineering, Tsinghua Univ. Beijing, China. 1998 .............................................................. Research Assistant, National Ceramic Lab, Beijing, China. 1999 - present ............................................... Graduate Teaching and Research Associate, The Ohio State University PUBLICATIONS Research Publication 1. Wang, Haibo, Jong-Kook Lee, Amr Moursi, John J. Lannutti. “Microstructural disassembly of calcium phosphates.” Journal of Biomedical Materials Research, Vol. 68A, p61-70, 2004. 2. Wang, Haibo, Jong-Kook Lee, Amr Moursi, David Anderson, Phillip Winnard, Heather Powell, John Lannutti. “Ca/P ratio effects on the degradation of hydroxyapatite in vitro.” Journal of Biomedical Materials Research, Vol. 67A, p599 - 608, 2003. 3. Wang, Haibo, Jiemo Tian. “Improvement of ZrO2 Ceramic Performance by Coating Small Amount CeO2 On 3mol%Y2O3－ZrO2 Powder.” 1st International High-Performance Ceramic Conference in Beijing, China. 1998. FIELDS OF STUDY Major Field: Materials Science and Engineering vi TABLE OF CONTENTS Page Abstract ………………………………………………………………….ii Dedication ..................................................................................................... iv Acknowledgments ..................................................................................................... v Vita ..................................................................................................... vi List of Tables ..................................................................................................... ix List of Figures ..................................................................................................... x Chapters: 1. Introduction ..................................................................................................... 1 1.1 The advantages and disadvantages of HA material................................ 2 1.2 Preparation of stoichiometric HA powders ............................................ 5 1.2.1 Syntheses based on theoretical compositions………………….5 1.2.2 Equilibrium syntheses in solution............................................... 7 1.2.3 Miscellaneous methods............................................................... 8 1.3 HA dissolution behavior and mechanism ............................................... 8 1.3.1 non-biological HA dissolving behavior in water and acid......... 9 1.3.2 Biology-related HA dissolving ................................................... 16 1.4 The unresolved issues and importance of study on HA degradation..... 21 1.5 Practical issues which influence HA degradation .................................. 23 1.5.1 HA impurity ................................................................................ 23 1.5.2 HA form of HA composites........................................................ 30 1.5.3 HA material particle generation.................................................. 36 2. Ca/P ratio effects on the degradation of hydroxyapatite in vitro ....................... 48 2.1 Introduction ............................................................................................. 48 2.2 Experiment design................................................................................... 50 2.3 Results .....................................................................................................52 2.4 Discussion ...............................................................................................54 2.4.1 Weight gain/surface precipitation............................................... 57 2.4.2 Potential in vivo significance ...................................................... 58 2.5 Conclusions ............................................................................................. 59 3 In vivo degradation results and microstructural disassembly............................. 86 vii 3.1 Introduction ............................................................................................. 86 3.2 Experiment............................................................................................... 88 3.2.1 Preparation of pure and biphasic HA.......................................... 88 3.2.2 In vitro sample preparation ......................................................... 90 3.2.3 Exposure to primary osteoblast culture ...................................... 91 3.2.4 Subcutaneous implantation ......................................................... 93 3.2.5 Bone implantation ....................................................................... 93 3.2.6 Specimen Harvest........................................................................ 94 3.3 Results .....................................................................................................95 3.3.1 In vivo study under skin and in bone on bulk HA disks............. 95 3.3.2 In vivo bone apposition and subcutaneous tests on HA/PMMA composite..................................................................................... 96 3.3.3 Grain pullout in vitro................................................................... 97 3.3.4 Grain pullout in vivo.................................................................... 98 3.3.5 Pure HA degradation in vivo....................................................... 100 3.4 Discussion................................................................................................ 100 3.5 Conclusions ............................................................................................. 104 4 Further study on hydroxyapatite degradation ..................................................... 138 4.1 Introduction ............................................................................................
Load more

Recommended publications
  • Educate Your Patients About Kidney Stones a REFERENCE GUIDE for HEALTHCARE PROFESSIONALS
    Educate Your Patients about Kidney Stones A REFERENCE GUIDE FOR HEALTHCARE PROFESSIONALS Kidney stones Kidney stones can be a serious problem. A kidney stone is a hard object that is made from chemicals in the urine. There are five types of kidney stones: Calcium oxalate: Most common, created when calcium combines with oxalate in the urine. Calcium phosphate: Can be associated with hyperparathyroidism and renal tubular acidosis. Uric acid: Can be associated with a diet high in animal protein. Struvite: Less common, caused by infections in the upper urinary tract. Cystine: Rare and tend to run in families with a history of cystinuria. People who had a kidney stone are at higher risk of having another stone. Kidney stones may also increase the risk of kidney disease. Symptoms A stone that is small enough can pass through the ureter with no symptoms. However, if the stone is large enough, it may stay in the kidney or travel down the urinary tract into the ureter. Stones that don’t move may cause significant pain, urinary outflow obstruction, or other health problems. Possible symptoms include severe pain on either side of the lower back, more vague pain or stomach ache that doesn’t go away, blood in the urine, nausea or vomiting, fever and chills, or urine that smells bad or looks cloudy. Speak with a healthcare professional if you feel any of these symptoms. Risk factors Risk factors can include a family or personal history of kidney stones, diets high in protein, salt, or sugar, obesity, or digestive diseases or surgeries.
    [Show full text]
  • Effect of the Addition of Alginate And/Or Tetracycline on Brushite Cement Properties
    molecules Article Effect of the Addition of Alginate and/or Tetracycline on Brushite Cement Properties Claudia Morilla 1,2,3, Elianis Perdomo 4, Ana Karla Hernández 1, Ramcy Regalado 1, Amisel Almirall 1, Gastón Fuentes 1,2,* , Yaima Campos Mora 1,2, Timo Schomann 2,3 , Alan Chan 3 and Luis J. Cruz 2 1 Biomaterials Center, University of Havana, La Habana 10400, Cuba; [email protected] (C.M.); [email protected] (A.K.H.); [email protected] (R.R.); [email protected] (A.A.); [email protected] (Y.C.M.) 2 Translational Nanobiomaterials and Imaging Group, Department of Radiology, Leiden University Medical Center, 2333 ZA Leiden, The Netherlands; [email protected] (T.S.); [email protected] (L.J.C.) 3 Percuros B.V., 2333 CL Leiden, The Netherlands; [email protected] 4 Faculty of Automatic and Biomedical Engineering, Technological University of Havana, La Habana 11300, Cuba; [email protected] * Correspondence: [email protected] or [email protected] Abstract: Calcium phosphate cements have the advantage that they can be prepared as a paste that sets in a few minutes and can be easily adapted to the shape of the bone defect, which facilitates its clinical application. In this research, six formulations of brushite (dicalcium phosphate dihydrated) cement were obtained and the effect of the addition of sodium alginate was analyzed, such as its capacity as a tetracycline release system. The samples that contain sodium alginate set in 4 or 5 min Citation: Morilla, C.; Perdomo, E.; and showed a high percentage of injectability (93%).
    [Show full text]
  • Remineralisation of Enamel Subsurface Lesions with Casein Phosphopeptide - Amorphous Calcium Phosphate in Patients with Fixed Orthodontic Appliances
    Y T E I C O S L BALKAN JOURNAL OF STOMATOLOGY A ISSN 1107 - 1141 IC G LO TO STOMA Remineralisation of Enamel Subsurface Lesions with Casein Phosphopeptide - Amorphous Calcium Phosphate in Patients with Fixed Orthodontic Appliances SUMMARY Darko Pop Acev1, Julijana Gjorgova2 One of the most common problems in everyday dental practice is the 1PZU Pop Acevi, Skopje, FYROM occurrence of dental caries. The easiest way to deal with this problem is its 2Department of Orthodontics prevention. A lot of research has been done to find a material that would “Ss. Cyril and Methodius” University, Skopje help to prevent the occurrence of dental caries, which means to stop tooth FYROM demineralization (loss of minerals from the tooth structure) and replace it with the process of remineralisation (reincorporating minerals in dental tissue). In this review article we will present the remineralisation potential of casein phosphopeptide - amorphous calcium phosphate (CPP-ACP) in clinical studies. We considered all articles that were available through the browser of Pubmed Central. After analyzing the results obtained from these studies, we concluded that casein phosphopeptide - amorphous calcium phosphate has significant remineralisation effect when used in patients with fixed orthodontic appliances. Keywords: Dental Remineralisation; Casein Phosphopeptide; Amorphous Calcium LITERATURE REVIEW (LR) Phosphate Balk J Stom, 2013; 17:81-91 Introduction of the enamel porous and sensitive to internal and external factors9. Apart of this, maintaining oral hygiene Dental caries is defined as localized destruction of is difficult in patients with fixed orthodontic appliances; tooth hard tissue with acids, produced during fermentation this is the reason for accumulating food debris on the of carbohydrates, by bacteria in dental plaque1,2.
    [Show full text]
  • Spray-Dried Monocalcium Phosphate Monohydrate for Soluble Phosphate Fertilizer Khouloud Nasri, Hafed El Feki, Patrick Sharrock, Marina Fiallo, Ange Nzihou
    Spray-Dried Monocalcium Phosphate Monohydrate for Soluble Phosphate Fertilizer Khouloud Nasri, Hafed El Feki, Patrick Sharrock, Marina Fiallo, Ange Nzihou To cite this version: Khouloud Nasri, Hafed El Feki, Patrick Sharrock, Marina Fiallo, Ange Nzihou. Spray-Dried Monocal- cium Phosphate Monohydrate for Soluble Phosphate Fertilizer. Industrial and engineering chemistry research, American Chemical Society, 2015, 54 (33), p. 8043-8047. 10.1021/acs.iecr.5b02100. hal- 01609207 HAL Id: hal-01609207 https://hal.archives-ouvertes.fr/hal-01609207 Submitted on 15 Jan 2019 HAL is a multi-disciplinary open access L’archive ouverte pluridisciplinaire HAL, est archive for the deposit and dissemination of sci- destinée au dépôt et à la diffusion de documents entific research documents, whether they are pub- scientifiques de niveau recherche, publiés ou non, lished or not. The documents may come from émanant des établissements d’enseignement et de teaching and research institutions in France or recherche français ou étrangers, des laboratoires abroad, or from public or private research centers. publics ou privés. Spray-Dried Monocalcium Phosphate Monohydrate for Soluble Phosphate Fertilizer Khouloud Nasri and Hafed El Feki Laboratory of Materials and Environmental Sciences, Faculty of Sciences of Sfax, Soukra Road km 4B. P. no 802−3038, Sfax, Tunisia Patrick Sharrock* and Marina Fiallo Université de Toulouse, SIMAD, IUT Paul Sabatier, Avenue Georges Pompidou, 81104 Castres, France Ange Nzihou Centre RAPSODEE, Université de Toulouse, Mines Albi, CNRS, Albi, France ABSTRACT: Monocalcium phosphate monohydrate (MCPM) was obtained by water extraction of triple superphosphate. The solubility of MCPM is 783.1 g/L, and is entirely soluble. Saturated MCPM solution dissociates into free phosphoric acid and monetite (CaHPO4), but evaporation to dryness by spray drying forms MCPM during crystallization.
    [Show full text]
  • Calcium Phosphate Bioceramics: a Review of Their History, Structure, Properties, Coating Technologies and Biomedical Applications
    Review Calcium Phosphate Bioceramics: A Review of Their History, Structure, Properties, Coating Technologies and Biomedical Applications Noam Eliaz * and Noah Metoki Biomaterials and Corrosion Lab, Department of Materials Science and Engineering, Tel-Aviv University, Ramat Aviv 6997801, Israel; [email protected] * Correspondence: [email protected]; Tel.: +972-3-640-7384 Academic Editor: Patrice Laquerriere Received: 11 February 2017; Accepted: 22 March 2017; Published: 24 March 2017 Abstract: Calcium phosphate (CaP) bioceramics are widely used in the field of bone regeneration, both in orthopedics and in dentistry, due to their good biocompatibility, osseointegration and osteoconduction. The aim of this article is to review the history, structure, properties and clinical applications of these materials, whether they are in the form of bone cements, paste, scaffolds, or coatings. Major analytical techniques for characterization of CaPs, in vitro and in vivo tests, and the requirements of the US Food and Drug Administration (FDA) and international standards from CaP coatings on orthopedic and dental endosseous implants, are also summarized, along with the possible effect of sterilization on these materials. CaP coating technologies are summarized, with a focus on electrochemical processes. Theories on the formation of transient precursor phases in biomineralization, the dissolution and reprecipitation as bone of CaPs are discussed. A wide variety of CaPs are presented, from the individual phases to nano-CaP, biphasic and triphasic CaP formulations, composite CaP coatings and cements, functionally graded materials (FGMs), and antibacterial CaPs. We conclude by foreseeing the future of CaPs. Keywords: bioceramics; biomineralization; bone cement; calcium phosphate; coating; composites; drug delivery; electrochemical deposition; functionally graded materials; nano-hydroxyapatite 1.
    [Show full text]
  • Phosphate & Rock
    IOSR Journal of Environmental Science, Toxicology and Food Technology (IOSR-JESTFT) e-ISSN: 2319-2402,p- ISSN: 2319-2399.Volume 8, Issue 11 Ver. III (Nov. 2014), PP 22-39 www.iosrjournals.org Comparative Study Of Rock Phosphate And Calcium Phosphate On The Growth &Biochemistry Of Brassica Juncea And It’s Impact On Soil Heath Sandhya Buddh Department Of Biotechnology Boston College For Professional Studies, Gwalior Abstract: A study was conducted to compare the effect of rock phosphate & calcium phosphate on the growth and the biochemistry of the plant Brassica juncea and its impact on soil health. The rock phosphate is highly favorable than tri-calcium phosphate for the mustard growth. Physiochemical effect of the plant was evaluated through the analysis of amino acid, pigment, shoot & root biomass content of the plant. The following parameters of soil (treated with Tri calcium phosphate & Rock phosphate) such as pH, EC, moisture, ash were analyzed. The pH of the soil mixed with tri-calcium phosphate and rock phosphate was decreased slightly from original & EC was increased .Impact of rock phosphate & calcium phosphate on the soil health can be observed by calculating TOC and nitrogen estimation at regular interval of days. Nitrogen concentration at 5th day is gradually decreases except control, R2 and R4 and after in 10th day and 20th day it becomes increased. The highest TOC value was observed on 10th day i.e. (C1)9.64 in calcium phosphate and R1 (10.17) on 1st day in rock phosphate. I. Introduction Phosphorus, one of the 17 chemical elements required for plant growth and reproduction, is often referred to as the ―energizer‖ since it helps store and transfer energy during photosynthesis.
    [Show full text]
  • Hydroxyapatite and Fluorapatite in Conservative Dentistry and Oral Implantology—A Review
    materials Review Hydroxyapatite and Fluorapatite in Conservative Dentistry and Oral Implantology—A Review Kamil Pajor, Lukasz Pajchel and Joanna Kolmas * Analytical Group, Department of Analytical Chemistry and Biomaterials, Faculty of Pharmacy with Laboratory Medicine Division, Medical University of Warsaw, 02-097 Warsaw, Poland * Correspondence: [email protected] Received: 29 July 2019; Accepted: 20 August 2019; Published: 22 August 2019 Abstract: Calcium phosphate, due to its similarity to the inorganic fraction of mineralized tissues, has played a key role in many areas of medicine, in particular, regenerative medicine and orthopedics. It has also found application in conservative dentistry and dental surgery, in particular, as components of toothpaste and mouth rinse, coatings of dental implants, cements, and bone substitute materials for the restoration of cavities in maxillofacial surgery. In dental applications, the most important role is played by hydroxyapatite and fluorapatite, i.e., calcium phosphates characterized by the highest chemical stability and very low solubility. This paper presents the role of both apatites in dentistry and a review of recent achievements in the field of the application of these materials. Keywords: hydroxyapatite; fluorapatite; dentistry; calcium phosphates 1. Introduction In recent decades, one has been able to observe huge progress in the field of dentistry. This results not only from the development of dental techniques and methods of therapy but also from significant developments in biomaterial engineering. The science of biomaterials is constantly increasing due to innovative modifications of already known materials or completely new biomaterials for applications in dentistry. Biodegradable polymers, bioactive ceramics, bioglass or metals covered with a layer of material facilitating osseointegration and, above all, composite materials are the main directions in the development of dental biomaterials [1–4].
    [Show full text]
  • Role of Strontium on the Crystallization of Calcium Hydrogen Phosphate Dihydrate (CHPD)
    Journal of Minerals & Materials Characterization & Engineering , Vol. 10, No.7, pp.625-636, 2011 jmmce.org Printed in the USA. All rights reserved Role of Strontium on the Crystallization of Calcium Hydrogen Phosphate Dihydrate (CHPD) K. Suguna 1, 2 , C. Sekar 3* 1 Department of Physics, Sri Sarada College for Women, Salem -636 016, TN, India. 2 Department of Physics, Periyar University, Salem- 636 011, TN, India. 3 Department of Bioelectronics and Biosensors, Alagappa University, Karaikudi-630003, TN, India. *Corresponding Author: [email protected] ABSTRACT Calcium hydrogen phosphate dihydrate (CHPD, CaHPO 4· 2H2O) or brushite is found quite frequently in urinary calculi (stones) . Crystallization of brushite has been carried out in sodium metasilicate (SMS) gel with and without adding ‘Sr’ as additive. In pure system, dicalcium phosphate anhydrous (DCPA, CaHPO 4) or monetite and hydroxyapatite (HA, Ca 5(PO 4)3(OH)) grew along with brushite. The presence of Sr suppressed the formation of HA and enhanced the number and size of monetite crystals and changed the morphology of brushite crystals from needle shape to octopus-like shape. The samples were characterized by powder & single crystal X-ray diffraction (XRD), scanning electron microscopy (SEM), X- ray fluorescence spectroscopy (XRF), Fourier transform infrared spectroscopy (FTIR) and thermal analyses (TG-DTA) . Keywords: Brushite , Crystal growth, Sr additive, SEM. 1. INTRODUCTION Calcium phosphates have been studied extensively because of their occurrence in normal and pathological calcifications. Due to their excellent biocompatibility, it is a well-known bioactive material suitable for bone and hard tissue replacement [1] . Hydroxyapatite (HA, Ca 5(PO 4)3(OH), octacalcium phosphate (OCP,Ca 8H2(PO 4)6·5(H 2O)), tricalcium phosphate ( β- TCP, Ca 3(PO 4)2), dicalcium phosphate dihydrate or calcium hydrogen phosphate dihydrate (CHPD, CaHPO 4·2H 2O), dicalcium phosphate anhydrous (DCPA, CaHPO4), tetracalcium [2] phosphate (TTCP, Ca 4(PO 4)2O) and amorphous calcium phosphate (ACP) are different 625 626 K.
    [Show full text]
  • Sonochemical Synthesis of Cellulose/Hydroxyapatite
    www.nature.com/scientificreports OPEN Sonochemical synthesis of cellulose/hydroxyapatite nanocomposites and their Received: 10 January 2018 Accepted: 20 April 2018 application in protein adsorption Published: xx xx xxxx Lian-Hua Fu1,2,3, Chao Qi2, Yan-Jun Liu1, Wen-Tao Cao1 & Ming-Guo Ma 1 Hydroxyapatite (HA) is the main mineral constituent in the hard tissue of vertebrate, which is recognized as an important biomedical material owing to its excellent bioactivity and biocompatibility. Herein, we report a facile and green sonochemical route for the rapid synthesis of cellulose/ HA nanocomposites in NaOH/urea aqueous solution. The in vitro behavior of the cellulose/HA nanocomposites was studied to evaluate the biological response of the nanocomposites following immersion in simulated body fuid for various periods (maximum of 28 days). The HA crystals formed on the surface of the nanocomposites were carbonate-containing apatite, which is similar to the naturally occurring calcium phosphate materials. The HA nanosheets (assembly of nanorods) were mineralized on the surface of the nanocomposites, and maximum mass of the nanocomposites was reached 1.82 times of initial mass after 28 days of soaking. Moreover, the as-prepared cellulose/HA nanocomposites have good cytocompatibility, and show a relatively high protein adsorption ability using hemoglobin as a model protein. These results indicate that the as-prepared cellulose/HA nanocomposites are promising for applications in various biomedical felds such as tissue engineering and protein/drug delivery. Hydroxyapatite (HA) is the main mineral component in the hard tissue of vertebrate bones and teeth as well as the most stable calcium phosphate phase under physiological conditions1,2.
    [Show full text]
  • Inhibitors and Promoters of Stone Formation
    View metadata, citation and similar papers at core.ac.uk brought to you by CORE provided by Elsevier - Publisher Connector Kidney International, Vol. 13 (1978), pp. 361—3 71 Inhibitors and promoters of stone formation HERBERT FLEISCH Department of Pathophysiology, University of Berne, Berne, Switzerland Currently, three main mechanisms are thought to Crystal growth and crystal aggregation be important in the formation of urinary stones: 1) In the past, attention was devoted mostly to the the relationship between the concentration of the formation and growth of crystals. Recently, interest precipitating substances in urine and the solubility of has been directed to an area which, until now, had the mineral phase formed, 2) the role of promoters of been neglected: the crystal aggregation. This term crystallization and aggregation, and 3) the part describes the process of crystals binding one to an- played by inhibitors of crystal formation and aggre- other, resulting in the formation of larger clusters. In gation (Fig. 1). vitro, aggregation of both calcium oxalate [16, 17] Saturation of urine and calcium phosphate crystals [18] occurs readily when the solution is supersaturated. Aggregation It is now widely accepted that even in normal could be the mechanism which distinguishes simple people, urine is ordinarily supersaturated with re- crystalluria, which occurs in most normal people, spect to calcium oxalate [1—6], octocalcium phos- from stone formation. This line of thought is phate [2, 3], hydroxyapatite [1, 2], and sometimes strengthened by the finding that while usually only with respect to brushite [1, 7, 8]. The degree of individual calcium oxalate crystals are found in nor- supersaturation is usually higher in patients with mal people, stone-formers often excrete large aggre- urinary stones [2—4, 7—10].
    [Show full text]
  • Treatment of Textile Waste Waters by Hydroxyapatite Co-Precipitation with Adsorbent Regeneration and Reuse W
    Treatment of Textile Waste Waters by Hydroxyapatite Co-Precipitation with Adsorbent Regeneration and Reuse W. Lemlikchi, P. Sharrock, M. O. Mecherri, M. Fiallo, Ange Nzihou To cite this version: W. Lemlikchi, P. Sharrock, M. O. Mecherri, M. Fiallo, Ange Nzihou. Treatment of Textile Waste Waters by Hydroxyapatite Co-Precipitation with Adsorbent Regeneration and Reuse. Waste and Biomass Valorization, Springer, 2012, 3 (1), pp.75-79. 10.1007/s12649-011-9096-0. hal-01632408 HAL Id: hal-01632408 https://hal.archives-ouvertes.fr/hal-01632408 Submitted on 16 Jan 2019 HAL is a multi-disciplinary open access L’archive ouverte pluridisciplinaire HAL, est archive for the deposit and dissemination of sci- destinée au dépôt et à la diffusion de documents entific research documents, whether they are pub- scientifiques de niveau recherche, publiés ou non, lished or not. The documents may come from émanant des établissements d’enseignement et de teaching and research institutions in France or recherche français ou étrangers, des laboratoires abroad, or from public or private research centers. publics ou privés. Treatment of Textile Waste Waters by Hydroxyapatite Co-Precipitation with Adsorbent Regeneration and Reuse W. Lemlikchi • P. Sharrock • M. O. Mecherri • M. Fiallo • A. Nzihou Abstract When dissolved calcium salts are reacted in abatement and introduced calcium concentration, indicat- aqueous medium in the presence of phosphate anions, a ing the feasibility of the process. gelatinous precipitate forms. Maturation of this precipitate eventually leads to the formation of hydroxyapatites (HA). Keywords Dye removal Hydroxyapatite Adsorbent HA is a stable solid with high specific surface area, and regeneration EliminationÁ rate Á Á interesting adsorption properties.
    [Show full text]
  • Preparation and Solubility of Hydroxyapatite
    JOURNAL O F RESEARC H of the National Bureau of Standards - A. Ph ys ics a nd Chemistry Vol. 72A, No. 6, N ovember- December 1968 Preparation and Solubility of Hydroxyapatite E. C. Moreno,* T. M. Gregory,* and W. E. Brown* Institute for Basic Standards, National Bureau of Standards, Washington, D.C. 20234 (August 2, 1968) Two portions of a syntheti c hydroxyapatite (HA), Ca" OH(PO'}J, full y characterized by x-ray, infrared, petrographi c, and chemi cal anal yses, were heated at 1,000 °C in air and steam atmospheres, respectively. Solubility isotherms for these two samples in the syste m Ca(OH}2 -H3PO,-H20 were determined in the pH range 5 to 7 by equilibrating the solids with dilute H3 PO. solutions. Both sam­ ples of HA disso lved stoichiometrically. The activity products (Ca + +)'( OH - ) (pO~f' and their standard errors-obtained by a least squares adjustment of the measurements (Ca and P concentrations and pH of the saturated solutions) subject to the conditions of electroneutralit y, constancy of the activity product, and stoichiometric dissolution - were 3.73 ± 0.5 x 10- 58 for the steam-h eated HA and 2_5, ± 0.4 x 10- 55 for the air-heated HA. Allowance was made in the calculations for the presence of the ion pairs [CaHPO. lo and [CaH2P04 1+ The hi gher solubility product for the air-heated HA is as­ cribed either to a change in the heat of formation brought about by partial dehydration or to a state of fine subdivision resulting from a disproportionation reacti on_ The solubility product constant s were used to cal culate the points of intersection (i.e_, sin gular points) of the two HA solubility isot herms with the isotherms of CaHPO.
    [Show full text]