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Adsorption of Cobalt, Barium, and Zinc from Very Dilute

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Adsorption of Cobalt, Barium, and Zinc from Very Dilute ADSORPTION OF COBALT, BARIUM, AND ZINC FROM VERY DILUTE SOLUTIONS Dissertation Presented in Partial Fulfillment of the Requirements for the Degree Doctor of Philosophy in the Graduate School of The Ohio State University By ORVILLE JAMES KVAMME, B.S., M.S. The Ohio State University 1952 Approved by: C7fji Adviser dviser Table of Contents Page I, Introduction................................. 1 II. Literature Survey........................... 4 A. Properties of Radiocolloids.......... 4 1. Dialysis........................... 4 2. Electrophoresis and Filtration... 5 3. Hadioautography.................... 8 4. Sedimentation and Centrifugation. 9 B. Target Separations by Filtration 12 C. Properties of the Filter Paper....... 16 D. Radiocolloids Interpreted in Terms of the Diffuse Double Layer Theory... 30 III. Experimental Procedure..................... 36 A. Target Chemistry....................... 36 B. Experimental Technique................ 42 IV. Experimental Results and Discussion....... 48 A. Adsorption of Divalent Cobalt, Barium, and Zinc on Filter Paper,.... 48 1. Dependence on......... pH.......... 48 a. Cobalt......................... 48 b„ Barium......................... 64 c. Zinc. ...... 72 2. Dependence on Concentration.... 80 3. Dependence on Ammonium Chloride Concentration...................... 87 £29772 -ii- Eflgft 4. Dependence on Manganous and Cup- ric Chloride Concentration......... 96 5. Dependence on Ammonium Sulfate Goncentra tion....................... 104 B. Nature of the Filter Paper Adsorption.. 109 1. Effect of Washing the Adsorbed Cohalt and Zinc..................... 109 2. Titration of the Filter Paper 116 3. Adsorption of Zinc at a Water- Hexane Interface.................... 119 C. Adsorption of Cesium on Filter Paper... 122 V. Summary.................... 126 VI. Conclusions................................... 134 VII, Bibliography............ 137 VIII. Autobiography................................ 140 -iii- Tables Page I. Effect of pH on Cobalt Adsorption after Three-Day Standing....................•>.... 49 II. Effect cf pH on Cobalt Adsorption by Paper and Glass with Filtration Within Ten Minutes after Titration............... 52 III. Adsorption of Cobalt by Successive Filters after Three-Day Standing....... 55 56 57 IV, Effect of pH on the Adsorption of Barium in Concentrations less than 1 x 10-8 g. atoms/30 ml.................. 66 V. Effect of pH on Barium Adsoprtion (Stable Barium Added)...................... 68 VI, Effect of pH on Adsorption of Zinc........ 73 74 VII. Effect of Concentration of Cobalt on its Adsorption....................... 81 VIII. Effect of Concentration of Zinc on its Adsorption........... 84 IX. Effect of Ammonium Chloride Concentra­ tion on Cobalt Adsorption............. 88 X. Effect of Ammonium Chloride Concentra­ tion on Zinc Adsorption....,.............. 94 XI. Effect of Manganous Chloride Concentra­ tion on Cobalt Adsorption................. 97 XII. Effect of Cupric Chloride Concentra­ tion on Zinc Adsorption......... 101 XIII. Effect of Ammonium Sulfate Concentra­ tion on Zinc Adsorption......... 105 XIV. Effect of Washing the Adsorbed Cobalt 110 XV. Effect of Washing the Adsorbed Zinc....... 112 £agft XVI. Effect of Washing the Adsorbed Zinc with Solutions of Various Acidities 114- XVII. Adsorption of Zinc by a Water-Hexane Interface......... 120 XVIII. Effect of pH on Adsorption of Cesium 123 -V- Figures P^ge 1. Effect of pH on Adsorption of Cobalt by Paper...................... 51 2. Effect of pH on Cobalt Adsorption by Glass and Paper............................. 59 3. Effect of pH on Adsorption of Cobalt by Successive Filters............ 60 A. Effect of pH on Adsorption of Cobalt by Glass..................................... 62 5. Effect of pH on Adsorption of Barium by Paper.... ................................ 67 6. Effect of pH on Adsorption of Barium by Paper, Stable Barium Added............. 70 7. Effect of pH on Adsorption of Zinc by Paper..................................... 75 8. Effect of Ammonia Concentration on Adsorption of Zinc.''..,......... 78 9. Effect of Ammonia Concentration on Adsorption of Cobalt........................ 79 10. Effect of Cobalt Concentration on Ad­ sorption of Cobalt by Paper................ 82 11. Effect of Zinc Concentration on Ad­ sorption of Zinc by Paper.................. 85 12. Effect of Ammonium Chloride Concentra­ tion on Adsorption of Cobalt by Paper 90 13. Effect of Ammonium Chloride on Cobalt Adsorption................... 92 1/+. Effect of Ammonium Chloride Concentration on Adsorption of Zinc by Paper............ 95 15. Effect of Manganous Chloride Concentra­ tion on Adsorption of Cobalt............... 98 -vi- Page 16. Effect of Cupric Chloride Concentra­ tion on Adsorption of Zinc................. 102 17. Effect of Ammonium Sulfate Concentra­ tion on Adsorption of Zinc....... ......... 106 18. Titration Curves for the Filter Paper 117 -vii- ACKNOWLEDGMBNT The author wishes to take this opportunity to express his appreciation to Professors M. H, Kurba­ tov and J. D. Kurbatov for their excellent instruction and advice in the accomplishment of this work. Besides problems of a technical nature that arose in the course of this study, their consideration of the personal problems of the author was particularly appreciated. To the United States Air Force, the author ex­ presses his sincere gratitude for making this work possible. INTRODUCTION It has been known for almost forty years that certain heavy elements, such as radioactive isotopes of lead, bismuth, and polonium, can be filtered at concentrations much below that of so-called “saturated solutions" of their oxides. As these solutions often exhibit properties which are more like colloids than true solutes, they have become known as "radiocolloids". More recently it has been shown that the elements, yttrium, zirconium, and lanthanum, exhibit the same property, when the concentration of their respective compounds are much lower than their solubilities. In the above examples of radiocolloids, each element had an oxidation state of three or more. This tendency of some radioactive isotopes to be adsorbed on filter paper has been utilized in separa­ tions of activated target materials, the value of which lies in its speed and simplicity of operation. However, as yet, there is no satisfactory explanation for this phenomenon of filter paper retention. Also, very little is known concerning the factors which influence target separations by filtration. This work has been conducted, with the following objectives in mind: (l) To determine whether elements in the plus -2- two oxidation state are removed from very dilute solutions by filter paper. (2) To determine the factors that influence filter paper retention, for the following general purposes: (a) To increase the scope and efficiency of target separations by filtration. (b) To attempt to provide a satisfactory explanation for the phenomenon of fil­ ter paper retention. (c) To provide a comparative study of ad­ sorption of cobalt, barium, and zinc —6 in concentrations lower than 1 x 10~ mole per liter. For this study of some divalent cations, radioactive cobalt, barium, and zinc were utilized as tracers, since the experimental conditions of this work were such that the concentrations of the solute were too small to be measured by other quantitative methods. All activity measurements were made on a Geiger counter. The effect of the following parameters upon filter paper retention were studied: The effect of pH, of concentration of several divalent cations, of ammonium chloride concentration, of ammonium sulfate concentra­ tion, and of washing the filter paper. In order to determine more of the nature of the filter paper retention, the following studies were made: Titration of the filter paper, determination of the effect of washing the adsorbed cobalt and zinc with wash solutions at different acidities, and comparison of filter paper retention with surface adsorption be­ tween a water-hexane layer. Filter paper retention of cesium was also measured to determine the possibility of a separation of radio­ active isotopes of the alkaline earth elements from a target material consisting of a compound of an alkali element. —4-— LITERATURE SURVEY Properties of Radiocolloids As a basis for the understanding of filter paper retention, the literature is reviewed according to the properties which distinguish radiocolloids from true solutes. Dialysis. F. Paneth (1913) (l) dialyzed a neutral solution of radio-lead nitrate against pure water. The solution contained RaD (Pb2^0), RaE (Bi2-1,0), and polon­ ium (Po2^®). The RaE and polonium were concentrated in Ihe original solution, whereas the lead isotope diffused into the pure water. When a solution of polon­ ium in nitric acid was made alkaline with ammonium hy­ droxide, there was no apparent precipitation; however, the solution which was previously capable of diffusion now did not show any polonium in the dialysate. This behavior was explained on the basis that radiocolloidal hydroxides of metals were present in neutral and basic solution, but not in acid. It was also found that RaE would diffuse through a membrane in acid solution. F. Paneth (1913) (2) studied the diffusion coefficients of these same radioactive substances in very dilute solutions. It was found that all of the radioelements diffused with normal speed in acid solution, but that the normal diffusion coefficients of polonium, RaE, and thorium B (Pb2^-2) decrease when their solutions are made neutral or basic with ammonium
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