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A sol3gel technique for production of spherically granulated zirconium(IV) phosphate of Termoksid-3A brand is described. The method includes the following main stages: electrolysis of a zirconium(IV) chloride solution to give a sol of zirconium(IV) hydroxide, drop dispersion of the sol into an ammonia solution, conversion of gel-spheres of zirconium(IV) hydroxide into zirconium(IV) phosphate, and washing and drying of gel-spheres. The physicochemical and ion-exchange properties of the product obtained were studied.

The investigation results on the structure, sorptive-selective properties and exchange reversibility of the adsorbent selective to cesium cations are presented in this paper. A trade mark of this adsorbent is Termoxid-35. The composition of Termoxid-35 is the ''mixed'' nickel ferrocyanide distributed over zirconium hydroxide as an inorganic carrier. The structure of the cation-exchanger was studied by the infrared spectroscopy and the X-ray diffraction, differential-thermal and thermo-gravimetric analyses. The adsorbent is the double-phase system consisting of a highly-dispersed amorphous phase of zirconium hydroxide and a micro-crystalline phase of mixed nickel ferrocyanide. The isotherms of cesium cation adsorption in the pH region of 6.2 to 9.6 in the presence of 1 mol/l NaCl are presented. The distribution coefficient for cesium in the Henry region increases with the pH of the solution and reaches 6:5 Â 10 5 cm 3 /g at pH ¼ 9:6. The distribution coefficient for cesium is more than 1:0 Â 10 4 cm 3 /g with the concentration of the cation in the solid phase of 0.1 mmol/g. The cesium cation sorption on the ion-exchanger is irreversible.

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