SORPTION OF ALKALINE AND ALKALINE-EARTH RADIONUCLIDES ON ZIRCONIUM-PHOSPHATE SORBENT TERMOXID-3A FROM AQUEOUS-SOLUTIONS

Sorption kinetic behavior of Cs-137, Sr-85, Ba-133 and Ra-223 has been studied in the system: inorganic sorbent on the base of zirconium pho sphate, Termoxid-3A, and diluted aqeous solutions. Chemosorption mecha nism with the limiting step of external diffusion of the reaction betw een radiostrontium and the sort,ent was established (n = 1.304 +/- 0.0 ). For barium, radium and cesium radionuclides this mechanism was foun d to have an ion-exchange character (n <1), with limiting step of exte rnal diffusion for barium and radium radionuclides and internal diffus ion for radiocesium. Termoxid-3A possesses good sorption kinetic prope rties. Values of the equilibrium distribution coefficients of the radi onuclides studied in the suggested conditions were similar to n . 10(3 ). Time for attaining equilibrium does not exeed 40 minutes. Purificat ion coefficient of Moscow potable water from radiostrontium was equal to similar to 100 when 1000 column volumes passed through. Immobilized with strontium sorbent (1.5 mg equiv. of Sr/g sorbent) keeps all its good sorption kinetic characteristics towards radionuclides studied bu t the mechanism of radiostrontium interaction with the sorbent changes its character from chemosorption to ion exchange (n = 0.75).