Sorption of alkaline and alkaline-earth radionuclides on zirconium phosphate sorbent Termoxid-3A from aqueous solutions

Sorption kinetic behavior of¹³⁷Cs,⁸⁵Sr,¹³³Ba and²²³Ra has been studied in the system: inorganic sorbent on the base of zirconium phosphate, Temoxid-3A, and diluted aqeous solutions. Chemosorption mechanism with the limiting step of external diffusion of the reaction between radiostrontium and the sorbent was established (n=1.304±0.0). For barium, radium and cesium radionuclides this mechanism was found to have an ion-exchange character (n<1), with limiting step of external diffusion for barium and radium radionuclides and internal diffusion for radiocesium. Termoxid-3A possesses good sorption kinetic properties. Values of the equilibrium distribution coefficients of the radionuclides studied in the suggested conditions were n·10³. Time for attaining equilibrium does not exeed 40 minutes. Purification coefficient of Moscow potable water from radiostrontium was equal 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 but the mechanism of radiostrontium interaction with the sorbent changes its character from chemosorption to ion exchange (n=0.75).