SORPTION OF STRONTIUM AND LANTHANUM ON POLYANTIMONIC ACID AND 2 PHOSPHATOANTIMONIC ACIDS

The sorption of strontium and lanthanum on antimonic acid (HAP) and on two phosphatoantimonic acids, H3Sb3O6(PO4)(2) (RH3) and H5Sb5O12(PO4) (2) (RH5) were studied by three types of measurements: kinetics of fix ation, distribution coefficients at trace level and sorption capacity. A 2H(+)/Sr2+ or 3H(+)/La3+ exchange stoichiometry and an affinity ord er of HAP > RH5 > RH3 for Sr and RH3 > HAP > RH5 far La were observed. The fixation kinetics is very fast for RH3. For HAP and RH5, there is a fast step followed by a slow diffusion-controlled step. The results are interpreted by comparing the chemical compositions and crystal st ructures of the three sorbents. Applications to radioactive waste trea tment are discussed.