Removal of Cs(I) and Sr(II) from Liquid Media with Crystalline Titanosilicates Prepared by Hydrothermal Synthesis

The water pollution with Cs+ and Sr2+ radionuclides in the nuclear fuel cycle is a pressing environmental problem. The selective adsorption of radionuclides onto inorganic sorbents of zeolite structure, exhibiting the ion-sieve effect, is a promising procedure for the treatment of the liquid radioactive waste formed. Titanosilicate of the CST structural type, corresponding to the formula Na1.64H0.36Ti2O3SiO4(H2O)1.84, was prepared by hydrothermal synthesis performed at 190°С and a pressure of 1.3 MPa for 24 h. This sorbent allows efficient removal of the Cs+ and Sr2+ cations from liquid media. The sorption exchange capacity qeq is 1.58 mg-equiv/g for Cs+ and 2.56 mg-equiv/g for Sr2+. Preliminary oxidation of Ti3+ to Ti4+ with H2O2 increases the sorption capacity for Cs+ and Sr2+. The phase composition, elemental composition, specific surface area, and pore size of the materials synthesized were determined. The titanosilicates obtained can be used as sorbents for liquid radioactive waste treatment.