Sorption studies of cesium on TiO2–SiO2 mixed gel spheres

TiO2–SiO2 mixed gel spheres used for the sorption studies of cesium were prepared via sol–gel method. The source solutions used for the process were prepared from different mixtures of 1 M TiCl4 and 1 M Na2SiO3 solutions and converted into droplets in a gelation column. The suitable spheres for cesium adsorption were obtained using a methyl isobutyl ketone solution as the drop formation medium and ammonia as the gelling agent. The mixed oxide gels were identified and characterized by Analysis Adsorptive (N2), DTA/TGA, FTIR and XRD analyses. The sorption behavior of Cs+ cations on TiO2–SiO2 mixed gel spheres has been studied as a function of TiO2 weight ratio, pH, time, cation concentration, temperature and competing ions. Sorption data have been interpreted in terms of Freundlich and Dubinin–Radushkevich equations. Sorption of Cs+ cations were found to be endothermic in nature with ΔH° (kJ/mol) of 5.06, and ΔS° (kJ/(mol K)) of 0.06. Negative ΔG° value obtained for Cs+ cations indicates the spontaneity of its sorption on mixed oxide gel spheres.