Diatomite modified by TiO2 for adsorption of U(VI)

Diatomite was modified with TiO2. The synthesized materials were characterized and used for removal of U(VI) from aqueous solutions. The influences of pH, contact time and temperature on U(VI) adsorption onto TiO2@diatomite were studied by batch technique, and X-ray photoelectron spectroscopy (XPS) was employed to analyze the experimental data. We compared the adsorption of U(VI) onto natural diatomite, TiO2 and TiO2@ diatomite made by sol-gel method. The dynamic process showed that the adsorption of U(VI) onto TiO2@diatomite matched the pseudo-second-order kinetics model, and the adsorption of U(VI) was significantly dependent on pH values. Through simulating the adsorption isotherms by Langmuir, Freundlich and Dubini-Radushkevich (DR) models, respectively, it could be seen that the adsorption patterns of U(VI) onto TiO2@diatomite were mainly controlled by surface complexation, and the adsorption processes were endothermic and spontaneous. The modification of diatomite by TiO2 shows a novel material for removing U(VI) from water environment for industrialized application.