High efficiency adsorption of uranium in solution using nano-TiO2 loaded with g-C3N4

In this study, g-C3N4 was used to load with nano-TiO2 (NT) to prepare g-C3N4 @NT with good dispersibility in aqueous solution for the separation of uranium(VI) from wastewater. The adsorption efficiency for uranium(VI) by g-C3N4 @NT reached 90 % within 30 min and the maximum adsorption capacity for uranium(VI) on g-C3N4 @NT was 557.4 mg g−1, which was significantly better than that of NT (270.3 mg g−1). The studies of isotherm model and kinetic model indicated that the adsorption process to uranium(VI) on g-C3N4 @NT was a single-layer chemisorption process. The interaction mechanism between uranium(VI) and g-C3N4 @NT was further proved by SEM and XPS, which was attributed to the filling of oxygen vacancies, the oxidation-reduction effect and the inner spherical surface complexation. The results showed that g-C3N4 @NT might be expected to be used in removing uranium(VI) in solution.