Designed Core–Shell Fe3O4@Polydopamine for Effectively Removing Uranium(VI) from Aqueous Solution

Adsorbents with the combination of magnetic separation and removal performance are expected for reducing the adverse impact of nuclear pollution. In this study, the core–shell Fe 3 O 4 @polydopamine (Fe 3 O 4 @PDA) was successfully synthesized and used for removal of uranium (U(VI)) ion from aqueous solution. The abundant N-containing groups derived from PDA exist as the chelate sites for U(VI) and contribute greatly for U(VI) removal. Experimental results show that Fe 3 O 4 @PDA (56.39 mg g –1 ) exhibits greater sorption capacity for U(VI) removal compared with the pure Fe 3 O 4 (9.17 mg g –1 ). The sorption isotherm can be well fitted with Freundlich model and the sorption process is endothermic and spontaneous. The removal of U(VI) can be explained by the complexation of U(VI) with –NH–, –NH 2 and C–O in the surface of Fe 3 O 4 @PDA by X-ray photoelectron spectroscopy (XPS) analysis.