Efficient removal of U(VI) from simulated seawater with hyperbranched polyethylenimine (HPEI) covalently modified SiO2 coated magnetic microspheres

Herein, we report on magnetic microspheres with numerous imine groups on the surface, which have great potential for U(VI) recovery in seawater. Hyperbranched polyethylenimine (HPEI) was covalently grafted onto the surface of the core–shell structured microspheres Fe3O4@SiO2. The microstructure and chemical composition of Fe3O4@SiO2-HPEI were comprehensively characterized. Consequently, the adsorption performance at low concentrations (3–30 μg L−1) under simulated seawater was investigated and the removal rate reached more than 90%. The superior performance of the Fe3O4@SiO2-HPEI is attributed to electrostatic force and chemical bonding (between amine/imine groups and U(VI)). We recommend, therefore, Fe3O4@SiO2-HPEI as a prospective alternative adsorbent in U(VI) recovery from seawater.