Constructing Ce-OH groups on CeO₂ for enhancing removal and recovery of uranium from wastewater and seawater

Efficient recovery of uranium from wastewater and seawater provides an important guarantee for the sustainable growth of nuclear energy. Herein, we skillfully use the alkali etching method to construct CeO₂ hollow spheres rich in Ce-OH groups for the removal and recovery of uranium from water matrixes. It is found that the CeO₂ exhibits fast adsorption kinetics (equilibrium time within 10 min) and moderate adsorption capacity (143.1 mg/g), and the removal efficiency of low concentration uranium (0.1 g/L and 1 g/L) reaches 100% within 1 min of adsorption. Moreover, the adsorption of uranium by CeO₂ is almost unaffected by common anions and cations in the environment, even if the concentration of anions is 1000 times that of uranium. More importantly, the CeO₂ can enrich uranium concentration in seawater by 167.9 times and the recovery rate reaches 83.9%. Mechanistic studies reveal that the adsorption of uranium by CeO₂ is mainly attributed to the rich Ce-OH groups on the surface of CeO₂, resulting in the rapid adsorption of U(VI) and mainly forms a single-bridge model. The findings of this study provide a green and efficient path for the removal and recovery of uranium from wastewater and seawater.