Graphene aerogel for photocatalysis-assist uranium elimination under visible light and air atmosphere

Abstract

Photocatalysis-assist transition of uranium from soluble ions to insoluble nanoparticles is benefit for the extraction of uranium but has been rarely realized under air atmosphere. Here we developed a novel graphene aerogel (GA), GA-200, for the photocatalytic removal of uranium from water under visible light and air atmosphere for the first time. By controlling the reduction degree, GA-200 remained numbers of functional groups for anchoring uranium and possessed high photocurrent response and narrow band gap to generate and transfer electrons/holes readily. Under visible light irradiation, neutral (UO2)O2·2H2O nanoparticles were formed and could evacuate from the surface of GA-200 to regenerate the active sites in-situ, resulting in a high removal capacity of 1050 mg/g. The mechanism was further studied. It was found that at the presence of O2 in air, the photochemistry property of uranyl itself played an essential role to generate H2O2 and (UO2)O2·2H2O was formed instead of UO2, which was different from that in oxygen-free atmosphere.