UV-induced simultaneous removal of GO and U(VI): The role of aggregation, photo-transformation, adsorption and reduction

Abstract

The photo-transformation of graphene oxide (GO) nanosheet and the photo-reduction of uranyl ion (U(VI)) have been widely studied separately. However, little attention has been given to the simultaneous photo-degradation of GO nanosheets and the photochemical reduction of U(VI) under ultraviolet (UV) illumination. In this study, the relationships among the UV-induced degradation of GO, the U(VI)-induced aggregation of GO, the adsorption of U(VI) on GO, and the UV-induced reduction of U(VI) as well as their roles in the UV-induced simultaneous photo-degradation of GO and photo-reduction of U(VI) were elucidated. These results indicated that the UV-induced transformation of GO occurred more quickly than the adsorption of U(VI) on GO. The presence of low concentration of U(VI) could promote the UV-induced transformation of GO at the initial stage, while UV irradiation weaken the efficiency of U(VI) ions in destabilizing GO nanosheets at the subsequent stage. Our findings are crucial for developing a highly efficient method to accomplish the simultaneous removal of GO and U(VI) in the actual environmental cleanup.