Graphene oxide sheathed cobalt vanadate porous nanospheres for enhanced uranium extraction

Uranium extraction from environment is not only conducive to the sustainable development of the nuclear energy industry but also significant to the remediation of radioactive contamination. Herein, effective adsorption sites for uranium extraction were introduced via the in situ growth of cobalt vanadate porous nanospheres on the graphene oxide (GO) layer (GO@Co2VO4 PNSs). Uranium adsorption capacity of the GO@Co2VO4 PNSs composite promoted significantly with 221.6% promotion compare to the pristine single GO and 80.8% promotion to the pristine Co2VO4 PNSs. The adsorption efficiency also enhanced distinctively to the single components of either GO or Co2VO4 PNSs at a wide pH value span from 3 to 6. The reusability efficiency kept at 89.94% even after five cycles of adsorption-desorption. XPS measurements and DFT calculations reveal that the adsorption affinity mainly originated from the oxygens of the cobalt vanadate porous nanospheres. What's more, the GO@Co2VO4 PNSs composite show effective uranium adsorption under a wide pH range, which paved the real application in the spent fuel disposal. The outstanding adsorption capacity, reliable reusability, and excellent removal efficiency further provide a theoretical guidance and potential application for environmental uranium-pollution remediation.