Graphene Oxide-based Nanomaterials for Uranium Adsorptive Uptake

The growth of nuclear power generation and the necessity to acquire uranium reserves for energy security and pollution regulation for environmental protection put much emphasis on the removal and recovery of uranium from aqueous solutions. Adsorption has been proved to be a promising method for this purpose method because of its high adsorption efficiency, easy operation, low cost, reusability and availability of massive adsorbents. Among a wide variety of adsorbents, graphene oxide (GO) has demonstrated excellent adsorption potential for uranium uptake and recovery due to its unique 2D structure, high specific surface area and abundant oxygen-containing functional groups. Regarding the functional groups, it can make GO with high dispersion and hydrophilicity and participate in the complexation of uranium, leading to high adsorption efficiency for uranium. In this review, the research status and progress of GO-based nanomaterials for uranium adsorption are summarized. Their adsorption capacities, influencing factors, kinetics, isotherms and thermodynamics are compared and discussed. The microscopic mechanisms of uranium adsorption onto these GO-based nanomaterials are elaborated at molecular level by spectral analysis, surface complexation models, and theoretical calculations. Meanwhile, the challenges and research trends in the study of uranium adsorption by GO-based nanomaterials are pointed out. We believe that our focused review provides not only a summarizing reference on the current status of uranium removal and recovery by GObased nanomaterials, but also future directions for related follow-up research and practical applications.