Carbon based adsorbents for the removal of U(VI) from aqueous medium: A state of the art review

Abstract

Carbon-based adsorbents such as activated carbon, biochar, and graphene materials are the most promising candidates for removing uranium from an aqueous solution. These materials could acquire different surface charges under different pH conditions and therefore are capable of adsorbing diverse uranium species from water. Another significant aspect of carbon-based adsorbents is their tunable surface characteristic to promote the targeted removal of uranium ions. In this review, we have summarized recent studies based on the strategies used for uranium species removal using afore mentioned carbon-based adsorbents. Different techniques used to prepare such adsorbents for the effective removal of uranium from wastewater has been discussed focusing the surface functionalization protocols. Discussions has been furnished on the key mechanisms involved in the uranium removal using the highlighted adsorbentswith reference to adsorption kinetics and isotherm models. The performance of various carbon-based adsorbents has been compared in terms of partition coefficient to assess their usefulness towards uranium removal applications. Further, a concise summary on DFT analysis has been supplied to elucidate uranium removal mechanisms by various carbon adsorbents. It is expected that this article will address the literature gapin the current status of carbon-based adsorbents for uranium removal with the perspectives of future works and challenges in this area.