Enhanced uranium adsorption performance of porous MXene nanosheets

Abstract

The recovery of uranium from nuclear wastewater holds considerable importance in safeguarding water resources and addressing the issue of nuclear energy scarcity. Recently, modified MXenes have emerged as a promising adsorbent for U(VI)-containing wastewater due to their abundant active sites and exceptional radiation resistance, but the incorporation of costly functional molecules is usually necessary to yield satisfactory performance. In this work, we synthesized a novel kind of nano-porous Ti3C2Tx MXene nanosheets using a simple pore-creating method with Cu2+ as catalysts, which were tested for U(VI) elimination. Impressively, the U(VI) adsorption capacity (299 mg/g) of the porous MXene nanosheets surpassed that of most previously reported modified MXene and other materials. Meanwhile, Pseudo-second-order kinetics and Freundlich models provided suitable descriptions of the adsorption process, indicating heterogeneous chemisorption occurred. Experimental and spectral analysis suggested that the enhanced U(VI) adsorption capacity of the porous MXene nanosheets primarily benefited from more active OH groups on their surface to form bidentate coordination with U(VI). This work provided a valuable concept for preparing new MXene-based adsorbent for uranium removal.