Enhancement and sustained uranium removal of 2D transition metal sulfide-graphene oxide composite/carbon cloth cathodes in capacitive deionization system

Abstract

Capacitive deionization (CDI) holds significant potential for the recovery of uranium from uranium-containing wastewater (UCW). However, the limited availability of active sites in carbon cathodes poses a challenge to the efficient adsorption of uranium, thereby impeding its practical application. In this study, three types of two-dimensional transition metal sulfide-graphene oxide composites (WS₂-GO, TiS₂-GO, and MoS₂-GO) were synthesized and subsequently coated onto carbon cloth (CC) electrodes. Among these, the MoS₂-GO composite demonstrated a remarkable enhancement in the accessibility of active sites, resulting in an approximately 14-fold increase in uranium separation efficiency. The MoS₂-GO/CC cathode demonstrated effective and continuous separation of uranium, achieving a maximum adsorption capacity of 74.38 mg/g even under low uranium concentration (5.0 mg/L). Remarkably, at the end of the tenth cycle, the cathode maintained a high removal efficiency of 93.2 %. This cathode capitalizes on the presence of abundant functional groups, chemical stability, and high electronic conductivity to enhance the adsorption and reduction of uranium through synergistic interactions. MoS₂-GO and CC can be effectively integrated through a coating technique. The MoS₂-GO/CC cathode enhances uranium recovery in CDI, providing novel insights into the development of high-performance composite electrode materials.