Mxene-chitosan composites in wastewater treatment: From adsorption and separation to catalytic remediation

MXene Chitosan (MX-CS) composites have emerged as a promising class of material for wastewater treatment, capitalizing on the synergy between 2D MX's high surface area, conductivity, CS's abundant functional groups, and biocompatibility. This review briefly outlines their synthesis to yield stable, homogenous MX-CS composites and highlights the versatile applications in water remediation. In dye-laden effluents, MX-CS adsorbent efficiently binds and removes organic dyes, while in heavy metals contaminated streams, they sequester metal ions through chelation and electrostatic interaction. The composites also enable oil-in-water emulsion separation, antifouling membrane barriers, achieving high separation efficiency, and serve as a high-performance electrode in capacitive deionization systems for desalination by leveraging MX conductivity to enhance salt removal. Additionally, MX-CS composites show potential in mitigating pharmaceutical pollutants via adsorption or catalytic degradation. This review concludes with an outlook on future research direction and emphasizes the need to improve long-term stability, reusability, and scalability of these composites from laboratory study to real-world wastewater treatment applications.