MXenes as adsorbents for water pollutants: Synthesis, performance, mechanisms, and challenges

With the increasing discharge of hazardous pollutants from industrial and agricultural activities, the demand for efficient water purification technologies has increased substantially. Among the various available methods, adsorption is distinguished by its simplicity, rapid kinetics, and broad applicability. MXene-based adsorbents have emerged as promising candidates for the removal of heavy metals, radionuclides, and organic pollutants owing to their large surface areas, tunable functionalities, and layered structures. This review systematically addresses (i) the synthesis strategies of MXenes, their subsequent functionalization, and physicochemical characterization; (ii) their adsorption performance for both inorganic and organic contaminants under diverse environmental conditions, with particular emphasis on influencing factors, reusability, and regeneration strategies; and (iii) adsorption mechanisms, which are comprehensively elucidated by integrating the mechanistic aspects underlying the pollutant removal cases discussed in (ii). To the best of our knowledge, no previous review has comprehensively combined MXene synthesis, adsorption under various conditions, mechanistic insights, and regeneration within a single framework, which underscores the novelty of this review. Despite the substantial progress, challenges persist in terms of large-scale production, cost efficiency, and long-term durability. Future perspectives highlight the need for advanced modeling and holistic evaluation to ensure sustainable and practical applications of MXene-based adsorbents.