The rise of MXenes: Synthesis, properties, and fabrication of advanced membranes

MXenes, a class of two-dimensional transition metal carbides, nitrides, and carbonitrides, have emerged as promising materials for advanced membrane separations due to their tunable physicochemical properties, high electrical conductivity, and hydrophilicity. This review comprehensively explores MXene synthesis methods, including etching, top-down, and bottom-up approaches, and their applications in membrane-based separations for wastewater treatment, desalination, and organic solvent nanofiltration. MXene-based membranes have demonstrated water permeability values ranging from 37 to 800 LMH/bar, which are up to five times higher than those of conventional polymeric membranes, while achieving >90 % rejection of dyes and multivalent ions. For example, Ti₃C₂T_x and Nb₂CT_x membranes show selective ion rejection exceeding 95 % for Mg²⁺ and SO₄^2-, along with stable performance over >120 h continuous operation without notable flux decline. These quantitative indicators underscore the superior permeability–selectivity balance and enhanced operational durability of MXene-based systems. However, challenges such as the scalability of synthesis, long-term stability in aqueous environments, and susceptibility to oxidation hinder their widespread adoption. Innovative strategies, including cross-linking, polymer encapsulation, and hybrid composites, are explored to address these limitations. The review also highlights MXenes multifunctional potential in smart membranes, catalytic degradation, and self-cleaning applications, underscoring their role in bridging conventional and modern separation technologies. Future research should focus on sustainable synthesis, large-scale production, and integration into industrial processes to realize their full potential.