MXene-based catalytic membranes for advanced wastewater treatment

The integration of membrane separation technology with advanced oxidation processes (AOPs) offers a promising approach to alleviate practical limitations associated with the permeability-selectivity trade-off by reducing membrane fouling and enhancing pollutant degradation. MXene-based catalytic membranes harness the synergistic benefits of AOPs and membrane filtration to achieve efficient and rapid water purification. This review summarizes the physicochemical properties of MXene (e.g., morphology, chemical and mechanical stability, and optoelectronic properties) and correlates their functions in regulating catalytic AOPs performance. We first introduced AOP-oriented synthesis and functionalization of MXene-based membranes, encompassing surface/interface engineering, heterostructure construction, interlayer regulation, and membrane architecture design. These approaches aim to regulate the chemistry of active site, electron transfer behaviors, and reactive species generation, providing a comprehensive framework for catalytic enhancement in membrane-based AOPs. Next, the latest progress in MXene-based AOPs was reviewed, elucidating the structure-activity relationship between the MXene features and the evolved reactive oxygen species, which ultimately determine pollutant removal selectivity and efficiency. Furthermore, this review highlights the factors in rational design of practical MXene-based catalytic membrane filtration systems, to maximize membrane catalytic efficiency and enhance filtration velocity. Finally, we propose research directions and challenges in on-demand fabrication and reactor-level engineering of catalytic MXene membrane to cater for real-world wastewater treatment scenarios.