Reactive Polymeric Membranes for Advanced Water Treatment: Bridging Mechanisms, Kinetics and Scalable Deployment

Reactive polymeric membranes are emerging as promising platforms for advanced water and wastewater treatment because they combine separation with in situ contaminant transformation. Unlike conventional membranes, which mainly retain pollutants, reactive polymeric membranes can enrich, activate, and degrade micropollutants during permeation through built-in radical, redox-active, conductive, or porous catalytic domains. This review discusses the development of intrinsic reactive polymer membranes for oxidative filtration, with emphasis on the links between polymer structure, transport behavior, reactive oxygen species generation, and degradation pathways. Key membrane classes are discussed, including stable-radical polymers, redox-active polymer networks, conductive polymer membranes, and porous conjugated polymer catalytic layers. The review also highlights the importance of reactive transport kinetics, including convection-diffusion-reaction coupling, residence time, Damköhler and Péclet numbers, and adsorption-enhanced degradation. Challenges such as fouling, polymer aging, leaching, byproduct formation, and toxicity-aware benchmarking are discussed within a broader roadmap for technology translation. The review identifies the grand challenges and milestone-based priorities for developing and deploying reactive polymer membranes, including performance targets, standardized reporting, realistic water matrices, scale-up, technology readiness levels, techno-economic analysis, life cycle assessment, artificial intelligence, and digital twins. Together, these elements guide the translation of reactive polymer membrane systems from laboratory research toward full-scale water treatment applications.