Bridging separation and degradation: Rethinking membrane processes as preconcentration and multi-technology coupling platforms for PFAS removal

Per - and polyfluoroalkyl substances (PFAS) are persistent environmental micropollutants or emerging contaminants that resist conventional degradation, and their removal has become a hot topic worldwide in recent years. Pressure-driven membrane separation technologies such as nanofiltration (NF) and reverse osmosis (RO) are widely applied for PFAS removal and generally show higher rejection of long-chain homologues, yet they suffer from inherent drawbacks: poor removal performance toward short-chain PFAS, proneness to membrane fouling, and reliance on phase transfer rather than destructive elimination, as PFAS are merely concentrated into secondary waste streams without mineralization. These limitations collectively give rise to intractable technical bottlenecks and environmental management challenges. Herein, this review presents the “membrane as a bridge” conceptual framework, which organizes membrane separation as a preconcentration, matrix regulation, and coupling unit within integrated PFAS treatment systems that synergize with advanced destructive technologies (e.g., advanced oxidation processes (AOPs) or advanced reduction processes (ARPs)). Specifically, this work systematically elucidates how membranes act as a bridge toward PFAS separation, concentrate management, and downstream or interfacial destruction, covering the design and functional modification of high-performance membranes for selective PFAS separation, the interfacial mechanisms governing PFAS rejection and membrane fouling, the rational construction of systems that couple membrane separation with degradation, and targeted mitigation strategies for key bottlenecks including short-chain PFAS removal, fouling control, and concentrate management. Thus, this review establishes a paradigm-shifting “membrane as a bridge” framework to integrate separation and destruction, providing theoretical guidance for the design of sustainable, mineralization-oriented, and efficient PFAS removal strategies.