Nanomaterial-enhanced membranes for PFAS remediation: Mechanistic insights, technology performance, and pathways to scalable implementation

Per - and polyfluoroalkyl substances (PFAS) pose an ongoing threat to the environment due to their stubborn carbon–fluorine bonds, extensive mobility, and documented toxicity. Traditional membrane technologies, such as reverse osmosis (RO) and nanofiltration (NF), are highly efficient (about 90 %) at removing long-chain PFAS. Still, their limitations in dealing with short-chain analogues, membrane contamination, and energy-intensive operations necessitate more advanced solutions. This review systematically evaluates the development of nanomaterial-reinforced membranes for PFAS removal, including grapHene oxide (GO), carbon nanotubes (CNTs), metal–organic frameworks (MOFs), covalent organic frameworks (COFs), MXenes, and hybrid nanocomposites. By integrating custom nanomaterials into polymer matrices, these membranes exploit synergistic mechanisms—dimensional rejection, electrostatic repulsion, hydrophobic adsorption, and photocatalytic degradation—to achieve >95 % retention of long-chain PFAS and > 80 % retention of short-chain PFAS under optimised conditions. We critically examine advanced configurations such as membrane distillation (MD) and forward osmosis (FO), which mitigate fouling and improve energy efficiency compared to conventional pressure-driven processes. Despite these advances, major challenges persist regarding scalability, long-term stability in complex wastewater matrices, and the cost-effective green synthesis of nanomaterials. In this review, we uniquely compare the performance trade-offs and mechanistic distinctions of GO, CNT, MOF, COF, and MXene composite membranes for both short-chain and long-chain PFAS removal, thereby providing a perspective that goes beyond prior literature. By outlining strategies such as smart responsive modules and hybrid degradation systems to overcome barriers to cost, scale-up, and variable water-matrix conditions, this work provides a cohesive roadmap for translating laboratory innovations into practical, field-ready solutions that meet regulatory demands and safeguard water quality.