Global Occurrence, Health Risks, and Treatment Challenges of PFAS in Wastewater: Prospects for Photocatalytic Membrane Technologies

Abstract Per- and polyfluoroalkyl substances (PFAS) persist in aquatic environments and resist conventional wastewater treatment, thereby sustaining long-term exposure risks. However, decision-making is hindered by uneven global monitoring, especially in Southeast Asia, along with method-dependent variations in occurrence or removal estimates, and limited pilot-scale evidence for truly destructive yet cost-credible treatments. This review synthesises global occurrence trends before and after major regulatory actions and compares reported removals across wastewater treatment plants (WWTPs), highlighting geographic variability, gaps in treatment efficiencies and method-dependent results. It also examines the health and environmental threats associated with legacy PFAS and their emerging alternatives when inadequately treated. Current PFAS remediation options (i.e., physical adsorption, membrane treatment, advanced oxidation processes (AOPs), and photocatalysis), are benchmarked against practical criteria (i.e., efficiencies, limitations, stability and cost). Particular attention is given to the advantages and challenges of photocatalytic technologies. In particular, membrane technology can considerably improve photocatalytic treatment. Photocatalytic membrane techniques may improve catalyst stability, reusability, and degradation yield. By reducing energy and secondary-waste burdens through catalyst reuse, photocatalytic membranes may be cost-credible. Their scalability depends on durable immobilisation, fouling control, and straightforward integration with current infrastructure. Therefore, these considerations highlight the necessity to investigate and enhance photocatalytic membrane systems for effective and sustainable PFAS remediation. Graphical abstract