Removal of per- and poly-fluoroalkyl substances by nanofiltration membranes in water and wastewater: A review

Abstract

Perfluoroalkyl and polyfluoroalkyl substances (PFASs) are persistent, highly mobile contaminants that conventional water treatment processes fail to remove effectively. Nanofiltration (NF) membranes have emerged as a promising method for PFAS removal because of their tunable properties to satisfy both selective removal and permeability. This review summarizes current advances in NF membranes and how the physicochemical properties of both PFASs and NF, along with their operational conditions, influence removal performance. PFAS removal via NF primarily occurs through steric (size) exclusion, followed by electrostatic repulsion between the membrane surface and PFAS molecules. Membrane characteristics such as pore size, surface charge, and morphology, as well as PFASs properties (e.g., molecular weight, functional groups, and chain length), significantly influence these interactions. Additionally, operational parameters and water quality factors (e.g., pH , divalent cations, natural organic matter, transmembrane pressure, and concentration) also affect removal efficiency. Several hybridization approaches have shown promise for improving the removal of short-chain PFASs, addressing a major limitation of NF that relies on steric exclusion. This review provides a holistic assessment of NF-based PFAS removal, emphasizing the correlations between material properties, operating conditions, and removal mechanisms. It also highlights current research gaps, particularly the need for studies under realistic water matrices for practical applications. © 2026 The Korean Society of Industrial and Engineering Chemistry.