Carrier-Mediated Selective Transport of PFAS across Liquid Membranes

Abstract

Per- and polyfluoroalkyl substances (PFAS) are persistent pollutants whose environmental mobility and biological accumulation are governed by transport across phase boundaries. Although biological PFAS transport has been extensively investigated, synthetic systems capable of mediating selective PFAS transport remain underdeveloped. Here, we report a family of synthetic carriers (P1–7) that enable structure-dependent, directional PFAS transport across liquid membranes under mild pH gradients. Binding interactions were characterized by ultraviolet–visible (UV–Vis) and nuclear magnetic resonance (NMR) spectroscopic studies and supported by density functional theory (DFT) calculations. Transport efficiencies were quantified by liquid chromatography–mass spectrometry (LC–MS). Structural variations were found to modulate the host–guest interactions, enabling selective transport of targeted PFAS from competitive aqueous mixtures with efficiencies exceeding 90%, whereas competing species remain largely untransported. Negligible transport occurs in the absence of a carrier. The practical applicability of the system was further demonstrated using lake water (Austin, TX, USA) containing ppm-level competing inorganic ions, with selective PFOS transport remaining effective at the associated ppt-level concentrations. These findings establish selective artificial PFAS transport as a tunable supramolecular-mediated process and provide a conceptual foundation for PFAS removal, separation, and potential detoxification.