Amphipathic fluoroamine-functionalized hydrogels for enhanced selective removal of anionic pfas from water

Effective treatment of per- and polyfluoroalkyl substances (PFAS) in an affordable manner is highly demanded to meet stringent water protection standards. Herein, we introduce a fluoroamine dual-site hydrogel (QFgel) designed to structurally match amphipathic PFAS molecules, facilitating selective interactions for the effective PFAS removal from water. Specifically, the synergistic effects of quaternized and fluorinated functional groups in QFgel can promote electrostatic-fluorophilic dual-site interactions with both the perfluoroalkyl and anionic headgroups at the ends of PFAS. As a result, these dual-site interactions achieve high selectivity (sorption coefficients ranging from 1.75 to 4.0) and ultrahigh sorption capacity (up to 2,835 mg g^-1), resulting in over 95.6% removal of 17 PFAS types at environmentally relevant concentrations in real water matrices. Notably, pilot-scale applications with a kilogram-scale QFgel-adsorber effectively treats up to 12,400 and 9,215 bed volumes of PFAS-contaminated drinking water (i.e., tap water) before the breakthrough point of perfluorooctanesulfonic acid (PFOS) and perfluorooctanoic acid (PFOA) ([PFAS]₀ = ~ 0.35 µg L^-1, 2 m³ per day). After 46 days of continuous operation, the adsorber is regenerated using a saline-methanol mixed eluent, achieving 96.5% desorption and up to 1,633-fold PFAS enrichment, while reducing eluent use by 70% compared to commercial sorbents. This work advances PFAS remediation by offering a scalable, cost-effective solution, and contributes to sustainable water resource protection.