An overlooked resin composition effectively captures and releases various PFAS including challenging short-chain structures.
Kan Xiping X, Zhang Sizhuo S, Sarkar Swagotom S, Liu Jinyong J et al.
Capturing per- and polyfluoroalkyl substances (PFAS) from water via adsorption remains vital yet challenging due to the lack of effective sorbents with high affinity across the wide structural diversity, particularly the highly mobile short-chain PFAS. This limitation also challenges the performance of PFAS passive samplers. Here, we report a homemade anion exchange resin with polystyrene and triethylamine structures (PS-NEt3+) that is highly effective at capturing and releasing PFAS. PS-NEt3+outperformed commercial benchmarks in capturing various legacy and emerging PFAS across multiple matrices, exhibiting particularly high affinity for short-chain PFAS (>85% uptake) in the presence of inorganic competitors. PS-NEt3+also demonstrated superior uptake at a low sorbent dose (30 mg/L) for broad-spectrum PFAS, including unknown structures, in highly polluted scenarios with both inorganic and organic competitors. The 75/25 mixture of PS-NEt3+and a commercial resin further improves the capture of the 40 PFAS analytes in USEPA Method 1633. The mixture achieved a median regeneration recovery of 97% when eluted with methanol containing ammonium acetate. The high PFAS affinity and selectivity of the mixture make it an ideal receiving phase for passive samplers by overcoming the enduring challenge of limited uptake and early sorbent breakthrough in previous passive sampling studies. Furthermore, while resins with long or asymmetric amines have been considered superior for PFAS capture in previous studies, the surprisingly high performance of PS-NEt3+ challenges this prevailing assumption and opens new avenues for PFAS sorbent selection.