Interference of PFAS sorption on zeolites from natural water characteristics

Abstract

Per- and polyfluoroalkyl substances (PFAS) are emerging anthropogenic pollutants of concern and are associated with potential human and environmental health concerns. PFAS removal can be achieved using adsorbents such as activated carbon and ion exchange resins. Recently, zeolites have been identified as another potential adsorption technology with increased selectivity and product regenerability that is not currently achieved with other adsorbents. Zeolite CP814E∗ (BEA) was tested in batch reactions for PFAS removal in different water matrix characteristics, including pH, select cations, humic acids (HA), fulvic acids (FA), and natural organic matter (NOM). In synthetic EPA waters, BEA performance increased compared to ultrapure water testing. BEA performance also significantly increased in the presence of Na⁺, Ca²⁺, and Mg²⁺ ions compared to ultrapure waters. PFOA and PFOS sorption did not vary significantly in the 6–9 pH range. HA, FA, and NOM did not significantly impact the sorption of PFOA and PFOS on the BEA at 1 g/L zeolite loading. One organic interferent, Suwannee River humic acids, did reduce PFOA sorption when the ratio of adsorbent to liquid was reduced to 0.1 mg/L. BEA retained sorption capacity over seven thermal regeneration cycles, and a BEA test with a real water demonstrated PFOA, PFOS and PFHxS adsorption at the parts per trillion level.