Pilot-scale comparison of granular activated carbons, ion exchange, and alternative adsorbents for per- and polyfluoroalkyl substances removal

Eight granular activated carbons (GAC), four anion exchange (IX) resins, and two alternative adsorbents (AAs) were tested for the removal of per- and polyfluoroalkyl substances (PFAS) from a groundwater source used for drinking water. The study was conducted using pilot(meter)-scale columns operated in continuous-flow mode for 16–26 months. Comparison between GAC adsorbents showed that bituminous GACs exhibited higher adsorption than non-/sub-bituminous GACs. Testing of a reactivated and new GAC showed no significant differences with respect to PFAS adsorption. Of the four IX resins tested, one resin showed superior adsorption when compared with all three IX resins. A surface-modified bentonite adsorbent showed superior removal efficiencies over all adsorbent types tested here. These results provide benchmark performance and adsorption capacities at pilot-scale for various adsorbents and highlight the promise of AAs to remove PFAS from water sources with low (ng/L) concentrations.