Adsorption of Seven PFAS on Beta Zeolite

Per- and polyfluoroalkyl substances (PFAS) are emerging pollutants of concern. While traditional adsorbents such as activated carbon and ion exchange resins have been used to adsorb PFAS from water, they often lack the ability to be easily regenerated. Zeolite CP814E* was tested for its ability to adsorb seven PFAS, including PFBA, PFBS, PFHxA, PFHxS, 6:2FTS, PFOA, and K-PFOS. At concentrations less than 1 ppm, the zeolite adsorbed the PFAS in the order PFOA > 6:2FTS > K-PFOS > PFHxS > PFHxA > PFBS > PFBA. For all analytes modeled, the adsorption behavior best fits a modified two-step surfactant adsorption model (R2 = 0.99) except for K-PFOS (R2 = 0.88), showing distinct differences in adsorption behavior at high and low concentrations. Longer-chain PFAS tended toward more Langmuir behavior (L-shape), while shorter-chain PFAS displayed L-S and S-type adsorption. The majority of PFAS were quickly removed from the solution with >80% of the perfluorocarboxylic acids (PFCAs) and >60% of the perfluorosulfonic acids (PFSAs) removed in 30 seconds.