Performance of different sorbents toward stabilizing per- and polyfluoroalkyl substances (PFAS) in soil

Contamination of soils with poly- and perfluoroalkyl substances (PFAS) has been reported worldwide and stabilization is recognized as an effective approach for in situ remediation. In this study, biochar, GAC, RemBind® 100, and RemBind® 100X were evaluated with respect to their performance stabilizing 10 PFAS in soil. The results indicated that compared to unamended controls, GAC, RemBind® 100, and RemBind® 100X decreased the water and acidic water leachable PFAS by 99%. This was irrespective of PFAS chain length. Further aging of the sorbents in soil did not cause any release of the stabilized PFAS. Amendment of biochar to the same soil at the same dose led to significant decrease of leaching for long chain PFAS. The stabilization of short chain PFAS, such as PFBS, PFHxA, GenX, and PFHpA by biochar, however, was significantly lower than those by other sorbents. Interestingly, increasing contact time significantly improved the sorption of these short-chained PFAS to biochar.