Electrokinetic remediation for removal of per- and polyfluoroalkyl substances (PFASs) from contaminated soil

Uncontrolled use and disposal of per- and polyfluoroalkyl substances (PFASs) in recent decades has resulted in extensive soil and groundwater contamination, necessitating counteraction. Electrokinetic remediation (EKR) offers a promising approach to in-situ soil remediation. Two novel modifications to conventional EKR were tested for the first time in a laboratory-scale study, to explore the capacity of EKR for PFAS removal. The first modification was a two-compartment setup designed for PFAS extraction from soil to an electrolyte-filled chamber. The second was a single-compartment setup designed to transport and confine contaminants in a chamber filled with granular activated carbon (GAC), thus, combining extraction with stabilisation. Electromigration varied for individual compounds, based mainly on perfluorocarbon chain length and functional group. The results indicated up to 89% concentration and extraction of ∑PFASs for the two-compartment setup, with removal efficiency reaching 99% for individual PFASs with C ≤ 6. Removed PFASs were concentrated adjacent to the anode at the anion exchange membrane, while short-chain compounds were extracted in the anolyte. The single-compartment setup achieved 75% extraction and accumulation of ∑PFASs in GAC. This demonstrates, for the first time, good effectiveness of coupling EKR with AC stabilisation for PFAS removal from soil. Perfluorocarbon chain length was a dominant factor affecting treatment efficiency in both setups, with very high removal rates for short-chain PFASs.