Remediation of per- and polyfluoroalkyl substances (PFAS) contaminated soil via soil washing with various water-organic solvents.

The feasibility of soil washing for remediating PFAS-contaminated clay soil using various water-organic solvents was systematically investigated based on the combination of batch and column tests. Batch tests using 22 types of solvents highlighted that 0 % (water) and 5 % solvents could effectively extract PFCAs (≤ C9), while long-chain PFCAs (≥ C10) and PFSAs required 80 % solvents for optimal extraction, with efficiency in the order of EtOH ≤ MeOH < Acetonitrile (ACN), suggesting a strong correlation with carbon chain lengths and functional head groups. Column tests with six selected washing solutions indicated rapid desorption of PFOA and PFOS initially, peaking at liquid-to-solid (L/S) ratios of 3-4 for 0 % and 5 % solutions, and at an L/S ratio of 1 for 80 % solutions.