Electrochemical treatment of PFAS in fractionated foam

Foam fractionation is emerging as a promising option to remove and concentrate PFAS from polluted water and soil resources. Here, we investigate the electrochemical treatment of foamate resulting from the simultaneous application of soil washing and foam fractionation for the remediation of PFAS-contaminated soil. The effect of the applied current density, flowrate, initial PFAS concentration and organic matter content was first assessed on a synthetic solution. Fractionated foam was then treated, and concentration profiles of detected C4-C8 perfluoroalkane sulfonic acids (PFSAs), the fluorotelomer sulfonate 6:2 FTS, and C4-C8 perfluoroalkyl carboxylic acids (PFCAs) were investigated. Electrochemical degradation of the fractionated foam proceeded through the generation of short chain intermediates. Most of PFOS degradation occurred within the first 10 min of treatment, with a resulting reduction of ∼68% of the initial total PFAS content. However, no further significant reduction of PFOS was observed within 5 h, concentration of C < 8 PFSAs did not decrease, while PFCAs concentration increased likely due to their generation as degradation intermediates. Electrochemical treatment of fractionated foam must be further studied to extend the degradation performance to several PFSAs, as well as to ensure complete mineralization of PFCAs within a reasonable timeframe. To this aim, matrix-specific interferences demand investigation. Furthermore, advancement in reactor configuration may guarantee enhanced performance driven by maximized PFAS contact with the electrode surface.