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The effective removal of PFAS from chemically complex landfill leachate remains a significant challenge for the solid waste industry. To address this, a membrane electrochemical reactor (MER) was investigated for PFAS removal from landfill leachate at low pH (∼2.0) in the anode chamber. The MER achieved 95.6 % PFAS removal from landfill leachate within seven hours of operation, with 98.3 % of perfluorosulfonic acids (PFSA) and 85.5 % of perfluorocarboxylic acids (PFCA) removed from the leachate. Short-chain PFSAs (C ≤ 6, 92.5–99.1 %) were removed more efficiently than PFCAs (C ≤ 6, 80.8–90 %), possibly due to their stronger affinity for the air–water interface, which enhanced foam-based separation. Long-chain PFAS (C > 6) showed near-complete removal (96.1–100 %). Importantly, PFAS precursors such as fluorotelomer carboxylic acids and perfluoroalkane sulfonyl fluorides were not detected in defoamed leachate, suggesting their removal through both oxidative transformation and foam-phase partitioning in the MER. Simple pH adjustment to 2.0 using concentrated H 2 SO 4 , conducted for comparison with the MER, resulted in 83.1 % of PFAS separation into foam and 11.3 % into settled solids. Additionally, short-chain PFAS were separated into foam (59.2–84.7 %) and settled solids (5.7–13 %), while long-chain PFAS showed similar trends with 78.3–86 % in foam and 5.3–18.2 % in settled solids. The addition of 0.1 M NaHCO 3 before pH adjustment enhanced foam formation, increasing PFAS separation in foam to 92.5 %. This study highlights MER’s effective PFAS removal performance without any solid precipitate generation. Further research should explore the effect of MER operational conditions and leachate–PFAS chemistry on the treatment performance.
Saha et al. (Thu,) studied this question.