One-Stop PFAS Remediation with a Hydrophobic Deep Eutectic Solvent: Integrated Enrichment and Expanded Mineralization via Molten Alkali

Per- and polyfluoroalkyl substances (PFAS) are highly persistent contaminants whose remediation is limited by the lack of practical destruction technologies, especially for short-chain perfluoroalkyl sulfonic acids (PFSAs, C n F 2n+1 SO 3 H). We report an integrated preconcentration and mineralization platform that combines hydrophobic deep eutectic solvent (HDES) enrichment with molten alkali treatment to achieve rapid, near-complete PFAS mineralization under ambient pressure. Following rapid PFAS extraction into HDES, a 150–200 °C molten alkali efficiently mineralized sulfonated PFAS, including long (n = 8 PFOS), short (n = 4 PFBS), and ultrashort (n = 1 TFMS) chains. Fast PFAS decay was confirmed by 19 F NMR spectroscopy, and near-quantitative fluoride and sulfate recovery within 1 h was verified by ion chromatography. Compared to HDES-only systems, molten alkali suppresses fluorine loss and accelerates mineralization via rapid desulfonation followed by progressive defluorination of the fluoroalkyl backbone. Although heating is required, strong PFAS enrichment and the low heat capacity of HDES limit overall energy demand. This platform enables rapid capture and mineralization of nearly all PFAS classes, including the most recalcitrant short- and ultrashort-chain sulfonates, and is, to our knowledge, the only approach that both removes and destroys the full PFAS spectrum under relatively mild conditions.