Electrothermal mineralization of per- and polyfluoroalkyl substances (PFAS) for soil remediation

Per- and polyfluoroalkyl substances (PFAS) are persistent and bioaccumulative pollutants that can easily accumulate in soil, posing threat to environment and human health. Current PFAS degradation processes often suffer from low efficiency, high energy and water consumption, or lack of generality. Here, we develop a rapid electrothermal mineralization (REM) process to remediate PFAS-contaminated soil. With environmentally compatible biochar as conductive additive, the soil temperature increases to >1000 °C within seconds by direct current pulse input, converting PFAS to calcium fluoride with inherent calcium compounds in soil. The general electrical mineralization process is applicable for remediating various PFAS contaminants in soil, with high removal efficiencies (>99.9%) and mineralization ratios (>90%). While retaining soil particle size, composition and water infiltration rate, REM facilitates an increase of exchangeable nutrient supply and arthropod survival in soil. REM has a significant reduction of energy consumption and greenhouse gas emission over existing soil remediation practices.