DESTROYING THE INDESTRUCTIBLE: STATE OF THE ART APPROACHES TO ENVIRONMENTAL REMEDIATION OF PER AND POLYFLUOROALKYL SUBSTANCES (PFAS)

Per- and polyfluoroalkyl substances (PFAS) are among the most persistent and ubiquitous anthropogenic contaminants due to the exceptional strength of the carbon–fluorine bond. This comprehensive narrative review critically evaluates state-of-the-art remediation technologies for PFAS across aqueous, solid, and subsurface matrices, with emphasis on destructive approaches that achieve mineralization rather than sequestration. Drawing on peer-reviewed literature, regulatory documents, and field demonstrations (primarily 2016–2025), the review examines conventional sorption and pump-and-treat systems, advanced oxidation/reduction processes, thermal and mechanochemical destruction, biological and phytoremediation strategies, pretreatment/concentration technologies, in situ methods, and hybrid systems. Key topics addressed include analytical challenges in verifying true mineralization, byproduct toxicity, cost-effectiveness, performance against short-chain and novel PFAS replacements (e.g., GenX, PFBS), and the regulatory–technology interface at stringent MCLs such as the U.S. EPA’s 4 ng L⁻¹ threshold. Comparative analysis shows that while sorption technologies enable drinking-water compliance, only high-temperature thermal processes, supercritical water oxidation (SCWO), hydrothermal alkaline treatment (HALT), and optimized reductive/electrochemical systems consistently approach complete defluorination. Field-scale case studies highlight practical viability, yet economic burdens, matrix effects, and the formation of short-chain byproducts remain major limitations. The review identifies research priorities and advocates integrated treatment trains to close the widening gap between regulatory demands and technological capability.