Water-based matrices thermal treatment for per- and polyfluoroalkyl substances (PFAS): A critical review on transformation mechanisms, role of radicals, and perspective towards.

Per- and polyfluoroalkyl substances (PFAS) are highly persistent and hazardous environmental contaminants that pose significant risks to human health and ecosystems. Their unique physicochemical characteristics such as hydrophobicity, oleophobicity, chemical and mechanical stability, and resistance to physicochemical and biological degradation, present considerable challenges for effective removal from aqueous matrices. Among available strategies, thermal treatment technologies have emerged as a promising approach due to their capacity for rapid PFAS degradation across diverse compound types and their high maturity. This critical review provides a comprehensive evaluation of recent advances in thermal treatment methods for PFAS in aqueous matrices. The focus is on innovative methods, such as microwave-assisted thermal treatment (MAT), supercritical water oxidation (SCWO), electrical discharge plasma (EDP), and atmospheric pressure plasma jet (APPJ). Several key aspects such as transformation mechanisms, the role of reactive radicals, the formation of incomplete by-products, defluorination rates, and the scalability of these technologies are critically analyzed. In addition, this review highlights key research gaps that remain and outlines perspective research directions for improving the effectiveness, environmental safety, and practical implementation of thermal treatment approaches in PFAS mitigation.