Our research group has been investigating plasma-based technologies for the decomposition of per- and polyfluoroalkyl substances (PFAS) for many years [1]. Owing to their surfactant properties, PFAS tend to accumulate at gas–liquid interfaces. This interfacial enrichment facilitates their interaction with energetic electrons and ions, as well as with localized high-temperature regions generated by plasma, thereby enabling rapid and efficient decomposition.
In this study, we present several plasma-based approaches that we have developed for PFAS decomposition, including plasma generated inside gas bubbles, diaphragm discharge plasma, and plasma generated above the water surface. The decomposition characteristics of these systems are compared, with particular attention to decomposition products and possible reaction mechanisms.
Furthermore, we have developed an approach in which PFAS are concentrated in a foam layer formed on the water surface by microbubble injection and subsequently exposed to pulsed plasma [2]. This approach has demonstrated exceptionally high decomposition performance. Based on these results, we discuss the importance of concentrating PFAS at the plasma–liquid interface and of controlling the plasma conditions to achieve efficient PFAS decomposition.

PFAS, plasma, minealization