Altering PFAS degradation chemistry by enabling parallel reductive and oxidative processes.

We report that the degradation chemistry of hexafluoropropylene oxide dimer acid (HFPO-DA), a per- and polyfluoroalkyl substance (PFAS), can be altered by enabling uncoupled parallel reductive and oxidative processes (PROP) by simultaneous radical generation via ultrasonication and UV irradiation. PROP significantly suppresses trifluoroacetic acid (TFA), a dominant end product in the degradation of perfluorocarboxylic acids (PFCAs), which are of emerging health concern, and promotes much deeper fragmentation of long-chain transformation products.