Bromine-photosensitized degradation of perfluorooctanoic acid

Per- and polyfluoroalkyl substances (PFAS) have been decomposed photochemically by using manganese dioxide (MnO₂) as oxidant, sulfuric acid (H₂SO₄) as solvent, and bromine (Br₂) as photocatalyst, to produce several smaller organofluorine compounds, and ultimately a yield of up to 4% of the fluorine as HF. These fluorinated intermediates and product have been characterized with ¹⁹F NMR spectroscopy. The carbon from the PFAS was converted to CO₂ with a detected yield of up to 10-15%. The reagents and apparatus to carry out this degradation are inexpensive and readily obtained, especially because NaBr can be substituted for Br₂ as the sole source of bromine. A similar set of end products were observed with either perfluorooctanoic acid or polytetrafluoroethylene, demonstrating this process can possibly be used to degrade a variety of PFAS. Our results demonstrate the ability to degrade PFAS in a simple, controlled manner at lower temperatures and using less expensive reagents than current industrial methods.