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.