UV degradation of PFAS involves complex reactions beyond simple defluorination

A new study reveals that UV-induced degradation of PFAS chemicals involves a more complex mechanism than previously understood, with sequential reactions driving the breakdown process. Researchers found that PFAS molecules undergo reactions with hydrated electrons, hydroxyl radicals, and hydroxide ions, leading to carbon-carbon bond cleavage. The carboxylate group in fragmented products is essential for further defluorination, and high pH enhances degradation by promoting fragmentation and C=C formation. The study corrects a common misinterpretation of the chain-shortening process and identifies formate, not CO2 or CO, as the primary product. These findings advance understanding of PFAS pollution remediation and could inform the design of more readily degradable fluorochemicals.