Defluorination of Persistent Perfluoroalkyl Substances by Visible Light Under Ambient Conditions

Perfluoroalkyl substances (PFASs) have been extensively utilized in various industries. However, their extremely high stability poses significant challenges, such as environmental persistence and waste treatment. Current PFAS decomposition approaches typically require harsh conditions. Thus, there is a pressing need to develop a new technique capable of decomposing them under mild conditions. Here, we showcase a method wherein perfluorooctanesulfonate, known as a "persistent chemical," and Nafion, a widely utilized sulfonated perfluoropolymer for ion-exchange membranes, undergo efficient decomposition into fluorine ions under ambient conditions via the irradiation of incoherent visible LED light onto semiconductor nanocrystals (NCs). This decomposition reaction is driven by cooperative mechanisms involving light-induced ligand displacements and Auger-induced electron injections via hydrated electrons and higher excited states. Our findings not only demonstrate the feasibility of efficiently breaking down various PFASs under mild conditions but also pave the way for advancing toward a sustainable fluorine-recycling society.