Confined Irradiation Vacuum Ultraviolet Abatement Technique for Perfluorinated Compounds

This study introduces a vacuum ultraviolet (VUV, 100–200 nm) confined irradiation (CI) technology designed to achieve complete mineralization (and defluorination) of per- and polyfluoroalkyl substances (PFASs) without the use of chemical or nanomaterial additives. The CI system generates a concentrated energy field through a quasi-collimated VUV beam that is thermally isolated from the external environment, with the reaction solution maintained at a millimeter-scale height (9–15 mm). This configuration mitigates both self- and mutual-quenching of photons and free radicals (FRs), thereby enhancing overall reactivity. The high-yield generation of oxidizing FRs enabled a novel degradation pathway for the complete mineralization of ten PFAS compounds by promoting product ketonization and inhibiting molecular polymerization. The proposed CI mechanism aligns with the well-documented reconstruction of species/energy behavior in nano-confined catalysis. However, unlike nanoconfinement, CI regulates the reaction zone at a fixed scale rather than compressing it to nanometer or sub-nanometer precision. By ensuring geometric alignment between the confined irradiation zone and reaction intermediates, the CI system stabilizes specific reaction pathways, enabling complex chain reactions to proceed efficiently within a single reactor environment. Its capacity to suppress side reactions presents significant potential for enhancing H2O2 production and the synthesis of heavy olefins.