Efficient simultaneous degradation and dechlorination of the photo-recalcitrant emerging disinfection byproduct, 2-chlorophenol (2-CP), was achieved by vacuum-ultraviolet (VUV) system for the first time. Different from the conventional UV system, the combined action of direct photolysis and hydroxyl radical-based oxidation in VUV system led to a prominently higher removal efficiency for 2-CP. Furthermore, given the limitations of conventional vacuum ultraviolet (VUV) system, a novel Vacuum Ultraviolet/Graphite Carbon Nitride (VUV/g-C3N4) system with high adaptability to varying environmental conditions is developed. Compared with conventional VUV and UV/g-C3N4 systems, the VUV/g-C3N4 system demonstrates much higher degradation and dehalogenation efficiencies for 2-CP. Especially, VUV/g-C3N4 system can still exhibit outstanding performance even under the conditions of high acidity, high concentrations of humic acid and sulfate ions; alkaline condition and the presence of bicarbonate ions can further promote the 2-CP removal. In addition, the feasibility of VUV/g-C3N4 system is verified by the stable operation of it in both river water and tap water. Different from conventional photochemical systems relying on hydroxyl radicals, the dominant reactive species for 2-CP degradation by VUV/g-C3N4 system was identified to be superoxide radicals. Conclusively, this study provided a novel advanced oxidation system for the efficient treatment of halogenated phenols.

Novel vaccum-UV based advanced oxidation system for efficient degradation and dehalogenation of chlorophenols

ACS Fall 2021

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