Elimination of pefloxacin and levofloxacin by dual-wavelength UV activated peroxymonosulfate system (VUV/UVC/PMS)

In recent years, the pervasive presence of antibiotics in surface water and their potential ecological risks have garnered significant attention. The advanced oxidation system of a dual-wavelength UV (VUV/UVC) synergistic peroxymonosulfate (PMS) has been employed as a potential technology for removing organic pollutants from water. The VUV/UVC/PMS process entails the irradiation of PMS with VUV (185 nm) and UVC (254 nm) to concurrently generate hydroxyl radicals (·OH), sulfate radicals (SO 4 ·- ), and singlet oxygen ( 1 O 2 ). This process has markedly enhanced pefloxacin (PEF) and levofloxacin (LEV) degradation efficiency. The experimental findings suggest that the VUV/UVC/PMS system attains optimal degradation of PEF and LEV under conditions of low initial PEF and LEV concentrations, elevated initial PMS concentration, elevated reaction temperature, and an initial pH of 11. In this system, ·OH, SO 4 ·- , and 1 O 2 are the main active species responsible for the degradation of LEV, contributing 84.46%, 5.52%, and 7.98%, respectively. Through EEM spectra and high-resolution mass spectrometry analysis, the degradation pathways of PEF and LEV were inferred, and the synergistic mechanism between VUV and PMS was revealed. A comparison of the individual processes with the VUV/UVC/PMS system showed a significant reduction in energy consumption, with PEF degradation energy consumption decreasing by 7.58%-41.87% and LEV degradation energy consumption decreasing by 2.7%-76.34%. The study indicates that the VUV/UVC/PMS system possesses the advantages of high efficiency, low energy consumption, and simple operation, making it a green and sustainable process for treating antibiotic pollution in surface water.