Degradation of enrofloxacin in aqueous by DBD plasma and UV: Degradation performance, mechanism and toxicity assessment

Enrofloxacin (ENRO) as a highly toxic antibiotic poses great threats to human health and environmental safety. In this study, a novel technology of coupling dielectric barrier discharge (DBD) and ultraviolet (UV) was investigated to efficiently degrade ENRO in aqueous, and had a higher degradation rate. The ENRO degradation rate achieved approximately 93.9% at 30 min, and approximately 1.20 g kWh−1 of energy yield (G50) was observed for the combined system. The addition of H2O2 and K2S2O4 improved the ENRO degradation due to the generation of ·OH and ·SO42-. In the presence of NO3–, the ENRO degradation played a tendency to promote first and then decrease, and the presence of SO42- resulted in the positive effect, while the negative effect was shown in the presence of Cl- and CO32–. The trapping experiment indicated that ·OH played an important part in the ENRO degradation. The addition of UV into the DBD system decreased H2O2 concentration in deionized water, and increased ·OH concentration. The DFT analysis showed the degradation mechanisms of ENRO at a molecular level. The degradation of ENRO mainly involved the oxidation of the piperazine group, the removal of ethyl acetate and the substitution of the F atom. The toxicity of ENRO and its degradation intermediates was evaluated.