Degradation of norfloxacin by copper-doped Bi(2)WO(6)-induced sulfate radical-based visible light-Fenton reaction

In this work, a series of Cu(ii)-doped Bi(2)WO(6) nanomaterials with good photo-response properties were facile synthesized and used to obtain efficient peroxymonosulfate (PMS) activation activity for norfloxacin (NOF) removal under visible LED light irradiation. It was found that Cu–Bi(2)WO(6) presents superior catalytic performance for NOF degradation in comparison with pristine Bi(2)WO(6), attributed to the partial substitution of Bi(3+) by Cu ions. Moreover, the effects of experimental conditions were carefully investigated, including PMS concentration, catalyst dosage and initial pH, and the experimental data fitted well with the pseudo-first-order model. Experimental results implied that there was a synergic effect of visible LED light energy and the sulfate radical (SR)-Fenton reaction. Additionally, the 5Cu–Bi(2)WO(6) nanomaterial presented the best degradation efficiency of 89.27% and exhibited high NOF degradation in 5 cycles with limited Cu leaching. Furthermore, EPR and radical quenching experiments were performed to identify the reactive oxygen species presented in the SR-photo-Fenton reaction. Finally, the major degradation intermediates of NOF were detected, and a possible degradation pathway was given. Thus, a mechanism of the significant photocatalytic activity enhancement by copper doping of the Bi(2)WO(6) catalyst was proposed.