Insight into the degradation of p-nitrophenol by visible-light-induced activation of peroxymonosulfate over Ag/ZnO heterojunction

In this report, the peroxymonosulfate activation over Ag/ZnO heterojunction under visible light (Ag/ZnO/PMS/Vis) for p-nitrophenol (p-NP) contaminant degradation was conducted in detail. Herein, the catalyst dosage was decreased, and the results showed that a dosage of 0.5 g L−1 Ag/ZnO and 4 mM PMS almost completely degraded 30 mg L−1 p-NP after 90 min of irradiation. In addition, the PMS activation mechanism of Ag/ZnO/PMS/Vis system was proposed by investigations of the influence of PMS concentration, the FTIR spectra, UV–Vis spectroscopy, and electrochemical analyses. Additionally, the role of SO4•– in the photocatalytic reaction is determined by a combination of a trapping test using isopropanol and tert-butanol as probe compounds and electron spin resonance (ESR) spectroscopy. This report provides a potential alternative to remove persistent organic contaminants in sewage using PMS incorporated with Ag/ZnO under visible light irradiation. [Display omitted] •Ag/ZnO/PMS/Vis system for p-nitrophenol degradation was investigated for the first time.•A dosage of 0.5 g L−1 Ag/ZnO and 4 mM PMS almost completely degrade 30 ppm p-NP after 90 min.•SO4•– serves as the primary oxidant in Ag/ZnO/PMS/Vis system.•PMS activation mechanism for p-nitrophenol removal is coherently cast light on.