Heterogeneous activation of peroxymonosulfate by Cu+-decorated g-C3N4 under sunlight for degradation of organic pollutants

This article is an in-depth study of the basis of Cu+-decorated triazine-based g-C3N4 (Cu+/g-C3N4) nanosheet-activated H2O2. In this study, peroxymonosulfate (PMS) was activated by Cu+/g-C3N4 under sunlight and used to treat simulated wastewater RhB. The properties of g-C3N4 and Cu+/g-C3N4 were characterized by UV–Vis DRS and PL. The results indicated that the introduction of Cu+ in g-C3N4 can enhance the separation of photogenerated electron-hole pairs. The Cu+/g-C3N4(1:4) samples exhibited the best PMS activation performance under sunlight when 0.5 g/L catalyst dose and 0.5 mmol/L PMS concentration were used, and the removal rate of RhB reached 95.7% in 30 min. Moreover, better catalytic activity of the system can be achieved in the initial pH range of 2.0–10.0. The investigation results of the catalytic mechanisms showed that the prepared Cu+/g-C3N4 catalyst constructs a dual reaction center of Cu+/Cu2+ cycling and eCB−/hVB+ transfer for efficient PMS activation. The degradation of pollutants benefits from the participation of a variety of free radicals, which are generated by sunlight-assisted heterogeneous activation of PMS. This study has resulted in substantial progress in activating multiple oxidants with a single heterogeneous catalyst and provides a feasible way to treat refractory wastewater using Cu+/g-C3N4 with PMS under sunlight.