Search

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-C3N4under sunlight and used to treat simulated wastewater RhB. The properties of g-C3N4and Cu+/g-C3N4were characterized by UV–Vis DRS and PL. The results indicated that the introduction of Cu+in g-C3N4can 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-C3N4catalyst 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-C3N4with PMS under sunlight.

Classical Fe-based Fenton catalysts have limited applications due to many disadvantages. Herein, Cu+/g-C3N4catalysts were successfully prepared by a one-step thermal polymerization method. The physicochemical of g-C3N4and Cu+/g-C3N4were characterized by XRD, SEM, FTIR, XPS and BET. The best performance of Cu+/g-C3N4(1:4) catalyst can be obtained when the doping molar ratio of CuSO4·5H2O to melamine is 1:4, which appeared as flakes with abundant mesopores and the BET specific surface area is increased 2.5 times of pure g-C3N4. Such unique structures were constructed by embedding Cu+in triazine-based g-C3N4nanosheets and forming Cu-N coordination bonds. The Cu+/g-C3N4(1:4) samples also exhibited the greatest Fenton-like catalytic performance under neutral conditions when the dosage of catalyst and H2O2were 0.5g/L and 25mmol/L, respectively, the degradation of RhB reached 92.9% in 10min. Moreover, the high catalytic activity of this catalyst can be achieved at different initial pH in range of 5.0–12.0, especially in a strong alkaline environment. The investigation of the working mechanisms of the catalyst suggested that the Cu atom and g-C3N4were dual active sites, the degradation of pollutants mainly depends on •OH radicals and other active species produced by it. A benefit of the unique structure was limited Cu leaching, which prevented secondary environmental pollution. This strategy has resulted in substantial progress in overcoming the drawbacks of traditional Fe-based Fenton catalysts and has shown great potential for applications in the field of wastewater treatment.