Activation of peroxymonosulfate by graphitic carbon nitride loaded on activated carbon for organic pollutants degradation

Abstract Graphitic carbon nitride supported on activated carbon (g-C 3 N 4 /AC) was prepared through an in situ thermal approach and used as a metal free catalyst for pollutants degradation in the presence of peroxymonosulfate (PMS) without light irradiation. It was found that g-C 3 N 4 was highly dispersed on the surface of AC with the increase of surface area and the exposition of more edges and defects. The much easier oxidation of C species in g-C 3 N 4 to C O was also observed from XPS spectra. Acid Orange 7 (AO7) and other organic pollutants could be completely degraded by the g-C 3 N 4 /AC catalyst within 20 min with PMS, while g-C 3 N 4 +PMS and AC+PMS showed no significant activity for the reaction. The performance of the catalyst was significantly influenced by the amount of g-C 3 N 4 loaded on AC; but was nearly not affected by the initial solution pH and reaction temperature. In addition, the catalysts presented good stability. A nonradical mechanism accompanied by radical generation (HO and SO 4 − ) in AO7 oxidation was proposed in the system. The C O groups play a key role in the process; while the exposure of more N-(C) 3 group can further increase its electron density and basicity. This study can contribute to the development of green materials for sustainable remediation of aqueous organic pollutants.