Enhanced visible-light activation of persulfate by g-C3N4 decorated graphene aerogel for methyl orange degradation

Abstract

In the present work, the degradation of methyl orange (MO) by visible-light-driven photocatalytic activation of persulfate (PDS) was studied. Macro-aerogel g-C3N4-doped graphene aerogel (GA) composite with stratified structure was fabricated by a simple hydrothermal method and applied as a recoverable heterogeneous catalyst along with visible light (VL) irradiation for activation of PDS. The microstructure, physical-chemical and photoelectrochemical properties of composite catalysts were characterized and various reaction parameters including the reaction systems, catalyst activator dose, PDS concentration, g-C3N4 doping amount and the initial pH of the solution were evaluated on the MO removal efficiency. Photocatalytic activation of GA for MO degradation was enhanced significantly after modified by g-C3N4. Under optimum conditions (15 mg/L MO, 75 mg/L PDS and 0.012 g/L GCN-3), the catalytic efficiency of g-C3N4 doped GA with the mass ratio of 3:7 (GCN-3) was 2.96 times than that of GA. The strengthening effect of GCN-3 benefited from the synergistic effect of the photogenerated hole (h+), the CO functional groups and rapid electron transfer in GCN-3/VL/PDS system. Given the flexibility and recyclability of GCN-3, the GCN-3/VL/PDS system is a promising technique for practical wastewater purification.