Microwave-coupled wet oxidation technique enhanced the efficient degradation of methyl orange organic wastewater by graphene-supported nano zero-valent iron (nZVI/GN)
摘要
Dye wastewater, known for its complex composition, recalcitrant nature, and high chemical oxygen demand, has always been a formidable challenge in the field of wastewater treatment. Here, we report the efficient degradation of methyl orange (MO) organic wastewater over graphene-loaded nano zero-valent iron (nZVI/GN) composites via the unique microwave-coupled wet oxidation technique in a self-developed high-pressure hydrothermal microwave reactor. Due to the synergistic interplay between microwave irradiation and the nZVI/GN composite, the conversion efficiency of reactants in the microwave-induced degradation process surpassed 99% within a mere 5 min, which is unattainable by conventional heating (CH) method. Through mechanism research, we found that electrons in nZVI transfer outward to generate · OH and O2 · −, achieving oxidative decomposition of MO. The degradation process could be significantly enhanced by the multiple effects of locally-generated plasma and hot spots, as well as the non-thermal effect, under microwave irradiation. This research offered a highly effective approach for continuous degradation of dye wastewater and revealed the potential of microwave wet oxidation combined with wave-absorbing materials as a wastewater degradation technique.