Study On The Catalytic Degradation Of Methyl Orange And Activation Of CO₂ By DBD Plasma

Industrial wastewater pollution is increasingly seriously due to acceleration of the process of industrialization in China,and azo dye wastewater is one of the industrial wastewater to be hardly treated.In this thesis dielectric barrier discharge?DBD?plasma technology was used to treat azo dye wastewater simulated by methyl orange.The results of experiment showed that the methyl orange dye was obviously degradedunder DBD plasma.In oder to increase the degradation effects of methyl orange dye the catalyst was added in reaction system of DBD plasma.The experiment results showed that,compared with DBD treatment only,the degradation rate of methyl orange was increased by 20%under the combined effects of DBD plasma and MIL-101.Methyl orange dye can be degraded under ultraviolet light.DBD plasma can produce ultraviolet light.The results of experiments indicated that the degradation rate of methyl orange was increased by 40%under MIL-101 with DBD plasma than under MIL-101 with UV.The experiment results reveal that the MIL-101 is a good catalyst in the DBD plasma reaction system,and the synergistic effect of plasma MIL-101 catalyst can well promote the degradation of methyl orange.The influencing factors for the degradation of methyl orange,including the concentration of solution,air flow,discharge voltage and catalyst dosage,were investigated in the experiments.In the optimized condition of the discharge voltage of 22 kV,0.6 g/L catalyst,120 m L/min air flow rateand110mg/L of initial methyl orange,the degradation rate of methyl orange reached 92%on MIL-101 in 10 min.MIL-101 supported Fe₂O₃ catalyst?Fe₂O₃/MIL-101?was prepared.The results of characterization by TEM and XRD showed that iron oxide particle size,which was evenlydistributedon MIL-101surface,was from 5 to 10 nm.In condition of the discharge voltage 22 kV,0.3 g/L of catalyst and 120 m L/min air flow velocity,the DBD plasma reaction with Fe₂O₃/MIL-101can degrade 92%of initial 150 mg/L of methyl orange solution in 10 min.The experimental results show that the MIL-101 loaded iron oxide catalyst can improve the efficiency of methyl orange degradation.Carbon dioxide is the world's most abundant reserves of carbon resources.Conversion of carbon dioxide with water vapor intovalue-added chemicals or new fuels has attracted considerableattention under the current background of fossil resourcesdepletion and increase of CO₂ emission.This conversion process can beconsidered to fit in the revolutionary“cradle-to-cradle”concept because the waste?greenhouse gases?can be convertedinto a new feedstock?fuel or raw material for the chemicalindustry?.In this thesis,reaction of CO₂ and water vapor in DBD plasma with catalyst were investigated.The results of experiment showed that CO₂ and H₂O can convert to CO,H_2,O₂ and CH₄.It was found that the discharge voltage has a great influence to the yield of the reaction.The suitabledischarge voltage is good for the conversion of CO₂.The production of methane is not only related to the catalyst and discharge voltage,but also to the hydrogen produced from reaction.The conversion rate of carbon dioxide can reach 57%under 10%MoO₃/Al₂O₃ catalyst withDBD plasma.The maximum yield of methane was 5.6%under 3%RuO₂/Al₂O₃catalyst with DBD plasma.