| In recent years,volatile organic compounds（VOCs）have caused the increasing air pollution.Because it is low cost and it can effectively degrade VOCs,non-thermal plasma technology has become a research hotspot.In this paper,with the synthetic goethite as the precursor,goethite/cordierite catalysts were prepared by repeated impregnation.Its morphology and component were characterized by XRD,BET and SEM.This study used barrier discharge（DBD）reactor,combined with goethite/cordierite composite catalyst to study the removal of benzene,toluene and xylene simulated exhaust gas,and the influence of calcination temperature,load,energy density,initial concentration,residence time and relative humidity were systematically investigated.And the reaction mechanism was explored by analyzing the degradation products.The results showed:When the load of goethite was 4% and the calcination temperature was 350 ℃,the degradation rate of the benzene reached the maximum,and the specific surface area of goethite was 71.794 m2/g.And the degradation rate of pollutants increases with the increase of the energy density,decreases with the increase of the flow rate,decreases with the increase of the concentration,increases at first and then decreases with the increase of the relative humidity.The degradation rate of pollutants reached the maximum in the relative humidity of about 70% at normal pressure and temperature.Therefore,the effect of goethite on the degradation of pollutants was investigated at the flow rate of 0.3 m3/h,the concentration of 400 mg/m3 and the relative humidity of 70%.The DBD reaction system and DBD with goethite/cordierite reaction system degraded the benzene simulated exhaust gas at the energy density of 1248 J/L.Their degradation rate of benzene was 62.04% and 73.36%,the energy efficiency was 0.72 g/kWh and 0.85 g/kWh,the ozone concentration was 132.8 mg/m3 and 36.8 mg/m3,the selectivity of carbon oxides was 67.13% and 82.14% and NO2 concentration was 7.95 mg/m3 and 1.70 mg/m3 respectively.The DBD reaction system and DBD with goethite/cordierite reaction system degraded the toluene simulated exhaust gas at the energy density of 960 J/L.Their degradation rate of toluene was 78.98% and 86.69%,the energy efficiency was 1.17 g/kWh and 1.3 g/kWh,ozone concentration was 148.8 mg/m3 and 45.6 mg/m3,carbon oxide selectivity was 63.36% and 79.15% and NO2 concentration was 2.36 mg/m3 and 1.14 mg/m3 respectively.The DBD reaction system and DBD with goethite/cordierite reaction system degraded the xylene simulated exhaust gas at the energy density of 960 J/L.Their degradation rate of xylene are 80.38% and 88.26%,and the energy efficiency is 1.21 g/kWh and 1.36 g/kWh,the ozone concentration was 115.2 mg/m3 and 30.4 mg/m3,the selectivity of carbon oxides was 66.9% and 82.01% and NO2 concentration was 2.37 mg/m3 and 1.17 mg/m3 respectively.The results showed that goethite could significantly improve the degradation rate of pollutants,the selectivity of carbon oxides,the energy efficiency and the by-product concentration.Goethite is cheap and easy to obtain so that it was suitable for industrial application. |
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