介质阻挡放电—针铁矿协同降解“三苯”模拟废气

发布时间：2018-01-03 19:16

本文关键词：介质阻挡放电—针铁矿协同降解“三苯”模拟废气　出处：《合肥工业大学》2017年硕士论文　论文类型：学位论文

【摘要】：近年来挥发性有机物(VOCs)造成的大气污染日趋严重,低温等离子体技术由于其经济有效的优点而成为近年研究的热点。本文以合成针铁矿为前驱体,用反复浸渍法制备了针铁矿/堇青石催化剂,并对其进行了BET、XRD及扫描电镜等表征。本研究采用介质阻挡放电产生低温等离子体,协同针铁矿降解“三苯”(苯、甲苯、二甲苯)模拟废气,考察了针铁矿的煅烧温度和负载量、电源输入功率、初始浓度、停留时间与相对湿度对其降解率的影响,并对降解产物进行分析进而探究反应机理。研究表明:当针铁矿负载量为4%,煅烧温度为350℃时效果最佳,此时针铁矿比表面积为71.794 m~2/g。等离子体对污染物的降解率随能量密度的升高而升高,随模拟废气流量的增大而减小,随浓度的升高而降低,随相对湿度的增加先升高后降低,常温常压下在相对湿度70%左右时达到最大。因此在流量0.3 m~3/h、浓度400 mg/m~3、相对湿度70%左右考察针铁矿对污染物降解效果的影响。介质阻挡放电降解苯模拟废气,当输入能量密度为1248 J/L时,针铁矿/堇青石体系和单独DBD对苯的降解率为62.04%及73.36%,能量效率为0.72 g/kWh及0.85g/kWh,臭氧浓度为132.8 mg/m~3及36.8 mg/m~3,碳氧化物选择性为67.13%及82.14%,NO_2浓度为7.95 mg/m~3及1.70 mg/m~3。介质阻挡放电降解甲苯模拟废气,当输入能量密度为960 J/L时,针铁矿/堇青石体系和单独DBD对甲苯的降解率为78.98%和86.69%,能量效率为1.17 g/kWh和1.3g/kWh,臭氧浓度为148.8 mg/m~3和45.6 mg/m~3,碳氧化物选择性63.36%和79.15%,NO_2浓度为2.36 mg/m~3和1.14 mg/m~3。介质阻挡放电降解二甲苯模拟废气,当输入能量密度为960 J/L时,针铁矿/堇青石体系和单独DBD对二甲苯的降解率为80.38%和88.26%,能量效率为1.21 g/kWh和1.36 g/kWh,臭氧浓度为115.2 mg/m~3和30.4 mg/m~3,碳氧化物选择性为66.9%和82.01%,NO_2浓度为2.37 mg/m~3和1.17 mg/m~3。实验结果表明,针铁矿可以显著提高低温等离子体对“三苯”的降解率、碳氧化物的选择性和能量效率,同时降低副产物浓度,廉价易得的针铁矿适合工业应用。
[Abstract]:In recent years, volatile organic compounds (VOCs) caused by air pollution is becoming more and more serious, low temperature plasma technology has become a research hotspot in recent years due to its economic and effective advantages. In this paper the synthesis of goethite as precursor, by repeatedly dipping prepared goethite / cordierite catalyst, and the BET, XRD and scanning electron microscope. Characterized. This study adopts low-temperature plasma generated by the dielectric barrier discharge, synergistic degradation goethite three benzene (benzene, toluene, xylene) simulated exhaust gas, the effect of calcination temperature of goethite and the load, the power input power, initial concentration, residence time and relative humidity influence on the degradation rate, and the the degradation products were analyzed in order to explore the reaction mechanism. The results show that: when the goethite load is 4%, calcination temperature is 350 degrees centigrade is best, the goethite surface area of 71.794 m~2/ g. plasma on pollution The degradation rate increased with the energy density increases, decreases with the increase of simulated exhaust gas flow, and decreased with increasing concentration, with the increase of the relative humidity increased first and then decreased, under normal temperature and pressure in about 70% relative humidity reached maximum. So the flow of 0.3 m~3/h, the concentration of 400 mg/m~3 and 70% relative humidity about the effects of goethite on the degradation of pollutants. The simulation of dielectric barrier discharge gas benzene degradation when the input, the energy density is 1248 J/L, goethite / cordierite system and single DBD for benzene degradation rate was 62.04% and 73.36%, the energy efficiency of 0.72 g/kWh and 0.85g/kWh, the ozone concentration of 132.8 mg/m~3 and 36.8 mg/m~3. Carbon oxide selectivity is 67.13% and 82.14%, the concentration of NO_2 was 7.95 mg/m~3 and 1.70 mg/m~3. dielectric barrier discharge simulation degradation of toluene waste gas, when the input energy density is 960 J/L, goethite / cordierite system and single D The BD degradation efficiency of toluene was 78.98% and 86.69%, the energy efficiency of 1.17 g/kWh and 1.3g/kWh, the ozone concentration of 148.8 mg/m~3 and 45.6 mg/m~3, 63.36% and 79.15% carbon oxide selectivity, the concentration of NO_2 was 2.36 mg/m~3 and 1.14 mg/m~3. simulated exhaust gas dielectric barrier discharge when the degradation of xylene, the input energy density is 960 J/L, the degradation of cordierite system the rate of p-xylene and single DBD goethite were 80.38% and 88.26%, the energy efficiency of 1.21 g/kWh and 1.36 g/kWh, the ozone concentration of 115.2 mg/m~3 and 30.4 mg/m~3, carbon oxide selectivity is 66.9% and 82.01%, the concentration of NO_2 was 2.37 mg/m~3 and 1.17 mg/m~3. experimental results show that goethite can significantly improve the degradation of "three benzene" the rate of low temperature plasma, carbon oxide selectivity and energy efficiency, while reducing by-product concentration, goethite is inexpensive and suitable for industrial applications.

【学位授予单位】：合肥工业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：X701

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