| 环境因素对气相甲苯光氧化反应机制的影响 |
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| 引用本文： | 曹媛媛,郭 婷,耿春梅,杨 文,殷宝辉.环境因素对气相甲苯光氧化反应机制的影响[J].环境科学研究,2015,28(4):653-659. |
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| 作者姓名： | 曹媛媛 郭 婷 耿春梅 杨 文 殷宝辉 |
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| 作者单位： | 1.浙江师范大学地理与环境科学学院, 浙江 金华 321004 |
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| 基金项目： | 国家自然科学基金项目(41275135);浙江省教育厅项目(Y201122815);浙江省科研院所专项科技条件建设(2012F10019) |
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| 摘 要： | 以低压汞灯为光源,采用石英管连续流动态反应系统和特氟龙气袋静态反应系统,研究了环境因素〔RH(相对湿度)、温度、光照强度、有氧(空气)/无氧(氮气)气氛条件〕对低浓度(10~20 mg/L)气相甲苯光氧化过程的影响. 结果表明:①RH对甲苯光氧化反应影响显著. 干燥条件(RH为0%~5%)下甲苯光氧化去除率在8.3%~8.7%之间；当环境中有水蒸气存在(RH为20%)时,甲苯光氧化去除率降至6.5%~7.2%,其后光氧化去除率随着RH的进一步增加而逐渐增大,在RH为60%时达到最大值(9.4%~11.5%)；但当RH继续增至80%时,去除率迅速降至4.4%~5.6%. ②甲苯光氧化去除率随着温度、光照强度的增加而提高. ③无论是干燥(RH为0%~5%)还是湿润(RH为60%)环境下,甲苯在有氧气氛下的去除率均高于无氧气氛；甲苯在有氧气氛下光氧化产物主要是苯和苯甲醛,在无氧气氛中的产物主要是苯. ④在干燥、有氧条件下,O(1D)应是甲苯光氧化的活性物种；在湿润、有氧条件下,甲苯的光氧化主要是通过·OH氧化降解；在无氧条件下,甲苯的光氧化主要是通过甲苯的直接光解完成.
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| 关 键 词： | 甲苯 光氧化 相对湿度 产物 反应机制 |
Effects of Environmental Factors on Photooxidation Mechanism of Gaseous Toluene |
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| CAO Yuanyuan,GUO Ting,GENG Chunmei,YANG Wen and YIN Baohui.Effects of Environmental Factors on Photooxidation Mechanism of Gaseous Toluene[J].Research of Environmental Sciences,2015,28(4):653-659. |
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| Authors: | CAO Yuanyuan GUO Ting GENG Chunmei YANG Wen and YIN Baohui |
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| Affiliation: | 1.College of Geography and Environmental Sciences, Zhejiang Normal University, Jinhua 321004, China2.College of Geography and Environmental Sciences, Zhejiang Normal University, Jinhua 321004, China ;Atmospheric Environment Institute, Chinese Research Academy of Environmental Sciences, Beijing 100012, China3.Atmospheric Environment Institute, Chinese Research Academy of Environmental Sciences, Beijing 100012, China |
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| Abstract: | Abstract:The photooxidation of gaseous toluene using a low-pressure mercury UV lamp as the irradiation source was described. The influence of environmental factors, such as relative humidity (RH), temperature (T), light intensity (I) and aerobic/anaerobic atmosphere on the photooxidation efficiency of toluene with low concentrations (10-20 mg/L) were studied in a quartz tube reactor using a dynamic experiment system. The intermediate products generated during the photooxidation of toluene were studied in the Teflon reactor using a static experimental system. The experimental results indicated that:1) RH significantly affected the toluene photooxidation. The removal rates of toluene were between 8.3% and 8.7% under the drying condition (RH=0%-5%). When water vapor was introduced into the air, the removal rate of toluene was reduced to 6.5%-7.2% (RH=20%). With the increase of RH, the photooxidation removal rate of toluene also increased, and the peak removal rates of toluene were between 9.4% and 11.5% under RH=60%. When RH increased to 80%, the removal rate of toluene was rapidly reduced to 4.4% to 5.6%. 2) The photooxidation removal rate of toluene tended to improve with the increase of environmental temperature or light intensity. 3) The removal rate of toluene in the aerobic atmosphere (air) was higher than that in the anaerobic atmosphere (nitrogen) in both dry (RH=0%-5%) and humid environments (RH=60%). The intermediate of photooxidation of toluene in the nitrogen medium was benzene, while the intermediates in the air medium were benzene and benzaldehyde. 4) Under the aerobic dry atmosphere, the active species of photooxidation of toluene were perhaps O (1D), while it was ·OH in humid environment. Under the anaerobic atmosphere, the removal of toluene was mainly derived from the direct degradation by UV (185 nm) irradiation. |
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| Keywords: | toluene photooxidation relative humidity intermediate products reaction mechanisms |
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