Zhao Xu, Quan Xie, Zhao Ya-Zhi, Zhao Hui-Min, Chen Shuo, Chen Jing-Wen
Department of Environmental Science and Technology, Dalian University of Technology, Dalian 116024, China.
J Environ Sci (China). 2004;16(6):938-41.
Heterogeneous photocatalytic degradation of gamma-HCH on soil surfaces was carried out to evaluate the photocatalytic effectiveness of alpha-Fe2O3 and TiO2 toward degrading gamma-HCH on soil surfaces. After being spiked with gamma-HCH, soil samples were loaded with alpha-Fe2O3 or TiO2 and exposed to UV-light irradiation. Different catalyst loads, 0%, 2%, 5%, 7%, and 10% (wt.) alpha-Fe2O3; 0%, 0.5%, 1%, 2: (wt.)TiO2, were tested for up to 7 d irradiation. The effects of soil thickness, acidity, and humic substances were also investigated. The obtained results indicated that the gamma-HCH photodegradation follows the pseudo-first-order kinetics. The addition of alpha-Fe2O3 or TiO2 accelerates the photodegradation of gamma-HCH, while the photodegradation rate decreases when the content of alpha-Fe2O3 exceeds 7% (wt.). The degradation rate increases with the soil pH value. Humic substances inhibit the photocatalytic degradation of gamma-HCH. Pentachlorocyclohexene, tetrachlorocyclohexene, and trichlorobenzene are detected as photodegradation intermediates, which are gradually degraded with the photodegradation evolution.
开展了γ-六六六在土壤表面的非均相光催化降解实验，以评估α-Fe2O3和TiO2对土壤表面γ-六六六的光催化降解效果。向土壤样品中添加γ-六六六后，负载α-Fe2O3或TiO2，并进行紫外光照射。测试了不同催化剂负载量，即0%、2%、5%、7%和10%（重量）的α-Fe2O3；0%、0.5%、1%、2%（重量）的TiO2，照射时间长达7天。还研究了土壤厚度、酸度和腐殖质的影响。所得结果表明，γ-六六六的光降解遵循准一级动力学。添加α-Fe2O3或TiO2可加速γ-六六六的光降解，而当α-Fe2O3含量超过7%（重量）时，光降解速率降低。降解速率随土壤pH值升高而增加。腐殖质会抑制γ-六六六的光催化降解。检测到五氯环己烯、四氯环己烯和三氯苯为光降解中间体，它们会随着光降解过程逐渐降解。
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