【作者】 周作明；

【导师】 杨仁斌；

【作者基本信息】 湖南农业大学 ， 环境工程， 2002， 硕士

【摘要】 三唑磷是20世纪70年代开发出的一种硫代磷酸酯类杀虫杀螨剂，具有低毒、高效、广谱的特点，是甲胺磷、乐果等农药的换代产品，具有良好的应用前景。但三唑磷在施用过程中将不可避免的进入河流、湖泊等水体，造成环境污染和生态破坏，如何防治这些问题具有十分重要的现实意义。 光氧化降解是农药施用后在环境中的主要降解途径，农药光稳定性对农药的药效持久性及在环境中的残留消失动态具有直接影响。为此本文进行了三唑磷在水体中光降解的实验研究，考察了光源、光催化剂及光敏剂、水体pH值、腐殖质成分等因素对三唑磷光降解的影响，并对UV-Fenton处理三唑磷废水进行了研究。实验结果如下： （1）光源的影响：在选择的三种光源（太阳光、300W、500W高压汞灯）中，汞灯照射下三唑磷的降解速度明显大于太阳光，并且随汞灯功率的增加而加快。三种光源下三唑磷的半衰期分别为301.37min、77.02min、35.73min； （2）光敏剂的影响：选用丙酮作光敏剂，试验结果表明，丙酮对三唑磷的光敏效果非常明显，当丙酮在水中的浓度为1％（V/V）时，太阳光、300W和500W高压汞灯照射下三唑磷的光解半衰期分别缩短为43.87min、16.43min、9.76min； （3）pH值的影响：用pH=5.0、7.0、9.0、11.0的四种缓冲溶液进行试验，结果表明，随着pH值的逐渐增大，光解速率递增。太阳光、300W汞灯、500W汞灯照射下三唑磷的半衰期分别由 pH=5.0时的266.60min、75.34min、52.91min减少到pH=11.0时的154.03min、47.80min、35.01min。 （4）腐殖质的影响：试验中腐殖质中的两个主要成分富里酸（FA）和腐殖酸（HA）对三唑磷的光解表现出共同的特性，即在太阳光下，二者均表现出一定的光敏性，而在高压汞灯照射下，二者均表现出了明显的光猝灭效应。 （5）光催化剂的影响：选用的光催化剂（TiO₂、H₂O₂，及TiO₂／H₂O₂混合物）中，H₂O₂的作用效果优于TiO₂，而当二者共同使用时催化效果更佳，说明二者具有协同效应。 （6）在直接光氧化和向水体充入空气的光氧化条件下进行了UV、UV-H₂O₂、UV-Fenton、UV-类Fenton四种工艺处理含三唑磷废水的实验研究，结果表明：光氧化处理改善了含三唑磷水样的可生化性；曝气使处理效果显著提高；UV-Fenton、UV-类Fenton两种工艺的处理效果较好，处理效果达到80％左右，远高于另外两种工艺的处理效果。更多还原

【Abstract】 Triazophos was a type of low-toxic, high-effective and broad-spectrum phosphorothioate pesticide and acaricide, which was developed in 1970s. It was thought to become the substitution of other pesticide such as methamidophos and dimethoate, so it had a good potential of application. On the other hand, it wound be inevitably into waters (rivers, lakes etc.) when it was used, which wound cause environmental pollution and ecological destruction. How to improve and prevention these problems had practical significance.Photooxidation was one of the main degradation approaches of pesticides in environment. Photo-stability had a direct influence on the effectiveness and persistent of pesticides. So the photooxidative degradation of triazophos in water was studied in this paper. Factors effecting the degradation rate, including types of light sources, photooxidation catalyzers and sensitizers, the pH value of water and the component of humus were investigated in the experiment, and the treatment of wastewater containing triazophos using UV-Fenton was also studied in this paper. The experimental results were as follows.(1) Effect of light sources. Among the three light sources, i.e. sun light , 300W and 500W high-voltage mercury lamp, the degradation rate of triazophos under mercury lamp was higher than sun light, and increasing with the raising of mercury lamp voltage. The half life of triazophos degradation under three light sources are 301.37minutes, 77.02minutes and 35.73minutes respectively.(2) Effect of photosensitizers. Acetone was selected as photosensitizer. It had a distinct effect on photodegradation of triazophos. When the concentration of acetone was 1%(V/V) in water, the half life of triazophos photodegradation under sun light , 300W and 500W high-voltage mercury lamp reduced to 43.87minutes, 16.43minut.es and 9.76minutes.(3) Effect of pH value. Experiment was conduct in four buffer which pH value was 5.0\7.0>9.0 and 11.0 respectively and triazophos photodegradation rate increasing with the raising of pH value. Under the irradiation of sun light and 300W, 500W high-voltage mercury lamp, when pH value increased from 5.0 to 11.0, the half-life of triazophos decreased from 266.60 minutes,75.34 minutes, 52.91 minutes to 154.03minutes, 47.80minutes, 35.01 minuteso(4) Effect of the humus. The two components of humus (fulvic acid and humic acid) had the same characteristic between photodegradation of triazophos, i.e. under the irradiation of high-voltage mercury lamp, the two components exhibited the obvious photoquenching effect, and under the irradiation of sun light, the two components showed the distinct photosensitizing effect.(5) Effect of photocatalyzers. TiO2 and H2O2 were used as photocatalyzers. Experiment results showed that H2O2 was better than TiO2,and the mixture of the two compounds was the best, because it had cooperation effect.(6) The treatment of wastewater containing triazophos using UV, UV-H2O2, UV-Fenton(Fe2+), UV-Fenton(Fe3+) were tested under the conditions with and without aerating air. The result showed that photooxidation can improve the biodegradability of this type of water; the removal rate of COD improved markedly by aerating air. Both UV-Fenton(Fe2+) and UV-Fenton(Fe3+) the removal rate of COD was reached above 80% after treating 120 minutes, distinctly higher than UVand UV/H2O2.Author: Zhou Zuo-ming(Environmental Science and Engineering) Directed by Prof. Yang Ren-bin更多还原