【作者】 黄德智；

【导师】 岳永德；

【作者基本信息】 安徽农业大学 ， 农药学， 2004， 硕士

【摘要】 本文以高压汞灯为光源，研究了除草剂绿麦隆在水溶液中的光化学降解,以不同水质、pH、色素、有机溶剂和表面活性剂等对绿麦隆光解的影响；初步研究了绿麦隆在水溶液中的光化学降解产物。得出了以下主要结果：1.在高压汞灯和太阳光照射下，绿麦隆在水中的光解半衰期分别是14.72min和192.54h。在2种光源下，绿麦隆的光解速率顺序为：高压汞灯＞太阳光,并且绿麦隆在水溶液中的光化学降解符合一级动力学方程；绿麦隆在5种水质的水中降解速率的顺序为：重蒸水＞自来水＞湖水＞池塘水＞河水。2.在高压汞灯下，绿麦隆在pH5、pH7、pH9缓冲溶液中的光解半衰期分别为13.84min、15.37min、16.31min；绿麦隆水溶液在酸性条件下比中性和碱性条件下光解明显加快。3.在高压汞灯下，4种色素对水中绿麦隆的光解均起光猝灭作用，光猝灭效率分别为: 甲基蓝为20.12%、甲基绿为10.54%、刚果红为26.24%、甲基橙为28.31%，随着色素浓度增大，光猝灭作用增强。4.在高压汞灯下，5种表面活性剂对绿麦隆水溶液呈光猝灭作用,光猝灭效率分别为: 农乳404为10.54%、农乳601为27.96%、农乳500为25.24%、农乳603为21.05%、CTAB为11.22%。农乳404、农乳601、CTAB随着浓度的增大，对绿麦隆的光猝灭作用增强，而农乳500、农乳603随着浓度的增大，对绿麦隆的光猝灭作用减弱。5.在高压汞灯下，含有少量的丙酮、甲醇和乙腈溶液中，绿麦隆的光化学反应符合一级动力学方程。6.在高压汞灯下，几种阴、阳离子对绿麦隆的光解试验结果表明：低浓度的锰离子和镁离子对绿麦隆的光解起光敏化作用，其光敏化率分别为：Mn2+为4.10%、Mg2+为4.49%。当浓度增大时，则起光猝灭作用；向绿麦隆溶液中添加硝酸盐和亚硝酸盐后，其光猝灭效率分别为：NO3－为19.51%、NO2-为8.25%，随着硝酸盐和亚硝酸盐浓度的增大，对绿麦隆光解的猝灭作用也在增大；氯离子和溴离子对绿麦隆的光解均有敏化作用, 其光敏化率分别为：Cl－为10.82%、Br－为3.90%。光敏化作用随氯离子浓度的增大而减小，而溴离子则随浓度的增大光敏化作用也增大，但是碘离子在低浓度时呈现较强的光猝灭作用，其光猝灭效率为： 22.31%，当碘离子浓度增大时，表现出更强的光猝灭作用。 <WP=7>7.在高压汞灯下，水溶液中绿麦隆长时间照光后，生成无机物Cl-、NO3-、NH4+、CO2。8.绿麦隆光解中间产物通过GC－MS的检测，得到了二种光解产物，其分子量分别为：167和149，其分子结构式分别为：　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　还检测到光解产物中含有烷烃系列同系物的衍生物，从而也证明了绿麦隆长时间照光后转变为无机物的结论。更多还原

【Abstract】 The photochemical degradation of chlorotoluron irradiated by high pressure mercury lamp　(HPML) was investigated. The effects of types of water,　pH , pigments and surfactants on photodegradation of chlorotoluron in aqueous solution were observed. Photoproducts of chlorotoluron in aqueous solution under HPML were also identified. The main study results were summarized as follows:1.The photodegradation half-life of chlorotoluron in aqueous solution under HPML and sunlight was 14.72 min and 192.54 h. The photolysis rate of chlorotoluron under HPML was easily degraded under two light sources, and the photolysis kinetics of chlorotoluron in aqueous solution followed a first order reaction. The photolysis rate of chlorotoluron in five different types of water under HPML were found to increase by the order of doubly distilled water>tap water>lake water (Chaohu lake)>paddy water>river water.2.The photolysis half-life of chlorotoluron in buffer solutions of pH5、pH7、pH9 under HPML was 13.84min、15.37min and 16.31min respectively. The result showed that the photolysis half-life of chlorotoluron decreased with the increasing of solution pH.3.Four pigments could retard the photolysis rate of chlorotoluron in aqueous solution under HPML, the photosensitive efficiency was methyl blue -20.12%,methyl green -10.54%,congo red -26.24%,methyl orange -28.31% respectively.The photoquenching effects on photodegradation of chlorotoluron were increased with the concentration of different pigments increasing.4. Five surfactants could retard the photolysis rate of chlorotoluron in aqueous solution under HPML. The photosensitive efficiency was 　nongru-404 -10.54%,nongru-601 -27.96%,nongru 500 -25.24%,nongru 603 -21.05% and CTAB -11.22% respectively. The photoquenching effects on photodegradation of chlorotoluron were improved with the concentration of nongru-404、nongru-601 and CTAB increasing. While the photoquenching effects on photodegradation of chlorotoluron were weakened as the concentration of nongru-500 and nongru-603 <WP=9>increased.5.The photolysis kinetics of chlorotoluron including　a little acetone, methyl alcohol and acetonitrile in aqueous solution followed a first order reaction under HPML. 6.Several negative and positive ions could change the rate of photochemical degradation of chlorotoluron under HPML. The results: Mn2+ and Mg2+ could accelerate photochemical degradation of chlorotoluron in aqueous solution and had photosensitive effects on photochemical degradation of chlorotoluron in low concentration, the photosensitive efficiency was Mn2+ +4.10% and Mg2+ +4.49% respectively, but in high concentration acted as photoquenching effects on photochemical degradation of chlorotoluron; NO3- and NO2- had significantly photoquenching effects on photochemical degradation of chlorotoluron in aqueous solution , the photosensitive efficiency was NO3- -19.51% and NO2- -8.25% respectively, with concentration of them increasing, they took on photoquenching effects on photochemical degradation of chlorotoluron in aqueous solution much; Cl- and Br- could accelerate the rate of photochemical degradation of chlorotoluron in aqueous solution in low concentration under HPML, the photosensitive efficiency was Cl- +10.82%, Br- +3.90% respectively,and with concentration of Cl- increasing, the rate of photochemical degradation of chlorotoluron was decreased ,but as concentration of Br- increasing, the rate of photochemical degradation of chlorotoluron was increased，but I- could retarded the rate of photochemical degradation of chlorotoluron in aqueous solution under HPML, the photosensitive efficiency was -22.31% ,and as concentration of I- increasing， I- acted as photoquenching much.7.Photoproducts of chlorotoluron under HPML for a long time in aqueous solution were minerals such as Cl-、NO3-、NH4+、CO2.8.The middle photoproducts of chlorotoluron in aqueous solution were identified by GC-MS, obtained two photoproducts of chlorotoluron in aqueous solution under HPML, their molecular weights were 167 and 149, wi更多还原