【作者】 袁芳；

【导师】 杨仁斌；

【作者基本信息】 湖南农业大学 ， 环境工程， 2007， 硕士

【摘要】 多效唑是一种应用非常广泛的植物生长调节剂，有关其在稻田环境中的降解研究以及在水环境中的化学行为报道很少，本论文通过研究多效唑在水环境中的化学行为以及在稻田环境中的降解行为，包括多效唑残留量检测方法、多效唑在稻田环境中的降解、光降解及其影响因子和多效唑模拟废水的处理，为多效唑的合理使用、评价其环境安全性和开展生态环境修复提供科学依据，也能为多效唑农药生产废水处理工艺研究提供参考。论文主要内容如下：第一章为绪论，主要对农药在稻田环境中的残留消解、在水体中的光化学降解以及Fenton试剂处理农药废水等方面的相关概念、理论和国内外研究现状以及多效唑各方面的研究进展进行了简要的介绍和评述，同时指出了本研究的内容、意义以及目标。第二章研究并建立了多效唑在稻田环境中的残留检测方法，并用该方法研究了多效唑在稻田水土环境中的残留降解行为，结果表明：（1）建立了一种稻田环境中多效唑GC残留检测和分析方法。该方法选用丙酮水混合溶液（1／1，v／v）提取土壤中的多效唑，二氯甲烷提取植株中的多效唑，提取液用二氯甲烷萃取三次，再用石油醚与丙酮混合液（4／1，v／v）作淋洗液填有2cm厚无水硫酸钠+3g硅镁吸附剂+约2cm厚无水硫酸钠的层析柱净化，在优化的高效气相色谱条件下检测。在多效唑添加浓度范围内，样品中添加平均回收率在91.40％—106.90％，变异系数在2.52％—5.78％之间。稻田水、土样和植株中的最低检出浓度分别为：0.001mg／L、0.025mg／kg、0.05mg／kg。（2）15％多效唑可湿性粉剂按高剂量处理，其在稻田水、土壤和植株中的半衰期分别为5.50d、15.75d、2.93d（湖南）；8.88d、15.13d、2.36d（天津）。（3）按使用剂量处理，在水稻收获时，在湖南、天津两地土壤、稻米及稻壳中均未检出多效唑；按高剂量处理，在水稻收获时，在湖南和天津土壤中的残留量分别为0.034mg／kg和0.025mg／kg。第三章研究了多效唑在水中的光化学降解行为，结果表明：（1）多效唑在不同光源下，其光降解速率有较大的差异，光降解速率顺序为：高压汞灯＞紫外灯＞太阳光；（2）在高压汞灯下，多效唑光降解速率随着初始浓度的增大而减慢。在同一初始浓度下，随着时间的延长，多效唑光降解率的变化逐渐减慢；（3）多效唑水溶液采用三种不同的通气方法处理，其光降解速率顺序为：通O₂＞不通气＞通N₂，表明多效唑在水中的光降解主要是光氧化降解；（4）在几种不同水质中多效唑光降解速率为：去离子水＞井水＞河水＞池塘水＞稻田水，各种不同水质的水中所含溶解性有机物和无机物以及电导率的不同是造成多效唑光降解差异的主要原因；（5）在pH缓冲溶液中，pH值对多效唑的光降解速度影响较大，多效唑的光降解速率在pH6和pH7中降解最快，在酸性和碱性环境中不利于多效唑的光降解。（6）多效唑在不同金属离子溶液中的实验表明，Fe³⁺离子对多效唑具有敏化作用，敏化效应随离子浓度增加呈上升趋势，Cu²⁺和Ca²⁺对多效唑具有猝灭作用，且其光降解半衰期与Cu²⁺和Ca²⁺添加浓度呈正相关；（7）从四种化肥对多效唑光降解试验可知，磷酸二氢钾对多效唑的光降解有微弱的敏化作用，其半衰期与添加浓度呈负相关，在添加10mg／L时对多效唑光解的影响最大。而尿素、碳酸氢铵和氯化钾表现出猝灭作用；（8）在高压汞灯下，胡敏酸和富里酸的存在使多效唑的光降解速率降低，表现出了显著的光猝灭效应。（9）H₂O₂对多效唑的光降解表现出很强的敏化作用。在高压汞灯下，随H₂O₂浓度增大，多效唑光降解速率不断加快，当H₂O₂浓度达到20mg／L时，敏化效率不再提高。第四章研究了几种因素对多效唑模拟废水降解研究，比较了UV／Fenton、UV／类Fenton和UV／H₂O₂等几种光氧化体系对多效唑模拟废水处理的效果，结果表明：（1）在对多效唑模拟废水初步研究的基础上，确定了初步试验操作条件：[H₂O₂]为0.1 mol·L^-1，[Fe²⁺]为7mmol·L^-1，反应pH值为4，反应时间为80min：（2）在正交实验的基础上，对多效唑模拟废水的四种影响因素进行优化，结果表明，多效唑随H₂O₂用量、pH、Fe²⁺浓度和反应时间的增加，降解率不断增大，COD去除率也不断增大，当H₂O₂用量为0.2mol／L、pH 4、Fe²⁺浓度为7mmol·L^-1和反应时间达到80min时，多效唑降解的最多，COD的去除效果最好，其去除率达到85％以上，之后COD去除率基本维持稳定。（3）比较了UV、UV／H₂O₂、UV／Fenton、UV／类Fenton四种光氧化体系对多效唑模拟废水的处理。在相同光照条件下，经过150min的反应，UV／Fenton、UV／类Fenton、Fenton体系多效唑废水CODcr的去除率达到了85％以上。第五章对本研究工作进行了总结和讨论，并提出了本研究的创新点和有待进一步研究的内容。更多还原

【Abstract】 Paclobutrazol {（+/-R^*, R^*）-B-[（4-Chlorophenyl） methyl]-alpha-（1, 1-dimethylethyl）-1H-1, 2,4-thiazol-1-ethanol}is one kind of Plant Growth Regulator, which is popularized to use all overthe world today, but little information is available about its degradation behavior in the paddy andchenmical behavior in aqueous solution. In order to comprehensively evaluate environmentalsecurity of Paclobutrazol and for its reasonab application and ecological environmental restoration,and to provide referrence for production wastewater processing craft of Paclobutrazol, this paperaims to study the degradation of Pachlobutrazol in the paddy and photolysis of Paclobutrazol inaquatic environment, including the determination of Paclobutrazol, the degradation ofPaclobutrazol in the paddy and photolysis of Paclobutrazol in in aquatic environment, theinfluence as factors and disposed of pesticide wasterwater. The main results obtained were asfollows.Chapter one was introduction, in which the basic concepts, theories and current advances athome and abroad were reviewed briefly on residue degradation in the paddy enviroment,photolysis and the disposed of pesticide wasterwater with Fenton reagent. In addition, researchadvance of Paclobutrazol was summarized concisely. The contents and significances of thisresearch was also included in this chapter.In the chapter two,it studies and builds up the method of residual detemination of PlantGrowth Regulator 15％Paclobutrazol WP in the water, soil and paddy, and the degradation ofPaclobutrazol in the paddy. The results showed:（1）A new analytical method for deteminingresidues of Paclobutrazol in water, soil and paddy by GC was developed. The soil samples wereextracted with acetone water solution（1/1,v/v）, and the paddy sample extracted withdichoromethane, then the extract re-extracted three times with dichoromethane, choose petroleumplus acetone（4/1,v/v） for pour solution. The quantification of the Paclobutrazol residue wasestablishied by GC. The results showed that the average recoveries of the method was from91.40％—106.90％at the fortified levels of 0.05～1.0mg/kg （ water sample mg/L） for the samples,and coefficient of variation was in range of 2.52％—5.78％. The minimun detectable limits inwater, soil and paddy were 0.001mg/L、0.025mg/kg、0.05mg/kg, respectively. The parameterssuch as accuracy, sensitivity, precision for the method were good to satisfy the essential rules ofpesticide residue determination. （2） At the application rate of 6000g/hm², the half-life ofPaclobutrazol in the water, soil and paddy were 5.5d, 15.75d, 2.93d（Hunan）, 8.88d, 15.13d, 2.36d（Tianjin）, respectively. （3） At the application rate of 3000g/hm², during the rice harvest, itdidn’t detected Paclobutrazol among the rice and rice busk in Hunan and Tianjin. At theapplication rate of 6000g/hm², during the rice harvest, the final residual was 0.034mg/kg and0.025mg/kg, respectively, in Hunan and Tianjin.Chapter three was Studies on the photochenmical degradation of Paclobutrazol in aqueoussolution. The results showed that: （1） In natural water, the photolysis rate of Paclobutrazol hasgreat disparity under high-pressured mercury lamp, ultraviolet lamp and sunlight. Its order is thehigh-pressured mercury lamp＞ultraviolet lamp＞sunlight. （2） Under the high-pressured mercurylamp, the photolysis rate decreased with the increasing of initial concentration of Paclobutrazol.Under the identical initial concentration, photolysis rate of Paclobutrazol gradually tended to begentle with the extended time. Under the high-pressured mercury lamp, the differentconcentrations of dissolved oxygen in the pure water showed different orders of photolysis rate ofPaclobutrazol in the solutions. Its order was ventilate O₂＞not ventilate O₂ and N₂＞ventilateN₂. The dissolved oxygen had an important effect on photooxidation of Paclobutrazol. （4） Thephotolytic rates of Paclobutrazol in different aquatic solutions showed the followingsequences: pure water＞well water＞river water＞pond water＞paddy water. The main reason to causethe difference of photolysis of Paclobutrazol was the differences of dissolved organic, inorganicmatrix and conductivity in different natural water systems, pH value played an important role inthe photolysis rate of Paclobutrazol in the pH buffer solution. It showed that the photolysis ratewas quicker in pH6 and pH7 than in other buffer solutions. Photolysis of Paclobutrazol was stablein acid water and alkalinity water. （6）in metallic ion solution, Fe3 made the half-life ofPaclobutrazol reduce, and the effect increases along with the ion concentration increases. Cu²⁺ andCa²⁺ showed photo-quenching effects on photolysis of Paclobutrazol and the photolytic half-lifewas posotively correlated to the concentration of Cu²⁺ and Ca²⁺. （7） From the experiments of fourfertilizers towards photolysis rates of Paclobutrazol under the high-pressured mercury lamp, itshowed that KH2PO4 had photosensitizing effects on Paclobutrazol. Its photolytic half-life wasnegatively correlated to the concentration of KH₂PO₄. When the concentration of KH₂PO₄ reached10mg/L, the photolysis effect of Paclobutrazol is the largest.However, NH₄HCO₃, urea and KClall showed photo-quenching effects on photolysis of Paclobutrazol. （8） under the high -pressuredmercury lamp, the higher concentration of HA and FA could reduce the photolysis rates, and haveremarkable photo-quenching effects on photolysis of Paclobutrazol. （9） under the high-pressuredmercury lamp, the photolysis rate of Paclobutrazol will be accelerated by the concentration ofH₂O₂. the higher the concentration of Paclobutrazol is the quicker the potolysis rate ofPaclobutrazol is. When the concentration of Paclobutrazol reached 20mg/L, photolysis rate didn’t increase again.In the chapter four, it studied the four effect factors to the treatment wasterwater ofsimulation Paclobutrazol with orthogonal experiment. This paper compared with the treatmenteffects of wastewater containing Paclobutrazol with UV/Fenton(Fe²⁺), UW/ Fenton(Fe³⁺) andUV/H₂O₂. The result showed that （1）On the Basis of reasearch on herbicide simulationwastewater, determination the condition of the experiments by charging the amount of initialH₂O₂, Fe²⁺, pH and reaction time were made: [H₂O₂]=0.1mol·L^-1, [Fe²⁺]=7mmol·L^-1, pH=4,reaction time=80min. （2） On the Basis of reasearch on herbicide simulation wastewater, carrieson the optimization to Paclobutrazol simulation wastewater in four kind of influences factor. Withthe increase of H₂O₂ and Fe²⁺ doses, pH value and reaction time, the photolysis rate ofPaclobutrazol increased, then the chemical oxygen demand removal rate increased also. But whenthe doses of H₂O₂ reached 0.2mol/L, the doses of Fe²⁺ reached 7mmol/L, pH value reached 4and the time surpassed 80min, the photolysis rate of Paclobutrazol up to largest, the chemicaloxygen demand removal rate was the largest and it reached 85％. Then the chemical oxygendemand removal rate maintained stable. （3） This paper compared with the treatment effects ofwastewater containing Paclobutrazol using Fenton reagent, UV/Fenton(Fe²⁺), UV/ Fenton(Fe³⁺)and UV/H₂O₂. Under the same illumination condition, after 150min, the chemical oxygen demandremoval rate of UV/Fenton(Fe²⁺), UV/ Fenton(Fe³⁺) and Fenton reagent reached above 85％.In the last chapter, a summary was done on the research results, and meanwhile theinnovation of the research and the projects that need to be further studied were suggested.更多还原