【作者】 张雅萍；

【导师】 陈鸿汉； 毕二平；

【作者基本信息】 中国地质大学（北京） ， 地下水科学与工程， 2014， 博士

【摘要】 农药对环境造成的影响日益严重。农药进入环境后不仅会对当地的环境产生危害，还可以通过大气或者是水流进行长距离迁移从而造成大范围的影响。农药的疏水性影响着其环境行为及归宿。不同疏水性农药在环境介质中的迁移方式是不同的，因此，研究不同疏水性农药在相间界面上的迁移机理是十分必要的。吸附作用可以有效抑制迁移，通过对高疏水性农药在固-气相间以及低疏水性农药在固-液相间吸附机理的研究，可以帮助解释农药在相间界面迁移的机理。本研究中通过固体逸度计以及批实验的方法，研究了不同环境温度（T）和有机碳含量（foc）条件下高疏水性的滴滴涕及其代谢产物（DDTs）在固-气相间的分配作用，以及pH值和共存阳离子影响下环丙氨嗪在固-液相间的吸附作用。综合分析了农药的相间吸附机理，成果可为有效地防治农药迁移对环境造成的影响提供依据。主要的研究成果如下：（1）土壤介质中foc的增加（从0.62%到4.73%），使得土壤的体积密度下降（从1.53g cm-3到1.39g cm-3）。这造成了高疏水性农药的土壤-气分配系数（KSA）不随foc的增加等比例增加。（2）环境温度高于0oC时，温度的升高使得KSA与辛醇-气分配系数（KOA）之间的斜率接近1。通过对高疏水性农药在土壤-气相间分配的焓变（ΔHSA）进行分析可知：ΔHSA随着农药疏水性的增加而增加。相对于p,p’-的滴滴涕（DDT）、滴滴伊（DDE）以及滴滴滴（DDD）来说，o,p’-的DDT、DDE以及DDD更难从土壤环境迁移到大气环境中。（3）通过分析，选择了影响KSA的主要因素（即：有机物的KOA、foc以及T）为参数，建立了可预测DDT及其代谢产物KSA的多参数预测方程（样本数n=96，r2=0.909， RSSR=0.266）。（4）为了解土壤有机质性质对低疏水性农药在固-液相间吸附作用的影响，用H2O2对腐殖酸进行了氧化。氧化使得一部分腐殖酸变成了富里酸。因为富里酸分子表面的吸附点位比腐殖酸要少，从而使得环丙氨嗪的吸附量下降。当环丙氨嗪的平衡液相浓度为4mg L-1时，经H2O2改性后，吸附剂的固相吸附量比未改性时减少了13.37%。（5）环丙氨嗪在颗粒混合介质上的吸附机理包括表面吸附和分配作用，而改性颗粒混合介质对环丙氨嗪的吸附机理则主要是分配作用。随着pH值的上升（从4.0到7.2），环丙氨嗪在溶液中的质子化作用减小，由于静电作用以及吸附剂表面的阳离子交换作用减弱，使得环丙氨嗪在颗粒混合介质上的吸附平衡常数下降（kd从43.88L kg-1降至30.55L kg-1）。共存阳离子（Na+和Ca2+）会与质子化的环丙氨嗪产生竞争作用，从而导致吸附量的降低。更多还原

【Abstract】 The release of pesticides to environment is causing serious problems. Pesticidesin soil environment could not only harm the local environment, but also contribute tothe global environment contamination by long transport through atmosphere andwater flow. The hydrophobicity affects the distribution of pesticides, transportion andenvironmental fate. In view of the damage caused by pesticides in environmentsystem, it is very important to understand transportion and phase diffusion mechanismof different hydrophobic pesticides in the environment. Thus, the partition of DDTsbetween solid and gas phase under the conditions of different environmentaltemperatures and soil organic carbon contents (foc) was studied by solid fugacitymeter. The sorption mechanisms of cyromazine in solid-liquid systems under theconditions of different pH and coexisting cations were investigated by batchexperiments. The results of this study can provide a basis for the control andprevention of pesticide pollution. The main conclusions are as follows:(1) The increasing of foc(from0.62%to4.73%) results in an increase of soil-airpartition coefficients (KSA). However, the increasing trend is not in direct proportionto KSAdue to the decrease of the bulk density of the solids (from1.53g cm-3to1.39gcm-3).(2) With increasing temperature (T: above0oC), the slop between log KSAandlog KOA(octanol-air partition coefficients) is close to1. The enthalpy change of thesoil-air partition (ΔHSA) increases with the increasing hydrophobicity of pesticides.ΔHSAvalues of o,p’-isomers (DDT, DDE, DDD) are larger than those of p,p’-isomers, which means that more energy is required to remove o,p’-isomers from soilto air.(3) Based on the effects of different factors on KSA, a multi-parameter regressionequation including fOC, KOA, and T of dichloro-diphenyl-trichloroethanes and itsmetabolites (DDTs) was regressed (n=96, r2=0.909, RSSR=0.266), which can be usedto predict KSA. (4) In order to know the effects of property of organic matter on sorption, part ofthe humic acid was oxidized to fulvic acid by H2O2oxidation treatment. Because thequantity of sorption sites on fulvic acid is less than that of humic acid, the decreasingsorption sites led to negative influence on sorption. At an equilibrium aqueousconcentration of4mg L-1, sorption of cyromazine to solids decreased by13.37%afterH2O2oxidation.(5) Sorption mechanisms of cyromazine on artificial solid particle includeadsorption and partition. The sorption process of cyromazine on modified artificialsolid particle media is mainly partition. The increase of solution pH from4.0to7.2resulted in a decrease of kdfrom43.88L kg-1to30.55L kg-1. Coexisting cations (Na+and Ca2+) would compete with protonated cyromazine for sorption sites whichbrought negative effect on sorption.更多还原