【作者】 张从良；

【导师】 王福安；

【作者基本信息】 郑州大学 ， 化学工艺， 2007， 博士

【摘要】 随着集约化畜牧业的发展，畜禽疾病越来越复杂，兽药种类及用量也与日俱增，由此引发生态环境的不良反应，对人类健康所造成的危害越来越严重。我国对兽药在水生和陆生环境中的蓄积、分布、转移、渗透、吸收、降解、消除、归宿等环境行为以及对生态环境和人类社会影响的研究，尚处在竟相研究阶段。作为河南省自然科学基金项目（No．0611033400）和河南省教育厅自然科学基金项目（No．2006610002），本文以磺胺类药物为对象，进行水溶解度及溶解过程热力学、正辛醇／水分配系数及热力学分配行为、土壤中含量分析、土壤中迁移性和吸附性、微生物降解性等基础研究，具有重要的学术理论意义和工程应用前景。用氢氧化钠溶液作提取液，建立了测定土壤环境中磺胺嘧啶等八种磺胺类药物含量的紫外分光光度定量分析方法。正辛醇／水分配系数K_ow是药物与生物膜间相互作用评价系统研究的定量参数，是决定药物分子转移、渗透、吸收、分布、消除的关键数据，而有关不同温度下磺胺类药物正辛醇／水分配系数及热力学分配行为研究甚少。运用传统摇瓶法和紫外分光光度法，实验测定了298.15-333.15K温度范围内七种常见磺胺类药物八个温度下的正辛醇／水分配系数K_ow。根据流体相平衡理论，建立了正辛醇／水分配系数随温度变化的热力学模型，计算了308.15K下七种常见磺胺类药物在正辛醇／水体系中分配过程的△H_w→1、△S_w→1、△G_w→1数据以及K_ow的温度效应系数。探讨了磺胺类药物在正辛醇／水系统中的热力学分配行为。磺胺类药物分子向正辛醇相的分配过程主要为焓变驱动过程，向外界放热，正辛醇分子比水分子能更好地将磺胺类药物分子溶剂化。磺胺类药物分子向正辛醇相分配过程的熵变均为负值，体系的有序度增加。药物的水溶解度数据及溶解过程热力学是药物水环境迁移、传递、降解、归宿行为研究的基础。本文采用平衡法测定了298.15-333.15K温度范围内七种磺胺类药物在水中的溶解度数据。采用差示扫描量热技术测定了四种磺胺类药物的熔点和熔化热。运用基于流体相平衡分子热力学的λh方程和改进Apelblat方程成功关联了溶解度实验数据。根据溶解过程热力学，由溶解度实验数据计算出六组磺胺类药物水溶液的超额焓H^E和七种磺胺类药物在水中的溶解焓变△H_s、溶解熵变△S_s。H^E＞0，表明磺胺类药物分子与水分子之间的交互作用弱于水分子间的缔合作用，磺胺类药物溶于水的过程中缔合键的断裂占主导地位，表现为吸热过程。△H_s、△S_s均为正值，说明磺胺类药物在水中的溶解为熵变驱动过程。溶解过程的熵增加，表明磺胺类药物分子进入水中时扰乱了水分子的排列，使体系的有序度降低，混乱度增加，熵增加。溶解过程的吸热效应，表明磺胺类药物分子与水分子间的作用强度较水分子的弱，从而新产生的磺胺类药物分子与水分子间作用键的能量不足以弥补水分子原有缔合键断裂所需要的能量，使体系需要向外界吸收热量，表现为焓增加。磺胺类药物在水中的溶解焓变数值与其熔化热数值相差不大，说明溶解过程中磺胺类药物分子与水分子之间的络合、缔合等特殊交互作用弱。还建立了磺胺类药物水溶解度与分子价键连接性指数间的定量相关模型，确定了模型参数，为磺胺类药物水溶解度的预测奠定了基础。通过静态吸附实验测得磺胺嘧啶在砂土、壤土、粘土中的平衡吸附数据，其吸附等温线均较好地符合Freundlich吸附等温方程。据此求得吸附系数、吸附过程Gibbs自由能变△G′。按吸附等温方程和吸附等量方程算得磺胺嘧啶在粘土中的等量吸附焓变△H、等量吸附熵变△S与等量吸附自由能变△G。△H＜0，表明吸附为放热过程。△S＜0，表明吸附过程中体系的有序度增加。△G＞0，表明吸附为非自发过程，△G＜40kJ·mol^-1，表明吸附过程为物理吸附。溶液pH值过高或过低均不利于磺胺嘧啶的吸附，最大吸附量点为pH=8。通过动态土柱淋溶实验研究了磺胺嘧啶在土壤环境中的纵向迁移行为。实验结果表明，磺胺嘧啶在不同土壤中的迁移状况差异较大，其迁移能力为：砂土＞粘土＞壤土，并指出土壤质地和有机质含量是影响磺胺嘧啶在土壤中淋溶向下迁移能力的重要因素。通过室内模拟降解，实验测得磺胺嘧啶在湖水和猪场废水环境中好氧和厌氧降解动力学数据，建立了降解动力模型，确定了降解速率常数和半衰期等动力学参数。磺胺嘧啶在湖水和猪场废水环境中好氧和厌氧降解均服从生物降解一级动力学规律。磺胺嘧啶在猪场废水中厌氧微生物降解速率高于其好氧组，而磺胺嘧啶在湖水中厌氧微生物降解速率低于其好氧组。磺胺嘧啶对湖水和猪场废水中细菌的生长具有一定的刺激作用，而对真菌和放线菌的生长影响不明显。通过室内模拟降解，实验测得六种磺胺类药物在土壤环境中的降解动力学数据，建立了降解动力模型，确定了降解速率常数和半衰期等动力学参数。六种磺胺类药物在土壤环境中降解均遵从生物降解一级动力学规律。实验范围内磺胺嘧啶在土壤中降解的较佳条件为：砂土、308.15K和25mg·kg^-1。六种磺胺类药物在砂土中的微生物降解均较慢，其微生物降解速率常数按磺胺对甲氧嘧啶、磺胺甲恶唑、磺胺二甲氧嘧啶、磺胺间甲氧嘧啶、磺胺嘧啶和磺胺二甲基嘧啶的顺序依次减小。更多还原

【Abstract】 With the booming of intensive stockbreeding, poultry diseases have became complex and difficult, and more and more species and quantities of veterinary drugs are used for solving the problem. Subsequently, the impact of contaminated ecological environmental on human being’s health has been aggrandized dramatically. Some measures revealed that most of the veterinary drugs used in China are of the category of drugs for food animals in which antimicrobial drugs, especially sulfonamides, macrolides and quinolones, are predominant and their market share over 60%. Nowadays, systematic studies on the accumulation, transportation, and transformation of veterinary drugs in aquatic and terrestrial environment, as well their effects on various organisms are still scarce, especially compared to that of developed countries. Consequently, it is critically to conduct researches to investigate the environmental behavior of veterinary drugs, which would be helpful for accessing the security of veterinary drugs utilization in aquatic and terrestrial environment and modifying the contaminated soil. This research was financed by the Natural Science Fund （No.0611033400） of Henan Provincial Department of Science and Technology in 2006, and by the Natural Science Fund （No.2006610002） of Henan Provincial Education Department in 2006 for basic research.A method of UV spectrophotometry was established to determine the concentration of sulfadiazine in soil by using sodium hydroxide solution as extractant. It was shown in the tests that the linear range of standard carve was 2-10mg·L^-1 and the correlation coefficient was 0.9999 （RSD=1.74%）; the average recovery was 98.9%. Compared with method of titration dead-stop, results for two methods were identical approximately. This method had many advantages, such as convenience, speed, and accurate.A shake-flask method was used to determine the 1-octanol/water partition coefficients of sulfamethazine, sulfadimethoxine, sulfamethoxydiazine, sulfamonomethoxine, sulfamethoxazole, sulfaquinoxaline and sulfachloropyrazine from （298.15 to 333.15） K. The results showed that the 1-octanol/water partition coefficient of each sulfonamide decreased with the increase of temperature. Based on the fluid phase equilibrium theory, the thermodynamic relationship of 1-octanol/water partition coefficient depending on the temperature is proposed, and the changes of enthalpy, entropy, and the Gibbs free energy function for sulfonamides partitioning in 1-octanol/water are determined, respectively. Sulfonamides molecules partitioning in 1-octanol/water is mainly an enthalpy driving process, during which the order degrees of system increased. The temperature effect coefficient of 1-octanol/water partition coefficient is discussed. The results show that its magnitude is the same as that of values in the literature. However, from the viewpoint of the fluid phase equilibrium theory, the effect on 1-octanol/water partition coefficient cannot be ignored when temperature varies drastically. It is necessary that the temperature should be controlled exactly on determining the 1-octanol/water partition coefficient.Using a static equilibrium method, the solubilities of sulfadiazine, sulfamethazine, sulfadimethoxine, sulfamethoxydiazine, sulfamonomethoxine and sulfamethoxazole in water have been determined experimentally from （298.15 to 333.15） K. The melting points and heats of fusion for 4 sulfonamides have been determined experimentally through DSC. According to Scatchard-Hildebrand theory and solubility parameters, the solubility change law for sulfonamides in water and its probable causes were discussed. The experimental data were correlated withλh equation and modified Apelblat equation; the constants of equations were obtained. Based on relationship between the parameter h inλh equation and excess enthalpies H^E, the excess enthalpies for six systems, the solution enthalpies△H_s and solution entropies△S_s for seven sulfonamides in water, were calculated using experimental data. Their variation law for sulfonamides aqueous solution and probable causes were discussed in terms of molecular interaction. Mathematical models for the molecular valance connectivity indexes and aqueous solubilities of sulfonamides were established; the constants of equations were obtained; the aqueous solubilities for 12 sulfonamides were predicted successfully. A study of 12 sulfonamides showed high correlations （r=0.9103） between their aqueous solubilities and molecular connectivity indexes, making possible the prediction of the partition behaviors of sulfonamides on the basis of their connectivity.Static experiments for sorption behavior of sulfadiazine in soils were carried out to investigate the influence of temperature, and pH on adsorption. The results indicated that the adsorption isotherms of sulfadiazine in three kinds of soils were well described by the Freundlich type, adsorption constant of organic mater of sulfadiazine averaged 0.103, and the Gibbs free energy function variations for sulfadiazine adsorption were 4.771-6.440kJ·mol^-1 at 298.15K. Adsorption of sulfadiazine decreases with increasing temperature and its maximum adsorption is noticed at pH=8.Leaching experiments of dynamic soil column were conducted to study the transport of sulfadiazine in soils. Sulfadiazine showed different ability to be transported downward with moving water in three kinds of soil column. The transportation sequence of sulfadiazine in the tested soils was sand＞clay＞loam. Soil texture and soil organic matter content are two important influencing factors. Through indoor simulation degradation experiments, microbial degradation for sulfadiazine in lake water and piggery wastewater were carried out to investigate the influence of oxygen supply mode and organic matter content in water on microbial degradation for sulfadiazine. The results indicated that the anaerobic degradation rate of sulfadiazine in piggery wastewater was more rapid than that for aerobic degradation; the anaerobic degradation rate of sulfadiazine in lake water was slower than that for aerobic degradation. Moreover, the study also showed that the number of bacteria except fungi and actinomycete grew significantly.Through indoor simulation degradation experiments, microbial degradations for six sulfonamides in sandy soil were carried out to investigate the influence of soil types, concentrations and temperatures on degradation for sulfadiazine. The results indicated that the microbial degradations of six sulfonamides in sandy soil were slow, which their rate constants order was SMD=SMX＞SDM＞SMM＞SD＞SM₂. Their degradations were mainly caused by non-biological degradations, rather than by microbial degradation, which was mostly related to their strong antibacterial activities.更多还原