【作者】 张媛；

【导师】 陈慧；

【作者基本信息】 西北师范大学 ， 环境科学， 2007， 硕士

【摘要】 环境激素是环境中存在的一类化学物质,它可以改变人类和野生动物的内分泌系统,导致生殖、发育和行为异常。邻苯二甲酸酯是一类重要的环境激素,它主要用作增塑剂,近年来,随着塑料制品的大量生产和使用,邻苯二甲酸酯不断进入环境,已成为全球最普遍的一种污染物。论文以研究3种邻苯二甲酸酯类环境激素物质邻苯二甲酸二甲酯(DMP)、邻苯二甲酸二乙酯(DEP)和邻苯二甲酸二丁酯(DBP)在黄河兰州段沉积物中吸附与解吸特性为主要内容。邻苯二甲酸酯难溶于水,在水中的含量较低,需要对样品进行前处理。选用Waters公司的HLB(200mg,6mL)固相萃取小柱,采用固相萃取技术对极性不同的3种物质进行前处理,设计正交实验,对影响固相萃取的几个主要因素(洗脱剂组成、洗脱剂用量、洗脱速率及清洗剂组成)进行优化,确定最佳的固相萃取条件和液相色谱法分析条件。以DMP、DEP和DBP为代表物质,分析它们在沉积物上的等温吸附变化,比较讨论了3种平衡吸附模型(Linear方程、Frendlich方程和Langmiur方程)对于描述3种邻苯二甲酸酯在沉积物上吸附等温线的准确性,获得了DMP、DEP和DBP三种物质的吸附等温方程,预测邻苯二甲酸酯在沉积物上的吸附行为。结果表明三种物质的吸附等温线呈非线性,吸附等温线符合Frendlich方程,建立了吸附模型。同时对于影响吸附的因素(温度、pH值、离子强度和重金属离子以及沉积物处理方式)进行分析讨论,发现出了温度有影响外,其他四个因素对与PAEs的吸附影响很小。论文选取DMP为PAEs在沉积物上解吸行为的研究对象,DMP的整个解吸过程分为快速和缓慢两个过程。DMP在沉积物中时间阶段不同,它的解吸的速率不同,呈现出随时间延长和接近平衡状态时,速率逐渐减小的趋势。应用四种不同的解吸动力学方程(一级动力学方程、抛物线方程、双常数方程和Elovich方程)对解吸变化进行描述和分析,确定解吸模型,发现其解吸过程是一个非均相扩散过程。更多还原

【Abstract】 Environmental hormone is a class of chemical compounds in environment. It may affect human and wildlife on their normal endocrines ,cause reproductive, developmental and behavioral disorder. Phthalate acid esters(PAEs) are an important group of environmental hormone. Their main applications are as plasticizers in the manufacture of plastics. In recent years, large amount of plastics have caused a wide distribution of PAEs into environment. PAEs become one of the most prevalent contaminants. The adsorption and desorption characterize of three phthalate acid esters dimethyl phthalate (DMP), diethyl phthalate(DEP)and di-butyl phthalate (DBP)on sediment t along the Yellow River in lanzhou have been studied in this paper, which are environmental hormone.Phthalate acid esters are slightly soluble in water, which make it necessary to pretreatment before determination. Three PAEs were extracted from water sample using solid phase extraction on HLB cartridge (200mg, 6mL), a production of Waters corporation. Several main factors (eluting solvent, eluting volume, eluting rate and washing solvent) in solid-phase extraction (SPE) were optimized by orthogonal design. The optimum condition of SPE and the analyzed condition of liquid chromatogram were established.The adsorption isotherms of DMP, DEP and DBP on sediment were obtained using the batch equilibration method. A model describing the adsorption behavior of PAEs on sediment was according to the experiment data. The research result indicated that the adsorption isotherm of PAEs , regardless of ionic and neutral forms ,were non-linear and obeyed to the Freundlich equation. MeantimeAdsorption isotherm equation of DMP, DEP and DBP are obtained by analysing the isotherm adsorption change of three PAEs and comparing the accuracy of the three adsorption equilibrium model (Linear equations, Frendlich equation and Langmuir equation) is described three phthalates adsorption isotherms on sediments .The results showed that adsorption isotherms of three PAEs were non-linear and obeyed to the Freundlich equation. Meanwhile, the factors (temperature, pH, ionic strength, heavy metal ions and sediment treatment) which affect the adsorption were discussed, it is found the temperature change have effect on adsorption of PAEs, but other four factors have no effect on it. DMP is selected as investigation object for desorption behavior from sediment in this papers. The whole desorption process of DMP is divided into fast and slow part. The DMP desorption rate is diffirent in different time on sediment, it showed that the rate decreased gradually with extending time and approaching to equilibrium. Desorption model is determined by applying four different desorption kinetics equation (a kinetic equation, parabolic equation, Two-constant equation and Elovich equation).It is found that desorption process is a non-homogeneous diffusion process.更多还原