【作者】 王晓东；

【导师】 赵新华；

【作者基本信息】 天津大学 ， 环境工程， 2007， 博士

【摘要】 近年来,人们在研究中发现一些人工合成的有机物可能会严重破坏人和动物体内的激素,导致内分泌功能的紊乱。这些被认为是第三代环境污染物的内分泌干扰物质己成为一个全球性的社会问题,引起了人们越来越多的关注。内分泌干扰物(EDCs)已成为环境污染特别是饮用水安全的重大问题,目前的研究主要集中在对内分泌干扰物的环境调查、毒理学研究及评价方法学的建立方面,而对其在环境及饮用水中的控制与去除缺乏研究积累。本论文针对环境内分泌干扰物的污染问题,以饮用水为研究对象,选择在饮用水源中普遍存在并具有内分泌干扰活性的两种有机污染物-壬基酚(NP)和双酚A(BPA)为模型污染物,建立了方便、准确的测定饮用水中NP、BPA的方法,较系统地研究了活性炭吸附和臭氧化降解去除饮用水中两种内分泌干扰物的效能与过程机制,为该工艺实际用于去除饮用水的NP、BPA提供有价值的基础参数。利用C18固相萃取柱(3 mL, 500 mg)富集和净化水样,采用高效液相色谱分离、荧光检测建立了同时测定饮用水中壬基酚、双酚A的方法,并对影响固相萃取回收率的实验条件进行了优化。结果表明,以甲醇/二氯甲烷体积比20:80的混合液为洗脱剂,pH在2~3之间,过样速率控制在10mL/min可以得到最高的固相萃取回收率。不同加标水平的NP和BPA的回收率为95.3%~98.6%,其相对标准偏差为2.5%~3.7%。该方法成功用于饮用水的测定。活性炭由于吸附容量大、吸附速度快和易于再生被广泛用于饮用水的深度处理,但活性炭用于去除水中的内分泌干扰物的研究少有报道。本研究选取了四种不同材质的市售活性炭,并用N2吸附法和X射线光电子能谱进行了表征。在静态试验中,采用瓶点法测定了四种活性炭的吸附等温线,分别用Langmuir公式和Freundlich公式进行拟合,发现活性炭吸附NP、BPA更符合Freundlich方程;从Freundlich方程的系数k可以看出,各种材质的GAC都可以有效去除水中的NP、BPA;吸附容量方面,煤质活性炭>木质活性炭>椰壳活性炭,吸附容量主要取决于活性炭比表面积,但活性炭表面化学特性也起了非常重要的作用,活性炭表面含氧量高不利于活性炭对NP、BPA的吸附;较低的pH值和温度有利于NP、BPA的吸附;试验中考察了腐殖质对吸附量的影响,并建立了EDCs-腐殖质双组分体系的吸附模型,从对模型的分析可以看出,腐殖质与NP、BPA产生强烈的竞争吸附,尤其是在NP、BPA浓度较小时,使NP、BPA的吸附容量大大降低;试验中,还进行了动力学试验,结果表明:活性炭吸附NP、BPA过程符合一级动力学方程,活性炭粒径小更有利于提高NP、BPA的吸附速率;另外,活性炭柱的动态试验发现NP、BPA穿透时间远远长于TOC的穿透时间,即使活性炭对TOC的吸附已达到饱和,活性炭仍然对NP、BPA有一定的吸附能力,水中的天然有机物为该条件下的控制化合物,因此实际应用中只需要考虑TOC的去除即可满足NP、BPA去除要求,这也说明给水处理中已广泛采用的用于去除有机物的活性炭吸附床不需其它改造即可达到良好的去除NP、BPA效果;对于现有的活性炭吸附床,去除水中微量的NP、BPA几乎不增加成本。采用臭氧氧化工艺对饮用水典型中内分泌干扰物NP、BPA去除特性进行了研究。研究表明:单独臭氧氧化对水中的NP、BPA具有很好的去除效果,初始浓度为1.0mg/L,在0.5、0.75和1.00mg/L的臭氧总投加量条件下,NP去除率分别为63.2%、82.4%和94.6%,BPA去除率分别为60.3%、80.4%和91.4%;随着NP、BPA初始浓度的增加,NP、BPA的去除率随之降低;提高水样pH和温度,有利于NP、BPA的去除;虽然臭氧可以有效去除水中的NP、BPA,但并未被完全矿化;臭氧紫外线联合氧化,不仅可以缩短反应时间、减少臭氧的用量,而且可以提高矿化程度;动态试验中,利用响应面模型的试验方法,建立臭氧投加量、TOC和停留时间与BPA去除率的二次响应面模型,该模型具有较高的回归率(R2=0.9989),且试验和模型预测值的相对误差在1.0%~4.1%范围内,与试验结果吻合程度较高;通过对模型的分析可知,三个影响因素对BPA去除率影响从大到小的顺序为:臭氧投加量、TOC、停留时间。更多还原

【Abstract】 In the past several years,the researchers found that some organic compounds could disturb the incretion of human beings and vertebrates by destroying the hormone. At present, endocrine disrupting chemicals (EDCs), as environmental pollutants of the third generation,became a worldwide problem. The EDCs pollutants have been paid more and more attention in recent years.EDCs have become an important problem to environmental pollution,especially to drinking water safety. Studies on EDCs at present mainly focused on environmental investigation,toxicological study and establishment of estimate method. However, controlling and removal of EDCs in environment and drinking water are short of study accumulation. The thesis aimed at treating EDCs in drinking water. Nonylphenol(NP) and Bisphenol A (BPA)were selected as the model pollutants which have endocrine disrupting effects and exist generally in drinking water source. A sample and highly method was established for the determination of NP and BPA from drinking water. And the efficiency and mechanism of activated carbon adsorption and ozonation were systematically studied. This study provided valuable information to the practical removal NP and BPA in drinking water by these two processes.A comprehensive analytical method based on solid phase extraction-high performance liquid chromatography-fluorescence detection (SPE-HPLC-FLU) has been established for the determination of nonylphenol and bisphenol A in water. Clean-up of the water samples was performed on the C18 solid extraction cartridges (3mL, 500mg). A number of parameters that may affect the recovery of SPE were investigated. It is shown that the most efficiency extraction of the target compounds was achieved by using a solvent mixture of methanol-methylene chloridein(20:80,V/V) as the eluting solvent,pH value of 2~3 and the flow rate of 10ml/min. Recoveries for nonylphenol and bisphenol A at different spiked levels were ranged from 95.3%～98.6% with relative standard deviations of 2.5%～3.7%.The method developed was successfully applied to the determination of nonylphenol and bisphenol A in drinking water.Activated carbons are widely used as an adsorption for the removal of pollutants from drinking water because of their high adsorption capacity, fast adsorption kinetics and easy of regeneration. But studies on removal EDCs using activated carbons are lack of report. Four commercial activated carbons with different based materials were selected in this study. Physical properties including surface area, average pore diameter, and micropore volume and chemical structure of the activated carbons were characterized by N2 adsorption experiment and X-ray photoelectron spectroscopy (XPS). Batch adsorptions were conducted using the bottle-point method. Adsorption isotherms of NP and BPA onto carbons were fitted into Langmuir and Freundlich pattern. It was found that adsorption isotherms were fitted better to Freundlich equation than Langmuir equation and all carbons could efficiently remove low concentration of NP and BPA from water. The overall order of Freundlich coefficient k value is coal based carbon> wood based carbon > coconut based carbon, which means that the capacity is the highest for coal based carbon and the lowest for coconut based carbon. Pore Volume could be the most important for adsorption, but the surface chemical character was as also important due to electrical interaction. The high O content of carbon surface lead a negative effect to absorption capacity and low pH value, low temperature lead a positive effect to adsorption. The effect of humus in water to the removal was also studied and EDCs-humus bi-component adsorption model was established, it was found that there is strong competition between EDCs and humus. Due to this competition adsorption capacity of NP, BPA greatly decreased especially when NP, BPA’s concentration is very low. The adsorption kinetics test results indicated that the adsorption of NP, BPA followed the first-order kinetics and the smaller diameter GAC could increase adsorption velocity. In the column experiment, the breakthrough time of NP, BPA was greatly longer than that of TOC. The carbon owns certain adsorption capacity even if the carbon has no adsorption capacity for TOC. Humus was found as the key compound. That is to say, the consideration of humus removal is enough to meet the requirement of NP, BPA removal. The exiting activated carbon bed could employ to removal trace NP, BPA from water without any change and hardly increase the cost of water treatment.The ozone oxidation of representative endocrine disruptor (NP, BPA) in drinking water was investigated. With the initial concentration of 1.0mg/L,the removal efficiency of NP, BPA degradation could be measure up to 63.2%,82.4%,94.6% and 60.3%,80.4%,91.4% when the dosage was 0.5mg/L,0.75mg/L,1.00mg/L respectively. The removal efficiency decreases along with the increase of NP, BPA’s concentration. High pH value and high temperature lead a positive effect on the removal of NP, BPA. NP, BPA can removal by Ozonation efficiently but can not be mineralized entirely. Ozonation combined with UV can not only shorten the reaction time and reduce the dosage of ozone but also improve the degree of mineralization. In the dynamic experiment the response methodology (RSM) was used to study the effect of ozonation on the removal of BPA. Three influencing variables (dosage of ozone, TOC and settle time) on the BPA removal were evaluated using a second-order polynomial multiple regression model. Analysis of variance shows a high coefficient of determination (R2) value of 0.9989, thus ensuring a satisfactory adjustment of the second-order regress model with the experiment data. Analysis on the model indicates that the dosage of ozone is the key factor which influences the removal efficiency of BPA, the next is TOC and the last is the settle time.更多还原