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毒性效应引导的二苯甲酮类紫外防晒剂BP-4氯胺-紫外转化机制研究
Alternative TitleToxicity directed transformation characteristics of UV-filter Benzophenone-4 in chloramination (photo-induction) disinfection process
杨帆
Subtype硕士
Thesis Advisor魏东斌
2018-06
Degree Grantor中国科学院生态环境研究中心
Place of Conferral北京
Degree Name理学硕士
Degree Discipline环境科学
KeywordBp-4,氯胺消毒,氯胺-光联处理,转化机理,急性毒性 Bp-4, Chloramination, Uv-induced Chloramination, Transformation Mechanism, Acute Toxicity
Abstract

       2-羟基-4-甲氧基-5-磺酸二苯甲酮(BP-4)是目前国内产量最大,应用最广泛的紫外防晒剂。近年来,BP-4在多种环境基质、生物体内频繁检出,其潜在的环境与健康风险不容忽视。消毒是水处理的必要环节,氯化消毒因价廉、高效、便于操作等诸多优势,仍然是目前全球使用最普遍的消毒方式。为了避免氯化消毒处理中三卤甲烷、卤乙酸等毒性消毒副产物的生成,氯胺、紫外等替代消毒方式逐渐被开发应用。而BP类污染物在氯胺消毒、紫外消毒过程中的转化行为尚不清楚,因此本文选择BP-4为研究对象,主要探讨其在氯胺(光)消毒过程中的转化机理和毒性变化,并考察了pH、氯胺剂量、共存离子对转化行为的影响。主要结论如下:

      (1)揭示了紫外防晒剂BP-4在氯胺消毒处理中的转化行为和毒性变化特征。借助UHPLC-MS检测所得质谱信息、同位素标记等信息识别出23种主要产物,其中19种产物中含有N元素,9种产物中含有Cl元素,产物中包含8对同分异构体。结合实验现象和化学反应原理,提出了BP-4在氯胺消毒处理中的转化路径,主要涉及氨基取代、氯代、氧化、水解、偶联等化学反应。pH值和氯胺剂量可以影响BP-4的降解程度、降解速度和产物毒性。随着pH的升高,BP-4的降解程度和转化速率增大,毒性逐渐升高。随着氯胺剂量的增加,BP-4的降解程度和速率增加,毒性先升高后降低,5倍氯胺剂量时毒性最大。通过对产物与毒性的相关性分析,推测P13和P13’两个苯醌类产物为主要致毒物质。在溴碘离子共存时共检测出4种含溴产物,5种含碘产物,并识别了它们的分子结构。

      (2)揭示了BP-4在氯胺-光联合消毒体系中的转化行为。研究发现BP-4在紫外光照射条件下并不会被降解,但BP-4在氯胺反应体系中生成的中间体可迅速被光解,共检测出10种光解产物。且光照处理后毒性迅速升高。随着pH的升高和氯胺剂量的增加,反应体系的毒性也逐渐升高。相关性统计分析结果表明产物P2和P5可能是主要的毒性产物。氯胺-光联合处理体系中溴、碘离子的存在减弱了反应后溶液的毒性、以及毒性上升的趋势。

Other Abstract

      The 2-hydroxy-4-methoxybenzophenone-5-sulfonic acid (BP-4) is the most widely used UV filter all over the world. It has been frequently found in natural environment and living organisms. The potential environmental and health risk should not be neglected. Disinfection is an essential unit in water treatment process. Chlorine is the most commonly used disinfectant at present due to its low cost, high efficiency, and convinent operation. In order to eliminate the formation of trihalomethanes, haloroacetic acids and other disinfection by-products, chloramination, UV and some other new disinfection tecniques have been applied as surrogate disinfection methods. However, the transformation characteristics and toxicity varirtion trend of BP-4 during chloramination and UV treatment are not clear. Therefore, this study selected BP-4 as target, the transformation characteristics of BP-4 and the change of the acute toxicity during chloramination (post-UV) were explored. The influence of pH values, dosages of chloramine, and coexistence of bromide or iodide ions, were respectively investigated as well. The main conclusions were as below:

      (1) The transformation characteristics and toxicity variation of BP-4 during chloramination treatment were studied. With the help of high performance liquid chromatography-high resolution mass spectrometry, 23 major products were identified. among them, 19 products contained N elements and 9 contained Cl elements, 8 pairs of isomers were found. Based on the organic chemistry reaction principles and isotope labeling experiments, the transformation pathways of BP-4 chloramination were proposed. It was found that, with the increase of pH, the degradation degree and rate of BP-4 increased, and the toxicity increased gradually. With the increasing dosages of chloramine, the degree and rate of BP-4 degradation increased, while the toxicity first increased and then decreased, with the toxicity peak appeared at the dosage of 5 molar equivalent to BP-4. It was speculated that two quinones P13 and P13' were possible toxic products by analyzing the correlation between the products relative content and toxicity. In the presence of bromide and iodide ions, 4 bromine-containing products and 5 iodine-containing products were produced.

      (2) The transformation characteristics and toxicity variation of BP-4 during chloramination-UV were studied. It was found that BP-4 could not be degraded by UV irradiation, while the intermediates of BP-4 formed in chloramination could be converted rapidly under UV irradiation. Ten products have been identified in chloramination-UV treatment system. As for the reaction solution of BP-4 and chloramine, further UV irradiation would lead to a rapid increase in toxicity. With the increase of pH and doasage of chloramine, the acute toxicity increased gradually. It was speculated that P2 and P5 were the main toxic products by correlation analysis between the relative content and toxicity. In the presence of bromide and iodide ions, the toxicity and the rate of toxicity increasing trend were reduced.

Pages76
Language中文
Document Type学位论文
Identifierhttp://ir.rcees.ac.cn/handle/311016/41564
Collection环境化学与生态毒理学国家重点实验室
Recommended Citation
GB/T 7714
杨帆. 毒性效应引导的二苯甲酮类紫外防晒剂BP-4氯胺-紫外转化机制研究[D]. 北京. 中国科学院生态环境研究中心,2018.
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