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化学学报
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化学学报 ›› 2009, Vol. 67 ›› Issue (21): 2505-2510. 上一篇    下一篇

研究论文

在饮水中典型溶解性有机氮酪氨酸氯化生成氯仿的机理分析

楚文海   高乃云*   赵世嘏   邓慧萍   

  1. (同济大学污染控制与资源化研究国家重点实验室 上海 200092)
  • 投稿日期:2009-01-05 修回日期:2009-05-26 发布日期:2009-07-02
  • 通讯作者: 楚文海 E-mail:feedwater_2008@163.com
  • 基金资助:

    “十一五”国家科技支撑计划项目(No. 2006BAJ08B06;2007BAC26B03 and 2006BAJ08B02);上海市科委重点科技项目(No. 072312001)和国家高技术研究发展计划（863）(No.2002AA601130;2004AA649410)资助项目

Formation of Chloroform during Typical Dissolved Organic Nitrogen Tyrosine Chlorination in Drinking Water

Chu, Wenhai    Gao, Naiyun*    Zhao, Shijia    Deng, Huiping   

  1. (State Key Laboratory of Pollution Control and Resources Reuse, Tongji University, Shanghai 200092)
  • Received:2009-01-05 Revised:2009-05-26 Published:2009-07-02

PDF

1862

被引次数

6

饮用水氯化消毒可以有效杀灭细菌, 但同时会产生危害人体健康的消毒副产物(DBP). DBP生成机理研究是有效控制DBP的前提. 溶解性有机氮(DON)是DBP的重要前体物, 选取典型DON-丙氨酸(Ala)、苯丙氨酸(Phe)和酪氨酸(Tyr)作为氯仿(CF)等DBP的前体物, 研究三种氨基酸(AA)的耗氯量和CF产率; 同时考察了Tyr氯化中间产物2,4,6-TCP的氯化特性和CF产率; 采用GC/MS扫描和前线轨道理论验证, 探讨了CF的主要生成路径. 研究发现, 在同等氯化反应条件下, 由于侧链基团的不同, Tyr的耗氯量以及CF产率都明显高于Ala和Phe, 从而说明Tyr确实是一种重要的CF前体物质. CF的主要生成路径为Tyr→ 4-MCP → 2,4-DCP → 2,4,6-TCP → CF. 氯胺消毒工艺可有效控制CF的生成, 并能减少2,4,6-TCP的产生, 但不能确保饮用水的生物安全性. 氯化消毒之前将Tyr等重要前体物去除可能是控制CF等DBP更加有效的措施.

关键词: 饮用水, 溶解性有机氮, 酪氨酸, 消毒副产物, 氯仿, 机理

Chlorination disinfection of drinking water effectively prevents waterborne diseases, but results in unintended disinfection byproducts (DBPs) from the reactions between organic materials in water and disinfectants. As alanine (Ala), phenylalanine (Phe) and tyrosine (Tyr) exist in much source water, the chlorination characteristic of the three amino acids (AA) and the formation pathways for chloroform (CF) during chlorination of model Tyr were studied. Chlorine demand and CF yield of the important intermediate product 2,4,6-trichlorophenol (2,4,6-TCP) were also examined. The results indicated that chlorine demand and CF yield of Tyr were much higher than those of Ala and Phe based on the same chlorination conditions, which indicated that Tyr was an important precursor of CF. Based on the analysis of GC/MS and calculation of frontier electron densities (FED2), the formation pathway of CF during chlorination of Tyr was proposed as Tyr→ 4-monochlorophenol (4-MCP) → 2,4-dichlorophenol (2,4-DCP) → 2,4,6-TCP → CF. The yields of CF and 2,4,6-TCP could be reduced by switching chlorination to chloramination. However, the disinfection performance of chloramination is inferior to chlorination. The removal of precursor (Tyr, etc) before disinfection may be a more promising method to reduce the generation of CF.

Key words: drinking water, dissolved organic nitrogen, tyrosine, disinfection by-product, chloroform, formation mechanism