Formation of N-nitrosodimethylamine (NDMA) from dimethylamine during chlorination
Formation of N-nitrosodimethylamine (NDMA) from dimethylamine during chlorination
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DOI：
10.1021/es010684q
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发表时间：
2002-02-15
影响因子：
11.4
通讯作者：
Sedlak, DL
中科院分区：
文献类型：
--
作者：
Mitch, WA;Sedlak, DL
二级废水和饮用水的氯消毒可导致产生浓度分别约为万亿分之100和万亿分之10（ng/L）的强致癌物N-亚硝基二甲胺（NDMA）。对NOW前体的实验室实验表明，在二甲胺和其他仲胺的氯化过程中可以形成NDMA。氯化过程中NDMA的形成可能涉及通过一氯胺和二甲胺反应缓慢形成1，1-二甲基肼，然后快速氧化为NOMA和其他产物，包括二甲基氰胺和二甲基甲酰胺。其他途径也导致氯化过程中NDMA的形成，如次氯酸钠与二甲胺的反应。然而，NOMA形成的速率比当一氯胺与二甲胺反应时观察到的速率慢大约一个数量级。由于竞争反应，该反应表现出强烈的pH依赖性。通过在氯化之前去除氨、通过断点氯化或避免使用一氯胺进行饮用水消毒，可以减少氯化过程中NDMA的形成。
Chlorine disinfection of secondary wastewater effluent and drinking water can result in the production of the potent carcinogen N-nitrosodimethylamine (NDMA) at concentrations of approximately 100 and 10 parts per trillion (ng/L), respectively. Laboratory experiments with potential NOW precursors indicate that NDMA formation can form during the chlorination of dimethylamine and other secondary amines. The formation of NDMA during chlorination may involve the slow formation of 1,1-dimethylhydrazine by the reaction of monochloramine and dimethylamine followed by its rapid oxidation to NOMA and other products including dimethylcyanamide and dimethylformamide. Other pathways also lead to NDMA formation during chlorination such as the reaction of sodium hypochlorite with dimethylamine. However, the rate of NOMA formation is approximately an order of magnitude slower than that observed when monochloramine reacts with dimethylamine. The reaction exhibits a strong pH dependence due to competing reactions. It may be possible to reduce NDMA formation during chlorination by removing ammonia prior to chlorination, by breakpoint chlorination, or by avoidance of the use of monochloramine for drinking water disinfection.