Department of Chemical Engineering, Yale University, New Haven, Connecticut 06520, USA.
Environ Sci Technol. 2010 Feb 15;44(4):1224-31. doi: 10.1021/es902840h.
Nitrosamine formation has been associated with wastewater-impacted waters, but specific precursors within wastewater effluents have not been identified. Experiments indicated that nitrosamines form in low yields from quaternary amines, and that the nitrosamines form from the quaternary amines themselves, not just lower order amine impurities. Polymeric and benzylated quaternary amines were more potent precursors than monomeric quaternary alkylamines. Pretreatment of quaternary amines with ozone or free chlorine, which deactivate lower order amine impurities, did not significantly reduce nitrosamine formation. The nitrosamine formation pathway is unclear but experiments indicated that transformation of quaternary amines to lower order amine precursors via Hofmann elimination was not involved. Experiments suggest that the pathway may involve quaternary amine degradation by amidogen or chloramino radicals formed from chloramines. Quaternary amines are significant constituents of consumer products, including shampoos, detergents, and fabric softeners. Although quaternary amines may be removed by sedimentation during wastewater treatment, their importance should be evaluated on a case-by-case basis. The high loadings from consumer products may enable the portion not removed to serve as precursors.
亚硝胺的形成与受废水影响的水有关，但废水废水中的特定前体尚未确定。实验表明，季铵盐从低产率生成亚硝胺，并且亚硝胺是由季铵盐本身形成的，而不仅仅是低阶胺杂质。聚合和苄基化季铵盐比单体季铵烷基胺更具活性前体。用臭氧或自由氯预处理季铵盐，会使低阶胺杂质失活，但不会显著减少亚硝胺的形成。亚硝胺的形成途径尚不清楚，但实验表明，季铵盐通过霍夫曼消除转化为低阶胺前体的过程并不涉及。实验表明，该途径可能涉及由氯胺形成的氨氧基或氯氨基自由基对季铵盐的降解。季铵盐是洗发水、洗涤剂和织物柔软剂等消费品的重要成分。尽管季铵盐在废水处理过程中可能通过沉淀去除，但应根据具体情况评估其重要性。高浓度的消费产品可能使未去除的部分成为前体。
