N-Nitrosamines Formation from Secondary Amines by Nitrogen Fixation on the Surface of Activated Carbon

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• 作者：Lokesh P. Padhye ; Benjamin Hertzberg ; Gleb Yushin ; Ching-Hua Huang
• 刊名：Environmental Science & Technology
• 出版年：2011
• 出版时间：October 1, 2011
• 年：2011
• 卷：45
• 期：19
• 页码：8368-8376
• 全文大小：893K
• 年卷期：v.45,no.19(October 1, 2011)
• ISSN：1520-5851

文摘

Our previous study demonstrated that many commercial activated carbon (AC) particles may catalyze transformation of secondary amines to yield trace levels of N-nitrosamines under ambient aerobic conditions. Because of the widespread usage of AC materials in numerous analytical and environmental applications, it is imperative to understand the reaction mechanism responsible for formation of nitrosamine on the surface of ACs to minimize their occurrence in water treatment systems and during analytical methods employing ACs. The study results show that the AC-catalyzed nitrosamine formation requires both atmospheric oxygen and nitrogen. AC鈥檚 surface reactive sites react with molecular oxygen to form reactive oxygen species (ROS), which facilitate fixation of molecular nitrogen on the carbon surfaces to generate reactive nitrogen species (RNS) likely nitrous oxide and hydroxylamine that can react with adsorbed amines to form nitrosamines. AC鈥檚 properties play a crucial role as more nitrosamine formation is associated with carbon surfaces with higher surface area, more surface defects, reduced surface properties, higher O₂ uptake capacity, and higher carbonyl group content. This study is a first of its kind on the nitrosamine formation mechanism involving nitrogen fixation on AC surfaces, and the information will be useful for minimization of nitrosamines in AC-based processes.