Duirk Stephen E, Gombert Bertrand, Croué Jean-Philippe, Valentine Richard L
Department of Civil and Environmental Engineering, University of Iowa, Iowa City, IA 52242-1527, USA.
Water Res. 2005 Sep;39(14):3418-31. doi: 10.1016/j.watres.2005.06.003.
A comprehensive model describing monochloramine loss in the presence of natural organic matter (NOM) is presented. The model incorporates simultaneous monochloramine autodecomposition and reaction pathways resulting in NOM oxidation. These competing pathways were resolved numerically using an iterative process evaluating hypothesized reactions describing NOM oxidation by monochloramine under various experimental conditions. The reaction of monochloramine with NOM was described as biphasic using four NOM specific reaction parameters. NOM pathway 1 involves a direct reaction of monochloramine with NOM (k(doc1) = 1.05 x 10(4)-3.45 x 10(4) M(-1) h(-1)). NOM pathway 2 is slower in terms of monochloramine loss and attributable to free chlorine (HOCl) derived from monochloramine hydrolysis (k(doc2) = 5.72 x 10(5)-6.98 x 10(5) M(-1) h(-1)), which accounted for the majority of monochloramine loss. Also, the free chlorine reactive site fraction in the NOM structure was found to correlate to specific ultraviolet absorbance at 280 nm (SUVA280). Modeling monochloramine loss allowed for insight into disinfectant reaction pathways involving NOM oxidation. This knowledge is of value in assessing monochloramine stability in distribution systems and reaction pathways leading to disinfection by-product (DBP) formation.
本文提出了一个描述在天然有机物（NOM）存在下氯胺损失的综合模型。该模型纳入了氯胺的同时自动分解以及导致NOM氧化的反应途径。这些竞争途径通过一个迭代过程进行数值求解，该过程评估了在各种实验条件下描述氯胺对NOM氧化的假设反应。氯胺与NOM的反应被描述为双相反应，使用了四个NOM特定反应参数。NOM途径1涉及氯胺与NOM的直接反应（k(doc1)=1.05×10(4)-3.45×10(4)M(-1)h(-1)）。NOM途径2在氯胺损失方面较慢，可归因于氯胺水解产生的游离氯（HOCl）（k(doc2)=5.72×10(5)-6.98×10(5)M(-1)h(-1)），这占了氯胺损失的大部分。此外，发现NOM结构中游离氯反应位点分数与280nm处的特定紫外吸光度（SUVA280）相关。对氯胺损失进行建模有助于深入了解涉及NOM氧化的消毒剂反应途径。这些知识对于评估分配系统中氯胺的稳定性以及导致消毒副产物（DBP）形成的反应途径具有重要价值。
