Fu Jun, Qu Jiuhui, Liu Ruiping, Zhao Xu, Qiang Zhimin
State Key Laboratory of Environmental Aquatic Chemistry, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China.
Chemosphere. 2009 Jan;74(2):181-6. doi: 10.1016/j.chemosphere.2008.09.091. Epub 2008 Nov 14.
Maintenance of monochloramine concentration during water disinfection is important to ensure the microbial safety of drinking water. The decay of monochloramine always occurs and some substances present in the water can accelerate this process. Copper often exists in ionic form in water, but the effect of Cu(II) on the decomposition of monochloramine is largely unknown. In this paper, a series of experiments were carried out under varying conditions of pH, Cu(II) and initial monochloramine concentrations. Results showed that the decomposition rate of monochloramine was greatly enhanced by Cu(II), and this enhancement decreased with the increase of solution pH and the decrease of Cu(II) concentration. It was proposed that the monochloramine decomposition in the presence of Cu(II) was catalyzed via complexation between Cu(II) and monochloramine. The X-ray absorption fine structure experiments gave further evidence to this conclusion. The results will provide useful information for selecting proper disinfection method in water disinfection where Cu(II) exists and reasonable monochloramine dosage during chloramination.
在水消毒过程中维持一氯胺浓度对于确保饮用水的微生物安全性很重要。一氯胺的衰减总是会发生，并且水中存在的一些物质会加速这一过程。铜在水中常以离子形式存在，但Cu(II)对一氯胺分解的影响在很大程度上尚不清楚。本文在不同的pH值、Cu(II)和初始一氯胺浓度条件下进行了一系列实验。结果表明，Cu(II)极大地提高了一氯胺的分解速率，并且这种提高随着溶液pH值的升高和Cu(II)浓度的降低而减小。有人提出，在Cu(II)存在下，一氯胺的分解是通过Cu(II)与一氯胺之间的络合作用催化的。X射线吸收精细结构实验为这一结论提供了进一步的证据。这些结果将为在存在Cu(II)的水消毒中选择合适的消毒方法以及氯胺化过程中合理的一氯胺用量提供有用信息。
