摘要：

为了满足用稳定性二氧化氯消毒饮用水的小型水厂快速检测余氯的需要,作者对邻联甲苯胺与ClO₂和Cl₂显色反应的原理进行了分析,结果表明,在相同条件下,余氯量相同的Cl₂与邻联甲苯胺显色反应产生的颜色深度是ClO₂的5倍。根据这一结果,用pH6.5的Na₂HPO₄-KH₂PO₄缓冲溶液将传统测定余氯的比色法中的K₂CrO₄-K₂Cr₂O₇模仿标准色阶稀释5倍,同时增大显色液层厚度,以提高检测灵敏度,使之能直接用于稳定性二氧化氯消毒处理后的饮用水中余氯的检测。经碘量法验证,该方法简便、快速、灵敏、准确。

关键词: 二氧化氯, 比色分析, 饮用水

Abstract:

In order to meet the requirements of rapid determination of residual chlorine in drinking water in small water plants that uses the stable chlorine dioxide to disinfect drinking water,the principle of color reaction of omethyl benzidine with chlorine dioxide and chlorine is discussed. The result shows that under the same detecting conditions,the color darkness of the color reaction resulted from the same amount of residual chlorine with omethyl benzidine is 5 times of the color reaction resulted from chlorine dioxide with o-methyl benzidine. According to this result,the imitational standard color rank of K₂CrO₄-K₂Cr₂O₇ used in traditional method of the detecting residual chlorine of colorimetric determination will be diluted 5 times by using the buffer solution of Na₂HPO₄-KH₂PO₄(pH=6.5). And,the thickness of the color layer will be increased so as to enhance the sensitiveness of determination,making this method be directly used for detecting residual chlorine in the drinking water with stable chlorine dioxide after disinfected. This method was verified by iodimetry,and the result shows that it is simple,fast,sensitive and accurate.

Key words: chlorine dioxide, colorimetric analysis, drinking water

中图分类号: 

• TU991.21