重铬酸钾法测定COD中的干扰及消除

Elimination of Interference on COD Measurement by K_2Cr_2O_7 Method

化学需氧量(COD)是描述水质有机物污染程度、评价水质好坏和污水治理效果的重要指标之一。目前,COD的测定大都采用重铬酸钾硫酸回流法。当水体中存在Cl-、NO2-、S2-、Fenton等物质时,会影响化学需氧量的测定结果。讨论了采用重铬酸钾法测定化学需氧量时,以上几种物质对测定结果的干扰情况。着重探讨各种影响因素在不同情况下的消除方法以及各种消除干扰方法的优缺点。

Chemical oxygen demand（COD） is one of the important indicators to describe the degree of organic pollution of water quality, evaluate water quality and effectiveness of sewage treatmen. At present, the sulfuric acid potassium dichromate reflux method is the most use to determinate COD. If existing materials such as Cl^- ,NO2^- ,S^2- ,Fenton reagent in the water, they will influence the result of chemical oxygen demand （COD） measurement. The article discussed that when we determine COD with K2Cr2O7, what the interference situation of the result would be. The article is emphasized discussing the method of removing various influencing factors and explained the virtue and shortcoming of the method.