水体中化学需氧量检测过程中氯离子干扰消除方法研究进展

Research advances prevailing over chloride interference in the determination of chemical oxygen demand in water bodies

化学需氧量(COD)是评价水体受有机物污染的重要指标。在COD检测中,氯离子(Cl-)是影响结果准确性的主要干扰物。受水体特别是高氯废水中的Cl-的干扰,COD检测往往存在较大误差。本文对近年来水中COD检测过程中Cl-的干扰(Cl-的浓度从1000到25000mg·L^(-1))消除方法进行评述,包括在COD检测标准方法基础上改进的汞盐-Cl-比例优化法、氯气吸收校正法、低浓度氧化剂法、氯耗氧曲线校正法、催化剂改进法、密闭消解法等,以及以羟基自由基为主要氧化剂与有机物发生反应的全新检测方法如光电催化氧化法,为水体特别是高氯废水中COD的准确、快速、低污染检测提供了参考。

Chemical oxygen demand（COD）is an important index for representing the degree of organic pollution in water bodies. The chloride ion（Cl-）is the main interference material affecting the accuracy during the determination of COD. The COD measurement error is often large in water especially in high chlorine wastewater due to the interference of chlorine ions.In this paper, the most recent research progress to overcome the chloride interference（the chloride ion concentration is from 1000 to 25 000mg·L^（-1））of the determination of COD, including the improved and optimized methods such as the modified HgSO_4∶Cl-proportion method, the chlorine absorption correction method, the low concentration oxidant method, the chloride oxygen demand calibration curve method, the improved method of catalyst, the airtight container digestion method, and the new method- photoelectrochemical method, which based on the reaction between hydroxyl radicals and organic compounds, is briefly summarized, giv-ing a reference for the accurate, rapid and low-pollution determination of COD in water especially in high chlorine wastewater.