CHEN Fu-qiang， FU Xing
（State Key Laboratory of Precision Measuring Technology and Instruments（Tianjin University）, Tianjin 300072， China）
Abstract： Chemical oxygen demand (COD) is an important index to evaluate the water pollution level. The method of potassium dichromate is used as a national standard for determination of COD in China. Chloride is the most common interference in COD determination process. In order to solve the problem, this paper analyzes the effect of chlorine ion on the determination of COD in principle. And then a kind of measurement system is designed based on the structure of nanometer glass probe, which achieves rapid measurement of the concentration of chloride ions within a larger range and provides a new technical solution for improving the accuracy of the COD measurement. After theoretical studies and experimental verification on the distractions in the process of ion current detection, the effects of probe diameter and bias voltage on the system measuring range and sensitivity are discussed.
Key words： chemical oxygen demand (COD); chlorine ion; ionic current; nanometer probe
CLD number： TP274+.5Document code： A
Article ID： 1674-8042（2018）03-0219-07doi： 10.3969/j.issn.1674-8042.2018.03.003
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一种用于COD测定修正的氯离子在线检测技术
陈富强， 傅星
（精密测试技术及仪器国家重点实验室（天津大学）， 天津 300072）
摘要:化学需氧量（COD）是评价水质污染程度的重要指标， 我国采用重铬酸钾法作为国家标准的COD 测定方法。 针对该方法的测量结果受氯化物影响较大的问题， 从原理上分析了氯离子对于COD测定过程的影响规律， 并设计了一种基于纳米玻璃探针结构的氯离子浓度检测系统， 在较大的量程范围内实现了氯离子浓度的快速测量， 为提高COD测量的准确性提供了一种新的技术方案。 同时还对离子电流检测的影响因素进行了理论研究和实验验证， 讨论了探针直径和偏置电压对系统量程和灵敏度的影响。
关键词:化学需氧量（COD）； 氯离子； 离子电流； 纳米探针
引用格式：CHEN Fu-qiang， FU Xing. Chloride ion on-line detection technology for COD correction. Journal of Measurement Science and Instrumentation, 2018, 9(3)： 219-225. ［doi：10.3969／j.issn.1674-8042.2018.03.003］
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