Abstract:

The improvement methods for eliminating the influence of chloride ions on the determination of the COD of high chloride-containing wastewater are discussed. It is thought that appropriate methods should be used for water samples having different chloride ion concentrations and COD’s. Their sectional determination and chloride oxygen demand calibration have been analyzed. When the chloride ion mass concentration is 2 000-15 000 mg/L，and COD is lower than 200 mg/L，sectional determination can be used，while chloride ion mass concentration is 2 000-20 000mg/L and COD is higher than 200 mg/L，chloride oxygen demand calibration can be used. Both of these two methods can eliminate the interference of chloride ions effectively. The results show that they are characterized by high accuracy，good repetition，easy operation and less pollution. It is recommended that for the water samples having chloride ion mass concentration higher than 20 000 mg/L and COD lower than 100 mg/L，potassium iodide-alkaline potassium permanganate method should be used.

Key words: high chlorine-containing wastewater, COD determination, sectional determination, curve calibration

摘要：

探讨了用于高氯废水COD测定时消除氯离子影响的相关改进方法,认为对不同氯离子浓度和COD的水样可分别采用相应的方法。并对其中的分段测定法、氯耗氧曲线校正法进行了实验分析,得出氯离子质量浓度在2 000~15 000 mg/L、COD<200 mg/L时可用分段测定法;氯离子质量浓度在2 000~20 000 mg/L、COD>200 mg/L时可用氯耗氧曲线校正法。这两种方法都可以有效消除氯离子的干扰使结果准确度高、重复性好且操作方便、减少污染。而对氯离子质量浓度>20 000 mg/L、COD<100 mg/L的水样推荐使用碘化钾碱性高锰酸钾法。

关键词: 高氯废水, COD测定, 分段测定法, 曲线校正法

CLC Number: 

• X703