污水中COD测定实验方案的探讨

在采用国家标准方法进行重铬酸钾法测定污水中COD实验教学过程中,存在试剂费用高、二次污染严重等缺点。新方案在不使用硫酸银和硫酸汞的条件下,取水样20.00 mL,加入10.00 mL重铬酸钾标准溶液和24 mL硫酸（密度为1.84 g/mL）,加热回流2 h。实验结果减少了污染物的排放量,而且大大降低了实验费用,可以作为绿色化教学实验方案推广应用。

Study on Greening Teaching Experiment of COD Measurement in Wastewater

There are several disadvantages such as high reagent expenses, re-contamination, etc, in teaching experiment of COD measurement with national standard method. The proposed method is applied to the determination of COD in wastewater with satisfactory result at the condition of 20. 00 mL water sample, 10. 00 mL potassium dichromate standard solution, 24 mL sulfuric acid and with- out silver sulfate and mercuric sulfate. Not only the amount of discharged pollutant but also the cost of experiment are greatly reduced, therefore this method can be used as greening teaching experiment project.