摘要
探讨了高氯离子质量浓度对水样COD测定的影响及消除影响的方法——标准曲线校正法。结果表明:对于Cl-含量为15 000 mg/L、COD为100 mg/L的水样,在先不加硫酸银催化剂的情况下,让Cl-在酸性条件下被重铬酸钾氧化回流1 h,冷却后加入0.4 g Hg SO4煮沸即可,以完全掩蔽水样中剩余的Cl-,再待冷却后加入Ag2SO4催化氧化回流1 h,通过滴定得到COD表观值,扣除Cl-校正值得到样品真实COD值。利用此方法测得的COD值与实际值具有良好的一致性,可用于高氯低COD废水的测定。
The influence of high chloride ion mass concentration on determination of COD in wastewater samples and the method of eliminating the influence -- standard curve calibration method were discussed. When the content of Cl^- was 15 000 mg/L and the COD was 100 mg/L in the wastewater samples, Cl^- was oxidized by potassium dichromate and the samples were refluxed for one hour without silver sulfate catalyst in acidic conditions, 0.4 g HgSO4 was added after cooling, and the samples should be boiled to mask the remaining Cl^- completely. After cooling again, the wastewater samples should be added with Ag2SO4 for catalytic oxidation and be refluxed for one hour. The apparent value of COD was obtained by titration. The true COD values of the wastewater samples were achieved by deducting the cor- rection value of Cl^-. There was a good consistency between the measured value using this method and the true value of COD. The method could be used for determining the wastewater with high concentration of chlorine ion and low COD value.
出处
《中国给水排水》
CAS
CSCD
北大核心
2015年第24期112-115,共4页
China Water & Wastewater
关键词
高氯离子
COD
重铬酸钾法
校正曲线
high concentration of chlorine ion
COD
potassium dichromate method
calibration curve
