运城盐湖卤水化学需氧量的测定

目的]探索氯耗氧曲线校正法测定盐湖卤水中的COD值的效果。方法]用氯耗氧曲线校正法测定运城市盐湖卤水的化学需氧量，并与其他的一些化学分析方法进行比较。结果]在测定条件下，氯离子极易被重铬酸钾氧化，氯离子完全氧化时间为30min。CODCr（C1）与氯离子浓度之间有较好的线性关系，线性回归方程为Y=0．2224x-0．519，相关系数r=0．9876。通过测定得知，水样中氯离子的浓度为3503．85mg／L，通过耗氧曲线及方程得出运城市盐湖卤水中的CODCr的值为438．18mg／L，显示其污染较严重，需要进一步保护。结论]用氯耗氧曲线校正法测定盐湖卤水COD值操作简单、简便、准确度高、精密性好，同时还可避免汞盐污染环境。

Detection of the Brine Chemical Oxygen Demand in Saline Lake of Yuncheng City

Objective] The aim was to explore the effect of detecting COD value in the brine from the Saline Lake by the method of chloride oxygen demand calibration.Method] The method of chloride oxygen demand calibration was used to detect the chemical oxygen demand in the brine from the Saline Lake of Yuncheng City and it was compared with other chemical analysis.Result] Under the testing condition,the chloride ion was oxidized by potassium dichromate very easily and the fully oxidation time of chloride ion was 30min.There was a better linear relationship between CODcr(Cl) and the concn.of chloride ion.The linear regression equation was y=0.222 4 x-0.519 and the correlation coefficient was 0.987 6.The concn.of chloride ion in the water sample was 3 503.85 mg/L though detection.The CODcr value in the brine from the Saline Lake of Yuncheng City was 438.18 mg/L through counting by the oxygen demand calibration curve and the equation,which showed that the water was polluted seriously and it needed further protection.Conclusion]Using the method of chloride oxygen demand calibration to detect the COD value in the brine from the Saline Lake was simple and convenient,with high accuracy and good precision.Meantime,it could prevent polluting environment mercury salt.