改进的高氯废水COD_(Cr)的测定方法

因高浓度氯离子对COD测定产生干扰,对HJ 828—2017《水质化学需氧量的测定重铬酸盐法》测定高氯废水COD_(Cr)进行了改进,在原氧化体系下,对于HJ 828—2017,将硫酸汞投加比例提高至40∶1,COD_(Cr)测定相对误差范围为-2.56%~2.08%;通过增加硫酸汞投加量,即可有效地降低浓度为4000 mg/L以下的氯离子的干扰。用该方法进行实际废水的测定,2种废水的测量相对标准偏差分别为1.88%和1.27%,加标回收率分别为104%和97%,实验结果准确可靠。

Chemical Oxygen Demand(COD)analysis of wastewater with interference of high concentration chloride ions was improved based on the potassium dichromate method employed in HJ 828-2017.Under the original oxidation system,for the method of HJ 828-2017,the dosage ratio of mercury sulfate is increased to 40:1,and the relative error range of COD_(Cr) determination is from-2.56%to 2.08%.By increasing the dosage of mercury sulfate solution,the interference of chloride ions below 4000 mg/L can be effectively reduced.The potassium dichromate method was applied in practice,the relative deviations of the two kinds of wastewater were 1.88%and 1.27%,and the recovery rate was 104%and 97%respectively.The experimental results are accurate and reliable.