密封消解法测定高盐废水COD时的最佳实验条件选择

THE BEST TESTING CONDITIONS OF DETERMINING COD_(Cr) IN HIGH SALINITY WASTEWATER WITH THE METHOD OF SEAL DIGESTION

通过对密封消解法测定高盐废水COD的消解时间、氧化剂浓度、掩蔽剂比例等实验条件研究 ,确定了适合高盐废水COD测定的最佳实验条件 ,并用混配水样和实际水样进行验证。研究结果表明 :消解时间为 30min ,掩蔽剂比例为 10 1,对不同范围的COD采用不同浓度的氧化剂 ,混配水样和实际水样中的氯离子对COD测定干扰很小 ,方法的准确度较好 ,相对误差 <8 3% ,加标回收率 >92 %。

This paper presents the best testing conditions of determining COD Cr in high salinity wastewater with the method of seal digestion after a study of testing factors—time for digestion,concentralion of oxidation agent,and proportion of covering agent,which are verified by using standard water sample and actual water sample.The results indicates that the best testing conditions are that time for digenstion should be 30 minutes, proportion of covering agent should be HgSO 4∶Cl -=10∶1,concentration of oxidation agent should vary with concentration of COD Cr .It also shows that Cl - in standard water sample and actual water sample has a little affect on the determination of COD Cr .Accuracy of the method is good,the relative error is less than 8 3% and the marked recovery is more than 92%.