哈希快速消解法测定高氯废水COD_(Cr)的优化

Optimization of the Determination of COD_(Cr) in High-chlorine Wastewater by HACH Rapid Digestion Method

采用哈希（HACH）20 min快速消解分光光度法,对高氯废水化学需氧量CODCr的快速测定进行了探讨试验.通过多种条件试验探索出简单方便、快速测定高氯废水CODCr的优化方法.该方法采用样品与硫酸汞外部络合预处理,消除氯离子干扰,在165℃的条件下与硫酸-硫酸银及强氧化剂重铬酸钾一起加热消解20 min,冷却至室温后,于420 nm波长下测定剩余Cr6＋的含量,结果与在线分析仪测定结果基本一致,与HJ/T70-2001《高氯废水化学需氧量的测定氯气矫正法》测定结果相比,相对误差为7.28％～9.8％,可以满足该单位生产控制及应急监测的需要.

By using HACH 20 min rapid digestion spectrophotometry,the CODCrin high-chlorine wastewater was investigated.The optimization method was simple and convenient and could rapidly determine the CODCrin high-chlorine wastewater through various experiments.The method used samples with mercury sulfate to carry on the external complexation pretreatment for eliminating the interference of chloride ion.Sulfuric acid and silver sulfate and strong oxidation agent potassium dichromate mixed together at 165 ℃ with 20 min heating.After cooling to room temperature,the content of residual Cr6+was determined at 420 nm wavelength.The determination results were basically consistent with online analyzer.Compared with the results according to the standardHigh-chloride Wastewater—Determination of Chemical Oxygen Demand—Chlorine Correction Method'(HJ/T70—2001),the relative error was in the range between 7.28% and9.8%,which could meet the requirements for operation control and emergency monitoring.