摘要
建立了非银汞复合试剂+硫磷混酸+重铬酸钾+大体积密封瓶消解样品,进行电位滴定批量测定COD的方法。自制了消解/滴定一体瓶与相应的消解器,非银汞复合试剂加量0.5 g(由硫酸锰/硫酸铜/硫酸铝钾/硫酸铬钾(质量比)=3∶2∶1∶1),0.1 mol/L K2Cr2O7加量10 mL,体积比为3∶1的硫磷混酸15 mL,水样加量10 mL,(160±5)℃温度下密封消解20 min,消解液直接由黄金电极电位滴定。实验结果表明:50 mg/L水平的实际样品COD,RSD≤4.78%,与HJ 828—2017的结果相对误差≤5.80%,应用于石化废水和其他水质分析,效果满意。
A new detection method of CODCr was established using a high volume of closed digestion mode coupled to gold electrode potentiometric titration with mixed reagent free of silver-mercury which consists of mixture of sulfuric phosphoric acid and potassium dichromate.The digestion//titration integrative bottle and the corresponding digester were custom-made.Theoptimized procedure for determining COD were as follows:adding 0.5 g mixed reagents of MnSO4,CuSO4,KAl(SO4)2,and KCr(SO4)2(mass ratio 3∶2∶1∶1)to mixture of sulfuric phosphoric acid(volume ratio 3∶1,15 mL)with 0.1 mol/L K2Cr2O7(10 mL)as the oxidant;closed digestion time was 20 min at(160±5)℃,and the sample of addition were 10 mL.The relative standard error(RSD)of COD was≤4.78%at 50 mg/L level,The relative error compared to results from HJ 828—2017 was≤5.80%.The improved method for determining COD overcame a lot of disadvantage andshortened the analysis time byone-third.The mixed reagents can be easily acquired and is cost effective.The method has been applied to petrochemical wastewater and other water COD analysis whereit showed satisfying result.
作者
陆克平
韩海外
周剑平
刘浩
Lu Keping;Han Haiwai;Zhou Jianping;Liu Hao(Inspection & MetrologyCenter, SINOPEC Anqing Company, Anqing 246002, Anhui, China;Wanxinan Product Quality Supervision and Testing Center, Anqing 246002, Anhui, China)
出处
《精细石油化工》
CAS
北大核心
2020年第1期41-45,共5页
Speciality Petrochemicals
关键词
密闭消解
消解/滴定一体瓶
重铬酸钾
硫磷混酸
电位滴定
COD
closed digestion
digestion/titration integrative bottle
potassium dichromate
potentiometric titration
mixture of sulfuric phosphoric acid
COD