摘要
机械式蒸汽再压缩技术(MVR),由于其高效节能的特点,在废水蒸发中应用越来越广泛。含氯化钠的废水经MVR蒸发后,浓缩液中氯离子质量分数>10%,严重干扰采用重铬酸钾法测定化学需氧量(COD)。为了消除高含量氯离子对COD测定的干扰,在高氯废水中加入硫酸溶液,加热将其中的氯离子以氯化氢形式挥发,再测定COD。将某废水经MVR蒸发浓缩液(氯质量分数为13%)和加入硫酸溶液(体积分数为80%)到COD消解管中,并用COD消解装置加热除氯。结果表明,该方法能够将高氯废水中的氯离子去除至<1 000mg/L,满足了重铬酸钾法测定COD标准检测方法对样品中氯离子含量的要求。采用该方法分别测定COD 100mg/L标样(氯质量分数为9%)、某废水MVR蒸发浓缩液样品(氯质量分数为13%)和MVR蒸发浓缩液经无害化处理后的样品(氯质量分数为8%)。结果表明,该方法具有良好的准确度和精密度,成功建立了氯离子质量分数为13%的高氯废水COD的快速测定方法。该方法直接利用COD消解装置进行氯离子去除,再进行快速密闭消解法测定COD,操作简单、快速。
Mechanical vapor recompression(MVR)is used for evaporation of wastewater widely because of high efficiency and energy saving.The concentration of chloride ion in the concentrated solution evaporated by MVR from wastewater containing sodium chloride was as high as more than 10%and the determination of chemical oxygen demand(COD)by dichromate method was interfered seriously by the high content of chloride ion.In order to eliminate the interference of high content chloride ion to COD determination,sulfuric acid solution was added to the wastewater with high content of chlorine followed by heating to volatilize the chloride ion to hydrogen chloride.The chlorine ion in mechanical vapor recompression(MVR)evaporation concentrated solution(chlorine ions mass fraction=13%)was removed in COD digestion tubes by adding sulfuric acid solution(80% by volume fraction)and heating.The chlorine ion removal conditions were optimized and the chlorine ion in the high chlorine wastewater could be removed to less than 1 000 mg/L,which met the requirement of COD standard analysis method by dichromate approach.The standard sample of COD 100 mg/L(chlorine ions mass fraction 9%),MVR evaporation concentration solution(chlorine ions mass fraction 13%)and MVR evaporation concentration solution after har mLess treatment(chlorine ions mass fraction 8%)were determined by this method,respectively,and the results showed good accuracy and precision.This rapid determination of COD in high chlorine waste water with chlorine ions mass fraction up to 13% was successfully established.The method was simple and fast for using COD digesting device to remove chlorine ions directly and then COD was determined by fast digested method.
作者
程龙军
彭娟
吉飞
胡元娟
郑帅飞
Cheng Longjun;Peng Juan;Ji Fei;Hu Yuanjuan;Zheng Shuaifei(Shenzhen Shentou Environmental Technology Company L im ited,Shenzhen,Guangdong 518049,China)
出处
《化学世界》
CAS
CSCD
2020年第6期402-407,共6页
Chemical World
基金
打造深圳标准专项(No.2017FQZZ0036)资助项目。
关键词
化学需氧量
高氯废水
机械式蒸汽再压缩技术蒸发浓缩液
氯离子去除法
重铬酸钾法
快速密闭消解法
chemical oxygen demand
waste water with high chlorine
mechanical vapor recompression evaporation concentrate
chlorine ion removal
potassium dichromate method
fast closed digestion
