化学需氧量(COD)在线分析仪技术研究

TECHNOLOGY RESEARCH ON COD ONLINE ANALYZER

COD指标采用在线自动监测仪可实时监测水质变化情况,氢氧基及臭氧氧化—电化学测定法运行可靠、操作简单,在实际中应用较广;UV自动分析仪具有简单、快速、价格低的特点,但应用的前提条件是需水质较为稳定,UV吸收信号与COD或TOC值之间有较确定的线性关系,在我国应用较少;总有机碳(TOC)法水样氧化比较彻底,操作和维护简便,不产生二次污染,但设备前期投资大,水样成分发生较大变化时,相关性需重新验证;流动注射分析式(FIA)逐渐取代了沿用多年的复杂化学操作,能同时测定多种组分,分析的速度、精度大幅度提高且操作简单,有较为广泛的应用前景。

Using on-line automatic monitoring can monitor the real-time change of water quality for COD indicator. Hydroxyl and ozone oxidation and electrochemical measurement runs reliably and is easy to operate,so it is widely used in practice. UV automatic analyzer with low price is simple and fast to use,but the precondition for application is that the water quality needs to be stable; there is certain linear relationship between UV absorption signal and COD or TOC values. Hence it is used less in our country. The water sample is oxidized more thoroughly by using TOC method which is simple and convenient to operate and maintain without producing secondary pollution. However,the investment on equipment at early stage is big; the correlation must be tested and verified again when great changes take place in the sample composition. Flow injection analysis( FIA) has gradually replaced the complex chemical operation which has been used for years. It can test a variety of components simultaneously with much faster speed and accuracy in analysis and it's easy to operate. Therefore,FIA has a wider application prospect.