微回流紫外分光光度法测定水质COD的研究

Research on the Rapid Determination of COD in Wastewater by the UV-spectrometry

在重铬酸钾法的基础上,以增加催化剂和氧化剂的相对用量来缩短回流时间,用紫外分光光度计测定稀释回流液吸光度来替代硫酸亚铁铵的滴定,构建了水质COD值与吸光度之间的关系模型。结果表明该法测定水样的最大吸收波长为349 nm,相对标准偏差小于2.6%,测定范围在10～700 mg/L,可以满足一般水质的快速测定要求。

On the basis of potassium dichromate method,the determination of COD in wastewaters was investigated by the ways of increasing the relative amount of the catalysts and the oxidants which shortened time greatly.The spectrometry was used to replace the titration with ammonium ferrous sulfate and the maximum absorptiom wavelength was 349 nm.The results showed that the method met determination requirements which water COD ranged 10~700 mg·L-1.The relative standard deviation was less than 2.6%,and showed good precision and accuracy.