浅谈重铬酸钾回流滴定法和重铬酸钾分光光度法两种污水COD测定方法在化验室的实际应用

Titration of Potassium Dichromate and Potassium Dichromate Reflux Spectrophotometric Method Two Effluent COD at the Practical Application of Laboratory

对于污水,我国规定用重铬酸钾法,其测得的值称为化学需氧量(COD)。传统的方法是在强酸性溶液中,用一定量的重铬酸钾氧化水中还原性物质,过量的重铬酸钾以试亚铁灵作指示剂,用硫酸亚铁铵溶液回滴。根据硫酸亚铁铵的用量算出水样还原性物质消耗氧的量,这就是重铬酸钾回流滴定法。在污水厂化验室,面对大量水样的COD测量,使用该方法会耗费化验员大量的操作时间。而利用重铬酸钾分光光度法进行COD测量,能使化验员轻松地面对大量水样的分析。

For sewage, the provisions of our country with potassium dichromate method, and its measured value is called chemical oxygen demand. Traditional methods were in strong acidic solution, with a certain amount of potassium dichromate oxidation of reducing substances in the water, excessive amounts of potassium dichromate with ferrous test as indicator of Hope, using ferrous ammonium sulfate solution drops back. In accordance with ferrous ammonium sulfate in water samples to calculate the amount of material to restore the volume of oxygen consumption, which was potassium dichromate titration reflux. At Wastewater Treatment Plant Laboratory, in the face of substantial water sample COD measurement, the use of this method would consume many hours of operation analysts, and the use of spectrophotometry for potassium dichromate COD measurement, laboratory technicians could easily face the substantial water kind of analysis.