液相臭氧化流动注射化学发光法测定水体化学耗氧量(COD)的研究:苯酚溶液COD测定

Measurement of Chemical Oxygen Demand by Flow Injection Ozonation Chemiluminescence Technique:Feasibility Study Based on the Model System of the Ozonation of Phenol

研究了紫外光辅助的苯酚臭氧化过程.利用溶解臭氧在水体中能够氧化鲁米诺产生发光现象,我们建立了流动注射液相化学发光测定COD的一种新方法.COD测定工作曲线为 y=34 276 lnx+63 269,线性相关系数为 0.995.线性范围0.6 mg/L到24 mg/L适合地表水COD监测.为了考察臭氧化法测定 COD的可行性,研究了苯酚的臭氧化反应动力学及反应机理,其直接和间接反应速率常数分别为383 mol-1·L·s-1和6.728×109 mol-1·L·s-1.几个实际淡水水样的COD测定结果显示新方法的 3 次测量标准偏差均小于 6%.与高锰酸钾 COD测定方法相比,新方法的结果要高 8.25%~25.82%,这表明紫外光辅助臭氧氧化与高锰酸钾氧化相比氧化能力能强.

COD measurement based on ozonation of phenol combining with UV radiation (UV/O_3) has been studied in the present work.Utilizing the phenomena that luminol can be oxidized by the dissolved ozone to produce luminescence,we established a new method of utilizing aqueous flow injection chemiluminescence to determine chemical oxygen demand (COD).A linear relationship y=34 276 lnx+63 269 was gained and correlation coefficient is 0.995.The linear range of 0.6 mg/L^24 mg/L for theoretical COD show the new method is fit for COD determination of natural water.The kinetics and mechanism of the ozonation reaction of phenol were studied in order to study the feasibility of determination COD by the flow injection chemiluminescence (FI-CL) technique utilizing ozonation combining with UV radiation.The direct and indirect reaction rate constants were acquired,which were 383 mol^(-1)·L·s^(-1) and 6.728×10~9mol^(-1)·L·s^(-1) respectivly.Several real world freshwater samples were analyzed and the results show that the relative error of COD_(FI-CL) for water samples was <6%.Compared with the results of the potassium permanganate method,COD of FI-CL is 8.25%~25.82% higher,due likely to the more effective oxidation originated from ozone.