TiO_2-KMnO_4体系光催化氧化-光度法测定化学需氧量

Determination of chemical oxygen demand by photocatalytic oxidation spectrophotometry with nano TiO_2-KMnO_4 system

基于纳米TiO2和KMnO4协同光催化氧化作用原理，建立了纳米光催化氧化体系测定化学需氧量（COD）的新方法。考察了测定化学需氧量的最佳条件，在含有0．1g TiO2、0．002mol／L KMnO4的50mL体系中，控温60℃，光照反应10min，COD值在2．5～80mg／L范围内与KMnO4吸光度变化值△A呈线性关系，其相应的线性方程为：△A=0．0023P（COD）＋0．0137，相关系数R=0．9977．COD值的检出限为1．5mg／L。用该法测定地表水和自来水的COD值，相对标准偏差分别为1．9％和2．9％，标准加入回收率分别为100．5％和97．0％。

A method for the determination of chemical oxygen demand by photocatalytic oxidation system was developed based on photocatalytic oxidation coeffect of nano TiO2 and KMnO4. The measurement principle is based on the fact that KMnO4 acts as an acceptor of photogenerated electrons and then increases the rate of photocatalytic oxidation of organic compounds. The optimum conditions were as follows： a 50 mL of solution containing 0.1 g TiO2 and 0.002 mol/L KMn04, photocatalytic reaction for 10 min at 60℃. The linear range is 2.5～ 80 mg/L for COD with the detection limit of 1.5 mg/L. The method has been applied to determining COD of ground water and tap water with the relative standard deviations of 1.9% and 2.9%, respectively, and the recoveries of 100.5% and 97.0%, respectively.