纳米光催化氧化测定不同水体化学需氧量的研究

Investigation of Photocatalytic Oxidation Assistance Photometry for Determination of Chemical Oxygen Demand of the different Water Body

采用简便的沉淀法制备的纳米氧化锌为光催化剂，重铬酸钾为光生电子接受体，研究了纳米氧化锌-重铬酸钾体系测定COD的方法，COD值在1～100mg／L之间有良好的线性关系，线性方程为Y=0.0007x＋0．0069，相关系数为r=0．9992，检测限为0.66mg／L。采用本方法扣CODMn国标法对不同水体样品进行比较测定发现，对低COD值样品本方法加标回收率在96．3％～100．6％之间，变异系数Cv％=1．1～3．4，准确度和精密度均优于CODMn国标法，弥补了低COD值样品国标法（CODMn）测定不准确的不足，且单个样品测定时间短，具有推广应用价值。

Nano- ZnO which was prepared by precipitation is photoeatalytic, potassium dichromate was used to accept photogeneration electron, making use of photometry for analysis the born Cr（ Ⅲ ） concentration to come to the indirect measurement water body COD value. The optimized operation conditions were selected and the photocatalytic oxidation mechanism was discussed. It was indicated that the application range was 1 - 100mg/L and the lowest detection limit was 0.66mg/L, the linear equation was y = 0.0007x ＋ 0.0069, r = 0.9992. Carried on a measurement to the actual water samples, the add- on reference liquid recovery rate was 96.3% ~ 100.6%, Cv% = 1.1 -3.4, the degree of accuracy and precision of this method was higher than the CODCr national standard method, made up the shortage that the national standard method （CODcr） measurement of low COD value sample was not accurate. The result was satisfactory.