一种新的快速测定水中COD的消化一分光光度法

A New Digestion-Spectrophotometric and Rapid Determination Method for COD in Water

探讨了在MnSO_4-CuSO_4复合催化剂、硫-磷混酸体系中,对样品进行恒温密封消解,用分光光度法测定溶液的COD值。实验得出测定化学需氧量的最佳条件:混酸H_2SO_4-H_3PO_4体积比为4:1,催化剂MnSO_4-CuSO_4质量比为1:2,MnSO_4-CuSO_4的总量为0．03g,消解温度为165℃,消解时间为15min。实验结果表明,此方法的测定结果与重铬酸钾法测定结果的相对误差≤5%,且有较好的重现性及较高的准确度与精密度。本法可同时消解多个试样,适用于大批量试样COD的测定,使试样的消解时间由标准法的2h缩短到了15min,同时用MnSO_4-CuSO_4复合催化剂代替价格昂贵的A_(g2)SO_4,大大降低了分析成本。

A rapid method of determining COD with the spectrophotometric method was researched.The MnSO_4-CuSO_4 compound catalyst and the sulfur-phosphorus mixture system were used to digest the sample in the constant temperature. The best experimental conditions was that the mixture H_2SO_4-H_3PO_4 volume ratio was 4:1,the catalyst MnSO_4-CuSO_4 quantity ratio was 1:2,total quantity of MnSO_4 and CuSO_4 was 0.03g.The digestive temperature was 165℃in 15min. The experimental results indicated that the relative error of the new method was less than 5%,and the method had the good reproduction quality,the high accuracy and precision,and could digest many test specimens simultaneously,was suit- able to the mass specimen COD determination.This method reduced the digestive time to 15min from 2h,the MnSO_4- CuSO_4 compound catalyst replaced expensive Ag_2SO_4 and reduced the analysis cost greatly.