环境监测实验教学中COD_(Cr)测定方法的改进

从催化剂种类、催化剂用量、加热回流时间这些方面,对环境监测实验教学项目水中COD_(Cr)的测定方法进行了一系列改进。结果表明,用MnSO4代替硫酸银作为催化剂,选择浓度为20 g/L的MnSO_4溶液2 mL,加热回流时间为40 min时,其COD_(Cr)的测定结果具有较高的精密度和准确度。改进后的方法具有节省时间、降低成本、测定快速准确的特点,适用于本科实验教学。

Improvement of Determination Method of CODcr in Environmental Monitoring Experimental Teaching

The traditional experimental method of CODcr determination in environmental monitoring experiment teaching is potassium dichromate tritration method. Due to the disadvantages of the method, including the high price of Ag2SO4 and the too long of heating reflux, it was not suitable for undergraduate experimental teaching. It was difficult for Therefore the method was improved in view of these shortcomings from the aspects of the types of catalyst, catalyst dosage and heating reflux time. The studies showed that CODcr determination results had high precision and accuracy by using MnSO4 as catalyst instead of Ag2SO4. The catalyst dosage was 2mL MnSO4 solution (20mg/L). The heating reflux time was 40 minute. The improved determination method had the advantages of short time and low cost. The method was fast and accurate. It was suitable for the undergraduate experimental teaching.