高锰酸盐指数测定方法(GB11892-89酸性法)的探讨

高锰酸盐指数值的测定影响因素较多,本文从反应酸度和加热时间两个方面进行研究。结果表明:在相同加热时间内,CODMn测定值随着反应酸度的增大而逐渐增大;在同一酸度情况下,CODMn测定值随着加热时间的延长而逐渐增大。基于以上两个前提,通过增加酸度并缩短加热时间进行高锰酸盐指数测定。结果表明:加入5mL硫酸,水浴加热12min,测得的CODMn值和国标GB11892-89酸性法测定结果无明显差异。

Discussion about the method of permanganate index determination

This study investigated the effects of reaction acidity and heating time on the permanganate index(CODMn) which is influenced by many factors when determination.The results showed that the value of CODMnincreased with increasing of reaction acidity while maintaining the heating time.It also increased while increasing heating time when determined at the same reaction acidity.Therefore,the value of CODMn can be determined by increasing the acidity and reducing the heating time.No significant differences were found between CODMn value determined with 5mL sulfuric acid and 12min heating time and that using GB11892-89 method.