KINETICS OF Mn2+-INDUCED HYDROGEN PEROXIDE DECOMPOSITION IN ALKALINE MEDIUM

摘要

The effect of manganese (Mn2+) on the decomposition of hydrogen peroxide in the typical bleaching conditions, as well as its decomposition kinetics, was investigated. The results showed that the decomposition of hydrogen peroxide was dramatically increased with the increase of Mn2+ concentration in the alkaline medium. The kinetic analysis showed that the decomposition of hydrogen peroxide agreed with a first-order reaction at a low Mn2+ level (< 3 ppm) in the system; however the reaction was greatly accelerated when the system contains more Mn2+. The relationship between the logarithm of hydrogen peroxide concentration and the reaction time was non-linear. The rate of hydrogen peroxide decomposition was increased with the reaction continuing, indicated that the formation of Mn3+, converted from Mn2+, would speed up the hydrogen peroxide decomposition. Combined the effect of the alkali concentration on hydrogen peroxide decomposition, a kinetic model for describing the concentration profile of hydrogen peroxide in the Mn2+ -containing alkaline medium was proposed.