Influence of mixed sulfur–nitrogen oxides on the redox kinetics of manganese ions in aqueous solution

Abstract

The influence of mixed sulfur–nitrogen oxides on the redox behaviour of manganese(II, III) species in aqueous solution was studied kinetically as a function of various concentrations and temperature. A series of oxides were found to reduce Mn^III to Mn^II, whereby these oxides undergo a Mn^III-induced hydrolysis reaction. The hydrolysis products were analysed by ion chromatography. These redox reactions can account for the inhibiting effect of the oxides on the metal-catalysed autoxidation of sulfur(IV) oxides in flue gas desulfurization systems. Possible reaction mechanisms are suggested.