MECHANISM AND KINETICS OF CHLORINE DIOXIDE REACTION WITH HYDROGEN-PEROXIDE UNDER ACIDIC CONDITIONS

The reaction of chlorine dioxide with hydrogen peroxide was studied in a well stirred batch reactor in a pH range of 3.60 to 5.07, which is of interest for commercial chlorine dioxide bleaching of chemical pulp . The reaction rate was determined by following the consumption of chl orine dioxide and hydrogen peroxide and the formation of chlorite. The rate equation was established. It was found that the concentration de pendencies of chlorine dioxide, hydrogen peroxide and hydroxide ion we re all first-order. A reaction mechanism compatible with the rate equa tion was proposed. Since it was found in previous work that chlorite i n chlorine dioxide solution by the addition of small amount of hydroge n peroxide potentially led to a decrease in the formation of organical ly bound chlorine during chlorine dioxide bleaching, two methods were suggested to implement this technique in a bleach plant.