A Study On Hydrogen Peroxide Based Production Of Environmental Benign Oxidant Chlorine Dioxide And Reactive Kinetics

Chlorine dioxide, as a green chemical, is increasingly be used in water purification, pulp bleaching, fat whitening and industrial wastes treating. In this paper, hydrogen peroxide based chlorine dioxide production is first investigated in a bench-scale experiment. Effects of reaction temperature, reaction pressure, sulfuric acid concentration, and sodium chlorate concentration, molar ratio of hydrogen peroxide to sodium chlorate on yield and purity of chlorine dioxide are studied. The optimum reaction conditions and parameters in producing chlorine dioxide are achieved. The present method can serve the demand of water treatment due to the sample chlorine dioxide had some advantages such as high purity attached 100% and reclaim rate(≥95%), low cost(≤11,000 RMB/ton). Meanwhile, recycle reclaiming of waste acid is researched. Waste acid can be greatly reduced by integrating reaction-evaporation-crystallization into a reactor.Based on the succeeding experiment for achieving chlorine dioxide with high purity and yield, the technique of producing stabilized chlorine dioxide solution- high purity sodium chlorite is put forward. The mixing cold solution of sodium hydroxide and hydrogen peroxide absorbs the chlorine dioxide production based on hydrogen peroxide. And purity and yield of generated sodium chlorite are both more than 95%. Product cost is reduced greatly. A clean production process of sodium chlorite is presented.Reaction mechanism is studied in this paper. Relevant reactions of hydrogen peroxide with species present in chlorine dioxide formation and other reactions relating to chlorine are analyzed. And an intermediate species, H2ClO3-ClO3 (activated complex) is proposed in existence. A best reasonable reaction course is achieved based on present experimental result, and also consolidates previous different mechanisms in different temperatures.The kinetic experiments for the formation of chlorine dioxide with or without sodium sulfate are also carried on in the paper. Combined with theoretical rate law derived from proposed hydrogen peroxide-chlorate mechanism, the general kinetic rate model is built. The following equation is found to be best correlate with experimental data:...