Electrochemical Production of Hydrogen Peroxide in Perchloric Acid Supporting Electrolytes for the Synthesis of Chlorine Dioxide

Abstract

This work focuses on the electrochemical production of hydrogen peroxide in supporting electrolytes containing perchlorate ions for being used as a reagent in the reduction of chlorates to produce chlorine dioxide, as a first step in the manufacture of portable ClO ₂ production devices. This study evaluates the effect of the current density, pressure, and temperature on the production of hydrogen peroxide, and concentrations over 400 mg L ^–1 are reached. The average rate for the formation of hydrogen peroxide is 9.85 mg h ^–1, and the effect of increasing electrolyte concentration (3.0 and 30.0 g L ^–1 perchloric acid), intensity, and pressure results in values of, respectively, −2.99, −4.49, and +7.73 mg h ^–1. During the manufacturing process, hydrogen peroxide is decomposed through two mechanisms. The average destruction rate is 1.93 mg h ^–1, and the effects of the three factors results in values of, respectively, +0.07, +0.11, and −0.12 mg h ^–1. Solutions of this hydrogen peroxide produced electrochemically in a perchloric acid aqueous electrolyte were used to reduce chlorates in strongly acidic media and produce chlorine dioxide. Conversions of around 100% were obtained, demonstrating that this electrochemical product can be used efficiently to reduce chlorates to chlorine dioxide.