Full and Sustainable Electrochemical Production of Chlorine Dioxide

Abstract

With the final purpose of manufacturing electrochemically-based devices that produce chloride dioxide efficiently, this paper focuses on the production of chlorates and hydrogen peroxide in two different electrochemical cells, in which operation conditions are selected to obtain high efficiencies, and in the subsequent combination of both electrochemically manufactured solutions to produce chlorine dioxide. Results demonstrate that suitable reagents can be produced by electrolyzing 20 g L−1 sodium chloride solutions at 50 mA cm−2 and 50 °C, and 3000 mg L−1 NaClO4 solutions at 5.0 mA cm−2 and 15 °C with current efficiencies of 30.9% and 48.0%, respectively. Different tests performed with these electrolyzed solutions, and also with commercial hydrogen peroxide and chlorate solutions, demonstrate that the ratio between both reagents plays a very important role in the efficiency in the production of chlorine dioxide. Results clearly showed that, surplus chlorate should be contained in the reagent media to prevent further reduction of chlorine dioxide by hydrogen peroxide and consequently, loses of efficiency in the process. During the reaction, a gas with a high oxidation capacity and consisting mainly in chloride dioxide is produced. The results contributed to the maximum conversion reached being 89.65% using electrolyzed solutions as precursors of ClO2, confirming that this technology can be promising to manufacture portable ClO2 devices.