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.

Highly Efficient Electrochemical Production of Hydrogen Peroxide Using the GDE Technology

“…The past few decades have seen a dramatic increase in the search for new technologies that are capable of producing chemical oxidants at substantial concentrations and in a highly efficient manner. Hydrogen peroxide (H 2 O 2 ) is a highly efficient, eco-friendly chemical oxidant, which has a wide range of applications in different sectors . H 2 O 2 has a high reduction potential ( E 0 = 1.77 vs standard hydrogen electrode, SHE) and produces nontoxic water when applied; as a result, this oxidant is widely applied in several industrial processes, including the synthesis of chemical products, paper bleaching, and wastewater treatment. − As part of the efforts to combat the SARS-CoV-2 virus, H 2 O 2 was widely employed as a reagent in the formulation of decontamination and disinfection products and for the cleaning of contaminated respiratory masks for reutilization due to its antimicrobial properties …”

“…As demonstrated in the literature, through the application of carbon-based cathode materials, O 2 is easily reduced to H 2 O 2 via the transfer of two electrons at a potential of 0.682 V vs SHE ,− Some studies reported in the literature have pointed out different ways to improve the production of H 2 O 2 through ORR via the 2-electron pathway; some of these ways include the following: Improvement of the catalytic properties of the cathode; this can be done by studying and developing new highly efficient cathode materials based on carbon black (CB) or through the addition/doping of organic or inorganic catalysts into carbonaceous materials; ,,− Improvement of oxygen supply in the electrochemical cell since the low solubility of oxygen in the cell causes the efficiency of the process to be controlled by diffusion. As reported in the literature, to help tackle this problem, some important progress has been made by performing the electrochemical operation under high pressure and at low temperature so as to improve oxygen solubility. ,,− optimizing the shape/configuration of carbon-based cathodes by employing gas diffusion electrodes (GDEs) in flow-by electrochemical reactors instead of flow-through electrode reactors. ,,, the design of more efficient electrochemical reactors with enhanced turbulence. ,, …”

“…Improvement of oxygen supply in the electrochemical cell since the low solubility of oxygen in the cell causes the efficiency of the process to be controlled by diffusion. As reported in the literature, to help tackle this problem, some important progress has been made by performing the electrochemical operation under high pressure and at low temperature so as to improve oxygen solubility. ,,− optimizing the shape/configuration of carbon-based cathodes by employing gas diffusion electrodes (GDEs) in flow-by electrochemical reactors instead of flow-through electrode reactors. ,,, the design of more efficient electrochemical reactors with enhanced turbulence. ,, …”

“…performing the electrochemical operation under high pressure and at low temperature so as to improve oxygen solubility. ,,− …”

“…optimizing the shape/configuration of carbon-based cathodes by employing gas diffusion electrodes (GDEs) in flow-by electrochemical reactors instead of flow-through electrode reactors. ,,, …”