Chromium Ion Redox Processes in Aqueous Solution during Treatment with Atmospheric Pressure Direct-Current Discharge in Oxygen

• Published in: High energy chemistry 2019-09, Vol.53 (5), p.385-389
• Main Authors: Shutov, D. A., Sungurova, A. V., Manukyan, A. S., Izvekova, A. A., Rybkin, V. V.
• Format: Article
• Language: English
• Subjects: Aqueous solutions; Argon; Chemistry; Chemistry and Materials Science; Chromium; Electric discharges; Oxidation; Physical Chemistry; Plasma Chemistry; Potassium dichromate; Rate constants; Redox reactions; Reduction
• ISSN: 0018-1439; 1608-3148
• DOI: 10.1134/S0018143919050126

The kinetic features of the oxidation–reduction processes of chromium ions during the treatment of potassium dichromate aqueous solutions with concentrations of 0.092–0.39 mmol/L in atmospheric-pressure dc discharge in oxygen at currents of 20–60 mA have been investigated. The solution served as the cathode of the discharge. It has been found that the discharge induces reversible Cr 6+ ↔ Cr 3+ redox reactions of chromium ions. The limiting degree of reduction of Cr 6+ ions slightly depends on the discharge current and decreases with an increase in the initial concentration of the solution. The apparent rate constants of oxidation and reduction have been found, and the energy efficiency of the process has been evaluated. The obtained data are compared with previously obtained results for electric discharge in air and argon. It has been shown that the discharge in argon is the most effective for carrying out the reduction process.