This work is devoted to the investigation of the method of wastewater treatment, containing heavy metals, and in particular, chromium ions using plasma technologies. The kinetic regularities of the oxidation-reduction processes of chromium ions under the effect of an atmospheric pressure DC discharge on potassium dichromate solution in argon at the current range of (20-80) mA and the concentration range of (0.1-0.5) mmol/L werestudied. The solution served as a discharge cathode. It was found that the discharge action stimulates the reactions of reduction of Cr6+ ions to Cr3+ ions and reverse reactions of oxidation of Cr3+ ions to Cr6+, i.e. oxidation-reduction reactions are reversible. The limiting degree of reduction of Cr6+ ions depended on the discharge current and the initial concentration of the solution. The maximum value of reduction degree was 0.6. It depends on the discharge current and initial concentration of solution. Regarding the degree of reduction discharges in air and argon show similar results, but in argon the reduction process proceeds faster and its energy efficiency are higher. The apparent rate constants of oxidation and reduction were found, and the energy efficiency of the process was estimated. The reduction rate constants were (0.015-0.003) s-1 whereas the value of energy efficiency was 4.2×10-2 chromium ions per 100 eV of inputted energy.

Study of processes of reduction-oxidation of chromium ions in aqueous solution under action of the direct current discharge of atmopheric pressure in argon

256th National Meeting (2018)

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