Decolorization of methyl violet in simulated wastewater by dielectric barrier discharge plasma

Abstract

In this study, the decolorization ratio of methyl violet and energy consumption were individually investigated in dielectric barrier discharges of O2, He, and He + O2 gases. The results showed that the highest decolorization ratio was achieved in the O2 gas discharge, followed by the He + O2 and He gas discharges, and the decolorization was almost the same in the He + O2 and O2 gas discharges. For the He gas discharge, the energy consumption was lowest but the decolorization ratio was also lower than 50%. For the O2 gas discharge, a decolorization ratio of 99.5% was achieved but a high energy density of 32.5 kJ/L was required. For the He + O2 discharge, a decolorization ratio of 96% was achieved and the required energy density was only 7.7 kJ/L. Therefore, from the experimental results, the discharge in a mixture of He + O2 gases is optimal for the decolorization of methyl violet. When He is mixed into O2, a high decolorization ratio can be achieved and a low energy density is required.