Effect of Conductivity on Dye Decolorization by Dielectric Barrier Discharge Using a Water Column Electrode

This paper presents a new plasma treatment system for decomposition of organic compounds in polluted water with high conductivity. The polluted water is normally set between two metal electrodes as a dielectric layer, but it is used as a grounded column electrode in the new treatment system. When the water column coming out of a grounded nozzle is close to an aluminum rod electrode covered by a glass tube subjected to an ac high voltage, a dielectric-barrier-discharge (DBD) occurs at the air gap between the water column and the glass. Since the DBD current flows along the water column electrode, the discharge current increase with increasing the conductivity of water. The decomposition of a blue dye in a high-conductive solution including with NaCl or MgSO4 is carried out. Experimental results show that the DBD occurs steadily and can decolorize indigo-carmine even when the conductivity of the solution was varied in the range of 0.1 mS/cm to 30 mS/cm. Simulation of power consumption in an equivalent circuit model also show that the higher-conductive solution over 30 mS/cm is also decolorized by DBD with the water column electrode. © 2023 The Institute of Electrical Engineers of Japan.