Process enhancement of organic pollutant removal by micro channel excited dielectric barrier discharge

Abstract

In this study, a micro-channel excited DBD plasma water treatment system is proposed to enhance the discharge and gas-liquid mass transfer processes simultaneously. As the core of the reactor, the micro-channel plays a crucial role in the process intensification. On the one hand, the micro-channel can reduce the initial discharge voltage and enhances the discharge intensity, because of the increased space charge density initiated by the transverse electric field formed by the charges accumulated on the micro-channel wall, as a result, the generation efficiency of active particles can be improved. On the other hand, the micro-channel can also reduce the air pressure resistance and enhance the bubbling process, due to the exciting effect of micro-channel discharge on air flow and plasma-water interaction, as a result, the utilization efficiency of active particles can be improved. Tetrabromobisphenol-S (TBBPS) is used as the target pollutant, with the initial condition of 500 mL, 0.2 mmol/L, the maximum removal is over 98 % after a 30 min treatment under an applied voltage of 18.4 kV. Applied voltage, air flow rate and water flow rate are the key parameters affecting the treatment efficiency. It can be concluded from the results of this study that the micro-channel excited DBD plasma is of significance favorable for the treatment of wastewater.