Improved Performance for Toluene Abatement in a Continuous-Flow Pulsed Sliding Discharge Reactor Based on Three-Electrode Configuration

Abstract

The degradation of toluene by non-thermal plasma has been evaluated in a continuous-flow sliding dielectric barrier discharge (SLDBD) reactor based on three-electrode configuration and compared with a traditional surface dielectric barrier discharge reactor. In order to optimize the electrical and geometry parameters of the SLDBD reactor, the effects of positive pulsed high-voltage (U+pulse), negative DC voltage (U−DC), pulse-forming capacitance (Cp)), inter-electrode gap, discharge length, and dielectric material have been systematically investigated. Morphological characterizations demonstrate that the steamer channels can propagate more homogeneously along the dielectric surface when a sufficient U−DC is applied under the condition of slight increase in energy. The average discharge power of the SLDBD reactor mainly depends on U+pulse, while which is less affected by U−DC. Unexpectedly, both toluene degradation efficiency and energy yield using the SLDBD increase significantly as U−DC, indicating that VOC degradation is not only determined by the energy primarily provided by U+pulse, but also depends on the drift of the ionized species induced by U−DC. Increasing Cp enhances the energy injected into the SLDBD reactor and leads to a higher toluene degradation efficiency, but lowers the energy yield when the other parameters remains unchanged. The optimal Cp is 0.67 nF. Shorter inter-electrode gap and longer discharge length appear to be more advantageous in terms of toluene degradation and energy yield. Quartz plate exhibits remarkably better degradation and energy performance than ceramic and polytef ones, leading to the maximum toluene degradation efficiency of 58% and energy yield of 0.85 g/kWh in this work.