Promoting streamer propagation, active species generation and trichloroethylene degradation using a three-electrode nanosecond pulsed sliding DBD nanosecond plasma

Abstract

This work is devoted to exploring the streamer dynamic of a nanosecond pulsed sliding dielectric barrier discharge (SLDBD) based on a three-electrode geometry, and evaluating its effectiveness for the degradation of a representative chlorinated volatile organic compound (VOC)-trichloroethylene (TCE) at ambient temperature. The surface streamer of nanosecond pulsed SLDBD presents two distinct phases: primary streamer with higher velocity and secondary streamer with lower velocity. The luminous intensity, propagation distance, and propagation velocity of the primary streamer are greatly promoted by increasing the negative DC voltage (U-DC) applied at the third electrode, whereas only a little difference can be observed in the luminous intensity and propagation velocity for the secondary streamer with different U-DC. The surface potential difference between the pulsed excited high-voltage and the negatively biased third electrodes (Upulse-DC) is the major cause for streamers propagation because of the increased electric field at the streamer head. The production of excited species such as N2(C3Πu), N2+(B2Σu+), and OH(A2Σ) are promoted with increasing U-DC. The formation of N2(C3∏u→B3∏g,337 nm ) accompanies the streamer propagation process by electrons impact process. The TCE degradation experiment exhibits that the degradation efficiency and energy yield are significantly improved when Upulse-DC exceeds 20 kV where an SLDBD plasma is ignited, which can be attributed to the promoted surface streamers propagation as well as greater number of chemical active species.