Discharge characteristics and reactive species production of unipolar and bipolar nanosecond pulsed gas–liquid discharge generated in atmospheric N₂

Abstract

In this paper, unipolar pulse (including positive pulse and negative pulse) and bipolar pulse voltage are employed to generate diffuse gas-liquid discharge in atmospheric N 2 with a trumpetshaped quartz tube. The current-voltage waveforms, optical emission spectra of excited state active species, FTIR spectra of exhaust gas components, plasma gas temperature, and aqueous H 2 O 2 , -NO , 2 and -NO 3 production are compared in three pulse modes, meanwhile, the effects of pulse peak voltage and gas flow rate on the production of reactive species are studied. The results show that two obvious discharges occur in each voltage pulse in unipolar pulse driven discharge, differently, in bipolar pulse driven discharge, only one main discharge appears in a single voltage pulse time. The intensities of active species (OH(A), and O(3p)) in all three pulsed discharge increase with the rise of pulse peak voltage and have the highest value at 200 ml min −1 of gas flow rate. The absorbance intensities of NO 2 and N 2 O increase with the increase of pulse peak voltage and decrease with the increase of gas flow rate. Under the same discharge conditions, the bipolar pulse driven discharge shows lower breakdown voltage, and higher intensities of excited species (N 2 (C), OH(A), and O(3p)), nitrogen oxides (NO 2 , NO, and N 2 O), and higher production of aqueous H 2 O 2 , -NO , 2 and -NO 3 compared with both unipolar positive and negative discharges.

Characteristics and performance of an integrated coplanar dielectric barrier discharge device for hand hygiene

“…The energetic electrons react with background gas molecules (e.g., N 2 ) and excite them to the upper state species, which increases the number of reactive particles, and thus the emission intensities of excited nitrogen species. [ 32 ]…”

“…[31] Figure 6b (e.g., N 2 ) and excite them to the upper state species, which increases the number of reactive particles, and thus the emission intensities of excited nitrogen species. [32] The temperature of plasma is a primary parameter for biomedical applications since it directly reflects the chemical reaction rate and affects the efficiency of bacterial sterilization. Under atmospheric pressure, the rotational temperature (T rot ) of excited nitrogen states N 2 (C) can be regarded as equivalent to the gas temperature.…”

Generation of High-Density Pulsed Gas–Liquid Discharge Plasma Using Floating Electrode Configuration at Atmospheric Pressure

“…Hence a stable gas-liquid discharge at AP is expected. Over the last two decades, various factors have been studied for improving discharge stability, including the electrode structures [10,11], the driving power supply [12,13], the working gases characteristic [14,15], and many other experimental parameters. In addition, the plasma characteristic could be different even under the same conditions [16], because it is influenced by electron transport.…”