The OES Diagnosis in Removal of HCHO by the Uniform Bipolar Nanosecond-Pulsed DBD Using Wire-Cylinder Electrode Configuration in Atmospheric N₂

Abstract

In this paper, the uniform bipolar nanosecondpulsed dielectric barrier discharge (NPDBD) with 15-ns rising time generating in a wire-cylinder reactor is employed to remove the gaseous formaldehyde in atmospheric pressure N 2 . The image, the waveforms of pulse voltage and discharge current, the optical emission spectra of the discharges, and the removal rate of formaldehyde are recorded and calculated, respectively. It is found that the emission intensity of OH (A 2 → X 2 , 0−0) rises when increasing the input power density (PD). Furthermore, with the increase of input PD and the emission intensity of OH (A 2 → X 2 , 0−0), the removal rate of formaldehyde rises correspondingly. The results also indicate that when the O 2 concentration rises within 0%-5%, the removal rate of formaldehyde increases, however, when the O 2 concentration rises within 5%-20%, the formaldehyde removal rate decreases correspondingly. In addition, at the same conditions, the DBD synergistically removing formaldehyde with Al 2 O 3 and TiO 2 could increase the removal rate by 10%-30% compared with the discharge only.Index Terms-Formaldehyde removal, nanosecond pulse, OH radical, uniform dielectric barrier discharge (DBD), wire-cylinder reactor.

Water Surface Plasma Source for Large Area Water Treatment by Using Volume Dielectric Barrier Discharge

“…It mainly contained the peaks, which were detected for the N 2 second-positive system (C 3 u -B 3 g ) at 295.7, 297. [16], [17], [18], [19], [20], [21]. N 2 ions first-negative system (B 2 + u → X 2 + g ) at 391.4 nm was detected [16].…”

“…The weak peaks were detected for the N 2 first-positive system (B 3 g → A 3 + u ) at 500-700 nm [18], OH (A-X) at 307 nm [24], and O 2 at 777.0 and 843.8 nm [16], [26], [26]. The weak OH peak is due to electron attachment reaction of O 2 [17]. The intensity of N 2 ions first-negative system is relatively weak because N 2 ions (B 2 + u ) is 18.76 eV of high ionization excitation potential and main energy level transition is due to the collision of free electrons [20].…”

“…The energy consumed in distilled water condition is 3 times higher than those of tap water. The nonelastic collisions of the electrons with air and water at plasma regions in the WSPS can induce N 2 in air and H 2 O to be dissociated, excited, and ionized [17]. Fig.…”

Role of O3 in the removal of HCHO using a DC streamer plasma

“…Most of the energized electrons collided with N 2 , O 2 and H 2 O, producing a series of reactive species (e.g. N 2 metastable, O atoms, OH radicals and etc) [38][39][40]. Figure 9 shows the optical emission spectra of streamer plasmas with or without the injection of HCHO.…”