NO_x Formation in the Plasma Treatment of Halomethanes

Abstract

A nonthermal, atmospheric pressure plasma, made-up of a BaTiO3 packed-bed reactor, has been used to study the formation of NOx and N2O during the plasma destruction of a range of volatile organic compounds (VOCs) and hazardous air pollutants, including chlorinated, brominated, fluorinated, and iodinated methane species, in a carrier gas of air. Using the plasma destruction of pure air as a baseline, it is found that the amount of NOx formed is unaffected by the addition of a few hundred parts per million of a simple hydrocarbon (e.g. methane). In the case of the fluorinated, chlorinated, and brominated methanes, we find enhanced production of NOx and a marked increase in the ratio of NO2 to NO formed, from approximately 1.1 in air and methane to approximately 2.3 in halogenated species. However, iodinated additives (specifically methyl iodide and diiodomethane) have remarkably different results compared to the other halogenated additives; they show enhanced increases in the NO2 to NO ratio ( approximately 6-13) and reduced NOx production. The enhanced conversion of NO to NO2 is attributed to reactions involving halogen oxides, e.g. ClO and IO.

Plasma-assisted catalysis for the destruction of CFC-12 in atmospheric pressure gas streams using TiO2

“…In a plasma discharge in air, NO, NO 2 and N 2 O are commonly produced [17,24] and are undesirable endproducts. They arise because excited-state nitrogen atoms formed in the plasma discharge react with molecular oxygen to form NO, which is further oxidised by atomic oxygen and ozone to NO 2…”

Plasma activation of methane for hydrogen production in a N2 rotating gliding arc warm plasma: A chemical kinetics study

“…Our previous study [29] showed that, the spectrum of the N 2 RGA was dominated by the radiative species such as N 2 (C), N 2 (B), and N 2 + (B). Nevertheless, the radiative lifetimes of these species are very short in atmospheric pressure plasmas [50,51], thus significantly limiting their contribution to the chemical reactivity of the N 2 plasma. Therefore, these species were not considered in this model, which is commonly seen in other modeling studies of CH 4 /N 2 plasmas [41,46,50].…”

Sustainable Non‐Thermal Plasma‐Assisted Nitrogen Fixation—Synergistic Catalysis

“…[17,55,58] Al ater study conductedb yT ang et al [59] also investigated plasma-based NO x synthesis using metal-oxide catalysts, which was worth comparing with Patil et al [55] because both studies examined the plasma-based NO x synthesis for as pecific energy inputr ange between 1300 and 1800 JL À1 .R esults from Patil [59] These two studies also investigated the effect of the plasma-discharge parameters, the results of which provided understanding of the potential plasma influence on the characterization of catalyst surfaces. [61] Note that BaTiO 3 was mainly used as the dielectric to generate plasma. [57,59] Another aspect of the synergyb etween catalyst and plasma is the influence of plasma on the catalyst.…”

“…In as tudy by Harling et al BaTiO 3 wasu sed to facilitate plasma-assisted NO x production. [61] Note that BaTiO 3 was mainly used as the dielectric to generate plasma. However, its catalytic activity should also be taken into account based on previousevidences of plasmacatalysti nteractions.…”