VOC Removal from Air by Plasma‐Assisted Catalysis‐Experimental Work

About the Development and Dynamics of Microdischarges in Toluene-Containing Air

“…Dielectric barrier discharges (DBDs) are an established approach for the generation of ozone and the abatement of air impurities from exhausts and off-gases [1][2][3]. In particular, the removal of volatile organic compounds (VOCs), specially odorous molecules, was widely studied by plasma and plasma-catalyst combination [3][4][5][6][7]. The conversion of VOCs in air is mainly via oxidising reactions driven by free radicals such as oxygen atoms O, OH, HO 2 , ions and other reactive species, e.g.…”

“…Although numerous publications describe the removal of a large variety of hydrocarbons in DBDs, with and without a catalyst (see e.g. [3][4][5][6][7] and references therein), an experimental study dedicated to the MD development in low-level VOC-containing air is still missing. Even small admixtures of VOCs (ppm or sub-ppm level) can cause distinct changes on the discharge dynamics.…”

Surface-Catalyzed Reaction between the Gases Hydrogen Chloride and Isoprene

“…8−11 Smaller amounts of volatile terpenes such as α-pinene, βpinene, and limonene (for which idealized "isoprene" is considered a progenitor) are also common but not ubiquitous. 12 Reactions of isoprene in the atmosphere have been studied 13 and oxygen containing fragments, as well as variously substituted oxygen bearing derivatives of the parent, are welldefined. 14−16 There is evidence that the oxygen bearing products result from initial reaction of isoprene with chlorine atoms, 17 oxides of nitrogen, 18 oxides of sulfur, 19 and what appears to be the hydroxyl (HO•) radical [perhaps generated from hypochlorous acid (HOCl), nitrous acid (HONO), and/ or intermediates in ozone reactions, and so forth] 14 as well as ozone itself.…”

“…Reactions of isoprene in the atmosphere have been studied and oxygen containing fragments, as well as variously substituted oxygen bearing derivatives of the parent, are well-defined. − There is evidence that the oxygen bearing products result from initial reaction of isoprene with chlorine atoms, oxides of nitrogen, oxides of sulfur, and what appears to be the hydroxyl (HO•) radical [perhaps generated from hypochlorous acid (HOCl), nitrous acid (HONO), and/or intermediates in ozone reactions, and so forth] as well as ozone itself . With particular regard to the latter, it has recently been proposed that there is pathway to HO• from the reaction of ozone with catechol in an aqueous environment and while other pathways to the HO radical are available, a similar mechanistic pathway might apply to its formation for reaction with isoprene. , The plethora of products of the ozonolysis of isoprene have been considered in some detail .…”

Toluene oxidation by non-thermal plasma combined with palladium catalysts

“…The emission of volatile organic compounds (VOC) from transportation and various industrial processes represents a significant source of air pollution, and therefore VOC removal from waste gas with high efficiency and low costs is an issue of major importance for human health and the environment. Non-thermal plasma is highly efficient in producing oxidizing species (such as atomic oxygen, ozone, hydroxyl radicals, etc), which may react with the VOC molecules and decompose them, and therefore various electrical discharges have been investigated for this purpose (Leys and Morent, 2012 ; Magureanu, 2012 ). On this basis, in the last years various non-thermal plasmas, such as microwave (Horikoshi et al, 2007 ), corona (Van Durme et al, 2009 ) dielectric barrier discharge (DBD), gliding arc (Yang et al, 2009 ), glow discharge (Zhang et al, 2012 ) have been widely investigated for the total oxidation of hydrocarbons in air.…”