Plasma Reactivity and Plasma-Surface Interactions During Treatment of Toluene by a Dielectric Barrier Discharge

Toluene removal is investigated in filamentary plasmas produced in N2 and in N2/O2 mixtures by a pulse high voltage energised DBD. Influence of the oxygen percentage (lower than 10%) and of the temperature (lower than 350°C) is examined. Toluene is removed in N2 through collisions with electrons and nitrogen excited states. The removal efficiency is a few higher in N2/O2. It increases when the temperature increases for N2 and N2/O2. Both H- and O-atoms play an important role in toluene removal because H can readily recombine with O to form OH, which is much more reactive with toluene than O. H follows from dissociation of toluene and of hydrogenated by-products by electron collisions. Detection of cyanhidric acid, acetylene, formaldehyde, and methyl nitrate strengthens that dissociation processes, to produce H and CH3, must be taken into account in kinetic analysis. Formation and treatment of deposits are also analysed.