Oxidation of acetylene by photocatalysis coupled with dielectric barrier discharge

Volatile organic compound removal from air requires oxidative processes associating high carbon dioxide selectivity like photocatalysis with fast kinetics like non-thermal plasma. A specially designed coupling reactor has been used to investigate the interaction between photocatalysis and non-thermal plasma. Acetylene has been selected as a model molecule to evaluate oxidation efficiencies. After determining the oxidative efficiency of both techniques used separately, the coupling of plasma with titania photocatalyst has been performed. The influence of UV-irradiation of a photocatalyst placed inside the discharge by external lamps has been investigated. It is reported that photocatalysis leads to a complete mineralization of acetylene, whereas more than 50% of the carbon balance based on CO and CO2 is missing when plasma alone is performed. The presence of a porous material inside the discharge improves the initial removal rate of acetylene. It tends to favor the formation of adsorbed organic species, indicating that part of plasma reactivity is transferred to the adsorbed phase. Finally, the use of additional external UV-light is reported to improve the formation of carbon dioxide, which means that photocatalysis can be usefully performed in an ionized gas.