Enhanced Oxidation of Xylene Using Plasma Activation of an Mn/Al2O3 Catalyst

Non-thermal plasma technology has great potential for the removal of the emission of volatile organic compounds (VOCs). However, the plasma-alone process may produce various undesired by-products that cause secondary pollutions. Here, a coaxial dielectric barrier discharge (DBD) reactor has been developed for the removal of xylene over an Al2O3-based catalyst (Mn/Al2O3, Co/Al2O3, Ce/Al2O3) at low temperatures. Compared with the plasma-alone process and other plasma-catalytic combined process, the combination of plasma and the Mn/Al2O3 catalyst obviously enhanced xylene conversion and substantially restrained the formation of by-product organic aerosol (up to 100%), and what is more is that our setup was more efficient than those in other studies. In the meantime, ozone could be effectively converted by the Mn/Al2O3 catalyst; as the main active group with a long period of existence during discharge, ozone adsorbed onto the surface of the catalyst under the action of Mn/Al2O3 and participated in the oxidation of xylene. Mn4+ and the high lattice oxygen content were the reasons for the highest efficiency of 1% Mn.