Oxidation Process of Xylene in Air Using $\hbox {Ag/TiO}_{2}$ Under Electron Beam Irradiation

Oxidation of xylene and its irradiation-induced organic by-products in air using Ag-loaded TiO₂(Ag/TiO₂) beds was studied under electron beam (EB) irradiation. The Ag/TiO₂ beds were placed in an irradiation or a nonirradiation space in order to distinguish the oxidation of xylene and its by-products by EB irradiation, a catalytic process, and a combination of the two. The oxidation reactions on the surface of the Ag/TiO₂ pellets were also distinguished based on the difference in the concentrations of xylene, CO₂, and CO in the presence of the Ag/TiO₂ bed or a noncatalyst (stainless-steel pellets) bed with the same occupation volume. Placement of the Ag/TiO₂ bed in the irradiation space resulted in the suppression of xylene decomposition, because xylene was decomposed exclusively in the gas phase regardless of the presence of the Ag/TiO₂ bed. On the other hand, production of CO₂ was observed in the gas phase of the irradiation space and on the surface of the Ag/TiO₂ pellets in both the irradiation and nonirradiation spaces. The concentration of CO₂ produced in the gas phase and on the Ag/TiO₂ pellet surface increased when the layer was placed in the nonirradiation space (near the irradiation space). CO₂ production was enhanced by loading Ag over the TiO₂ pellet surface. The highest concentration of CO₂ was obtained for Ag/TiO₂ with Ag content greater than 5 wt%. The production of CO₂ from the by-products on the Ag/TiO₂ pellet surface was evaluated from the difference in the concentrations of xylene and its by-products between the Ag/TiO₂ and noncatalyst beds.