Catalytic Decomposition of Ozone Gas by a Pd Impregnated ${\mathrm{MnO}}_2$ Catalyst

A new catalyst, which was made of ${\mathrm{MnO}}_2$ impregnated with Pd for decomposition of high humidity ozone gas, was developed and its catalytic activity decrease was analyzed in a finite difference type fixed bed reactor. The activity of the catalyst was higher than that of other catalysts and an activated carbon and does not decrease so much for a long term. Therefore, its lifetime is very long. The reaction rate was shown as a first-order reaction equation for each catalyst in any operation time both under dry and wet conditions. The rate-determining step was considered to be a chemical reaction of ozone. The reaction rate constant $k_t$ decreased through two steps, fast in an early period and slowly afterward. Then, $k_t$ was analyzed as the function of operation time t and inlet concentration $C_0$ at each humidity. From the analysis, the ozone removal performance in any size of reactor and in any time became possible to predict.