Reactor analysis for heterogeneous photocatalytic air purification processes

This thesis makes four distinct contributions to the literature on photocatalytic oxidative destruction of air contaminants.; (1) We presented here a complete reactor design analysis for a photocatalytic monolith to predict acetone and 1-butanol concentration profiles. The Navier-Stokes equations and mass transport equations were combined with illumination field to solve for the contaminant velocity and concentration profiles within a monolith channel. Computations have been performed within a monolith channel for four Reynolds numbers (10, 50, 100, 150) under two types of light illumination conditions (uniform and non-uniform illumination).; (2) Mass transfer and quantum efficiency limited conditions were imposed on the photocatalytic monolith to predict the reactor performance.; (3) The photocatalytic monolith channel, illuminated from either or both ends, provides a novel configuration for which radiation field profiles did not exist. We developed a planar emission model for the light intensity profiles within a monolith reactor. Radiometer and kinetic experiments were carried out to validate the model accuracy.; (4) Photocatalyzed degradation of trace level TCE and toluene in humidified air were examined by near-UV illumination and TiO{dollar}sb2{dollar} catalyst in a powder bed down flow reactor with residence time about 5.6 milliseconds. TCE photooxidation was very rapid under our experimental condition, and {dollar}sim{dollar}100% conversion was achieved for TCE concentrations up to 753 mg/m{dollar}sp3{dollar} as a single contaminant. Initial photo degradation rate for toluene was fitted by Langmuir-Hinshelwood form. The presence of sufficient TCE at 753 mg/m{dollar}sp3{dollar} promoted the toluene photooxidation reaction rate to achieve 100% toluene conversion in 5.6 milliseconds for feed toluene levels below 90 mg/m{dollar}sp3{dollar}. Higher toluene levels "quenched" this TCE promotion effect and also depressed TCE conversion. A mechanism was suggested to explain the TCE enhancement of toluene photooxidation rate.; This result is the first to demonstrate substantially complete conversion of BTX (benzene, toluene, xylene) compound and opens the door for a major improvement in catalyst activation through TCE or halide pretreatment.