MODELING OF A TiO2-COATED QUARTZ -WOOL PACKED-BED PHOTOCATALYTIC REACTOR

A fixed-bed, photocatalytic laboratory reactor aimed to degrade pollutants from water streamswas designed and built. Quartz wool coated with a thin film of TiO2 was employed as thereactor filling. The photocatalyst was placed in the reactor forming a loose packing toguarantee the intimate contact among reactants, photons, and the photocatalytic surface. Thisreactor was employed to study the photocatalytic decomposition of a model pollutant (formicacid). A reactor-radiation-reaction model was developed, which was comprised of the reactormass balance, radiation model, and kinetic model for the degradation of formic acid. The localsuperficial rate of photon absorption, which was necessary to evaluate the kinetic, wasobtained from the results of a radiation model. The Monte Carlo approach was employed tosolve the radiation model, where the interaction between photons and the TiO2-coated fibersof the packing was considered. The kinetic model was derived from a plausible kineticscheme. Experimental results obtained in the packed-bed reactor, operating in a differentialmode and without mass transfer limitations, were used to estimate the parameters of thekinetic model. A satisfactory agreement was observed between model simulations with thederived parameters and experimental results, with a root mean square error less than 8.3%.The developed methodology can be used for scaling up purposes.