posted on 2007-03-15, 00:00authored byIgnasi Salvadó-Estivill, David M. Hargreaves, Gianluca Li Puma
This paper presents a methodology for the evaluation of
the intrinsic photocatalytic oxidation (PCO) kinetics of indoor
air pollutants. It combines computational fluid dynamics
(CFD) modeling of the fluid flow in the reactor with radiation
field modeling and photocatalytic reaction kinetics to
yield a rigorous model of a flat-plate, single-pass, flow-through photocatalytic reactor for indoor air purification.
This method was applied to model the PCO of trichloroethylene
(TCE) in humidified air and to derive kinetic parameters
directly from kinetic data in an integral flow reactor. Steady-state PCO experiments of TCE over irradiated TiO2
(Degussa P25) thin films immobilized on glass supports
were carried out at different radiation intensities, flow rates,
and inlet substrate concentrations. The oxidation rate of
TCE was found to be first-order on the incident photon flux
and to follow a Langmuir−Hinshelwood type reaction
kinetics rate law. Mass transfer resistances were observed
at Reynolds numbers less than 46. Apparent quantum
yields were found to be up to 0.97 mol Einstein-1. A comparison
of the model prediction with the experimental results in
an integral reactor yielded pollutant-specific kinetic rate
parameters which were independent of reactor geometry,
radiation field, and fluid-dynamics. The kinetic parameters
would, therefore, be more universally applicable to the design
and scale-up of photocatalytic reactors for indoor air
purification.