Kinetic modeling of the photocatalytic degradation of air-borne pollutants

Authors

  • H. Ibrahim,

    1. Chemical Reactor Engineering Center, Faculty of Engineering Science, The University of Western Ontario, London, Ontario N6A 5B9, Canada
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  • H. de Lasa

    Corresponding author
    1. Chemical Reactor Engineering Center, Faculty of Engineering Science, The University of Western Ontario, London, Ontario N6A 5B9, Canada
    • Chemical Reactor Engineering Center, Faculty of Engineering Science, The University of Western Ontario, London, Ontario N6A 5B9, Canada
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Abstract

The photocatalytic conversion of organic model pollutants (acetone, acetaldehyde, and isopropanol) in a novel Photo-CREC-Air unit is considered. This photocatalytic unit features: (1) external near-UV lamps placed in parabolic reflectors, (2) a basket supporting the irradiated glass mesh holding TiO2 loadings to achieve high photoconversion rates, and (3) a fluid flow pattern securing high gas velocities in the near-mesh region. Given the high quantum efficiencies observed in Photo-CREC-Air and, as a result, the high prospects for this novel design, rate equations and associated mechanistic formulations are investigated. With this goal, a Langmuir–Hinshelwood model, involving a one-site model pollutant mechanism, is considered. The associated kinetic parameters with the related statistical indicators are established, using least-square nonlinear regression. It is found that this model is adequate for describing the photodegradation of acetone on both Degussa P25 and Hombikat UV-100. It is also observed that the same type of reaction rate model is less adequate for the photodegradation of acetaldehyde and isopropanol, in particular, for predicting the formation of carbon dioxide. © 2004 American Institute of Chemical Engineers AIChE J 50: 1017–1027, 2004

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