Formaldehyde removal from air via a rotating adsorbent combined with a photocatalyst reactor: Kinetic modeling

A novel rotating honeycomb adsorbent coupled with a photocatalytic reactor demonstrated by Shiraishi et al. is modeled here. In operation, the air pollutant formaldehyde was adsorbed from a simulated room (10 m(3)) onto a slowly rotating honeycomb, which then passed slowly through a small chamber (0.09 m(3)) in which locally recirculated heated air desorbed the formaldehyde and carried it through a photocatalytic reactor, which oxidized the desorbed material. The regenerated rotor-adsorbent then rotated back into the airtight chamber. This system was modeled at steady states and transient states to determine adsorption, desorption, and photocatalyst pseudo-first-order rate constants at the appropriate temperatures (ambient temperature for adsorption, 120-180 degrees C for desorption and photocatalysis). Intensity-corrected values for the photocatalytic rate constant k(cat) (cm(2)/(mW s)) deduced from fitting our model to the data of Shiraishi et al. were in good agreement with those calculated from five literature reports for formaldehyde photocatalytic destruction. (c) 2005 Elsevier Inc. All rights reserved.