Silica-titania Composite (STC)'s performance in the photocatalytic oxidation of polar VOCs

Lanfang H. Levine, Janelle L. Coutts, Jeffrey T. Richard, David Mazyck

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Abstract

The objective of this paper is to determine the performance of a Silica-Titania Composite (STC) in the photocatalytic oxidation (PCO) of polar VOCs for potential applications in trace contaminant control within space habitats such as the ISS and CEV Orion. Tests were carried out in a bench scale, STC-packed annular reactor under continuous irradiation by either a UV-C germicidal lamp (λmax=254 nm) or UV-A fluorescent black-light blue lamp (λmax = 365 nm) for the removal of ethanol (a predominant polar VOC in the ISS cabin). The STC's performance was evaluated in terms of the ethanol mineralization rate, mineralization efficiency, and the extent of its oxidation intermediate (acetaldehyde) formation in response to the type of light source (photon energy and photon flux) and relative humidity (RH) implemented. Results demonstrated that acetaldehyde was the only quantifiable intermediate in the effluent under UV illumination but not found in the dark adsorption experiments. The mineralization rate increased with an increase in photon energy (UV-C > UV-A) at the same incident photon flux as well as increased with increasing photon flux. However, photonic efficiency (or reaction quantum yield) decreased as the photon flux increased. More importantly, a higher photon flux gave rise to a lower effluent acetaldehyde concentration. The effect of RH on PCO was complex and intriguing because it affected both physical adsorption and photocatalytic oxidation. In general, increasing RH caused a decrease in adsorption capacity for ethanol and reduced the mineralization efficiency with a concomitant higher acetaldehyde evolution rate. The effect of RH was less profound than that of photon flux.

Original languageEnglish (US)
Title of host publication41st International Conference on Environmental Systems 2011, ICES 2011
PublisherAmerican Institute of Aeronautics and Astronautics Inc.
ISBN (Print)9781600869488
DOIs
StatePublished - 2011
Event41st International Conference on Environmental Systems 2011, ICES 2011 - Portland, OR, United States
Duration: Jul 17 2011Jul 21 2011

Publication series

Name41st International Conference on Environmental Systems 2011, ICES 2011

Conference

Conference41st International Conference on Environmental Systems 2011, ICES 2011
Country/TerritoryUnited States
CityPortland, OR
Period7/17/117/21/11

All Science Journal Classification (ASJC) codes

  • Environmental Engineering

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