TY - JOUR
T1 - The effect of photon source on heterogeneous photocatalytic oxidation of ethanol by a silica-titania composite
AU - Coutts, Janelle L.
AU - Levine, Lanfang H.
AU - Richards, Jeffrey T.
AU - Mazyck, David W.
N1 - Funding Information:
This work was funded by a Kennedy Space Center Innovative Partnership Program (IPP) grant and NASA's Exploration Life Support Program–Air Revitalization Element . The authors would like to thank Mr. Lawrence L. Koss for his assistance with the PCO test bed construction by making customized parts and OPTO 22 data logging.
PY - 2011/12/1
Y1 - 2011/12/1
N2 - The objective of this study was to distinguish the effect of photon flux (i.e., photons per unit time reaching a surface) from that of photon energy (i.e., wavelength) of a photon source on the silica-titania composite (STC)-catalyzed degradation of ethanol in the gas phase. Experiments were conducted in a bench-scale annular reactor packed with STC pellets and irradiated with either a UV-A fluorescent black light blue lamp (λmax = 365 nm) at its maximum light intensity or a UV-C germicidal lamp (λmax = 254 nm) at three levels of light intensity. The STC-catalyzed oxidation of ethanol was found to follow zero-order kinetics with respect to CO2 production, regardless of the photon source. Increased photon flux led to increased EtOH removal, mineralization, and oxidation rate accompanied by lower intermediate concentration in the effluent. The oxidation rate was higher in the reactor irradiated by UV-C than by UV-A (38.4 vs. 31.9 nM s-1) at the same photon flux, with similar trends for mineralization (53.9 vs. 43.4%) and reaction quantum efficiency (i.e., photonic efficiency, 63.3 vs. 50.1 nmol CO2 μmol photons -1). UV-C irradiation also led to decreased intermediate concentration in the effluent compared to UV-A irradiation. These results demonstrated that STC-catalyzed oxidation is enhanced by both increased photon flux and photon energy.
AB - The objective of this study was to distinguish the effect of photon flux (i.e., photons per unit time reaching a surface) from that of photon energy (i.e., wavelength) of a photon source on the silica-titania composite (STC)-catalyzed degradation of ethanol in the gas phase. Experiments were conducted in a bench-scale annular reactor packed with STC pellets and irradiated with either a UV-A fluorescent black light blue lamp (λmax = 365 nm) at its maximum light intensity or a UV-C germicidal lamp (λmax = 254 nm) at three levels of light intensity. The STC-catalyzed oxidation of ethanol was found to follow zero-order kinetics with respect to CO2 production, regardless of the photon source. Increased photon flux led to increased EtOH removal, mineralization, and oxidation rate accompanied by lower intermediate concentration in the effluent. The oxidation rate was higher in the reactor irradiated by UV-C than by UV-A (38.4 vs. 31.9 nM s-1) at the same photon flux, with similar trends for mineralization (53.9 vs. 43.4%) and reaction quantum efficiency (i.e., photonic efficiency, 63.3 vs. 50.1 nmol CO2 μmol photons -1). UV-C irradiation also led to decreased intermediate concentration in the effluent compared to UV-A irradiation. These results demonstrated that STC-catalyzed oxidation is enhanced by both increased photon flux and photon energy.
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U2 - 10.1016/j.jphotochem.2011.09.026
DO - 10.1016/j.jphotochem.2011.09.026
M3 - Article
AN - SCOPUS:80855131609
SN - 1010-6030
VL - 225
SP - 58
EP - 64
JO - Journal of Photochemistry and Photobiology A: Chemistry
JF - Journal of Photochemistry and Photobiology A: Chemistry
IS - 1
ER -