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The effect of photon source on heterogeneous photocatalytic oxidation of ethanol by a silica–titania composite

Paper ID Volume ID Publish Year Pages File Format Full-Text
26673 43970 2011 7 PDF Available
Title
The effect of photon source on heterogeneous photocatalytic oxidation of ethanol by a silica–titania composite
Abstract

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.

Graphical abstractFigure optionsDownload full-size imageDownload as PowerPoint slideHighlights► Effect of photon flux and energy on STC-catalyzed degradation of EtOH was examined. ► Effluent stream consisted only of EtOH, ACD intermediate, and CO2 product. ► Increased photon flux gave higher complete mineralization and high EtOH removal. ► Use of UV-C light over UV-A light also had positive effects on the reaction system. ► Quantum efficiency decreased as the limit of useable photons was met for the STCs.

Keywords
Photocatalytic oxidation; Photon energy; Photon source; Silica–titania composite (STC); Volatile organic compound (VOC)
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Publisher
Database: Elsevier - ScienceDirect
Journal: Journal of Photochemistry and Photobiology A: Chemistry - Volume 225, Issue 1, 1 December 2011, Pages 58–64
Authors
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Subjects
Physical Sciences and Engineering Chemical Engineering Bioengineering
Get Full-Text Now
Don't Miss Today's Special Offer
Price was $35.95
You save - $31
Price after discount Only $4.95
100% Money Back Guarantee
Full-text PDF Download
Online Support
Any Questions? feel free to contact us