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The effect of pH on the photonic efficiency of the destruction of methyl orange under controlled periodic illumination with UV-LED sources.

Tokode, Oluwatosin; Prabhu, Radhakrishna; Lawton, Linda A.; Robertson, Peter K.J.

Authors

Oluwatosin Tokode

Radhakrishna Prabhu

Linda A. Lawton

Peter K.J. Robertson

Abstract

The nature of photon interaction and reaction pH can have significant impacts on semiconductor photocatalysis. This paper describes the effect of pH on the photonic efficiency of photocatalytic reactions in the aqueous phase using TiO2 catalysts. The reactor was irradiated using periodic illumination with UV-LEDs through control of the illumination duty cycle ({esc}gc{esc}s) through a series of light and dark times (Ton/Toff). Photonic efficiencies for methyl orange degradation were found to be comparable at high {esc}gc{esc}s irrespective of pH. At lower {esc}gc{esc}s, pH effects on photonic efficiency were very distinct across acidic, neutral and alkaline pH indicating an effect of complementary parameters. The results suggest photonic efficiency is greatest as illumination time, Ton approaches interfacial electron-transfer characteristic time which is within the range of this study or charge-carrier lifetimes upon extrapolation and also when electrostatic attraction between surface-trapped holes, {lcub}TiIVOH{rcub}+ads and substrate molecules is strongest.

Journal Article Type Article
Publication Date Jun 15, 2014
Journal Chemical engineering journal
Print ISSN 1385-8947
Publisher Elsevier
Peer Reviewed Peer Reviewed
Volume 246
Pages 337-342
Institution Citation TOKODE, O., PRABHU, R., LAWTON, L.A. and ROBERTSON, P.K.J. 2014. The effect of pH on the photonic efficiency of the destruction of methyl orange under controlled periodic illumination with UV-LED sources. Chemical engineering journal [online], 246, pages 337-342. Available from: https://doi.org/10.1016/j.cej.2014.03.002
DOI https://doi.org/10.1016/j.cej.2014.03.002
Keywords TiO2 photocatalysis; pH effect; Methyl orange; Periodic illumination; UVLED; Photonic efficiency

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