Exploring the interparticle electron transfer process in the photocatalytic oxidation of 4-chlorophenol
Resource
Journal of Hazardous Materials 137 (3): 1362-1370
Journal
Journal of Hazardous Materials
Journal Volume
137
Journal Issue
3
Pages
1362-1370
Date Issued
2006
Date
2006
Author(s)
Abstract
This work aimed to investigate the interparticle electron transfer (IPET) process within the coupled-photocatalyst systems on the basis of the degradation of 4-chlorophenol (4-CP). TiO2, ZnO and SnO2 are used as the model photocatalysts owing to their increasing energy levels which correspond to the IPET concept. In the single-photocatalyst tests, ZnO tests are associated with the highest degradation rate constants (0.347 ± 0.083 h-1 at pH 7 and 0.453 ± 0.011 h-1 at pH 11) and a better DOC reduction than in other single catalyst tests under given conditions. ZnO/SnO2 coupled tests have constants of 0.612 ± 0.068 and 0.948 ± 0.069 h-1 at pH 7 and 11, respectively. Additionally, the 4-CP prefers the breakdown of chloride group in TiO2 system while proceeding hydroxylation reaction in ZnO systems. Meanwhile, a phenomenonlogical model coupled with the IPET effect was developed to explore the separation of photo-electrons and photo-holes within catalysts. Based on the model parameters, the recombination rate of photo-electrons and photo-holes in TiO2/SnO2 and ZnO/SnO2 systems is 20-45% lower than that obtained by a respective single catalyst. Thus, coupled-photocatalyst tests, TiO2/SnO2 and ZnO/SnO2 efficiently suppress the recombination, particularly for ZnO/SnO2 tests at pH 11. © 2006 Elsevier B.V. All rights reserved.
Subjects
Coupled-photocatalyst; Interparticle electron transfer process; Photodegradation
Other Subjects
Coupled photocatalysts; Degradation rate; Hydroxylation reaction; Interparticle electron transfer; Catalysts; Chlorine compounds; Degradation; Electron transitions; Mathematical models; Photocatalysis; Photooxidation; Phenols; 4 chlorophenol; tin derivative; titanium dioxide; zinc oxide; Catalysts; Chlorine compounds; Degradation; Electron transitions; Mathematical models; Phenols; Photocatalysis; Photooxidation; catalysis; chlorophenol; electron; ion exchange; photodegradation; photooxidation; article; catalyst; degradation kinetics; electron transport; energy; hydroxylation; oxidation kinetics; pH measurement; photocatalysis; photochemistry; photooxidation; reduction kinetics; Catalysis; Chlorides; Chlorophenols; Electrons; Hydrogen-Ion Concentration; Ions; Kinetics; Minerals; Oxidation-Reduction; Photochemistry
Type
journal article
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