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Heterogeneous photocatalytic oxidation of o-chloroaniline immobilizing on recyclable TiO2 / W. K. Choy in Industrial & engineering chemistry research, Vol. 47 N°20 (Octobre 2008) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 47 N°20 (Octobre 2008) . - P. 7564-7569 Titre : Heterogeneous photocatalytic oxidation of o-chloroaniline immobilizing on recyclable TiO2 Type de document : texte imprimé Auteurs : W. K. Choy, Editeur scientifique ; W. Chu, Editeur scientifique Année de publication : 2008 Article en page(s) : P. 7564-7569 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Photocatalytic  Oxidation  TiO2 Résumé : A mixture of sol−gel and commercial TiO2 powder was immobilized on a film to faciliate photodegradation. The photodecay of o-ClA in the mixture of TiO2 sol−gel and powder was about 20% faster then that solely made by the sol−gel solution. The performance of TiO2 film depended on the annealing temperature applied. The transformation of photoactive anatase to rutile phase was observed above 450 °C, which resulted in a slower photodecay of o-ClA. The use of quartz as substrate has proven to be superior to glass in the photoreaction, owing to the excellent optical property of quartz. The o-ClA decay could be further improved by weight increment on the film. A linear relationship between decay rate and weight of coating was acquired. Furthermore, TiO2 coating was found to be dependent on the light intensity. The direct photolysis was determined to be insignificant in the process, while the photocatalytic ability was directly proportional to the amount of TiO2 film coated on the slide. For practical application, the recycling performance of the film was examined. The reuse of the TiO2 film showed a promising performance with very low variation (±7%) of decay rate after nine consecutive usages. A mathematical model was also proposed to predict the o-ClA removal performance based on the film mass and light intensity. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800325v [article] Heterogeneous photocatalytic oxidation of o-chloroaniline immobilizing on recyclable TiO2 [texte imprimé] / W. K. Choy, Editeur scientifique ; W. Chu, Editeur scientifique . - 2008 . - P. 7564-7569. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 47 N°20 (Octobre 2008) . - P. 7564-7569 Mots-clés : Photocatalytic  Oxidation  TiO2 Résumé : A mixture of sol−gel and commercial TiO2 powder was immobilized on a film to faciliate photodegradation. The photodecay of o-ClA in the mixture of TiO2 sol−gel and powder was about 20% faster then that solely made by the sol−gel solution. The performance of TiO2 film depended on the annealing temperature applied. The transformation of photoactive anatase to rutile phase was observed above 450 °C, which resulted in a slower photodecay of o-ClA. The use of quartz as substrate has proven to be superior to glass in the photoreaction, owing to the excellent optical property of quartz. The o-ClA decay could be further improved by weight increment on the film. A linear relationship between decay rate and weight of coating was acquired. Furthermore, TiO2 coating was found to be dependent on the light intensity. The direct photolysis was determined to be insignificant in the process, while the photocatalytic ability was directly proportional to the amount of TiO2 film coated on the slide. For practical application, the recycling performance of the film was examined. The reuse of the TiO2 film showed a promising performance with very low variation (±7%) of decay rate after nine consecutive usages. A mathematical model was also proposed to predict the o-ClA removal performance based on the film mass and light intensity. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800325v

Photochemical degradation of 2,4,6-trichlorophenol in the brij 35 micellar solution / W. Chu in Industrial & engineering chemistry research, Vol. 48 N° 23 (Décembre 2009) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 48 N° 23 (Décembre 2009) . - pp. 10211–10216 Titre : Photochemical degradation of 2,4,6-trichlorophenol in the brij 35 micellar solution : pH control on product distribution Type de document : texte imprimé Auteurs : W. Chu, Auteur ; Y. F. Rao, Auteur ; C. Y. Kwan, Auteur Année de publication : 2010 Article en page(s) : pp. 10211–10216 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Photochemical--Degradation--Trichlorophenol--Brij  35  Micellar--Solution--pH  Control--Product  Distribution Résumé : Surfactants have been used for separating organic pollutants from contaminated soils in soil-washing process. The extracted pollutants can be effectively degraded upon UV irradiation in the presence of surfactant micelles. The photodecay rate of 2,4,6-trichlorophenol (2,4,6-TCP) by UV light at 253.7 nm and photonic efficiency of 2,4,6-TCP degradation reaction were investigated at different pH levels with the addition of nonionic surfactant solutions above the critical micelle concentration (cmc). A continual examination on intermediates at all pHs was conducted and photochemical processes induced the dechlorination of TCP to form di- and monochlorinated intermediates and phenol. An additional reaction was observed when the initial pH level was above neutral, at which chlorinated hydroquinones were the resulting intermediates through photohydrolysis process. Two reaction mechanisms, one at acidic and the other at basic conditions, were proposed and verified by the evidence presented in this study. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie9003943 [article] Photochemical degradation of 2,4,6-trichlorophenol in the brij 35 micellar solution : pH control on product distribution [texte imprimé] / W. Chu, Auteur ; Y. F. Rao, Auteur ; C. Y. Kwan, Auteur . - 2010 . - pp. 10211–10216. Industrial chemistry Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N° 23 (Décembre 2009) . - pp. 10211–10216 Mots-clés : Photochemical--Degradation--Trichlorophenol--Brij  35  Micellar--Solution--pH  Control--Product  Distribution Résumé : Surfactants have been used for separating organic pollutants from contaminated soils in soil-washing process. The extracted pollutants can be effectively degraded upon UV irradiation in the presence of surfactant micelles. The photodecay rate of 2,4,6-trichlorophenol (2,4,6-TCP) by UV light at 253.7 nm and photonic efficiency of 2,4,6-TCP degradation reaction were investigated at different pH levels with the addition of nonionic surfactant solutions above the critical micelle concentration (cmc). A continual examination on intermediates at all pHs was conducted and photochemical processes induced the dechlorination of TCP to form di- and monochlorinated intermediates and phenol. An additional reaction was observed when the initial pH level was above neutral, at which chlorinated hydroquinones were the resulting intermediates through photohydrolysis process. Two reaction mechanisms, one at acidic and the other at basic conditions, were proposed and verified by the evidence presented in this study. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie9003943