Modelling of quantum yields in photocatalytic membrane reactors immobilising titanium dioxide
Articolo
Data di Pubblicazione:
2006
Citazione:
Modelling of quantum yields in photocatalytic membrane reactors immobilising titanium dioxide / I.R. BELLOBONO, G. DE MARTINI, P.M. TOZZI, C. CANEVALI, F. MORAZZONI, R. SCOTTI, R. BIANCHI. - In: INTERNATIONAL JOURNAL OF PHOTOENERGY. - ISSN 1110-662X. - 2006(2006), pp. 26870.26870-26870.26878. [10.1155/IJP/2006/26870]
Abstract:
For some model molecules (methanoic and ethanoic acids, methane, and phenol), systematic investigations of quantum yields were carried out in the present paper, as a function of concentration and of absorbed radiant power. Quantum yields Phi(0), calculated from rates, followed an apparently Langmuirian function of initial concentration C-0, by which Phi(infinity) values at "infinite" concentration could be obtained. By having thus established that quantum yields of photomineralisation Phi(infinity) are independent of radiation wavelength, within the absorption range of semiconductor, but depend on radiant power, such a dependency was experimentally investigated. For all the investigated molecules, the maximum allowable values reached in the low radiant power range clearly appeared as a plateau. On the contrary, at high radiant power values, another plateau, at a value of about 1/4- 1/5 with respect to the maximum value, was evident. This was interpreted on the basis of a competition kinetics of hydroxyl radicals with themselves, leading to hydrogen peroxide formation, other than with substrate or intermediate molecules leading to full mineralisation. Modelling of quantum yields as a function of concentration and radiant power thus allows a fully consistent and trustworthy design of photoreactors.
Tipologia IRIS:
01 - Articolo su periodico
Elenco autori:
I.R. Bellobono, G. DE MARTINI, P.M. Tozzi, C. Canevali, F. Morazzoni, R. Scotti, R. Bianchi
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