Photomineralization of methane in air (10.0-1,000 ppm (mass/volume) of C) at 100% relative humidity (dioxygen as oxygen donor), was systematically studied at 318 ± 3 K, in an annular laboratory-scale reactor, by photocatalytic membranes immobilising titanium dioxide and tungsten trioxide as co-photocatalysts. Kinetics of both substrate disappearance, to yield intermediates, and total organic carbon (TOC) disappearance, to yield carbon dioxide, were followed. A kinetic model was employed, from which, by a set of differential equations, four final optimised parameters, k1 and K1, k2 and K2, were calculated, able to fit the whole kinetic profile adequately. Modelling of quantum yields, as a function of substrate concentration and irradiance, as well as of concentration of photocatalysts, was carried out very satisfactorily. Kinetics of hydroxyl radicals reacting between themselves, leading to hydrogen peroxide, other than with substrate or intermediates leading to mineralization, were considered, paralleled by second competition kinetics involving superoxide radical anion. When using appropriate blends of the two photocatalysts, limiting quantum yields ∞ values increase considerably and approach the maximum allowable value for the investigated molecule, in a much wider range of irradiances than that shown by the single catalysts mainly at low irradiances. This may be interpreted by strong competition kinetics of superoxide radicals generated by the catalyst defects, in the corresponding range of high irradiances. By this way, operation at high irradiance values is possible, without losing any efficiency for the mineralization process.
A Kinetic Approach to Photomineralization of Methane in Air by Membranes Based on TiO2/WO3 / Ignazio Renato Bellobono, G. Flavia, S. Michela, A. Angelo, M. Franca. - In: JOURNAL OF CHEMISTRY AND CHEMICAL ENGINEERING. - ISSN 1934-7375. - 14(2020 Jul), pp. 73-85.
|Titolo:||A Kinetic Approach to Photomineralization of Methane in Air by Membranes Based on TiO2/WO3|
GROPPI GARLANDINI, FLAVIA MARIA (Secondo)
|Parole Chiave:||Titanium dioxide and tungsten trioxide co-photo catalysts; photo catalytic membranes; quantum yields; gaseous methane mineralization; kinetic modelling|
|Settore Scientifico Disciplinare:||Settore FIS/07 - Fisica Applicata(Beni Culturali, Ambientali, Biol.e Medicin)|
Settore CHIM/03 - Chimica Generale e Inorganica
|Data di pubblicazione:||lug-2020|
|Digital Object Identifier (DOI):||http://dx.doi.org/10.17265/1934-7375/2020.03.001|
|Appare nelle tipologie:||01 - Articolo su periodico|