Influence of Irradiance, Flow Rate, Reactor Geometry, and Photopromoter Concentration in Mineralization Kinetics of Methane in Air and in Aqueous Solutions by Photocatalytic Membranes Immobilizing Titanium Dioxide
Photomineralization of methane in air (10.0–1000 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 immobilizing titanium dioxide as a function of substrate concentratio...
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| Format: | Article |
| Language: | English |
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Wiley
2008-01-01
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| Series: | International Journal of Photoenergy |
| Online Access: | http://dx.doi.org/10.1155/2008/283741 |
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| author | Ignazio Renato Bellobono Mauro Rossi Andrea Testino Franca Morazzoni Riccardo Bianchi Giulia de Martini Paola Maria Tozzi Rodica Stanescu Cristina Costache Liliana Bobirica Mauro Luigi Bonardi Flavia Groppi |
| author_facet | Ignazio Renato Bellobono Mauro Rossi Andrea Testino Franca Morazzoni Riccardo Bianchi Giulia de Martini Paola Maria Tozzi Rodica Stanescu Cristina Costache Liliana Bobirica Mauro Luigi Bonardi Flavia Groppi |
| author_sort | Ignazio Renato Bellobono |
| collection | DOAJ |
| description | Photomineralization of methane in air (10.0–1000 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 immobilizing titanium dioxide as a function of substrate concentration, absorbed power per unit length of membrane, reactor geometry, and concentration of a proprietary vanadium alkoxide as photopromoter. Kinetics of both substrate disappearance, to yield intermediates, and total organic carbon (TOC) disappearance, to yield carbon dioxide, were followed. At a fixed value of irradiance (0.30 W⋅cm-1), the mineralization experiments in gaseous phase were repeated as a function of flow rate (4–400 m3⋅h−1). Moreover, at a standard flow rate of 300 m3⋅h−1, the ratio between the overall reaction volume and the length of the membrane was varied, substantially by varying the volume of reservoir, from and to which circulation of gaseous stream took place. Photomineralization of methane in aqueous solutions was also studied, in the same annular reactor and in the same conditions, but in a concentration range of 0.8–2.0 ppm of C, and by using stoichiometric hydrogen peroxide as an oxygen donor. 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, which is able to fit the whole kinetic profile adequately. The influence of irradiance on k1 and k2, as well as of flow rate on K1 and K2, is rationalized. The influence of reactor geometry on k values is discussed in view of standardization procedures of photocatalytic experiments. Modeling of quantum yields, as a function of substrate concentration and irradiance, as well as of concentration of photopromoter, 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, and it is paralleled by a second competition kinetics involving superoxide radical anion. |
| format | Article |
| id | doaj-art-a5f73afb858b4b1c9e03f38c8b0dd0f3 |
| institution | Kabale University |
| issn | 1110-662X 1687-529X |
| language | English |
| publishDate | 2008-01-01 |
| publisher | Wiley |
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| series | International Journal of Photoenergy |
| spelling | doaj-art-a5f73afb858b4b1c9e03f38c8b0dd0f32025-02-03T06:01:40ZengWileyInternational Journal of Photoenergy1110-662X1687-529X2008-01-01200810.1155/2008/283741283741Influence of Irradiance, Flow Rate, Reactor Geometry, and Photopromoter Concentration in Mineralization Kinetics of Methane in Air and in Aqueous Solutions by Photocatalytic Membranes Immobilizing Titanium DioxideIgnazio Renato Bellobono0Mauro Rossi1Andrea Testino2Franca Morazzoni3Riccardo Bianchi4Giulia de Martini5Paola Maria Tozzi6Rodica Stanescu7Cristina Costache8Liliana Bobirica9Mauro Luigi Bonardi10Flavia Groppi11Environmental Research Centre, University of Milan, Camillo Golgi 19 Street, 20133 Milan, ItalyEnvironmental Research Centre, University of Milan, Camillo Golgi 19 Street, 20133 Milan, ItalyDepartment of Materials Science, University of Milano Bicocca, Cozzi 43 Street, 20126 Milan, ItalyDepartment of Materials Science, University of Milano Bicocca, Cozzi 43 Street, 20126 Milan, ItalyISTM, Institute of Molecular Sciences and Technologies, National Research Council (CNR), 20133 Milan, ItalyR&D Group, BIT srl, 20121 Milan, ItalyR&D Group, BIT srl, 20121 Milan, ItalyDepartment of Inorganic Technology and Environmental Protection, Polytechnic University of Bucharest, 011061 Bucharest, RomaniaDepartment of Inorganic Technology and Environmental Protection, Polytechnic University of Bucharest, 011061 Bucharest, RomaniaDepartment of Inorganic Technology and Environmental Protection, Polytechnic University of Bucharest, 011061 Bucharest, RomaniaLASA, Department of Physics, University of Milan and National Institute of Nuclear Physics (INFN), 20133 Milan, ItalyLASA, Department of Physics, University of Milan and National Institute of Nuclear Physics (INFN), 20133 Milan, ItalyPhotomineralization of methane in air (10.0–1000 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 immobilizing titanium dioxide as a function of substrate concentration, absorbed power per unit length of membrane, reactor geometry, and concentration of a proprietary vanadium alkoxide as photopromoter. Kinetics of both substrate disappearance, to yield intermediates, and total organic carbon (TOC) disappearance, to yield carbon dioxide, were followed. At a fixed value of irradiance (0.30 W⋅cm-1), the mineralization experiments in gaseous phase were repeated as a function of flow rate (4–400 m3⋅h−1). Moreover, at a standard flow rate of 300 m3⋅h−1, the ratio between the overall reaction volume and the length of the membrane was varied, substantially by varying the volume of reservoir, from and to which circulation of gaseous stream took place. Photomineralization of methane in aqueous solutions was also studied, in the same annular reactor and in the same conditions, but in a concentration range of 0.8–2.0 ppm of C, and by using stoichiometric hydrogen peroxide as an oxygen donor. 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, which is able to fit the whole kinetic profile adequately. The influence of irradiance on k1 and k2, as well as of flow rate on K1 and K2, is rationalized. The influence of reactor geometry on k values is discussed in view of standardization procedures of photocatalytic experiments. Modeling of quantum yields, as a function of substrate concentration and irradiance, as well as of concentration of photopromoter, 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, and it is paralleled by a second competition kinetics involving superoxide radical anion.http://dx.doi.org/10.1155/2008/283741 |
| spellingShingle | Ignazio Renato Bellobono Mauro Rossi Andrea Testino Franca Morazzoni Riccardo Bianchi Giulia de Martini Paola Maria Tozzi Rodica Stanescu Cristina Costache Liliana Bobirica Mauro Luigi Bonardi Flavia Groppi Influence of Irradiance, Flow Rate, Reactor Geometry, and Photopromoter Concentration in Mineralization Kinetics of Methane in Air and in Aqueous Solutions by Photocatalytic Membranes Immobilizing Titanium Dioxide International Journal of Photoenergy |
| title | Influence of Irradiance, Flow Rate, Reactor Geometry, and Photopromoter Concentration in Mineralization Kinetics of Methane in Air and in Aqueous Solutions by Photocatalytic Membranes Immobilizing Titanium Dioxide |
| title_full | Influence of Irradiance, Flow Rate, Reactor Geometry, and Photopromoter Concentration in Mineralization Kinetics of Methane in Air and in Aqueous Solutions by Photocatalytic Membranes Immobilizing Titanium Dioxide |
| title_fullStr | Influence of Irradiance, Flow Rate, Reactor Geometry, and Photopromoter Concentration in Mineralization Kinetics of Methane in Air and in Aqueous Solutions by Photocatalytic Membranes Immobilizing Titanium Dioxide |
| title_full_unstemmed | Influence of Irradiance, Flow Rate, Reactor Geometry, and Photopromoter Concentration in Mineralization Kinetics of Methane in Air and in Aqueous Solutions by Photocatalytic Membranes Immobilizing Titanium Dioxide |
| title_short | Influence of Irradiance, Flow Rate, Reactor Geometry, and Photopromoter Concentration in Mineralization Kinetics of Methane in Air and in Aqueous Solutions by Photocatalytic Membranes Immobilizing Titanium Dioxide |
| title_sort | influence of irradiance flow rate reactor geometry and photopromoter concentration in mineralization kinetics of methane in air and in aqueous solutions by photocatalytic membranes immobilizing titanium dioxide |
| url | http://dx.doi.org/10.1155/2008/283741 |
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