Documents disponibles écrits par cet auteur

Disinfection of natural water by solar photocatalysis using immobilized TiO2 devices / Asunción Acevedo in Transactions of the ASME. Journal of solar energy engineering, Vol. 133 N° 1 (Fevrier 2011) 

Public ISBD [article]  in Transactions of the ASME. Journal of solar energy engineering > Vol. 133 N° 1 (Fevrier 2011) . - 10 p. Titre : Disinfection of natural water by solar photocatalysis using immobilized TiO2 devices : efficiency in eliminating indicator bacteria and operating life of the system Type de document : texte imprimé Auteurs : Asunción Acevedo, Auteur ; Edward A. Carpio, Auteur ; Juan Rodriguez, Auteur Année de publication : 2012 Article en page(s) : 10 p. Note générale : Solar energy Langues : Anglais (eng) Mots-clés : Catalysis  Microorganisms  Photochemistry  Sol-gel  processing  Titanium  compounds  Water  treatment Index. décimale : 621.47 Résumé : Natural water has been disinfected using TiO2 as the fixed catalyst incorporated in a homemade photoreactor, in which the dimensions and the design parameters are representative of devices that are currently employed at larger scale. The catalyst was immobilized on the external surface of a cylinder of frosted glass situated in the longitudinal axis of a tubular glass reactor. Two alternative methods of immobilizing the catalyst on glass were studied: in the first, a commercial titanium oxide powder (Aeroxide® TiO2 P25) was mounted on a polymeric support; and in the second, it was applied by sol-gel deposition. Illumination was effected by installing the glass reactor in the irradiation chamber of a solar simulator. Under laboratory conditions, groundwater contaminated with cultured and wild bacteria was treated photocatalytically, and the influence of the photolysis, the pumping, and the catalysts was studied. The results obtained have demonstrated that the catalyst immobilized in the interior of the photoreactor presents similar results, in the disinfection of E. coli, as 0.5 g/l of TiO2 P25; and that, in 1.5 h approximately of simulated solar illumination (167 kWUVA s/m2) on the sol-gel deposit of TiO2, it is possible to eliminate 100% of the bacteria covered by international regulations in respect of water for human consumption. With regard to the aging assay of the system, it was observed at 250 h of operation a reduction in the effectiveness of the disinfection process. At 0 and 250 h of operation, the percentages of elimination of E. coli after 50 min of illumination were 100% and 99.5%, respectively. This reduction in the effectiveness of the process was due to the formation of a film of calcium carbonate adhering to the internal glass wall of the photoreactor, which is in contact with the liquid being treated, and to the presence of calcium carbonate precipitates on catalyst surface. DEWEY : 621.47 ISSN : 0199-6231 En ligne : http://asmedl.org/getabs/servlet/GetabsServlet?prog=normal&id=JSEEDO000134000001 [...] [article] Disinfection of natural water by solar photocatalysis using immobilized TiO2 devices : efficiency in eliminating indicator bacteria and operating life of the system [texte imprimé] / Asunción Acevedo, Auteur ; Edward A. Carpio, Auteur ; Juan Rodriguez, Auteur . - 2012 . - 10 p. Solar energy Langues : Anglais (eng) in Transactions of the ASME. Journal of solar energy engineering > Vol. 133 N° 1 (Fevrier 2011) . - 10 p. Mots-clés : Catalysis  Microorganisms  Photochemistry  Sol-gel  processing  Titanium  compounds  Water  treatment Index. décimale : 621.47 Résumé : Natural water has been disinfected using TiO2 as the fixed catalyst incorporated in a homemade photoreactor, in which the dimensions and the design parameters are representative of devices that are currently employed at larger scale. The catalyst was immobilized on the external surface of a cylinder of frosted glass situated in the longitudinal axis of a tubular glass reactor. Two alternative methods of immobilizing the catalyst on glass were studied: in the first, a commercial titanium oxide powder (Aeroxide® TiO2 P25) was mounted on a polymeric support; and in the second, it was applied by sol-gel deposition. Illumination was effected by installing the glass reactor in the irradiation chamber of a solar simulator. Under laboratory conditions, groundwater contaminated with cultured and wild bacteria was treated photocatalytically, and the influence of the photolysis, the pumping, and the catalysts was studied. The results obtained have demonstrated that the catalyst immobilized in the interior of the photoreactor presents similar results, in the disinfection of E. coli, as 0.5 g/l of TiO2 P25; and that, in 1.5 h approximately of simulated solar illumination (167 kWUVA s/m2) on the sol-gel deposit of TiO2, it is possible to eliminate 100% of the bacteria covered by international regulations in respect of water for human consumption. With regard to the aging assay of the system, it was observed at 250 h of operation a reduction in the effectiveness of the disinfection process. At 0 and 250 h of operation, the percentages of elimination of E. coli after 50 min of illumination were 100% and 99.5%, respectively. This reduction in the effectiveness of the process was due to the formation of a film of calcium carbonate adhering to the internal glass wall of the photoreactor, which is in contact with the liquid being treated, and to the presence of calcium carbonate precipitates on catalyst surface. DEWEY : 621.47 ISSN : 0199-6231 En ligne : http://asmedl.org/getabs/servlet/GetabsServlet?prog=normal&id=JSEEDO000134000001 [...]

Solar water disinfection studies with supported TiO2 and polymer-supported Ru (II) sensitizer in a compound parabolic collector / Juan Rodriguez in Transactions of the ASME. Journal of solar energy engineering, Vol. 132 N° 1 (Janvier 2010) 

Public ISBD [article]  in Transactions of the ASME. Journal of solar energy engineering > Vol. 132 N° 1 (Janvier 2010) . - pp. [011001/1-5] Titre : Solar water disinfection studies with supported TiO2 and polymer-supported Ru (II) sensitizer in a compound parabolic collector Type de document : texte imprimé Auteurs : Juan Rodriguez, Auteur ; Clido Jorge, Auteur ; Patricia Zuniga, Auteur Année de publication : 2010 Article en page(s) : pp. [011001/1-5] Note générale : Energie Solaire Langues : Anglais (eng) Mots-clés : Microorganisms  Photolysis  Ruthenium  Solar  absorber-convertors  Titanium  compounds  Water  treatment Index. décimale : 621.47 Résumé : Solar water disinfection was performed using TiO2 and a Ru(II) complex as fixed catalysts located in a compound parabolic collector photoreactor. Studies were performed in the laboratory as well as at a greenfield site. Under laboratory conditions, natural water contaminated with cultured bacteria was photocatalytically treated and the influence of the photolysis as well as of both catalysts was studied. Experiments were performed with contaminated water flowing at 12 l/min; under these conditions, photocatalytic experiments performed with a supported heterogeneous photocatalyst (Ahlstrom paper impregnated with TiO2) showed it to be effective in degrading bacteria in water. The Ru complex catalyst, however, showed no clear evidence for disinfecting water, and its efficiency was comparable to the simple photolysis. Under on-site experiments, bacteria contaminated water from the Yaurisque river at Cusco, Peru was treated. As a general trend, after photocatalytic treatment a reduction in the E-coli population present in water was observed. Whenever disinfection was achieved in the experiments, no regrowth of bacteria was observed after 24 h. However, a reduction in the prototype efficiency was observed both in laboratory and on-site experiments. This was ascribed to aging of the photocatalyst as well as due to the deposition of particles onto its surface. In cases in which incomplete disinfection resulted, a low rate of E-coli growth was observed 24 h after ending the experiment. However, pseudomones seem to be resistant to the treatment. DEWEY : 621.47 ISSN : 0199-6231 En ligne : http://asmedl.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JSEEDO00013200 [...] [article] Solar water disinfection studies with supported TiO2 and polymer-supported Ru (II) sensitizer in a compound parabolic collector [texte imprimé] / Juan Rodriguez, Auteur ; Clido Jorge, Auteur ; Patricia Zuniga, Auteur . - 2010 . - pp. [011001/1-5]. Energie Solaire Langues : Anglais (eng) in Transactions of the ASME. Journal of solar energy engineering > Vol. 132 N° 1 (Janvier 2010) . - pp. [011001/1-5] Mots-clés : Microorganisms  Photolysis  Ruthenium  Solar  absorber-convertors  Titanium  compounds  Water  treatment Index. décimale : 621.47 Résumé : Solar water disinfection was performed using TiO2 and a Ru(II) complex as fixed catalysts located in a compound parabolic collector photoreactor. Studies were performed in the laboratory as well as at a greenfield site. Under laboratory conditions, natural water contaminated with cultured bacteria was photocatalytically treated and the influence of the photolysis as well as of both catalysts was studied. Experiments were performed with contaminated water flowing at 12 l/min; under these conditions, photocatalytic experiments performed with a supported heterogeneous photocatalyst (Ahlstrom paper impregnated with TiO2) showed it to be effective in degrading bacteria in water. The Ru complex catalyst, however, showed no clear evidence for disinfecting water, and its efficiency was comparable to the simple photolysis. Under on-site experiments, bacteria contaminated water from the Yaurisque river at Cusco, Peru was treated. As a general trend, after photocatalytic treatment a reduction in the E-coli population present in water was observed. Whenever disinfection was achieved in the experiments, no regrowth of bacteria was observed after 24 h. However, a reduction in the prototype efficiency was observed both in laboratory and on-site experiments. This was ascribed to aging of the photocatalyst as well as due to the deposition of particles onto its surface. In cases in which incomplete disinfection resulted, a low rate of E-coli growth was observed 24 h after ending the experiment. However, pseudomones seem to be resistant to the treatment. DEWEY : 621.47 ISSN : 0199-6231 En ligne : http://asmedl.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JSEEDO00013200 [...]