Abstract:Recebido em 16/3/05; aceito m 28/7/05; publicado na web em 20/1/06 TiO 2 IMMOBILIZATION ONTO CONCRETE: CHLOROFORM AND PHENOL PHOTODEGRADATION. TiO 2 immobilization on concrete was studied using mixtures with cement, varnish and resin. The UV radiation sources were a germicide UV lamp and solar light. Aqueous solutions of chloroform (CHCl 3 ) and of phenol were prepared and recirculated over the TiO 2 immobilized surfaces. The immobilized TiO 2 surfaces showed better photocatalytic efficiency for phenol degrada… Show more
“…Therefore, attempts have been made to separate TiO 2 photocatalysts via a variety of supported materials including glass microspheres, graphene, zeolites, and concrete. [13][14][15][16] Hollow glass microspheres (HGM) are widely used in various fields. [17][18][19] HGM-TiO 2 is an important composite material and became commercially available.…”
Chromium and sulfur co-doped nanometer TiO 2 hollow glass microspheres (Cr/S/TiO 2 -HGM) were synthesized by a sol-gel method. Characterization used X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), N 2 adsorption-desorption (Brunauer-Emmett-Teller (BET) measurements) and UV-Vis diffuse reflectance spectroscopy. The photocatalytic activity was evaluated by photodegradation of indigo carmine in an aqueous solution under visible light irradiation. The results indicated that the Cr/S/TiO 2 containing 0.60% (atomic ratio) chromium and 1.2% (atomic ratio) sulfur calcined at 500 °C for 2 h had high catalytic efficiency under visible light irradiation. The floating Cr/S/TiO 2 -HGM catalyst had greater photocatalytic activity than Cr/S/TiO 2 powder. Therefore, Cr/S/TiO 2 -HGM is a promising, high-performing, visible-light-driven, and more reusable photocatalyst.
“…Therefore, attempts have been made to separate TiO 2 photocatalysts via a variety of supported materials including glass microspheres, graphene, zeolites, and concrete. [13][14][15][16] Hollow glass microspheres (HGM) are widely used in various fields. [17][18][19] HGM-TiO 2 is an important composite material and became commercially available.…”
Chromium and sulfur co-doped nanometer TiO 2 hollow glass microspheres (Cr/S/TiO 2 -HGM) were synthesized by a sol-gel method. Characterization used X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), N 2 adsorption-desorption (Brunauer-Emmett-Teller (BET) measurements) and UV-Vis diffuse reflectance spectroscopy. The photocatalytic activity was evaluated by photodegradation of indigo carmine in an aqueous solution under visible light irradiation. The results indicated that the Cr/S/TiO 2 containing 0.60% (atomic ratio) chromium and 1.2% (atomic ratio) sulfur calcined at 500 °C for 2 h had high catalytic efficiency under visible light irradiation. The floating Cr/S/TiO 2 -HGM catalyst had greater photocatalytic activity than Cr/S/TiO 2 powder. Therefore, Cr/S/TiO 2 -HGM is a promising, high-performing, visible-light-driven, and more reusable photocatalyst.
“…The percentages of semiconductors were based on [10] work. It is expected with the results of this paper that the composite shows potential to be used as a coating on health services that, on top of its photocatalyst capacity, also has durability, easy maintenance and is less harmful to the environment.…”
Photodegradation or photocatalysis is a chemical degradation process that occurs when an inorganic semiconductor is exposed to ultraviolet (UV) light. UV light (wavelength 320 -400 nm) has enough energy to detach an electron from the last layer of the semiconductor, leading to the conduction band, leaving a hole in the valence band. In these bands, chemical reduction and oxidation reactions occur, respectively. These reactions degrade diverse surface dirt, dissociating them into simpler and less offensive substances such as CO 2 and H 2 O. In this work, we studied the potential of photocatalysis of a composite based on a semiconductor encapsulated in epoxy resin, in the degradation of Staphylococcus aureus, pathogen with a high degree of hospital contamination, in order to apply it to the construction in hospital facilities. The experiments were carried out with a fabrication of only epoxy resin tablets and tablets with the composite, at various concentrations of the semiconductor and glass powder. Through contamination of these tablets and their exposure to sunlight and the ambient light, contamination on their surfaces was verified. The results indicated potential photodegradation capacity of the composite.
“…;Diamanti et. al., 2008), a pulverização do semi-condutor após conformação do componente e antes do endurecimento li, 2007) e pós-tratamento com agentes ligantes orgânicos (Santos, 2004;Kondo, 2006e Diamanti et. al., 2008.…”
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“…Para a área de concretos e argamassas, constata-se que parte das pesquisas adiciona o semi-condutor durante a mistura (Cassar et. al., 2003;Santos & Kondo, 2006). Nesses casos, o teor de dióxido de titânio utilizado é bastante variado, havendo casos em que foi usada uma concentração de 1% da massa total e outros com 15% (Furumura et.…”
Section: 4 4 4 P P Pr R Ro O Od D Du U Uç ç çã ã ãO O O D D De E Eunclassified
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