Browsing by Keyword "TiO"
Now showing 1 - 2 of 2
Results Per Page
Sort Options
Item Comparative study on the photocatalytic behaviour of titanium oxide thermal sprayed coatings from powders and suspensions(2009-05-25) Toma, F. L.; Berger, L. M.; Jacquet, D.; Wicky, D.; Villaluenga, I.; de Miguel, Y. R.; Lindeløv, J. S.; MercadoThis work presents a study of the microstructures and photocatalytic behaviour of titanium oxide coatings obtained by thermal spraying of agglomerated nanopowders and suspensions. Fine TiO2 Degussa P25 nanopowder, generally considered as the reference material in photocatalytic applications, was used as the material feedstock. HVOF process and suspension thermal spraying were used to prepare photocatalytic titania coatings. The coatings were mainly characterised by means of SEM and X-ray diffraction. The photocatalytic performance was evaluated based on decolouration of the pink dye Rhodamine B and degradation of gaseous acetaldehyde. A lower degree of pollutant degradation was found for deposits prepared by HVOF spraying of granules due principally to the low content of the photocatalytically active phase, i.e. anatase. Complete photocatalytic degradation of the organic compounds was recorded for the suspension-sprayed coatings. Based on the current results, suspension thermal spraying appears to be the better choice for preparing photocatalytically active titanium oxide surfaces for the removal of organic pollutants.Item Parameters Influencing the Photocatalytic Activity of Suspension-Sprayed TiO2 Coatings(2014-10) Toma, Filofteia Laura; Berger, Lutz Michael; Shakhverdova, Irina; Leupolt, Beate; Potthoff, Annegret; Oelschlägel, Kathrin; Meissner, Tobias; Gomez, José Antonio Ibáñez; de Miguel, Yolanda; TRAZABILIDAD CIRCULAR; MercadoPhotocatalytic properties of titania have been studied very intensively for a variety of applications, including air and water purification. In order to clarify the influence of the phase composition and other parameters, thermal spraying with suspensions was applied to produce photocatalytically active titania coatings starting from two commercially available anatase and rutile submicron powders. Aqueous suspensions containing 40% solids by weight were sprayed with an HVOF process using ethylene as the fuel gas. The spray parameters were chosen in order to produce mechanically stable coatings and to preserve a high content of the initial crystalline phases of the powders. The coating microstructures, phase compositions, and surface properties were characterized. The photocatalytic performance was evaluated by degradation of the pink dye Rhodamine B (RB) using two techniques: degradation of an aqueous solution of RB and discoloration of impregnated RB. All the coatings exhibited photocatalytic activity to varying degrees, depending on the phase composition as well as other factors, namely, the coating microstructure, surface morphology, surface hydroxylation, light absorption, and interaction with the pollutant.