Deposição de filmes finos de TiO2 em superfície de vidro e avaliação das suas propriedades fotocatalíticas

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Universidade Federal de Goiás


Water is one of the most abundant and most important available resources for life's existence and permanence. The National Water Agency reports that there is an increasingly inversely proportional relationship between demand and the availability of freshwater, it makes necessary to reuse this natural resource so that the world population does not enter into water chaos. Thus, the main problems encountered are the population increase and the intensification of industrial activities, which contributes to the generation of possible outbreaks of water resources contamination. However, the treatment performed by the ETAs and ETEs are not prepared to remove these compounds, which are largely toxic and difficult to degradation. Thus, advanced oxidative processes (POAs) are alternative technologies that are under strong interest in the scientific environment due to the high potential of removing these recalcitrant components. Among the POAs stands out the heterogeneous photocatalysis, which consists of photoactivating an inorganic semiconductor, such as TiO2, with consequent generation of highly oxidisant species. Titanium oxide (TiO2) has three crystallographic forms, being, anatase, rutile and Brokita. The synthesis method is highly determinant in obtaining these types of structure and, consequently, in the property of oxide. This work aimed to obtain titanium dioxide in the form of films using the Peroxo-Titanium complex Method (CPT), moreover, evaluating the calcination temperature, successive layers and addition of P25 in the films, and influence on the photochemical efficiency of Discoloration of the Tartrazine organic dye. The precursor gel was obtained by solubilization of titanium isopropoxide in H2O2 28% in ice bath. The TiO2 films were deposited by manual immersion, silk screen and with the aid of a brush on the glass plate of 20x76mm previously cleaned with piranha solution (H2SO4: H2O2) ratio in mol of 4:1. The films were thermally treated at temperatures of 450 º C and 550 º C for 1h30min. The resulting material was structurally characterized in the XW, morphologically in SEM and the composition was verified in the EDX. Heterogeneous photocatalysis assays were performed, exposing the tartrazine solution to the radiation of the mercury lamp and sunlight, in the time of 120 minutes and 390 minutes. In general, the formation of biphasic materials with photocatalytic activity was observed; The photocatalytic film that presented the best photocatalytic performance was the T3 material with 30% addition of P25 for promoting the total discoloration of the dye in 100%, with kap of 0.0693, it can be emphasized that the films have catalytic activity both in Presence in artificial and natural ultraviolet light; and have not shown to be toxic, with a small mortality rate Artemia salina less than 30%. The efficiency was related to the presence of a mixture of anatase/rutile phases similar to P25, which generates an effect of heterojunction increasing the photochemical efficiency to promote oxidative reactions and adsorption, favoring the discoloration of the organic compost resistant, and bringing advantages of TiO2 films, such as the reuse of glass spheres in various catalytic processes without the loss of photochemical efficiency, and the ease of removal of the material at the end of the photocatalytic process.



Cristalização, Filmes finos, Fotocatálise, Crystallization, Thin Films, Photocatalysis


GONÇALVES, E. J. Deposição de filmes finos de TiO2 em superfície de vidro e avaliação das suas propriedades fotocatalíticas. 2019. 78 p. Dissertação (Mestrado em Química) - Universidade Federal de Goiás, Catalão, 2019.