Síntese e caracterização de TiO2 e aplicação na degradação fotocatalítica do corante amarelo reativo BF-4G
TiO2 has been extensively investigated for the removal of pollutants from the most diverse types of effluents. It is a material that presents several crystalline structures, low toxicity, low cost and good thermal and photochemical stability, with potential for application in heterogeneous photocata...
| Autor principal: | Massaroli, Cristielen Rizzon |
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| Formato: | Trabalho de Conclusão de Curso (Graduação) |
| Idioma: | Português |
| Publicado em: |
Universidade Tecnológica Federal do Paraná
2021
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| Assuntos: | |
| Acesso em linha: |
http://repositorio.utfpr.edu.br/jspui/handle/1/24288 |
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| Resumo: |
TiO2 has been extensively investigated for the removal of pollutants from the most diverse types of effluents. It is a material that presents several crystalline structures, low toxicity, low cost and good thermal and photochemical stability, with potential for application in heterogeneous photocatalysis because it has high capacity of degradation of pollutants in aqueous solutions. TiO2 is found in three different crystalline structures: anatase, rutile and brookita, the first two being the ones with the highest photocatalytic activity. In this sense, the present study had as objective to study the influence of the calcination temperature on the morphological-structural properties of TiO2 and to evaluate its efficiency in the photocatalytic degradation reaction of the BF-4G reactive yellow dye used in the textile industry. TiO2 was synthesized by the polymeric precursor method and calcined at temperatures of 500, 700and 900 ºC. The obtained oxides were characterized by X-ray diffractometry (XRD), scanning electron microscopy with X-ray dispersive energy detectors (SEM-EDS), photoacoustic spectroscopy, Fourier transform infrared spectroscopy (FTIR) and point of zero charge (PZC).The calcination temperature had a significant influence on the physicochemical properties of TiO2. The increase of the calcination temperature resulted in an increase of the Crystallite size and also of the ratio of the rutile related to the anatase phase. It was found that the temperature of 500 ºC was not high enough to eliminate all of the organic matter present in the precursor polymer of TiO2. The band gap energy values determined for the TiO2 calcined at 500, 700 and 900 ºC were, respectively, 3.0 eV; 2.9 and 3.80 eV; and 3.0 and 3.98 eV. The increase of the calcination temperature resulted in a reduction of the value of the point of zero charge value for TiO2. The morphology of the oxides was characteristic of non - uniform agglomerates of irregular shape. The degradation of the dye was evaluated by photolysis (absence of photocatalyst, only action of ultraviolet radiation), in which 92% discoloration of the synthetic solution occurred in 120 minutes of reaction. Then, the performance of TiO2 calcined at 700 ºC was investigated. The results showed that the adsorption process (absence of ultraviolet radiation, only action of the photocatalyst) was not efficient for the discoloration, resulting in a color reduction of only 13%, however the photocatalytic process (using photocatalyst and ultraviolet radiation) resulted in 98.6% of discoloration after 120 minutes of reaction, characterizing an efficient process of decolorizing of the synthetic solution of the BF-4G reactive yellow dye. A pseudo-first order kinetics model was adequately fitted to the experimental data obtained in this work. |
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