Título:	Síntese e caracterização de nanopartículas magnéticas com revestimento duplo de sílica e dióxido de titânio com elevada atividade fotocatalítica para degradação do corante azul de metileno
Autor(es):	Fernandes, Ítalo Lacerda
Orientador(es):	Coaquira, José Antonio Huamaní
Assunto:	Magnetita Sílica Titânia Hidrotérmicos Fotodegradação Corante azul de metileno
Data de publicação:	4-Abr-2022
Data de defesa:	22-Dez-2021
Referência:	FERNANDES, Ítalo Lacerda. Síntese e caracterização de nanopartículas magnéticas com revestimento duplo de sílica e dióxido de titânio com elevada atividade fotocatalítica para degradação do corante azul de metileno. 2021.115 f., il. Tese (Doutorado em Nanociência e Nanobiotecnologia) — Universidade de Brasília, Brasília, 2021.
Abstract:	Multifunctional nanocompositesbased on magnetic cores are being extensively studied currently focusing biomedical, environmental and engineering applications. In this study, we synthesized double-coated magnetic nanoparticles (MNP) by the solvothermal method to obtain the MNP@SiO2@TiO2nanocomposite. The MNP were coated with a silica shell using the sol-gel method. Additionally, the hydrolysis and condensation of titanium (IV) isopropoxide was used for a second coating layer of TiO2on SiO2. Several techniques were used to characterizethe properties of MNP@SiO2@TiO2nanocomposite. Atomic Force Microscopy showed NPM of the order of 5 nm, consistent with the estimated size of individual NPM by Transmission Electron Microscopy. On the other hand, the almost spherical aggregates formed by NPM have an average size of 116 nm; the coating estimated by the same technique was of the order 15 nm and the titania coating was of the order 34 nm. X-ray diffraction patterns showed the formation of TiO2anatase, without rutile or brookite. The estimated surface area was 167 m2g-1for MNP@SiO2@TiO2. The excellent photocatalytic activity of MNP@SiO2@TiO2was demonstrated by degrading methylene blue (MB) dye under UV irradiation. Results indicate that the synthesized nanocomposite reduced the 95% the MB dye concentration in the first 30 minutes, which is larger than the 47% obtained when the commercial TiO2, Degussa P25, was tested. Results indicate that the first 120 minutes are enough to get 99.9% of photocatalytic reduction. To our knowledge, there is noother material showing that strong photocatalytic action against methylene blue dye. The magnetic properties of MNP@SiO2@TiO2shows that this nanocomposite can easily be separated from the solution using an external magnetic field. Our results indicate that its stable photocatalytic activity is warranted, at least four times, without any significant loss of activity. The results indicate that the successfully obtained MNP@SiO2@TiO2nanocomposite is interesting for wastewater treatment applications and it features promising to degradate other water contaminan
Unidade Acadêmica:	Instituto de Ciências Biológicas (IB)
Informações adicionais:	Tese (Doutorado) — Universidade de Brasília, Instituto de Ciências Biológicas, Programa de Pós-Graduação em Nanociência e Nanobiotecnologia, 2021.
Programa de pós-graduação:	Programa de Pós-Graduação em Nanociência e Nanobiotecnologia
Aparece nas coleções:	Teses, dissertações e produtos pós-doutorado

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