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Previous issue date: 2014-02-10 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior - CAPES / Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico - CNPq / A demanda por materiais com alta homogeneidade obtidos a temperaturas
relativamente baixas vem alavancando a busca por processos qu?micos substituintes
do m?todo cer?mico convencional. Esse trabalho tem como objetivo a obten??o de
pigmentos nanom?tricos encapsulados (core-shell) a base de TiO2, dopados com
?ons de metais de transi??o (Fe, Co, Ni, Al) atrav?s de 3 (tr?s) m?todos de s?ntese:
precursores polim?ricos (Pechini); hidrotermal de microondas; e co-precipita??o
associado ? qu?mica sol-gel. O estudo foi motivado pela simplicidade, rapidez e
baixo consumo de energia caracter?sticos desses m?todos. Os sistemas de custos
s?o acess?veis, pois que permitem atingir um bom controle da microestrutura, aliada
a elevada pureza, com controle estequiom?trico e de fases permitindo obter
part?culas de tamanho nanom?trico. As propriedades f?sicas, qu?micas, morfol?gicas,
?pticas e estruturais dos materiais obtidos foram analisadas utilizando diferentes
t?cnicas de caracteriza??o de materiais. Os p?s pigmentantes foram testados na
descolora??o e degrada??o utilizando um fotoreator, atrav?s da solu??o do corante
remazol amarelo ouro (RNL), a partir da filtra??o destas, resultando na separa??o da
solu??o filtrante e dos pigmentos, para posterior realiza??o de medidas de UV-Vis.
As diferentes temperaturas de calcina??o adotadas ap?s a obten??o dos p?s, nos
diferentes m?todos foram: 400 ?C a 1000 ?C. Utilizando uma concentra??o fixa de
10% (Fe, Al, Ni, Co) em massa em rela??o ? massa do tit?nio, viabilizando
tecnologicamente e economicamente o estudo. Atrav?s da t?cnica de microscopia
eletr?nica de transmiss?o (MET) foi poss?vel analisar e confirmar a forma??o
estrutural das part?culas de pigmentos nanom?tricos encapsulados, apresentando
di?metro dos p?s de TiO2 entre 20 nm e 100 nm, e espessura da camada recoberta
de Fe, Ni e Co entre 2 nm e 10 nm. O m?todo de s?ntese mais eficiente entre os
estudados no trabalho foi o co-precipita??o associado ? qu?mica sol-gel, no qual
foram obtidos os melhores resultados, sem a necessidade da obten??o de p?s pelo
processo de calcina??o / The demand for materials with high consistency obtained at relatively low
temperatures has been leveraging the search for chemical processes substituents of
the conventional ceramic method. This paper aims to obtain nanosized pigments
encapsulated (core-shell) the basis of TiO2 doped with transition metals (Fe, Co, Ni,
Al) through three (3) methods of synthesis: polymeric precursors (Pechini);
hydrothermal microwave, and co-precipitation associated with the sol-gel chemistry.
The study was motivated by the simplicity, speed and low power consumption
characteristic of these methods. Systems costs are affordable because they allow
achieving good control of microstructure, combined with high purity, controlled
stoichiometric phases and allowing to obtain particles of nanometer size. The
physical, chemical, morphological, structural and optical properties of the materials
obtained were analyzed using different techniques for materials characterization. The
powder pigments were tested in discoloration and degradation using a photoreactor
through the solution of Remazol yellow dye gold (NNI), such as filtration, resulting in
a separation of solution and the filter pigments available for further UV-Vis
measurements . Different calcination temperatures taken after obtaining the post, the
different methods were: 400 ? C and 1000 ? C. Using a fixed concentration of 10%
(Fe, Al, Ni, Co) mass relative to the mass of titanium technologically and
economically enabling the study. By transmission electron microscopy (TEM)
technique was possible to analyze and confirm the structural formation nanosized
particles of encapsulated pigment, TiO2 having the diameter of 20 nm to 100 nm,
and thickness of coated layer of Fe, Ni and Co between 2 nm and 10 nm. The
method of synthesis more efficient has been studied in the work co-precipitation
associated with sol-gel chemistry, in which the best results were achieved without the
need for the obtainment of powders the calcination process
| Identifer | oai:union.ndltd.org:IBICT/oai:repositorio.ufrn.br:123456789/19639 |
| Date | 10 February 2014 |
| Creators | Andrade, Jean Carlos Silva |
| Contributors | 06296687877, http://lattes.cnpq.br/2365059843175411, Macedo, Daniel Ara?jo de, 01152094416, http://lattes.cnpq.br/1027496814443777, Galdino, Jos? Nildo, 87555492415, http://lattes.cnpq.br/3713583703008385, Moraes, M?rcio Luiz Varela Nogueira de, 01157194745, http://lattes.cnpq.br/2573306822477569, Nascimento, Rubens Maribondo do, Paskocimas, Carlos Alberto |
| Publisher | Universidade Federal do Rio Grande do Norte, PROGRAMA DE P?S-GRADUA??O EM CI?NCIA E ENGENHARIA DE MATERIAIS, UFRN, Brasil |
| Source Sets | IBICT Brazilian ETDs |
| Language | Portuguese |
| Detected Language | English |
| Type | info:eu-repo/semantics/publishedVersion, info:eu-repo/semantics/doctoralThesis |
| Source | reponame:Repositório Institucional da UFRN, instname:Universidade Federal do Rio Grande do Norte, instacron:UFRN |
| Rights | info:eu-repo/semantics/openAccess |
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