Síntese, caracterização de óxido de alumínio a partir de esferas híbridase aplicação na conversão do glicerol: influência do grau de substituição e polimerização da carboximetilcelulose
Catalytic supports based on aluminum oxide were synthesized by the method of hybrid spheres using carboxymethylcellulose (CMC) as organic precursor (template) and aluminum nitrate as inorganic precursor. The characterizations were performed by thermal chemical analysis (TGA), X-Ray diffraction (X...
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| Formato: | Dissertação |
| Idioma: | por |
| Publicado em: |
Universidade Federal do Rio Grande do Norte
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| Endereço do item: | https://repositorio.ufrn.br/jspui/handle/123456789/21293 |
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| Resumo: | Catalytic supports based on aluminum oxide were synthesized by the method of hybrid
spheres using carboxymethylcellulose (CMC) as organic precursor (template) and
aluminum nitrate as inorganic precursor. The characterizations were performed by
thermal chemical analysis (TGA), X-Ray diffraction (XRD), fourier transform infrared
(FTIR) spectroscopy, scanning electron microscopy (SEM) and N2 physisorption. The
study of synthesis indicated that the characteristics of the biopolymer (degree of
substitution and polymerization) directly influence on the maximum value of the ratio
between the organic and inorganic precursor for the formation of hybrid spheres. The
physicochemical properties of the final material (crystallinity, porosity, surface area
and morphology) showed a direct dependence on the biopolymer properties (degree of
substitution and polymerization), indicating the versatility of this synthesis route. The
FTIR spectra confirm the formation of a hybrid material when comparing the pure
CMC spectrum with the obtained solids after drying. The XRD results show a profile
of amorphous and crystalline material for the different samples. For some solids were
possible to identify the formation of a crystalline phase related to the hydrated
alumina, aluminium oxide and copper oxide. The images obtained by SEM analysis
showed the formation of a material with sponge-like morphology after calcination,
characteristic of highly porous solid. The N2 adsorption/desorption isotherm profile
confirms the formation of micro-mesoporous materials with a specific surface area
between 50-162 m2.g-1 for the supports and 112-303 m2.g-1 for the copper-based
catalysts, indicating an increase in the area after the addition of Cu by impregnation
due to redissolution and recrystallization of alumina phase. Catalytic tests were tested
in the glycerol conversion reaction (92-15%) to added value products in order to
confirm their real viability. |
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