Síntese e caracterização de membranas zeolíticas tipo mfi e aplicação em separação de aromáticos
The synthesis of MFI-type zeolite membranes was carried by the process in situ or hydrothermal crystallization. We studied the homogenization time of the room temperature and gel filtration just before the crystallization step performed out in an oven, thus obtaining a more uniform zeolite film. The...
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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/123456789/17704 |
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| Resumo: | The synthesis of MFI-type zeolite membranes was carried by the process in situ or
hydrothermal crystallization. We studied the homogenization time of the room
temperature and gel filtration just before the crystallization step performed out in an oven,
thus obtaining a more uniform zeolite film. The powder synthesized zeolite (structure
type MFI, Silicalite) was characterized by several complementary techniques such as Xray
diffraction (XRD), scanning electron microscopy (SEM), thermal analysis,
temperature programmed desorption (TPD), Fourier Transform infrared spectroscopy
(FTIR) and textural analysis by nitrogen adsorption (specific surface area). For the
purpose of evaluating the quality of the layer supported on the ceramic support, N2
permeation tests were carried starting from room temperature to 600 °C, where values
were observed values more appropriate permeation from 200 °C. With the data obtained,
it was made into a graph of temperature versus permeation function, the curve of surface
diffusion was found. For scanning electron microscopy, we observed the formation of
homogeneous crystals and the zeolite film showed no fissures or cracks, indicating that
the process of synthesis and subsequent treatments not damaged the zeolite layer on the
support. Carried permeation studies were found values ranging from 3.64x10-6 to
3.78x10-6, 4.71x10-6 to 5.02x10-6, to pressures 20 and 25 psi, respectively. And the
mixture xylenes/N2 values were between 5.39x10-6 to 5.67x10-6 and 8.13x10-6 to
8.36x10-6, also for pressures of 20 and 25 psi. The values found for the separation factor
were 15.22 at 400 °C in the first experiment and 1.64 for the second experiment at a
temperature of 150 °C. It is concluded that the Silicalite membrane was successfully
synthesized and that it is effective in the separation of binary mixtures of xylenes |
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