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| Author(s): |
Tatiana Mello da Costa Faro
Total Authors: 1
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| Document type: | Master's Dissertation |
| Press: | Campinas, SP. |
| Institution: | Universidade Estadual de Campinas (UNICAMP). Instituto de Química |
| Defense date: | 2011-02-21 |
| Examining board members: |
Munir Salomão Skaf;
Charlles Rubber de Almeida Abreu;
Rogério Custodio
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| Advisor: | Munir Salomão Skaf; Vitor Rafael Coluci |
| Abstract | |
Zeolites are aluminosilicates whose structure consists of TO4 tetrahedra (with T=Si,Al) that share all its corners with the neighboring tetrahedra, thus forming a three-dimensional network highly porous and with a low density. The substitution of Si with Al in the zeolitic matrix leads to the generation of a net negative charge, balanced by the presence of exchangeable cations in the material. Zeolites are important objects of study because they are used industrially as molecular sieves, ion exchangers and catalysts. The location the exchangeable cations in the zeolite crystallographic sites and the identity of these cations are factors that govern the adsorption of gases and other small molecules in the zeolite and the catalytic behavior of the zeolite. Although many experimental techniques are used to characterize those cations, there are situations in which some of the exchangeable cations can not be located accurately by experimental methods; in these cases, computational studies by Molecular Dynamics (MD) simulations are very useful to help elucidate the location of the exchangeable cations in the zeolitic structure and its respective mobilities. In this work, we carried out molecular dynamics simulations of the zeolites NaX and BaX in the rigid matrix approximation and considering the vibration of the matrix atoms with the intention to analyze the influence of the vibration of the zeolitic matrix in the determination of several properties of the system, such as the location of the exchangeable cations and the absorption spectra of these cations in the far infrared region. Zeolite NaX was chosen because it is the precursor of almost all other type-X zeolites, so there are many experimental studies about it in the literature; zeolite BaX is important because barium faujasites are used in the industry in the separation process of aromatic molecules, such as xylenes (AU) | |
| FAPESP's process: | 08/08871-2 - Molecular dynamics simulations of zeolites with a flexible matrix |
| Grantee: | Tatiana Mello da Costa Faro |
| Support Opportunities: | Scholarships in Brazil - Master |