Adsorption of n-Pentane and iso-Octane for the Evaluation of the Porosity of Dealuminated BEA Zeolites
| Autor: | J.P. Marques, Peter J.M. Carrott, I. Gener, C. Carvalhal, M.M.L. Ribeiro Carrott, Patrícia A. Russo, F. Ramôa Ribeiro, M. Guisnet, José Manuel Lopes |
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| Přispěvatelé: | Stocker, M., Laboratoire de catalyse en chimie organique (LACCO), Université de Poitiers-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Centro de Engenharia Biologica e Quimica, Instituto Superior Técnico, Universidade Técnica de Lisboa (IST), Departamento de Engenharia Quimica |
| Jazyk: | angličtina |
| Rok vydání: | 2005 |
| Předmět: |
Inorganic chemistry
Zeolite BEA Steaming 02 engineering and technology 010402 general chemistry Molecular sieve 01 natural sciences law.invention chemistry.chemical_compound Adsorption law General Materials Science Calcination Zeolite Octane General Chemistry Microporous material [CHIM.CATA]Chemical Sciences/Catalysis 021001 nanoscience & nanotechnology Condensed Matter Physics 0104 chemical sciences Pentane Chemistry chemistry Mechanics of Materials 0210 nano-technology Porosity |
| Zdroj: | Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos) Agência para a Sociedade do Conhecimento (UMIC)-FCT-Sociedade da Informação instacron:RCAAP Microporous and Mesoporous Materials Microporous and Mesoporous Materials, Elsevier, 2005, pp.259 |
| ISSN: | 1387-1811 |
| Popis: | Adsorption of n-pentane and 2,2,4-trimethylpentane at 298 K was carried out in order to characterize the porosity of a series of HBEA dealuminated zeolites. The HBEA samples were prepared from a calcined parent sample by steaming, by treatment with hydrochloric acid and by treatment with ammonium hexafluorosilicate (HFS) solutions. The comparison of the adsorption results with those previously obtained by nitrogen adsorption, show that the use of this latter adsorptive alone is insufficient for evaluating the changes provoked by dealumination. The narrow mesopores which were found in the parent sample show distinct behaviour with respect to each of the organic adsorptives. Treatment with HFS solutions and steaming causes the most significant changes in the microporosity, decreasing the micropore volumes of the samples. The former also causes a substantial loss of external area. Treatment with HCl solutions primarily removes extra-framework aluminium species formed during calcination; while this treatment has no significant effect on the microporosity, it causes an increase in the external areas of the samples. The removal of extra-framework aluminium species from the mesopores of the calcined sample contributes towards this increase. On the other hand, these mesopores are blocked during steaming and treatment with HFS solutions. |
| Databáze: | OpenAIRE |
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