Structural Changes in Nanoporous MFI Zeolites Induced by Tetrachloroethene Adsorption: A Joint Experimental and Simulation Study

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TitreStructural Changes in Nanoporous MFI Zeolites Induced by Tetrachloroethene Adsorption: A Joint Experimental and Simulation Study
Type de publicationJournal Article
Nouvelles publications2011
AuteursJeffroy, M, Weber G, Hostachy S, Bellat JP, Fuchs AH, Boutin A
JournalJournal of Physical Chemistry C
Volume115
Fascicule10
Pagination3854-3865
Année de publicationMar
Numéro1932-7447
Accession NumberISI:000288113400006
Résumé

A joint experimental and molecular simulation study was performed to investigate the,adsorption of tetrachloroethene on two MFI zeolites, ZSM-5 with a Si/Al ratio of 26.5, and silicalite-1, which is the pure silica form of ZSM-5. Adsorption isotherms and isosteric heats of adsorption of tetrachloroethene were measured and compared to molecular simulation results, Experimental curves for both MFI zeoliteS show a step at loading of 4 molecules.uc(-1) that was interpreted in terms of a structural change of the host framework. A thermodynamic analysis based on the Osmotic ensemble scheme allowed attributing this Step to a symmetry Change from ORTHO (orthorhombic form With Pnma symmetry) to PARA (orthorhombic form with P2(1)2(1)2(1) symmetry) of both adsorbents upon micropore filling. The adsorption. mechanism was also characterized. The first tetrachloroethene molecules adsorbs in the channel intersections of the MONO (monoclinic form with P2(1)/n11 symmetry) and ORTHO structures of silicalite-1 and ZSM-5, respectively. Then, the above mentioned structural change from ORTHO to PARA occurs, leading to a filling of Sinusoidal channels Until saturation was reached, i.e. similar to 8 molecules.uc(-1) for silicalite-1 and 6 molecules.nc(-1) for In addition simulation results indicate that the sodium cations in the ZSM-5 zeolite are located at the channel intersections during the,whole adsorption process.

URL<Go to ISI>://000288113400006
DOI10.1021/jp109447n
Importer un fichierStructural Changes in Nanoporous MFI Zeolites Induced by Tetrachloroethene Adsorption: A Joint Experimental and Simulation Study
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