Structured MFI film catalysts and adsorbents
A method originally developed at the division of Chemical Technology, Luleå University of Technology was tailored for the preparation of well-defined ZSM-5 films and zoned MFI films on supports suitable for catalysis and adsorption applications. Films were grown on monoliths, ceramic foams, alumina...
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ftluleatu:oai:DiVA.org:ltu-16949 2023-05-15T17:09:16+02:00 Structured MFI film catalysts and adsorbents Öhrman, Olov 2005 application/pdf http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-16949 eng eng Luleå Doctoral thesis / Luleå University of Technology 1 jan 1997 → …, 1402-1544 2005:07 http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-16949 Local 0dc3ee60-53d7-11db-9592-000ea68e967b info:eu-repo/semantics/openAccess Chemical Process Engineering Kemiska processer Doctoral thesis, comprehensive summary info:eu-repo/semantics/doctoralThesis text 2005 ftluleatu 2022-10-25T20:53:55Z A method originally developed at the division of Chemical Technology, Luleå University of Technology was tailored for the preparation of well-defined ZSM-5 films and zoned MFI films on supports suitable for catalysis and adsorption applications. Films were grown on monoliths, ceramic foams, alumina beads, soda glass beads and quartz glass. The supports were seeded with silicalite-1 crystals and hydrothermally treated in a single or several steps. The materials were evaluated by scanning electron microscopy, x-ray diffraction, N2 and NO2 sorption, x-ray photoelectron spectroscopy, ICP-AES, p-xylene isomerization and cracking of 1,3,5-tri-isopropylbenzene. The thickness of the continuous films could be controlled from 110 nm to 9 µm. Zoned MFI films were prepared from precursor ZSM-5 films by overgrowth with silicalite-1. A multi-step synthesis protocol was used to prevent excessive bulk crystallization. Ultrasound treatment was beneficial for removal of loosely attached crystals on top of the zeolite films. Defects such as cracks and open grain boundaries were observed by SEM and in concert, mesopores were observed by N2 sorption. Model parameters were fitted to experimental data from catalytic test reactions and these parameters indicated that thicker films contained more defects, probably in the form of open grain boundaries and cracks (mesopores) as observed by SEM and N2 sorption. Films supported on quartz were more catalytically active than films on alumina and soda glass. This was attributed to partial poisoning of the acid sites in the films on the latter two substrates, probably due to solid-state ion exchange of impurities such as alkali metals from the alumina and soda glass support to the film. As expected, thicker films possessed higher diffusion resistance than thin films. Surprisingly, a higher external activity was observed after zoning. This was attributed to formation of mesopores, migration of aluminum from the precursor ZSM-5 film to the external surface, and increased surface roughness upon ... Doctoral or Postdoctoral Thesis Luleå Luleå Luleå Luleå University of Technology Publications (DiVA) |
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Luleå University of Technology Publications (DiVA) |
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English |
topic |
Chemical Process Engineering Kemiska processer |
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Chemical Process Engineering Kemiska processer Öhrman, Olov Structured MFI film catalysts and adsorbents |
topic_facet |
Chemical Process Engineering Kemiska processer |
description |
A method originally developed at the division of Chemical Technology, Luleå University of Technology was tailored for the preparation of well-defined ZSM-5 films and zoned MFI films on supports suitable for catalysis and adsorption applications. Films were grown on monoliths, ceramic foams, alumina beads, soda glass beads and quartz glass. The supports were seeded with silicalite-1 crystals and hydrothermally treated in a single or several steps. The materials were evaluated by scanning electron microscopy, x-ray diffraction, N2 and NO2 sorption, x-ray photoelectron spectroscopy, ICP-AES, p-xylene isomerization and cracking of 1,3,5-tri-isopropylbenzene. The thickness of the continuous films could be controlled from 110 nm to 9 µm. Zoned MFI films were prepared from precursor ZSM-5 films by overgrowth with silicalite-1. A multi-step synthesis protocol was used to prevent excessive bulk crystallization. Ultrasound treatment was beneficial for removal of loosely attached crystals on top of the zeolite films. Defects such as cracks and open grain boundaries were observed by SEM and in concert, mesopores were observed by N2 sorption. Model parameters were fitted to experimental data from catalytic test reactions and these parameters indicated that thicker films contained more defects, probably in the form of open grain boundaries and cracks (mesopores) as observed by SEM and N2 sorption. Films supported on quartz were more catalytically active than films on alumina and soda glass. This was attributed to partial poisoning of the acid sites in the films on the latter two substrates, probably due to solid-state ion exchange of impurities such as alkali metals from the alumina and soda glass support to the film. As expected, thicker films possessed higher diffusion resistance than thin films. Surprisingly, a higher external activity was observed after zoning. This was attributed to formation of mesopores, migration of aluminum from the precursor ZSM-5 film to the external surface, and increased surface roughness upon ... |
format |
Doctoral or Postdoctoral Thesis |
author |
Öhrman, Olov |
author_facet |
Öhrman, Olov |
author_sort |
Öhrman, Olov |
title |
Structured MFI film catalysts and adsorbents |
title_short |
Structured MFI film catalysts and adsorbents |
title_full |
Structured MFI film catalysts and adsorbents |
title_fullStr |
Structured MFI film catalysts and adsorbents |
title_full_unstemmed |
Structured MFI film catalysts and adsorbents |
title_sort |
structured mfi film catalysts and adsorbents |
publisher |
Luleå |
publishDate |
2005 |
url |
http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-16949 |
genre |
Luleå Luleå Luleå |
genre_facet |
Luleå Luleå Luleå |
op_relation |
Doctoral thesis / Luleå University of Technology 1 jan 1997 → …, 1402-1544 2005:07 http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-16949 Local 0dc3ee60-53d7-11db-9592-000ea68e967b |
op_rights |
info:eu-repo/semantics/openAccess |
_version_ |
1766065272364466176 |