Desilication of highly siliceous zeolite ZSM-5 with NaOH and NaOH/tetrabutylamine hydroxide

The results of both chemical and XPS analysis pointed out that desilication of highly siliceous ZSM-5 of Si/Al = 164 was more effective in the surface zone than in the bulk, contrary to zeolite ZSM-5 of Si/Al = 31.6. According to the IR studies in parent zeolite the concentration of protonic sites w...

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Autores: Sadowska, K, Góra-Marek, Kinga, Drozdek, Marek, Kustrowski, Piotr, Datka, J, Martínez-Triguero, Joaquín|||0000-0003-4590-724X, Rey Garcia, Fernando|||0000-0003-3227-5669
Tipo de recurso: artículo
Fecha de publicación:2013
País:España
Institución:Universitat Politècnica de València (UPV)
Repositorio:RiuNet. Repositorio Institucional de la Universitat Politécnica de Valéncia
Idioma:inglés
OAI Identifier:oai:riunet.upv.es:10251/74907
Acceso en línea:https://riunet.upv.es/handle/10251/74907
Access Level:acceso abierto
Palabra clave:Desilication
Realumination
Highly siliceous zeolite
IR spectroscopy
Accessibility
Cracking
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spelling Desilication of highly siliceous zeolite ZSM-5 with NaOH and NaOH/tetrabutylamine hydroxideSadowska, KGóra-Marek, KingaDrozdek, MarekKustrowski, PiotrDatka, JMartínez-Triguero, Joaquín|||0000-0003-4590-724XRey Garcia, Fernando|||0000-0003-3227-5669DesilicationRealuminationHighly siliceous zeoliteIR spectroscopyAccessibilityCrackingThe results of both chemical and XPS analysis pointed out that desilication of highly siliceous ZSM-5 of Si/Al = 164 was more effective in the surface zone than in the bulk, contrary to zeolite ZSM-5 of Si/Al = 31.6. According to the IR studies in parent zeolite the concentration of protonic sites was very close to the concentration of Al indicating that all Al atoms can form Si-OH-Al. The results of our quantitative IR studies strongly support the realumination thesis, i.e. some Al atoms extracted in basic solutions are subsequently reinserted forming new acidic hydroxyls. In desilicated zeolites all Al atoms were able to form protonic sites, however part of them dehydroxylated during the activation of zeolite producing Lewis acid sites according to the stoichiometry: one protonic site was transformed into one Lewis site. Low temperature nitrogen adsorption revealed that the alkaline treatment of highly siliceous zeolite with 0.2 M NaOH/TBAOH mixture produced mesopores of smaller diameter and narrower pore size distribution than in the case of zeolite of medium Si/Al ratio. This result can be explained by low concentration of Al which similarly as TBA(+) cations plays the role of pore directing agents (PDA). Contrary to TEA(+), the presence of Al in desilication mixture, led to the formation of larger pores. Therefore, in highly siliceous zeolite TBA(+) played dominant role as PDA producing narrower pores. Highly siliceous zeolite with uniform distribution of relatively narrow pores may be useful catalyst or catalyst support. The influence of desilication temperature on porosity development was also investigated. The increase of desilication temperature from 338 to 353 K resulted in both more extensive demetalation (more Si and Al is extracted) and the distinct increase of the volume and surface of mesopores. Both lower concentration of protonic sites and higher concentration of Lewis sites confirmed partial zeolite destruction upon desilication at elevated temperature. The experiments of pivalonitrile sorption followed by IR spectroscopy showed a significant increase of accessibility of acid sites to bulky pivalonitrile molecules. (C) 2012 Elsevier Inc. All rights reserved.The research was partially carried out with the equipment purchased thanks to the financial support of the European Regional Development Fund in the framework of the Polish Innovation Economy Operational Program (Contract No. POIG.02.01.00-12-023/08).ElsevierInstituto Universitario Mixto de Tecnología QuímicaJagiellonian University in KrakowNational Science Centre, PoloniaEuropean CommissionRepositorio Institucional de la Universitat Politècnica de València Riunet20132013-03-01journal articlehttp://purl.org/coar/resource_type/c_6501VoRhttp://purl.org/coar/version/c_970fb48d4fbd8a85info:eu-repo/semantics/articleapplication/pdfapplication/pdfhttps://riunet.upv.es/handle/10251/74907reponame:RiuNet. Repositorio Institucional de la Universitat Politécnica de Valénciainstname:Universitat Politècnica de València (UPV)InglésengEuropean Commission https://doi.org/10.13039/501100000780 Operational Programme 'Innovative economy' POIG.02.01.00-12-023%2F08National Science Centre, Polonia https://doi.org/10.13039/501100004281 2011%2F01%2FB%2FST5%2F00915open accesshttp://purl.org/coar/access_right/c_abf2Reserva de todos los derechoshttp://rightsstatements.org/vocab/InC/1.0/info:eu-repo/semantics/openAccessoai:riunet.upv.es:10251/749072026-06-13T07:49:27Z
dc.title.none.fl_str_mv Desilication of highly siliceous zeolite ZSM-5 with NaOH and NaOH/tetrabutylamine hydroxide
title Desilication of highly siliceous zeolite ZSM-5 with NaOH and NaOH/tetrabutylamine hydroxide
spellingShingle Desilication of highly siliceous zeolite ZSM-5 with NaOH and NaOH/tetrabutylamine hydroxide
Sadowska, K
Desilication
Realumination
Highly siliceous zeolite
IR spectroscopy
Accessibility
Cracking
title_short Desilication of highly siliceous zeolite ZSM-5 with NaOH and NaOH/tetrabutylamine hydroxide
title_full Desilication of highly siliceous zeolite ZSM-5 with NaOH and NaOH/tetrabutylamine hydroxide
title_fullStr Desilication of highly siliceous zeolite ZSM-5 with NaOH and NaOH/tetrabutylamine hydroxide
title_full_unstemmed Desilication of highly siliceous zeolite ZSM-5 with NaOH and NaOH/tetrabutylamine hydroxide
title_sort Desilication of highly siliceous zeolite ZSM-5 with NaOH and NaOH/tetrabutylamine hydroxide
dc.creator.none.fl_str_mv Sadowska, K
Góra-Marek, Kinga
Drozdek, Marek
Kustrowski, Piotr
Datka, J
Martínez-Triguero, Joaquín|||0000-0003-4590-724X
Rey Garcia, Fernando|||0000-0003-3227-5669
author Sadowska, K
author_facet Sadowska, K
Góra-Marek, Kinga
Drozdek, Marek
Kustrowski, Piotr
Datka, J
Martínez-Triguero, Joaquín|||0000-0003-4590-724X
Rey Garcia, Fernando|||0000-0003-3227-5669
author_role author
author2 Góra-Marek, Kinga
Drozdek, Marek
Kustrowski, Piotr
Datka, J
Martínez-Triguero, Joaquín|||0000-0003-4590-724X
Rey Garcia, Fernando|||0000-0003-3227-5669
author2_role author
author
author
author
author
author
dc.contributor.none.fl_str_mv Instituto Universitario Mixto de Tecnología Química
Jagiellonian University in Krakow
National Science Centre, Polonia
European Commission
Repositorio Institucional de la Universitat Politècnica de València Riunet
dc.subject.none.fl_str_mv Desilication
Realumination
Highly siliceous zeolite
IR spectroscopy
Accessibility
Cracking
topic Desilication
Realumination
Highly siliceous zeolite
IR spectroscopy
Accessibility
Cracking
description The results of both chemical and XPS analysis pointed out that desilication of highly siliceous ZSM-5 of Si/Al = 164 was more effective in the surface zone than in the bulk, contrary to zeolite ZSM-5 of Si/Al = 31.6. According to the IR studies in parent zeolite the concentration of protonic sites was very close to the concentration of Al indicating that all Al atoms can form Si-OH-Al. The results of our quantitative IR studies strongly support the realumination thesis, i.e. some Al atoms extracted in basic solutions are subsequently reinserted forming new acidic hydroxyls. In desilicated zeolites all Al atoms were able to form protonic sites, however part of them dehydroxylated during the activation of zeolite producing Lewis acid sites according to the stoichiometry: one protonic site was transformed into one Lewis site. Low temperature nitrogen adsorption revealed that the alkaline treatment of highly siliceous zeolite with 0.2 M NaOH/TBAOH mixture produced mesopores of smaller diameter and narrower pore size distribution than in the case of zeolite of medium Si/Al ratio. This result can be explained by low concentration of Al which similarly as TBA(+) cations plays the role of pore directing agents (PDA). Contrary to TEA(+), the presence of Al in desilication mixture, led to the formation of larger pores. Therefore, in highly siliceous zeolite TBA(+) played dominant role as PDA producing narrower pores. Highly siliceous zeolite with uniform distribution of relatively narrow pores may be useful catalyst or catalyst support. The influence of desilication temperature on porosity development was also investigated. The increase of desilication temperature from 338 to 353 K resulted in both more extensive demetalation (more Si and Al is extracted) and the distinct increase of the volume and surface of mesopores. Both lower concentration of protonic sites and higher concentration of Lewis sites confirmed partial zeolite destruction upon desilication at elevated temperature. The experiments of pivalonitrile sorption followed by IR spectroscopy showed a significant increase of accessibility of acid sites to bulky pivalonitrile molecules. (C) 2012 Elsevier Inc. All rights reserved.
publishDate 2013
dc.date.none.fl_str_mv 2013
2013-03-01
dc.type.none.fl_str_mv journal article
http://purl.org/coar/resource_type/c_6501
VoR
http://purl.org/coar/version/c_970fb48d4fbd8a85
dc.type.openaire.fl_str_mv info:eu-repo/semantics/article
format article
dc.identifier.none.fl_str_mv https://riunet.upv.es/handle/10251/74907
url https://riunet.upv.es/handle/10251/74907
dc.language.none.fl_str_mv Inglés
eng
language_invalid_str_mv Inglés
language eng
dc.relation.none.fl_str_mv European Commission https://doi.org/10.13039/501100000780 Operational Programme 'Innovative economy' POIG.02.01.00-12-023%2F08
National Science Centre, Polonia https://doi.org/10.13039/501100004281 2011%2F01%2FB%2FST5%2F00915
dc.rights.none.fl_str_mv open access
http://purl.org/coar/access_right/c_abf2
Reserva de todos los derechos
http://rightsstatements.org/vocab/InC/1.0/
dc.rights.openaire.fl_str_mv info:eu-repo/semantics/openAccess
rights_invalid_str_mv open access
http://purl.org/coar/access_right/c_abf2
Reserva de todos los derechos
http://rightsstatements.org/vocab/InC/1.0/
eu_rights_str_mv openAccess
dc.format.none.fl_str_mv application/pdf
application/pdf
dc.publisher.none.fl_str_mv Elsevier
publisher.none.fl_str_mv Elsevier
dc.source.none.fl_str_mv reponame:RiuNet. Repositorio Institucional de la Universitat Politécnica de Valéncia
instname:Universitat Politècnica de València (UPV)
instname_str Universitat Politècnica de València (UPV)
reponame_str RiuNet. Repositorio Institucional de la Universitat Politécnica de Valéncia
collection RiuNet. Repositorio Institucional de la Universitat Politécnica de Valéncia
repository.name.fl_str_mv
repository.mail.fl_str_mv
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score 15,301603

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