title: The role of mesopores in intracrystalline transport in USY zeolite: PFG NMR diffusion study on various length scales.
abstract: PFG NMR has been applied to study intracrystalline diffusion in USY zeolite as well as in the parent ammonium-ion exchanged zeolite Y used to produce the USY by zeolite steaming. The diffusion studies have been performed for a broad range of molecular displacements and with two different types of probe molecules (n-octane and 1,3,5-triisopropylbenzene) having critical molecular diameters smaller and larger than the openings of the zeolite micropores. Our experimental data unambiguously show that, in contrast to what is usually assumed in the literature, the intracrystalline mesopores do not significantly affect intracrystalline diffusion in USY. This result indicates that the intracrystalline mesopores of USY zeolite do not form a connected network, which would allow diffusion through crystals only via mesopores.
authors.affiliation: Fakultät für Physik und Geowissenschaften, Universität Leipzig, Linnéstrasse 5, D-04103 Leipzig, Germany.
authors.forename: P
authors.initials: P
authors.lastname: Kortunov
authors.forename: S
authors.initials: S
authors.lastname: Vasenkov
authors.forename: J
authors.initials: J
authors.lastname: Kärger
authors.forename: R
authors.initials: R
authors.lastname: Valiullin
authors.forename: P
authors.initials: P
authors.lastname: Gottschalk
authors.forename: M Fé
authors.initials: MF
authors.lastname: Elía
authors.forename: M
authors.initials: M
authors.lastname: Perez
authors.forename: M
authors.initials: M
authors.lastname: Stöcker
authors.forename: B
authors.initials: B
authors.lastname: Drescher
authors.forename: G
authors.initials: G
authors.lastname: McElhiney
authors.forename: C
authors.initials: C
authors.lastname: Berger
authors.forename: R
authors.initials: R
authors.lastname: Gläser
authors.forename: J
authors.initials: J
authors.lastname: Weitkamp
mesh_terms: D000327:Adsorption; D003460:Crystallization; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D009584:Nitrogen / Q000737:chemistry; D010316:Particle Size; D016062:Porosity; D000644:Quaternary Ammonium Compounds / Q000737:chemistry; D013499:Surface Properties; D017641:Zeolites / Q000737:chemistry*
chemical_list: D000644:Quaternary Ammonium Compounds; D017641:Zeolites; D009584:Nitrogen