title: Intracrystalline diffusion in mesoporous zeolites.
abstract: Specially synthesized extra-large crystallites of zeolite LTA with intentionally added mesoporosity are used for an in-depth study of guest diffusion in hierarchical nanoporous materials by the pulsed field gradient NMR technique. Using propane as a guest molecule, intracrystalline mass transfer is demonstrated to be adequately described by a single effective diffusivity resulting from the weighted average of the diffusivities in the two (micro- and meso-) pore spaces. Gas-kinetic order-of-magnitude estimates of the diffusivities are in satisfactory agreement with the experimental data and are thus shown to provide a straightforward means for predicting and quantifying the benefit of hierarchically structured nanoporous materials in comparison with their purely microporous equivalent.
authors.affiliation: Faculty of Physics and Earth Science, University of Leipzig, Leipzig, Germany.
authors.forename: Dirk
authors.initials: D
authors.lastname: Mehlhorn
authors.forename: Rustem
authors.initials: R
authors.lastname: Valiullin
authors.forename: Jörg
authors.initials: J
authors.lastname: Kärger
authors.forename: Kanghee
authors.initials: K
authors.lastname: Cho
authors.forename: Ryong
authors.initials: R
authors.lastname: Ryoo