The use of interference microscopy has enabled the direct
observation of transient concentration profiles generated by intracrystalline
transport diffusion in nanoporous materials. The thus accessible intracrystalline
concentration profiles contain a wealth of information which cannot be deduced
by any macroscopic method. In this paper, we illustrate five different ways for
determining the concentration-dependent diffusivity in one-dimensional systems
and two for the surface permeability. These methods are discussed by application
to concentration profiles evolving during the uptake of methanol by the zeolite
ferrierite and of methanol by the metal organic framework (MOF) manganese(II)
formate. We show that the diffusivity can be calculated most precisely by means
of Fick’s 1st law. As the circumstances permit, Boltzmann’s integration method
also yields very precise results. Furthermore, we present a simple procedure that
enables the estimation of the influence of the surface barrier on the overall
| Identifer | oai:union.ndltd.org:DRESDEN/oai:qucosa:de:qucosa:80111 |
| Date | 25 July 2022 |
| Creators | Heinke, Lars, Kärger, Jörg |
| Publisher | IOP Publishing |
| Source Sets | Hochschulschriftenserver (HSSS) der SLUB Dresden |
| Language | English |
| Detected Language | English |
| Type | info:eu-repo/semantics/publishedVersion, doc-type:article, info:eu-repo/semantics/article, doc-type:Text |
| Rights | info:eu-repo/semantics/openAccess |
| Relation | 023035 |
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