Intracrystalline Diffusivities and Surface Permeabilities Deduced from Transient Concentration Profiles: Methanol in MOF Manganese Formate

  • Autor:

    Kortunov, P. / Heinke, L. / Arnold, M. / Nedellec, Y. / Jones, D. / Caro, J. / Kärger, J. (2006)
  • Quelle:

    Journal American Chemical Society 129 (2007), 25, 8041–8047
  • Datum: 2006

  • Kortunov, P. / Heinke, L. / Arnold, M. / Nedellec, Y. / Jones, D. / Caro, J. / Kärger, J. (2006): „Intracrystalline Diffusivities and Surface Permeabilities Deduced from Transient Concentration Profiles: Methanol in MOF Manganese Formate“. In: Journal American Chemical Society 129 (2007), 25, 8041–8047

Abstract

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The intracrystalline concentration profiles during molecular uptake of methanol by an initially empty, single crystal of microporous manganese(II) formate (Mn(HCO2)2), representing an ionic inorganic−organic hybrid within the MOF family, are monitored by interference microscopy. Within these profiles, a crystal section could be detected where over the total of its extension (≈2 μm × 50 μm × 30 μm) molecular uptake ideally followed the pattern of one-dimensional diffusion.

Analysis of the evolution of intracrystalline concentration in this section directly yields the permeability of the crystal surface and the intracrystalline diffusivity as a function of the concentration of the total range of 0 ≤ θ ≤ 0.57 covered in the experiments. Within this range, the surface permeability is found to increase by 1 order of magnitude, while, within the limits of accuracy (±30%), the transport diffusivity remains constant, thus reflecting the properties of the lattice gas model.