Inflection behaviour in the loading dependence of the Maxwell-Stefan diffusivity of iso-butane in MFI zeolite

  • chair:

    Chmelik, C. / Heinke, L. / Kärger, J, / Schmidt, W. / Shah, D. / van Baten J. / Krishna, R. (2008)
  • place:

    Chemical Physics Letters 459 (2008), 1–6, 141–145
  • Date: 2008

  • Chmelik, C. / Heinke, L. / Kärger, J, / Schmidt, W. / Shah, D. / van Baten J. / Krishna, R. (2008): „Inflection behaviour in the loading dependence of the Maxwell-Stefan diffusivity of iso-butane in MFI zeolite“. In: Chemical Physics Letters 459 (2008), 1–6, 141–145

Abstract

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Configurational-bias Monte Carlo simulations of the adsorption isotherm for iso-butane (iC4) in MFI zeolite shows a strong inflection at a loading T = 4 molecules per unit cell. The consequence of the isotherm inflection on the loading dependence of the Maxwell–Stefan (M–S) diffusivity, Ð, was investigated using infra-red microscopy (IRM). The experimental data show that Ð decreases nearly linearly as T is increased to 4; further increase in T results in a sharp increase in Ð, with a cusp at T = 4. Kinetic Monte Carlo (KMC) simulations are used to rationalize the experimental observations. The simulations indicate that significant inter-molecular repulsions are present for T > 4.