A kinetic Monte Carlo study was made of the diffusion of linear n-hexane (nC6) and 2,2-dimethylbutane (22DMB) mixtures in silicalite. An investigation was made of the loading dependences of single-component self- and corrected diffusivities of nC6 at 300K. Anisotropic transition rates were implemented to account for the distribution of the molecules within the zeolite framework. Repulsive guest-guest interactions were modeled using the parameter introduced by Reed and Ehrlich (1981). The results were in good agreement with experimental quasi-elastic neutron scattering data (Jobic et al., 2006), although the influence of the adsorption isotherm inflection was not reproduced. A binary diffusion study of nC6/22DMB mixtures was performed by implementing the nC6 transition rates used for the single component study while 22DMB molecules propagated via intersection-intersection hops. This kinetic Monte Carlo model allowed for differing saturation capacities and accounted for interactions between molecules by introducing fij parameters. The results revealed the large impact of guest-guest interactions between nC6 and 22DMB upon both self- and corrected diffusivities of the two components. Molecule-size effects were found to be predominant near to 22DMB saturation capacity.

Kinetic Monte Carlo Study of Binary Diffusion in Silicalite. N.Laloué, C.Laroche, H.Jobic, A.Méthivier: Adsorption, 2007, 13[5-6], 491-500