Modeling of Diffusion in Zeolites

Keil, Frerich J.; Krishna, Rajamani; Coppens, Marc‐Olivier

doi:10.1515/revce.2000.16.2.71

Cited by 302 publications

(350 citation statements)

References 178 publications

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“…͑11͔͒, unlike the case of mesoporous materials in which the possibility of a dual transport mechanism involving gas and surface diffusions is well documented. The steric effects that cause a rapid decrease in self-diffusivities as a function of loading in micropores, 61,62 also exist in rough amorphous mesoporous materials, as we have just demonstrated. It is suggested that whenever trapping occurs in microporous or mesoporous materials, selfdiffusivities will rapidly decrease with pore loading, but transport ͑collective͒ diffusivities will be a much weaker function of pore loading.…”

Section: ͑11͒supporting

confidence: 56%

Knudsen self- and Fickian diffusion in rough nanoporous media

Malek

Coppens

2003

The Journal of Chemical Physics

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245

147

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The effect of pore surface roughness on Knudsen diffusion in nanoporous media is investigated by dynamic Monte Carlo simulations and analytical calculations. A conceptual difference is found between the roughness dependence of the macroscopic, transport diffusivity and the microscopic, self-diffusivity, which is reminiscent of diffusion in zeolites, where a similar difference arises due to adsorption effects and intermolecular interactions. Because of the dependence of the self-diffusivity on molecular residence times, self-diffusion may be roughness dependent, while transport diffusion is not. Detailed proofs are given. The differences become significant when the pore surface is rough down to molecular scales, as is the case, e.g., for many common sol-gel materials. Simulations are in good agreement with analytical calculations for several tested rough, fractal pore structures. These results are important for the interpretation of experimental diffusion measurements and for the study of diffusion-reaction processes in nanoporous catalysts with a rough internal surface.

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Section: ͑11͒supporting

confidence: 56%

Knudsen self- and Fickian diffusion in rough nanoporous media

Malek

Coppens

2003

The Journal of Chemical Physics

Self Cite

245

147

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“…Several groups have applied kinetic Monte Carlos simulations to zeolites. [26][27][28][29] For a detailed description of the kinetic Monte Carlo technique and its application to zeolites, we refer to the excellent review of Auerbach. 30 …”

Section: Kinetic Monte Carlomentioning

confidence: 99%

“…Here we only give a very short summary of the essential aspects; a more detailed discussion can be found in the literature 28,[259][260][261] The generalization of eq 35 to mixtures reads…”

Section: Multicomponent Diffusionmentioning

confidence: 99%

“…These simulations are particularly useful to obtain insight into the mechanism of diffusion. Applications of these simulations have been reviewed by Keil et al 28 A rigorous extension of transition theory beyond high loadinghasbeenproposedbyDubbeldamandco-workers. [285][286][287] In this technique one computes the free energy barrier of a tagged particle.…”

Section: Rare Event Simulations and Kinetic Monte Carlomentioning

confidence: 99%

“…The topic of diffusion in nanoporous materials is a very active area of research,andvariousreviewshavebeenpublished. 28,30,76,[255][256][257] …”

Section: Introductionmentioning

confidence: 99%

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