Perméation de gaz à travers une constriction nanoporeuse : théorie et simulations

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Submitted on 9 Nov 2016

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Perméation de gaz à travers une constriction nanoporeuse : théorie et simulations

Fouad Oulebsir, Romain Vermorel, Guillaume Galliero

To cite this version:

Fouad Oulebsir, Romain Vermorel, Guillaume Galliero. Perméation de gaz à travers une constriction

nanoporeuse : théorie et simulations. 13èmes Journéess d’études des Milieux Poreux 2016, Oct 2016,

Anglet, France. �hal-01394557�

Permeation of gas through nanoporous constrictions : theory and simulations

F. Oulebsir

, R. Vermorel

, G. Galli´ ero

a

Laboratoire des Fluides Complexes et leurs R´ eservoirs, Universit´ e de Pau et des Pays de l’Adour - Pau 64013 Cedex

Keywords: Nanoporous Materials, Transport Properties, Molecular Dynamics, Molecular Diffusion

Increasing Time / Diffusion Process

Reservoirs filled with identical, tagged LJ fluid particles

Repulsive solid wall with a microporous slit opening

Figure 1: Principle of our Molecular Dynamics numerical experiment

Fluid transport through carbon-based materials has several applications among which design of nanoporous carbons for gas separation, production of gas from shales and coal seams or geological CO2 sequestration. The determination of transport properties in such media is therefore of great interest.

In the context of carbon membranes, numerous experimental studies have reported the dependence of permeation and separation properties on thermodynamic conditions (pressure, temperature) and properties of the system (fluid species, structural properties of the membrane, etc) [1]. Recently, Botan et al. performed molecular simulations that reproduced some typical features of the experimental results found in the literature [2]. More precisely, these authors evidenced that steric effects inherent to fluid permeation through molecular size constrictions drive the overall transport properties of the membrane.

The present work focuses on molecular simulations of fluids permeating through single nanoporous constrictions. As a first approach, our molecular model consists in a monoatomic thick wall connecting two independent fluid reservoirs via a nanoporous slit (see 1). We report how permeation rates depend on several parameters, such as the size of the slit, thermodynamic conditions and the amplitude of molecular interactions. By means of simple theoretical models that reproduce our simulations data, we shed light on the range of mechanisms that rule molecular permeation through nanoporous constrictions.

We believe our results are of practical interest for the design of architectured nanoporous materials such as nanoporous graphenes.

References

[1] T. A. Centeno, A. B. Fuentes, Supported carbon molecular sieve membranes based on a phenolic resin, J. Membrane Sci., 160, 201-211 (1999).

[2] A. Botan, R. Vermorel, F. J. Ulm, R. J-. M. Pellenq, Molecular simulations of supercritical fluid permeation through disordered microporous carbons, Langmuir, 29, 9985-9990 (2013).

JEMP 2016 - Anglet, France - 12–14 Octobre 2016.