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Article Dans Une Revue Journal of Colloid and Interface Science Année : 2007

Thermal effects during adsorption of n-butane on a slilicalite-1 membrane. A non-equilibrium molecular dynamics study

Résumé

Non-equilibrium molecular dynamic (NEMD) simulations have been used to study the kinetics of adsorption of n-butane molecules in a silicalite membrane. We have chosen this simple well-known process to demonstrate that the process is characterized by two stages, both non-isothermal. In the first stage the large chemical driving force leads to a rapid uptake of n-butane in all the membrane and a simultaneous increase in the membrane temperature, explained by the large enthalpy of adsorption, H =−61.6 kJ/mol butane. A diffusion coefficient for transport across the external surface layer is calculated from the relaxation time; a value of 3.4×10−9 m2/s is found. During the adsorption, a significant thermal driving force develops across the external surface of the membrane, which leads to an energy flux out of the membrane during the second stage. In this stage a thermal conductivity of 3.4 × 10−4 W/Km is calculated from the corresponding relaxation time for the surface, confirming that the thermal conduction is the rate-limiting step. The aim of this paper is to demonstrate that a thermal driving force must be taken into account in addition to a chemical driving force in the description of transport in nano-porous materials.
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Dates et versions

hal-00454049 , version 1 (07-02-2010)

Identifiants

  • HAL Id : hal-00454049 , version 1

Citer

Isabella Inzoli, Jean-Marc Simon, Signe Kjelstrup, Dick Bedeaux. Thermal effects during adsorption of n-butane on a slilicalite-1 membrane. A non-equilibrium molecular dynamics study. Journal of Colloid and Interface Science, 2007, 313, pp.563. ⟨hal-00454049⟩
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