Effects of Adsorbent Deformation on the Adsorption of Gases in Slitlike Graphitic Pores: A Computer Simulation Study

Abstract

We present GCMC simulations of adsorption of argon in slitlike pores that can swell or shrink with adsorbate loading due to movement of the graphene layers. It is found that the shrinking or swelling depends on loading, pore size, and temperature. The complex functional dependence is illustrated by adsorption in slit pores of various sizes at a number of temperatures. For pores where the adsorbate layers are not commensurate with pore width, for example when the pore width is 8A, shrinkage is observed under subcritical conditions, while shrinkage followed by swelling occurs under supercritical conditions under extremely high external pressure. However for commensurate pores that can accommodate an integer number of layers under normal conditions, for example when the pore width is 10A, we observe only modest swelling at high pressures. For both sub- and supercritical conditions the dependence on loading is quite complex. When these results are compared with the equivalent rigid pores, we find that the difference in adsorption capacity, molar enthalpy of the adsorbed phase, and solvation pressure is significant only at high pressures under supercritical conditions. Under normal adsorption conditions, a rigid pore model should be a good approximation to the deformable model investigated here.

Solid deformation induced by the adsorption of methane and methanol under sub- and supercritical conditions

“…In this work we have studied solid deformation by carrying out GCMC simulations using a model of deformable graphitic slitshaped pores proposed by Do et al [21]. The change in the pore Distance (A) 9 1 0 1 1 1 2 1 3 1 4…”

“…Recent theoretical and computer simulation studies have seen a renewed interest in exploring the basic molecular mechanisms underlying this phenomenon [21,22]. Dergunov et al [23] have developed a model describing the elastic adsorption deformation of microporous adsorbents.…”

“…In this work we employed the model of deformable graphitic slit pores that was first proposed by Do et al [21] and applied Monte Carlo simulations [30] to study solid deformation induced by gas adsorption. This model was first applied to explore how swelling and shrinkage can affect the adsorption of argon in graphitic slit pores [21].…”

“…This model was first applied to explore how swelling and shrinkage can affect the adsorption of argon in graphitic slit pores [21]. In this paper we extend the application of this model to adsorbates with more complicated structures namely: methane (non-polar fluid) and methanol (polar fluid) with the intention of gaining more insight into the basic mechanism of solid deformation.…”

Adsorption-induced deformation of nanoporous materials—A review

“…A number of papers employed molecular modeling techniques for predictions of adsorption-induced strains in various nanoporous materials: Monte Carlo simulations 40,[81][82][83][84][85][86][87][88][89][90][91][92] or classical density functional theory (DFT). [93][94][95][96] At the same time, several purely analytical theories were also proposed.…”