Grand canonical Monte Carlo simulation of methane adsorbed in layered pillared pores

The phase behavior of methane confined in layered pillared pores has been simulated by using the grand canonical Monte Carlo (GCMC) method. In our simulation, the layered pillared pore is modeled by the approach of Yi et al. (X. Yi, K. S. Shing and M. Sahimi, Chem. Eng. Sci., 1996, 51, 3409) with uniform distribution of pillars between two solid walls. In the simulation, methane is described as a spherical Lennard-Jones molecule, and Steele's 10-4-3 potential is used to represent the interaction between methane and a layered solid wall. The site-site interaction is also used to calculate the interaction between methane and the pillars. We report the simulation results at three low temperatures, T=74.05, 103.67 and 148.1 K with three different pore widths (h sigma (p)=1.02, 1.70 and 2.38 nm). The adsorption isotherms and local density profiles are obtained. The hysteresis loop and capillary condensation of methane confined in layered pillared pores are observed, providing a good insight into the phase behavior of confined methane. In addition, the adsorption of methane in layered pillared pores at ambient temperature (T=300 K) is presented. Based on the simulation results at various porosities and different pore widths, the layered pillared pore with porosity of psi =0.94 and pore width h sigma (p)=1.02 nm is recommended as an adsorption storage material for methane at ambient temperature, thus demonstrating that the GCMC method is a useful tool for the design of layered pillared materials.