Grand canonical Monte Carlo GCMC adsorption simulation method

The grand canonical ensemble is appropriate for adsorption systems, in which the adsorbed phase is in equilibrium with the gas at some specified temperature. The use of a computer simulation allows us to calculate average macroscopic properties directly without having to explicitly calculate the partition function. The grand canonical Monte Carlo (GCMC) method as applied in this work has been described in detail earlier (55). The aspects involving binary fluid mixtures have been described previously in our Xe-Ar work (30). 

In this study, N2 adsorption in the internal pore of single SWNH particle and on external pores of bundled SWNH particles is simulated with grand canonical Monte Carlo (GCMC) method and the simulated isotherms are compared with the experimental results. 

The absolute adsorption isotherm as a function of gas-phase fuga ity is obtained directly from molecular simulations based on the grand canonical Monte Carlo (GCMC) method. Since the difference between absolute and excess adsorption is negligible at sub-atmospheric pressure, the low-pressure portion of the absolute isotherm can adso be determined from experiment. Eq. (2) is suitable for extrapolating the absolute isotherm from low to high pressure and Eq. (3) provides the conversion to excess adsorption. Experiments are needed to test these predictions of adsorption at high pressure. 

Up to now, numerous studies have been conducted on their synthesis [9,10], treatment [5,13] and physical properties [4], However only limited number of studies has been carried out on die adsorption of gas in CNTs, including experimental works [8,11] and molecular simulations [3,7,14-lS]. Adsorption behavior depends strongly on the microporous structure of the particular adsorbent. In this work the effect of pore size on the adsorption behavior is of interest. The adsorption equilibria of methane, ethane and their mixture into SWNTs were studied by using a Grand Canonical Monte Carlo (GCMC) method. We reported equilibrium isotherms of methane and ethane, and the selectivity from their equimolar mixture. 

Adsorption is modelled by Grand Canonical Monte Carlo (GCMC) fiill details of flie method and simulation protocols may be fi)und elsewhere [2]. By flying Grand Canonical molecular dynamics (GCMD) [8] to the model solid in an initially evacuated state, the pore throats in T passed through and pores in II accased by the fluids are also identified. 

This molecular simulation study focuses on the adsorption of water in mesoporous Vycor-like silica glasses, which are of great interest for geophysics, pharmaceutics, industry, or environment. The adsorbent was previously constructed by off-lattice methods to mimic the micro- and meso-textural properties of real Vycor. Whereas most of the previous studies focused on the dynamical or structural properties of confined water this one focuses on the thermodynamic properties which are actually essential prior to a molecular dynamics study for instance (to equilibrate the initial configuration). The Grand Canonical Monte Carlo (GCMC) method has... 

To capture more accurately the behavior of the adsorbates in micropores, it is often necessary to model them as non-spherical molecules with electrostatic interactions. Given the limited capabilities of DFT in this context, molecular simulation based on the Grand Canonical Monte Carlo (GCMC) technique has been established for the generation of adsorption isotherms in carbons [15,16, 17] and the determination of PSDs [18, 19, 20, 21, 22,23, 24, 25, 26]. A review on both methods is given in [27]. 

Simulation of adsorption has been performed in various ensembles canonical, grand canonical, isobaric-isothermal, and Gibbs ensemble. The choice of the ensemble depends on the nature of the investigated system and the aim of the simulations. In the case of adsorption on heterogeneous surfaces, usually the grand canonical Monte Carlo simulation method (GCMC) has been used. 

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