GCMC 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). 

The NLDFT and GCMC methods can be carried out to obtain a set of local isotherms for pores of different widths. The PSD is obtained by solving the GAI equation (Equation 4.28) in its discrete form ... 

Some examples where the authors apply the GCMC method for determining the PSD on different carbon materials can be found in the literature [67-75], However, the DFT method is more used than the GCMC one, because the DFT method is included in the software of commercial adsorption apparatuses. 

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. 

Molecular simulation has now become powerfrd means for the study of adsorbed molecules in high silica zeolites, and GCMC method is especially useful for predicting adsorption equilibria. However, information on forcefield parameters and charges are often inadequate, even in systems where the structure is well known. 

Cerius2 (MSI Inc.) was used throughout the simulations. Adsorption equilibria was carried out by GCMC method for same systems of experiments. Adsorbent model was pure silicious Y type that was same type as experimental adsorbent. Simulation forcefield parameters were new forcefield parameter obtained by Mellot et al l Solvent charges were determined with Charge-Equilibration method, respectively. 

In this study, equilibria were measured using fixed-bed adsoiption experiment. Molecular simulations by GCMC method did not go much welly Furthermore, examination is required. 

The adsorption equilibria were measured using a gravimetric method and were expressed as isotherms. A chromatographic method was used to get the initial slope of the isotherms. In the simulation, GCMC method was used to calculate amounts adsorbed for various conditions. When the experiment result and simulation result of chloroform are compared, the simulation for the acid site model was most agreement with chromatographic data and baratron data. The simulation result of tetrachloroethylene with three models corresponded mostly for the non-polar molecule, and above all the acid site model was the closest to the experiment result. Therefore, to get better coincidence between experimental data and simulation, it was found to be necessary to account for aluminum rather than silanol nest. 

The adsorption equilibria of methane, ethane and their mixture into single-walled carbon nanotuhes (SWNTs) were studied by using a Grand Canonical Monte Carlo (GCMC) method. The equilibrium isotherms of methane and ethane and the selectivity from their equimolar mixture were reported. 

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. 

In the work of Rowley et al. [1-3], the grand canonical Monte Carlo (gcmc) method was used to simulate Ar interacting with graphite. The surface was approximated as a continuum. In such a case, the sum in Eqn (4.3) is replaced by an integral in the x, y, and z dimensions (the graphite solid) and the potential reduces to a L-J 9-3 form that is a function only of the distance of the atom... 

The DFT and GCMC methods have been increasii y applied by many to derive the effective PSDs for carbons [15, 25, 114—131]. Most of these works use nitrogen at 77 K and argon at 87.3 K. 

Grand Canonieal Monte Carlo (GCMC) methods to aehieve equilibrium eonfigurations. for example in the simulation of adsorption. 

Fixed-bed adsoiption experiments of laboratory-scale were earned out to remove organic solvent vsptsis by several types of adsorbents. Binaiy adsoiption equilibria of azeotropic mixture-HSZ systems showed two azeotropic points. Those experiment data were compared with molecular simulation by the Grand Canonical Mtmte Cairo (GCMC) method. Experimental results for single and binary component system, including azeotropic mixture systems, could not be in agreement with the similation result correlated satisfoctorily. But it turns out that the tendency of the simulation result is the same as the experiment result... 

The grand canonical Monte Carlo (GCMC) method was applied to calculate adsorption equilibria of mediane, ethane and dieir mixture. At low pressure small pores filled rapidly due to strong wall potentials. The selectivity strongly depended on pressure and pore width. 

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