The structural properties and transport properties of electrolyte solutions are investigated by smart Brownian dynamics simulation based on the primitive model. To test the simulation program, the radial distribution functions of ions g+−(r) and g++(r) for KCl solution are calculated and compared with the results of previous simulations. And then, the effects of ions diameter and concentration on the structural properties and transport properties of electrolyte solution at 298K are extensively simulated. The results indicate that both the radial distribution function and the self-diffusion coefficient are more sensitive to the ion size than salt concentration. As the radius ratio of cation to anion increases, self-diffusion coefficients of both cation and anion become larger.

In this paper, the separation of binary gas mixture carbon monoxide and hydrogen using single-walled carbon nanotubes (SWNTs) is studied by grand canonical Monte Carlo (GCMC) simulation. All of the particle–particle interactions between hydrogen, carbon monoxide and carbon are modeled with Lennard–Jones potential. Widom test particle method in NVT ensemble is used in determining chemical potentials of the two components of the fluid. It can be concluded from the adsorption isotherms at 293.15Kthat the selectivity of carbon monoxide decreases with the increase of the bulk pressure. In the adsorption isostatics at 0.157MPa, the selectivity has a maximum along with the increase of temperature. However, to given pressure and temperature, the selectivity fluctuates violently with different van der Waals (VDW) distances or diameters of carbon nanotubes. For example, at 0.157MPa, 293.15 K, diameter of 0.892 nm and VDW distance of 1 nm, with the feed containing hydrogen and carbon monoxide both 50 mol%, carbon monoxide could be enriched up to 98 mol% in the adsorbate, so that the selectivity comes to 60. It can be indicated that carbon nanotube, as a novel material developed in the past 10 years, can make a very effective separation tool of certain gas mixtures.

Hydrogen storage in single-walled carbon nanotubes (SWNTs) is studied by grand canonical Monte Carlo (GCMC) simulation. Hydrogen-hydrogen and hydrogen-carbon interactions are both modeled with Lennard-Jones potential. Hydrogen-carbon interactions are integrated over the whole nanotube to get molecule-tube interactions. Three adsorption isotherms of di3erent diameters at 293:15 K, one adsorption isostatics at 2:66 MPa with radius of 0:587 nm, the amount of adsorption as a function of van der Waals (VDW) distance of nanotubes with the three diameters at 3 MPa (where the VDW distance is de-<ned as the distance between the walls of the nearest neighbor tubes in the bundle, as measured from the carbon centers) and the adsorption as function of continuously changing diameter are displayed. Finally, the in>uences of pressures, temperatures, the diameters and VDW distances of SWNTs on adsorption are discussed.

The solubilities of oxygen in 0.2, 0.5, 0.7 and 1.0MNa2CO3 solution have been measured at 300.15K and under pressures up to 10MPa using a magnetically stirred autoclave and a direct sampling technique. The accuracy of apparatuswas verified by duplicating the solubility of oxygen in purewater in literature. The experimental data of the solubility of oxygen in aqueous sodium carbonate solution were shown that the solubility of oxygen increases with increasing pressure and decreases with increasing salt concentration due to salting-out effect. The experimentally measured data were satisfactorily compared with the predicted values by our model based on non-primitive mean spherical approximation (MSA) and perturbation theory.

Because of the increasing interest in studying the phenomenon exhibited by charge-stabilized colloidal suspensions in confining geometry, we present a density functional theory (DFT) for a hard-core multi-Yukawa fluid. The excess Helmholtz free-energy functional is constructed by using the modified fundamental measure theory and Rosenfeld’s perturbative method, in which the bulk direct correlation function is obtained from the first-order mean spherical approximation. To validate the established theory, grand canonical ensemble Monte Carlo (GCMC) simulations are carried out to determine the density profiles and surface excesses of multi-Yukawa fluid in a slitlike pore. Comparisons of the theoretical results with the GCMC data suggest that the present DFT gives very accurate density profiles and surface excesses of multi-Yukawa fluid in the slitlike pore as well as the radial distribution functions of the bulk fluid. Both the DFT and the GCMC simulations predict the depletion of the multi-Yukawa fluid near a nonattractive wall, while the mean-field theory fails to describe this depletion in some cases. Because the simple form of the direct correlation function is used, the present DFT is computationally as efficient as the mean-field theory, but reproduces the simulation data much better than the mean-field theory.