A GRAND-CANONICAL MONTE-CARLO STUDY OF LENNARD-JONES MIXTURES IN SLITSHAPED PORES

The grand-canonical Monte Carlo (GCMC) technique has been used for sim ulating the adsorption of mixtures in slit pores with graphite propert ies. Spherical Lennard-Jones models were used to model methane and eth ane at super critical temperatures. A GCMC algorithm for mixtures whic h included attempts to change identities of particles was found to be more effective than conventional GCMC. Results were compared with dens ity functional theory (DFT) calculations of Tan and Gubbins (1992; J. phys. Chem., %, 845) and with ideal adsorbed solution theory (IAST) is otherms derived from single component data. Our simulation results wer e found to agree qualitatively rather than quantitatively with the DFT mixture results, the IAST was found to work well for the system studi ed. Adsorption selectivity was found to depend on packing consideratio ns as well as the relative potential well depths of the adsorbate wall interactions.