Nonequilibrium molecular dynamics simulation of transport and separation of gases in carbon nanopores. I. Basic results

We present the results of extensive nonequilibrium Molecular Dynamics simul ations of transport of a binary gas mixture of CO2 and CH4 through a carbon nanopore, in the presence of an external chemical potential or concentrati on gradient. The CH4 molecules are represented as Lennard-Jones (LJ) hard s pheres, while the CO2 molecules are modeled both as LJ hard spheres, as wel l as three-site linear structures to account for their quadrupole moments. The effect of the various factors, including the structure of the pore wall s, temperature, feed composition, and the molecular models and their parame ters, on the transport, adsorption, and separation of the gases is investig ated in detail. While the structure of the pore walls has virtually no effe ct on the separation factor, the temperature of the system, the pore size, and the molecular models and their parameters strongly influence it. (C) 19 99 American Institute of Physics. [S0021-9606(99)70631-8].