Experimental and computer simulation studies of the removal of carbon dioxide from mixtures with methane using AlPO4-5 and MCM-41

The selective adsorption of carbon dioxide-methane mixtures in AlPO4-5 and MCM-41 materials have been studied using gas chromatography mass spectromet ry and Grand Canonical Monte Carlo computer simulations. AlPO4-5 and MCM-41 are molecular sieves consisting of uniform arrays of unidimensional pore c hannels. The materials were shown to be selective for carbon dioxide under all conditions studied. There was qualitative agreement between experimenta l and simulation adsorption and selectivity data. Any discrepancies that we re observed were attributed to the effect of pore blocking by adsorbate mol ecules, which was not accounted for in the simulation model. In the case of MCM-41, quantitative differences in selectivity were the result of the sim plistic models of MCM-41 used in the simulations. Partial interaction poten tial models were used in Monte Carlo calculations to determine the factors that effect carbon dioxide selectivity over methane. Molecular shape and fl uid-wall interactions were found to have a significant effect on selectivit y, while electrostatics were less important.