Adsorption of CO2/CH4 and CO2/N2 mixtures in SBA-15 and CMK-5 in the presence of water: A computer simulation study

Adsorption of CO2/CH4 and CO2/N-2 gas mixtures in SBA-15 and CMK-5 is studied by Grand Canonical Monte Carlo. Simulations are carried out at 298K for pressures up to 50 atm in dry adsorbents and in the presence of preadsorbed water (3.5 or 11.1 mmol/g). Effects of preadsorbed water on adsorption of gas mixtures are different for hydrophilic and hydrophobic porous materials. For SBA-15 the presence of water has a negative effect on adsorption, significantly reducing both the adsorption capacity and selectivity to carbon dioxide. By contrast, in CMK-5 the capacity and selectivity increase with increasing content of preadsorbed water. The behavior of gas capacities in moist adsorbents is largely determined by adsorption in the mesoporous regions of the pore space, while the selectivities can be affected by adsorption in micropores of SBA-15 and in inter-pore spaces of CMK-5. (C) 2015 Elsevier B.V. All rights reserved.