Prediction of adsorption properties of CO2 and CH4 on DDR membrane via molecular dynamics simulation

Adsorption equilibrium for the single and binary systems of CO2 and CH4 on a DDR membrane was studied. Their adsorption isotherms on DDR membrane were simulated by Grand Canonical Monte Carlo (GCMC) simulation techniques. It was proved that the model of pure CO2 and CH4 gases adsorbed in DDR membrane can be described by Langmuir theory veraciously. Adsorption on the DDR membrane was favorable for CO2, and the competitive adsorption on DDR membrane took place in CO2-CH4 mixture with the same molar ratio of 50%. The adsorption equilibrium constants (K) of CO2 and CH4 on DDR membrane calculated at 298 K were 0.0081 kPa-1 and 0.0033(kPa)-1, respectively, which agreed with the reference results, 0.0089 kPa-1 and 0.0029(kPa)-1, indicating that the parameters used in the model of adsorption simulation were all correct.