Studies on adsorption behavior of benzene and propylene in MCM-22 by grand canonical Monte Carlo simulation

The adsorption behavior of benzene and propylene in MCM-22 zeolite was studied by grand canonical Monte Carlo(GCMC) simulations. From the mass clouds of GCMC simulations, it can be found that the benzene and the propylene molecules show different adsorption behavior in the zeolite cavities. Both benzene and propylene molecules were mainly adsorbed in the 10-MR channels and the 12-MR supercages. But obviously, propylene has higher localization than that of benzene. Besides the two localizations, propylene can be steadily located in the short 10-MR windows interconnecting the 12-MR supercages, while the benzene can not do. From the potential energy distribution, it can be seen that both benzene and propylene have two-pinked and the potential energy of propylene is higher than that of benzene, so benzene can be adsorbed more steadily than propylene. When the temperature rises from 298 K to 443 K, the numbers of propylene reduce significantly, while benzene changes little. When benzene and propylene were adsorbed in zeolite at the same time, they have competitive adsorption, therefore the potential energy distribution is changed obviously. The adsorption isotherms of benzene and propylene at different temperatures and 1 x 10(-3) - 5.0 kPa were simulated, the loadings of propylene are significantly lower than those of benzene.