Grand canonical Monte Carlo simulations of adsorption of mixtures of xylene molecules in faujasite zeolites

The selective adsorption of xylene isomers in sodium Y faujasite has been studied by grand canonical Monte Carlo simulation. Biased particle insertions and deletions were implemented to allow simulation of the adsorption of such complex molecules. For mixtures, a new method including orientational biased swap moves was proposed. Such algorithms were found to improve the efficiency significantly. m-Xylene was found to be adsorbed preferentially and the p-xylene/m-xylene selectivity predicted from the simulations was in good agreement with experiment. A detailed structural analysis of the adsorbed phases is presented.