Adsorption of xylene isomers in MOF UiO-66 by molecular simulation

This work presents results of molecular simulations on adsorption of mixtures of the four xylene isomers in the porous zirconium terephthalate UiO-66. The grand-canonical Monte Carlo simulations (GCMC) are compared to multi-component adsorption equilibrium data obtained by breakthrough experiments. Four different force fields for the xylenes were evaluated. The simulations confirm that the experimentally observed ortho-selectivity is preferential in relation to the other isomers. Additionally, it was found that there is a competition between the other three isomers (para-xylene, meta-xylene and ethylbenzene) for adsorption in the UiO-66 structure. Molecular simulation is applied as a powerful research tool in predicting adsorption equilibrium properties of potential adsorbent candidates for xylene isomers mixtures that are essential for the development of adsorption based separation processes. (C) 2014 Elsevier Inc. All rights reserved.