Effects of the side pockets on gas separation in metal-organic framework Cu-BTC: a molecular simulation study

The effects of the side pockets on gas separation in Cu-BTC were studied by performing molecular simulations on six binary mixtures in Cu-BTC with and without blocking the side pockets. The results show that the side pockets not only affect the selectivity behaviour greatly, but also enhance the selectivity significantly, particularly at pressures lower than 1.0 MPa. In addition, this work shows that the contribution of the side pockets can be related to the interactions between the adsorbate and Cu-BTC: the larger the difference in interactions of the adsorbates with Cu-BTC, the bigger the contribution of the pockets. Furthermore, this work shows that, at moderate pressures, the presence of side pockets can enhance selectivity by 30-50%, illustrating that for practical applications the presence of side pockets is beneficial for gas separation.