Sieving Effect for the Separation of C H /C H in an Ultrastable Ultramicroporous Zinc-Organic Framework.

The separation of C H from C H is one of the most challenging tasks due to the similarity of their physical properties. In addition, green synthetic protocol and adsorbent's stability are also the major concerns during the separation. Herein, under hydrothermal green synthesis conditions, an ultrastable ultramicroporous Zn-MOF was designed and synthesized with a high yield. The pore diameter of the Zn-MOF is 3.6 Å, which lies in between the diameters of C H (3.3 Å) and C H (4.2 Å) molecules, leading to an efficient separation of the C H /C H mixtures by the sieving effect. The practical separation performance of C H /C H was confirmed by the dynamic breakthrough experiments. Moreover, the high stability enables the adsorption capacity of the Zn-MOF to C H , which can be maintained under a wide range of pH (1-13). Molecular simulations were also performed to identify the different C H - and C H -binding sites in Zn-MOF.