Mixed Matrix Membranes Incorporated with Nanosized MOF-808 Particles for Improved C₂H₄/C₂H₆ Separation

The separation of C2H4/C2H6 is crucial for the efficient production of C2H4. The energy-efficient membrane technology has great potential in this separation. However, the similar physical properties of the two molecules make them extremely difficult in membrane separation. Herein, a series of nanosized MOF-808 particles were incorporated into a polyimide matrix to fabricate mixed matrix membranes (MMMs) for C2H4/C2H6 separation. The well-defined pore architecture of MOF-808 enables effective C2H4 purification through molecular sieving, while the restricted diffusion of C2H6 molecules within the MOF-808 channels facilitates remarkable kinetic separation. Importantly, the nanosized MOF-808 can be dispersed more evenly in the polymer matrix, significantly improving the compatibility between the polymer matrix and filler, thereby maximizing the sieving effect of MOF-808. The resulting nanosized MOF-808-based MMM demonstrates a high C2H4 permeability of 1187 barrer and a C2H4/C2H6 selectivity of 2.8, which has exceeded most of the MMMs reported so far and surpassed the 2013 upper bound. Our MMMs also show excellent long-term stability and antiplasticization performance. Our work highlights the effectiveness of enhancing the separation performance of MMMs by using reducing nanosized MOF-808, providing valuable insights for the design of MMMs for C2H4/C2H6 separation.