Etched ZIF-8 as a Filler in Mixed-Matrix Membranes for Enhanced CO2/N2 Separation

Graphical Filling the voids : Etched ZIF-8 (ZIF-8-E) crystals permeated by open through pores of size about 100 nm have been introduced into a polyethersulfone membrane matrix. The resulting material shows enhanced CO 2 /N 2 separation performance (see scheme). Zeolite ZIF-8 has been etched with acid to form microporous ZIF-8-E crystals. These were then introduced into a polyethersulfone (PES) membrane matrix to enhance its CO 2 /N 2 separation performance. Open through pores of size about 100 nm formed in the ZIF-8 crystals allow the ingrowth of polyethersulfone chains, ensuring a reduction in the number of nonselective voids, thereby achieving better interaction between ZIF-8-E and PES. As a result, the CO 2 /N 2 separation performance of the ZIF-8-E/PES membrane increased significantly, showing a CO 2 permeability of 15.7 Barrer and a CO 2 /N 2 ideal selectivity of 6.5.