Fabrication of triazine-based Porous Aromatic Framework (PAF) membrane with structural flexibility for gas mixtures separation

A transparent, freestanding Porous Aromatic Framework-97 (PAF-97) membrane was successfully synthesized via a one-step acid-catalyzed reaction. Due to the introduction of ether groups, the obtained PAF-97 membrane possesses enhanced structural flexibility, thus increasing the flexibility of the resulting membrane. This is proofed by the fact that the feeding pressure of the membrane reaches as high as 5.5 bar during the separation of gas mixtures. The Young's moduli of the membrane were 6.615 GPa and 11.11 GPa, either in a dry or hydrated state respectively. To be highlighted, under a feeding pressure of 3.6 bar, the PAF-97 membrane rendered the permeance values of 2.90 × 10−7, 1.29 × 10−8 mol m−2 s−1 Pa−1 for CO2 and CH4, respectively, with a CO2/CH4 permselectivity of 22.48.