Abstract
•A free-standing porous aromatic framework membrane (PAF-97) was successfully synthesized via acid-catalyzed polymerization.•PAF-97 membrane exhibited preferential CO2 permeation with a permeance of 2.90×10−7 molm−2s−1Pa−1 and CO2/CH4 permselectivity of 22.48.•The robust membranes made of porous aromatic frameworks have a potential application of natural gas sweetening.
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 5.5bar during the separation of gas mixtures. The Young’s moduli of the membrane were 6.615GPa and 11.11GPa, either in a dry or hydrated state respectively. To be highlighted, under a feeding pressure of 3.6bar, the PAF-97 membrane rendered the permeance values of 2.90×10−7, 1.29×10−8molm−2s−1Pa−1 for CO2 and CH4, respectively, with a CO2/CH4 permselectivity of 22.48.