ZIF-8 nanoplate/6FDA-DAM membrane for hydrogen extraction from propane dehydrogenation process

• Published in: Journal of membrane science 2023-11, Vol.685, p.121952, Article 121952
• Main Authors: Kim, Minsu, Yoo, Sungmi, Kwon, Ohchan, Choi, Eunji, Choi, Wooyoung, Ji, Hyungjoon, Won, Jong Chan, Kim, Yun Ho, Kim, Dae Woo
• Format: Article
• Language: English
• Subjects: Hydrogen separation; Mixed matrix membrane; Nanoplate; Propane dehydrogenation; Zeolitic imidazolate framework
• ISSN: 0376-7388
• DOI: 10.1016/j.memsci.2023.121952

High-aspect ratio materials can enhance gas separation performance compared to low-aspect ratio materials when incorporated into a polymer matrix to form mixed matrix membranes (MMMs). However, the filler shape effect on various properties of MMMs was not thoroughly discussed. Herein, we fabricated a mixed matrix membrane with two different shapes of metal-organic framework (MOF) and examined the MOF filler shape effect on mechanical, thermal, and gas separation properties. Zeolitic imidazolate framework-8 nanoplates (NZIF-8) were synthesized by conversion method with an aspect ratio of 20. Isotropic ZIF-8 particles (IZIF-8) were also synthesized, and both fillers were hybridized with a 6FDA-DAM (PI) polymer. 20 wt% NZIF-8/PI membrane exhibited high mechanical properties of 0.282 GPa for hardness and 3.5 GPa for modulus, which is higher than that of IZIF-8/PI membranes. The membrane was stable in high temperatures which is comparable to the pristine PI membrane, showing long-term thermal stability at 300 °C. Furthermore, high aspect ratio fillers allowed significant enhancement in hydrogen separation performance, showing hydrogen permeability of around 1800 Barrer with hydrogen/propane selectivity of 260 at 20 wt% ZIF-8 nanoplate loading, which is much enhanced than the membrane with isotropic ZIF-8 particles. The separation performances were consistent in ternary mixture separation under different conditions. These highly stable and selective properties can be promising for hydrogen extraction from the propane dehydrogenation process. [Display omitted] •Zeolitic Imidazolate Framework-8 nanoplates (NZIF-8) were synthesized by conversion method.•ZIF-8/6FDA-DAM (PI) mixed matrix membranes were fabricated with ZIF-8 fillers with different shapes.•Compared to IZIF-8, NZIF-8/PI MMM showed better mechanical properties with high thermal stability up to 300 °C.•Gas separation tests were performed under various proportions of the ternary gas mixture, which is similar to the PDH process.•20 wt% NZIF-8/PI MMM showed excellent separation performance with H2 permeability of 1451 Barrer and H2/C3H8 separation factor of 283.