Polyimide-derived carbon molecular sieve membranes for high-efficient hydrogen purification: The development of a novel phthalide-containing polyimide precursor

• Published in: Separation and purification technology 2022-11, Vol.301, p.121982, Article 121982
• Main Authors: Hou, Mengjie, Li, Lin, Song, Jing, Xu, Ruisong, He, Zilong, Lu, Yunhua, Pan, Zonglin, Song, Chengwen, Wang, Tonghua
• Format: Article
• Language: English
• Subjects: CMSM; Gas separation membrane; H2 purification; Polyimide; Pyrolysis
• ISSN: 1383-5866; 1873-3794
• DOI: 10.1016/j.seppur.2022.121982

•A novel phthalide-containing polyimide precursor was synthesized and employed to prepare the CMSMs for hydrogen purification.•The structural evolution from precursor to CMS was investigated.•The H2 separation performance of CMSMs was optimized by the pyrolysis temperature.•The optimized CMSMs show a high H2 permeability with superior H2 separation property. Hydrogen-based economy has been considered as a potential solution for energy security and sustainability in the future. And the ever-increasing demand for high-purity hydrogen (H2) provides an urgent force for the H2 purification technologies. Herein, a novel polyimide (BATPPP-6FDA) with rigid and contorted structure was synthesized and used as a precursor to fabricate the carbon molecular sieve membranes (CMSMs) for H2 purification. The structural changes from precursor to CMS were detected and the H2 separation performance of the membranes was optimized by the pyrolysis temperature. The CMSM pyrolyzed at 550 °C exhibited the highest H2 permeability of 10054.1 Barrer and moderate H2 permselectivity due to its highly disordered and turbostratic carbon structure originated from the generally decomposition of thermally labile -CF3 groups and the lactone rings of phthalide structure in the early stages (