巴勒
膜
聚酰亚胺
气体分离
选择性
碳化
分子筛
化学工程
微型多孔材料
材料科学
热解
磁导率
高分子化学
化学
有机化学
纳米技术
吸附
催化作用
工程类
图层(电子)
生物化学
作者
Shan Xu,Ning Zhao,Lei Wu,Shuanyan Kang,Zhiguang Zhang,Guolong Huo,Zhongde Dai,Nanwen Li
标识
DOI:10.1016/j.memsci.2022.120781
摘要
Tuning the relationship between the microporous structure of carbon molecular sieve (CMS) membranes and the corresponding gas permeability performance enables optimization for gas separation applications. The pre-crosslinked structure of the precursor plays a key role in improving the performance of the CMS membrane. Herein, the thermally crosslinkable brominated 6FDA-based polyimide (BMPI) by debromination is prepared and selected as the precursor to fabricate high performance CMS gas separation membranes. By heat-treating the BMPI membrane at 350 °C for 10 h, the debromination-induced crosslinking exhibited higher permeability over the uncrosslinked precursors, as it forms a pre-crosslinked structure that is more stable at 550 °C. A representative BMPI-350/10h-550 °C CMS membranes pyrolyzed at 550 °C had CO2 and O2 permeabilities of 11169 and 2182 Barrer with a CO2/CH4 and O2/N2 ideal selectivity of 26.5 and 5.4. These values are much higher than that of the un-crosslinkable precursor (6FDA-DAM) derived CMS membrane (PCO2 = 3465, αCO2/CH4 = 21.1). Even at the high carbonization temperature of 800 °C, the as-obtained CMS membrane still show a promising CO2 permeability of 1119 Barrer and a CO2/CH4 ideal gas selectivity of 41.2. Importantly, the excellent gas separation performance of CMS membranes obtained in this work exceeds the Robeson's upper-bound. This work outlines a new protocol to tailor CMS membrane microstructures to meet high permeability performance needs. These CMS membrane materials hold great potential in corrosive natural gas purification applications.
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