(518b) Tailoring Molecular Structures of Hybrid Carbon Molecular Sieve Membranes for Natural Gas Processing

Carbon molecular sieve (CMS) membranes are promising for excellent gas separation performance owing to their peculiar bimodal pore size distribution consisting of ultramicropores (pore diameter (d) < 0.7 nm) and micropores (0.7 nm < d < 2 nm). However, separating N₂/CH₄ mixture is still challenging because the relationship between CMS structure and N₂/CH₄ separation efficiency is poorly understood. In this presentation, I will report highly N₂-selective hybrid carbon molecular sieve (CMS) membranes fabricated by pyrolyzing rationally designed polyimide (PI) and ladder-structured polysilsesquioxane (LPSQ) blends [1]. The N₂/CH₄ single gas and N­₂/CH₄ mixed gas separation properties of CMS PI/LPSQ membranes are demonstrated by varying the PI/LPSQ ratios as well as pyrolysis temperatures. Furthermore, the effect of the SiO_x phases in hybrid CMS membranes on the N₂/CH₄ separation properties is elucidated using DFT calculations.

[1] H.J. Yu, J.H. Shin, A.S. Lee, S. S. Hwang, J.-H. Kim, S. Back, J. S. Lee. Tailoring selective pores of carbon molecular sieve membranes towards enhanced N₂/CH₄ separation efficiency. J. Membr. Sci. 620 (2021) 118814.