Yu, Hyun Jung Shin, Ju Ho Lee, Albert S. Hwang, Seung Sang Kim, Jeong-Hoon Back, Seoin Lee, Jong Suk 2024-01-19T15:30:57Z 2024-01-19T15:30:57Z 2021-09-02 2021-02-15 0376-7388 https://pubs.kist.re.kr/handle/201004/117398 Membrane-based separation technology is attractive for upgrading small-scale natural gas due to the benefits of the pressure-driven process with a small footprint. Very few carbon molecular sieve (CMS) membranes with high N-2/CH4 separation efficiency have been reported since the relationship between CMS structure and separation performance has not been fully elucidated. Here, we report the significance of controlling the effective pore size in our newly developed hybrid CMS matrix for enhanced N-2/CH4 selectivity based on experimental characterizations and density functional theory (DFT) calculations. A new class of CMS membranes with an excellent N-2/CH4 selectivity is demonstrated by pyrolysis of a homogeneous, hydrogen-bonded blend of BTDA-Durene:DABA (3:2) polyimide and ladder-structured poly(phenyl-co-3-(2-aminoethylamino)propyl)silsesquioxane (LPDA64). DFT calculations suggest that electron accumulation at SiOx phases of hybrid CMS membranes strongly hinders the diffusion of CH4 compared to N-2 due to a larger electron overlap, resulting in a smaller effective pore size. Moreover, elevating the pyrolysis temperatures enhanced the N-2/CH4 solubility selectivity due to the strong repulsive interaction between the newly formed ultramicropores with CH4. As a result, the hybrid CMS membranes showed an excellent single gas and N-2/CH4/C2H6 (20/76/4) mixed gas N-2/CH4 selectivity (28 and 16, respectively). English ELSEVIER GAS SEPARATION HYDROGEN SEPARATION SAPO-34 MEMBRANES PERFORMANCE CO2/CH4 Tailoring selective pores of carbon molecular sieve membranes towards enhanced N-2/CH4 separation efficiency Article 10.1016/j.memsci.2020.118814 1 JOURNAL OF MEMBRANE SCIENCE, v.620 JOURNAL OF MEMBRANE SCIENCE 620 scie scopus 000609142200003 2-s2.0-85093983352 Engineering, Chemical Polymer Science Engineering Polymer Science Article GAS SEPARATION HYDROGEN SEPARATION SAPO-34 MEMBRANES PERFORMANCE CO2/CH4 Carbon molecular sieve membrane N-2/CH4 separation SiOx phase DFT calculations Interaction energy