TY - JOUR
T1 - Improving Ethane/Ethylene Separation Performance under Humid Conditions by Spatially Modified Zeolitic Imidazolate Frameworks
AU - Luo, Dong
AU - Peng, Yun Lei
AU - Xie, Mo
AU - Li, Mian
AU - Bezrukov, Andrey A.
AU - Zuo, Tao
AU - Wang, Xue Zhi
AU - Wu, Yuan
AU - Li, Yan Yan
AU - Lowe, Alexander R.
AU - Chorążewski, Mirosl̷aw
AU - Grosu, Yaroslav
AU - Zhang, Zhenjie
AU - Zaworotko, Michael J.
AU - Zhou, Xiao Ping
AU - Li, Dan
N1 - Publisher Copyright:
© 2022 American Chemical Society
PY - 2022/3/9
Y1 - 2022/3/9
N2 - Gas separation performances are usually degraded under humid conditions for many crystalline porous materials because of the lack of water stability and/or the competition of water vapor toward the interaction sites (e.g., open metal sites). Zeolitic imidazolate frameworks (ZIFs) are suitable candidates for practical applications in gas separation because of their excellent physical/chemical stabilities. However, the limitation of substituent positions in common ZIFs has prevented extensive pore engineering to improve their separation performance. In a type of gyroidal ZIFs with gie topology, the Schiff base moiety provides additional substituent positions, making it possible to modify the spatial arrangement of hydrophobic methyl groups. Herein, a new gyroidal ZIF, ZnBAIm (H2BAIm = 1,2-bis(1-(1H-imidazol-4-yl)ethylidene)hydrazine), is designed, synthesized, and characterized. The spatially modified ZnBAIm exhibits improved thermal/chemical/mechanical stabilities compared to ZnBIm (H2BIm = 1,2-bis((5H-imidazol-4-yl)methylene)hydrazine). ZnBAIm can remain intact up to about 480 °C in a N2 atmosphere and tolerate harsh treatments (e.g., 5 M NaOH aqueous solution at room temperature for 24 h and 190 MPa high pressure in the presence of water). Moreover, the modified pore and window sizes have improved significantly the ethane/ethylene selectivity and separation performance under humid conditions for ZnBAIm. Breakthrough experiments demonstrate efficient separation of a C2H6/C2H4 (50/50, v/v) binary gas mixture under ambient conditions; more importantly, the C2H6/C2H4 separation performance is unaffected under highly humid conditions (up to 80% RH). The separation performance is attributed to combined thermodynamic (stronger dispersion interaction with C2H6 than with C2H4) and kinetic factors (diffusion), determined by density functional theory calculations and kinetic adsorption study, respectively.
AB - Gas separation performances are usually degraded under humid conditions for many crystalline porous materials because of the lack of water stability and/or the competition of water vapor toward the interaction sites (e.g., open metal sites). Zeolitic imidazolate frameworks (ZIFs) are suitable candidates for practical applications in gas separation because of their excellent physical/chemical stabilities. However, the limitation of substituent positions in common ZIFs has prevented extensive pore engineering to improve their separation performance. In a type of gyroidal ZIFs with gie topology, the Schiff base moiety provides additional substituent positions, making it possible to modify the spatial arrangement of hydrophobic methyl groups. Herein, a new gyroidal ZIF, ZnBAIm (H2BAIm = 1,2-bis(1-(1H-imidazol-4-yl)ethylidene)hydrazine), is designed, synthesized, and characterized. The spatially modified ZnBAIm exhibits improved thermal/chemical/mechanical stabilities compared to ZnBIm (H2BIm = 1,2-bis((5H-imidazol-4-yl)methylene)hydrazine). ZnBAIm can remain intact up to about 480 °C in a N2 atmosphere and tolerate harsh treatments (e.g., 5 M NaOH aqueous solution at room temperature for 24 h and 190 MPa high pressure in the presence of water). Moreover, the modified pore and window sizes have improved significantly the ethane/ethylene selectivity and separation performance under humid conditions for ZnBAIm. Breakthrough experiments demonstrate efficient separation of a C2H6/C2H4 (50/50, v/v) binary gas mixture under ambient conditions; more importantly, the C2H6/C2H4 separation performance is unaffected under highly humid conditions (up to 80% RH). The separation performance is attributed to combined thermodynamic (stronger dispersion interaction with C2H6 than with C2H4) and kinetic factors (diffusion), determined by density functional theory calculations and kinetic adsorption study, respectively.
KW - CH/CH separation
KW - dispersion interaction
KW - hydrophobicity
KW - thermal/chemical/mechanical stabilities
KW - zeolitic imidazolate framework (ZIF)
UR - http://www.scopus.com/inward/record.url?scp=85125919736&partnerID=8YFLogxK
U2 - 10.1021/acsami.2c00118
DO - 10.1021/acsami.2c00118
M3 - Article
C2 - 35191666
AN - SCOPUS:85125919736
SN - 1944-8244
VL - 14
SP - 11547
EP - 11558
JO - ACS Applied Materials and Interfaces
JF - ACS Applied Materials and Interfaces
IS - 9
ER -