1. Synergistic effect of molecular sieving and adsorption inhibition in MOF-based mixed matrix membranes for efficient O2/N2 separation.
- Author
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Qin, Zixian, Sun, Yuxiu, Zhang, Zhengqing, Zhang, Chenxu, Tang, Chi, Geng, Chenxu, and Qiao, Zhihua
- Subjects
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SEPARATION of gases , *MOLECULAR sieves , *MEMBRANE separation , *MOLECULAR size , *METAL-organic frameworks , *MICROPOROSITY - Abstract
A high-performance MOF-based mixed matrix membrane was constructed via incorporating o-BA modified ZIF-8 nanoparticles into PIM-1 matrices. The synergistic effect of molecular sieving and adsorption inhibition of the obtained membrane offers good chance for efficient mixed O 2 /N 2 separation. [Display omitted] • High-performance MOF-based MMMs were developed for mixed O 2 /N 2 separation. • The synergistic effect of size sieving and adsorption inhibition promotes excellent separation performance. • The modification of o-CB on the outer surface of ZIF-8 contributes to the improved interfacial compatibility. • The optimal membrane exhibits a mixed O 2 /N 2 selectivity of 8.9 with O 2 permeability of 796.5 Barrer. Oxygen/nitrogen (O 2 /N 2) separation is of great importance but faces huge challenges owing to their similar molecular size and close polarity. In this work, we construct a polymer of intrinsic microporosity (PIM-1) based mixed matrix membrane (MMM) for efficient O 2 /N 2 separation by using ZIF-8 as the sieving filler along with surface modification of o-carborane (o-CB) to strengthen selective N 2 adsorption fixation as well as polymer-filler interfaces. Markedly, the o-CB on the outer surface of ZIF-8 not only affords the requisite interfacial compatibility in molecular sieving MMMs, but also increases the diffusion difference between O 2 and N 2 by the preferential adsorption with N 2 molecules. This synergistic effect of molecular sieving and adsorption inhibition achieves efficient O 2 /N 2 diffusion differential separation. As expected, the optimal membrane with o-CB-ZIF-8 loading of 35 wt% exhibits an O 2 permeability of 796.5 Barrer and a mixed O 2 /N 2 selectivity of 8.9 with O 2 /N 2 (20:80, vol.) mixtures, exceeding the latest 2015 upper bound limits. Moreover, the according membrane module with o-CB-ZIF-8 loading of 20 wt% also displays moderate O 2 permeability of 391.7 Barrer and O 2 /N 2 selectivity of 5.5 under pressure of 1 bar. This work may provide a feasible platform for designing high-performance MOF-based membranes in air separations. [ABSTRACT FROM AUTHOR]
- Published
- 2024
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