Zeolitic imidazolate framework (ZIF)-71 nano-particles have been demonstrated as potential inorganic fillers for fabricating high-performance membranes for gas separation. The newly synthesized ZIF-71 nano-particles with a particle size of less than 100nm were compatibly incorporated in 6FDA-Durene polyimide membranes as novel mixed matrix membranes (MMMs). No obvious agglomeration between ZIF-71 nano-particles and the 6FDA-Durene matrix was observed. The effect of ZIF-71 loading on gas separation performance was investigated for H2, O2, N2, CO2, CH4, C2H4, C2H6, C3H6 and C3H8. The incorporation of ZIF-71 nano-particles improves both gas permeation properties and membrane resistance against plasticization. With a 20wt% ZIF-71 addition, the pure CO2 permeability of the MMM is increased by 3-fold, while the ideal CO2/CH4 selectivity is reduced from 16.4 to 12.8. In addition, the CO2 plasticization pressure is increased from 16atm to 30atm. The MMM embedded with 20wt% ZIF-71 also displays a remarkable enhancement of C3H6 permeability from 57.6 Barrer to 371 Barrer without significantly compromising the ideal C3H6/C3H8 selectivity. The Positron Annihilation Lifetime Spectroscopy (PALS) and gas sorption characteristics further indicate that the permeability improvement is mainly due to the enhanced diffusivity and the molecular sieving effect of ZIF-71 nano-particles for separating C3H6/C3H8.
Bibliographical noteFunding Information:
The authors would like to express their gratitude to National Research Foundation (NRF), Prime Minister׳s Office, Singapore , for its financial support on the Competitive Research Program (CRP award number: NRF-CRP-5-2009-5 ) with project entitled “New Biotechnology for Processing Metropolitan Organic Wastes into Value-Added Products” ( NUS Grant number: R-279-000-311-281 ) and the National University of Singapore (NUS) under the project entitled "Membrane research for CO 2 capture" (Grant number: R-279-000-404-133) for funding this research. The authors would also like to thank Mr. Yu Pan Tang for his valuable inputs and assistance in this work.
- Gas separation
- Mixed matrix membranes
- Molecular sieving effect
- Nano-sized ZIF-71
- Zeolitic imidazolate frameworks
ASJC Scopus subject areas
- General Materials Science
- Physical and Theoretical Chemistry
- Filtration and Separation