Abstract
Nanocage-like, hollow ZIF-8 (H-ZIF) polyhedral nanocrystals were synthesized via the use of seed crystals, epitaxial ZIF-8 growth, and excavation of ZIF-67 sacrificial templates. The highly porous and hollow structure of the H-ZIF polyhedral nanocrystals was confirmed by field-emission scanning electron microscopy (FE-SEM), transmission electron microscopy, energy-dispersive X-ray spectroscopy, X-ray diffraction (XRD), and Brunauer-Emmett-Teller analysis. The H-ZIF nanocrystals were distributed in an amphiphilic poly(vinyl chloride)-g-poly(oxyethylene methacrylate) (PVC-g-POEM) graft copolymer matrix to form mixed-matrix membranes (MMMs) for CO2/CH4 separation. The microphase-separated nature of the structure of the PVC-g-POEM was induced by the solubility difference between the hydrophobic PVC backbone and the hydrophilic POEM side chains. Specific interactions between the micro-structured PVC-g-POEM polymer matrix and the imidazole moiety of the H-ZIF enhanced the interfacial contact and improved the dispersion of the H-ZIF within the MMM; this was confirmed by XRD, FE-SEM, and differential scanning calorimetry. The hollow structure of the H-ZIF reduced the gas diffusion resistance of the MMM, resulting in increased gas permeability. Moreover, the molecular sieving properties and CO2-philic amine groups in the imidazole linkers of the H-ZIF led to high CO2 separation performance. The PVC-g-POEM/H-ZIF MMM exhibited an approximately fivefold increase in CO2 permeability, with a value of 210.6 barrer, compared to 43.5 barrer for a pristine PVC-g-POEM membrane with a CO2/CH4 selectivity of 14.3, which is close to upper bound reported by Robeson in 2008.
| Original language | English |
|---|---|
| Pages (from-to) | 427-434 |
| Number of pages | 8 |
| Journal | Separation and Purification Technology |
| Volume | 207 |
| DOIs | |
| Publication status | Published - 2018 Dec 22 |
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All Science Journal Classification (ASJC) codes
- Analytical Chemistry
- Filtration and Separation
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Mixed-matrix membranes containing nanocage-like hollow ZIF-8 polyhedral nanocrystals in graft copolymers for carbon dioxide/methane separation. / Lee, Jae Hun; Kwon, Hyuk Taek; Bae, Sunyoung; Kim, Jinsoo; Kim, Jong Hak.
In: Separation and Purification Technology, Vol. 207, 22.12.2018, p. 427-434.Research output: Contribution to journal › Article
TY - JOUR
T1 - Mixed-matrix membranes containing nanocage-like hollow ZIF-8 polyhedral nanocrystals in graft copolymers for carbon dioxide/methane separation
AU - Lee, Jae Hun
AU - Kwon, Hyuk Taek
AU - Bae, Sunyoung
AU - Kim, Jinsoo
AU - Kim, Jong Hak
PY - 2018/12/22
Y1 - 2018/12/22
N2 - Nanocage-like, hollow ZIF-8 (H-ZIF) polyhedral nanocrystals were synthesized via the use of seed crystals, epitaxial ZIF-8 growth, and excavation of ZIF-67 sacrificial templates. The highly porous and hollow structure of the H-ZIF polyhedral nanocrystals was confirmed by field-emission scanning electron microscopy (FE-SEM), transmission electron microscopy, energy-dispersive X-ray spectroscopy, X-ray diffraction (XRD), and Brunauer-Emmett-Teller analysis. The H-ZIF nanocrystals were distributed in an amphiphilic poly(vinyl chloride)-g-poly(oxyethylene methacrylate) (PVC-g-POEM) graft copolymer matrix to form mixed-matrix membranes (MMMs) for CO2/CH4 separation. The microphase-separated nature of the structure of the PVC-g-POEM was induced by the solubility difference between the hydrophobic PVC backbone and the hydrophilic POEM side chains. Specific interactions between the micro-structured PVC-g-POEM polymer matrix and the imidazole moiety of the H-ZIF enhanced the interfacial contact and improved the dispersion of the H-ZIF within the MMM; this was confirmed by XRD, FE-SEM, and differential scanning calorimetry. The hollow structure of the H-ZIF reduced the gas diffusion resistance of the MMM, resulting in increased gas permeability. Moreover, the molecular sieving properties and CO2-philic amine groups in the imidazole linkers of the H-ZIF led to high CO2 separation performance. The PVC-g-POEM/H-ZIF MMM exhibited an approximately fivefold increase in CO2 permeability, with a value of 210.6 barrer, compared to 43.5 barrer for a pristine PVC-g-POEM membrane with a CO2/CH4 selectivity of 14.3, which is close to upper bound reported by Robeson in 2008.
AB - Nanocage-like, hollow ZIF-8 (H-ZIF) polyhedral nanocrystals were synthesized via the use of seed crystals, epitaxial ZIF-8 growth, and excavation of ZIF-67 sacrificial templates. The highly porous and hollow structure of the H-ZIF polyhedral nanocrystals was confirmed by field-emission scanning electron microscopy (FE-SEM), transmission electron microscopy, energy-dispersive X-ray spectroscopy, X-ray diffraction (XRD), and Brunauer-Emmett-Teller analysis. The H-ZIF nanocrystals were distributed in an amphiphilic poly(vinyl chloride)-g-poly(oxyethylene methacrylate) (PVC-g-POEM) graft copolymer matrix to form mixed-matrix membranes (MMMs) for CO2/CH4 separation. The microphase-separated nature of the structure of the PVC-g-POEM was induced by the solubility difference between the hydrophobic PVC backbone and the hydrophilic POEM side chains. Specific interactions between the micro-structured PVC-g-POEM polymer matrix and the imidazole moiety of the H-ZIF enhanced the interfacial contact and improved the dispersion of the H-ZIF within the MMM; this was confirmed by XRD, FE-SEM, and differential scanning calorimetry. The hollow structure of the H-ZIF reduced the gas diffusion resistance of the MMM, resulting in increased gas permeability. Moreover, the molecular sieving properties and CO2-philic amine groups in the imidazole linkers of the H-ZIF led to high CO2 separation performance. The PVC-g-POEM/H-ZIF MMM exhibited an approximately fivefold increase in CO2 permeability, with a value of 210.6 barrer, compared to 43.5 barrer for a pristine PVC-g-POEM membrane with a CO2/CH4 selectivity of 14.3, which is close to upper bound reported by Robeson in 2008.
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UR - http://www.scopus.com/inward/citedby.url?scp=85049312094&partnerID=8YFLogxK
U2 - 10.1016/j.seppur.2018.06.076
DO - 10.1016/j.seppur.2018.06.076
M3 - Article
AN - SCOPUS:85049312094
VL - 207
SP - 427
EP - 434
JO - Separation and Purification Technology
JF - Separation and Purification Technology
SN - 1383-5866
ER -