Abstract
The thermal stability of ZIF membranes is important for high temperature separation applications but has not been systematically studied. This work highlights the results of a thermal stability study of ZIF-8 membranes in terms of material structure, H2/CO2 gas permeation and separation characteristics. During binary and single gas temperature dependent permeance tests conducted from 25 to 250 °C, both H2 and CO2 permeances decrease as a function of temperature. In the binary test, H2/CO2 selectivity increases between 25 and 225 °C, and then decreases as temperature is further increased between 225–275 °C. The results can be explained by the adsorption/diffusion mechanism. Beyond 275 °C, H2/CO2 permeance and selectivity drastically increase with respect to temperature and is indicative of ZIF-8 membrane partial carbonization during the dynamic 30 h temperature dependent test. The time/temperature dependency of the onset of ZIF-8 thin film structural change was deconvoluted in isothermal transient permeation experiments. Transient tests performed at 50, 100, 150 and 300 °C for 24 h indicate that ZIF-8 thin films maintain their crystallinity and structural integrity below 150 °C. However, at temperatures of 150 °C and greater the framework undergoes increased magnitudes of thermally induced carbonization as a function of temperature. Thermomechanically induced stresses between the ZIF-8 membrane thin film and α–alumina support may account for differences in static thermal stability observed when comparing ZIF-8 membranes and ZIF-8 crystalline powders.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 9-19 |
| Number of pages | 11 |
| Journal | Journal of Membrane Science |
| Volume | 532 |
| DOIs | |
| State | Published - Jun 15 2017 |
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Keywords
- Gas separation
- High temperature
- Membrane carbonization
- Thermal stability
- ZIF-8 membrane
ASJC Scopus subject areas
- Biochemistry
- Materials Science(all)
- Physical and Theoretical Chemistry
- Filtration and Separation
Cite this
Thermal stability of ZIF-8 membranes for gas separations. / James, Joshua B.; Lin, Jerry.
In: Journal of Membrane Science, Vol. 532, 15.06.2017, p. 9-19.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Thermal stability of ZIF-8 membranes for gas separations
AU - James, Joshua B.
AU - Lin, Jerry
PY - 2017/6/15
Y1 - 2017/6/15
N2 - The thermal stability of ZIF membranes is important for high temperature separation applications but has not been systematically studied. This work highlights the results of a thermal stability study of ZIF-8 membranes in terms of material structure, H2/CO2 gas permeation and separation characteristics. During binary and single gas temperature dependent permeance tests conducted from 25 to 250 °C, both H2 and CO2 permeances decrease as a function of temperature. In the binary test, H2/CO2 selectivity increases between 25 and 225 °C, and then decreases as temperature is further increased between 225–275 °C. The results can be explained by the adsorption/diffusion mechanism. Beyond 275 °C, H2/CO2 permeance and selectivity drastically increase with respect to temperature and is indicative of ZIF-8 membrane partial carbonization during the dynamic 30 h temperature dependent test. The time/temperature dependency of the onset of ZIF-8 thin film structural change was deconvoluted in isothermal transient permeation experiments. Transient tests performed at 50, 100, 150 and 300 °C for 24 h indicate that ZIF-8 thin films maintain their crystallinity and structural integrity below 150 °C. However, at temperatures of 150 °C and greater the framework undergoes increased magnitudes of thermally induced carbonization as a function of temperature. Thermomechanically induced stresses between the ZIF-8 membrane thin film and α–alumina support may account for differences in static thermal stability observed when comparing ZIF-8 membranes and ZIF-8 crystalline powders.
AB - The thermal stability of ZIF membranes is important for high temperature separation applications but has not been systematically studied. This work highlights the results of a thermal stability study of ZIF-8 membranes in terms of material structure, H2/CO2 gas permeation and separation characteristics. During binary and single gas temperature dependent permeance tests conducted from 25 to 250 °C, both H2 and CO2 permeances decrease as a function of temperature. In the binary test, H2/CO2 selectivity increases between 25 and 225 °C, and then decreases as temperature is further increased between 225–275 °C. The results can be explained by the adsorption/diffusion mechanism. Beyond 275 °C, H2/CO2 permeance and selectivity drastically increase with respect to temperature and is indicative of ZIF-8 membrane partial carbonization during the dynamic 30 h temperature dependent test. The time/temperature dependency of the onset of ZIF-8 thin film structural change was deconvoluted in isothermal transient permeation experiments. Transient tests performed at 50, 100, 150 and 300 °C for 24 h indicate that ZIF-8 thin films maintain their crystallinity and structural integrity below 150 °C. However, at temperatures of 150 °C and greater the framework undergoes increased magnitudes of thermally induced carbonization as a function of temperature. Thermomechanically induced stresses between the ZIF-8 membrane thin film and α–alumina support may account for differences in static thermal stability observed when comparing ZIF-8 membranes and ZIF-8 crystalline powders.
KW - Gas separation
KW - High temperature
KW - Membrane carbonization
KW - Thermal stability
KW - ZIF-8 membrane
UR - http://www.scopus.com/inward/record.url?scp=85014927527&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=85014927527&partnerID=8YFLogxK
U2 - 10.1016/j.memsci.2017.02.017
DO - 10.1016/j.memsci.2017.02.017
M3 - Article
AN - SCOPUS:85014927527
VL - 532
SP - 9
EP - 19
JO - Jornal of Membrane Science
JF - Jornal of Membrane Science
SN - 0376-7388
ER -