Abstract
Chabazite (CHA)-type zeolites are promising for the separation of CO2 from larger molecules, such as N2 (relevant to postcombustion carbon capture) and CH4 (relevant to natural gas/biogas upgrading). In particular, the pore size of CHA zeolites (0.37 × 0.42 nm2) can recognize slight molecular size differences between CO2 (0.33 nm) and the larger N2 (0.364 nm) or CH4 (0.38 nm) molecules, thus allowing separation in favor of CO2 through CHA membranes. Furthermore, the siliceous constituents in the CHA zeolite can reduce the adsorption capacity toward the smaller H2O molecule (0.265 nm) and, thus, the H2O permeation rate. This is highly desirable for securing good molecular sieving ability with CO2 permselectivity in the presence of H2O vapor. Indeed, a siliceous CHA film obtained with a nominal Si/Al ratio of 100 (CHA-100) showed high CO2/N2 and CO2/CH4 separation performance, especially in the presence of H2O vapor; ∼13.4 CO2/N2 and ∼37 CO2/CH4 separation factors (SFs) at 30 °C. These SFs were higher than the corresponding values (∼5.2 CO2/CH4 SFs and ∼31 CO2/CH4 SFs) under dry conditions; such improvement could be ascribed to defect blocking by physisorbed water molecules. Finally, the contribution of molecular transport through zeolitic and nonzeolitic parts was quantitatively analyzed by combining information extracted from image processing of fluorescence confocal optical microscopy images with a one-dimensional permeation model. It appears that ∼19 and ∼20% of the total CO2 permeance for CHA-100 were reduced due to transport inhibition by the physisorbed water molecules on the membrane surface and defect, respectively.
| Original language | English |
|---|---|
| Pages (from-to) | 3946-3960 |
| Number of pages | 15 |
| Journal | ACS Applied Materials and Interfaces |
| Volume | 11 |
| Issue number | 4 |
| DOIs | |
| Publication status | Published - 2019 Jan 30 |
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Keywords
- chabazite
- CO permselectivity
- defects
- hydrophobicity
- secondary growth
- siliceous zeolite film
ASJC Scopus subject areas
- Materials Science(all)
Cite this
Chabazite-Type Zeolite Membranes for Effective CO2 Separation : The Role of Hydrophobicity and Defect Structure. / Lee, Minseong; Hong, Sungwon; Kim, Dongjae; Kim, Eunjoo; Lim, Kyunghwan; Jung, Jae Chil; Richter, Hannes; Moon, Jong Ho; Choi, Nakwon; Nam, Jaewook; Choi, Jungkyu.
In: ACS Applied Materials and Interfaces, Vol. 11, No. 4, 30.01.2019, p. 3946-3960.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Chabazite-Type Zeolite Membranes for Effective CO2 Separation
T2 - The Role of Hydrophobicity and Defect Structure
AU - Lee, Minseong
AU - Hong, Sungwon
AU - Kim, Dongjae
AU - Kim, Eunjoo
AU - Lim, Kyunghwan
AU - Jung, Jae Chil
AU - Richter, Hannes
AU - Moon, Jong Ho
AU - Choi, Nakwon
AU - Nam, Jaewook
AU - Choi, Jungkyu
PY - 2019/1/30
Y1 - 2019/1/30
N2 - Chabazite (CHA)-type zeolites are promising for the separation of CO2 from larger molecules, such as N2 (relevant to postcombustion carbon capture) and CH4 (relevant to natural gas/biogas upgrading). In particular, the pore size of CHA zeolites (0.37 × 0.42 nm2) can recognize slight molecular size differences between CO2 (0.33 nm) and the larger N2 (0.364 nm) or CH4 (0.38 nm) molecules, thus allowing separation in favor of CO2 through CHA membranes. Furthermore, the siliceous constituents in the CHA zeolite can reduce the adsorption capacity toward the smaller H2O molecule (0.265 nm) and, thus, the H2O permeation rate. This is highly desirable for securing good molecular sieving ability with CO2 permselectivity in the presence of H2O vapor. Indeed, a siliceous CHA film obtained with a nominal Si/Al ratio of 100 (CHA-100) showed high CO2/N2 and CO2/CH4 separation performance, especially in the presence of H2O vapor; ∼13.4 CO2/N2 and ∼37 CO2/CH4 separation factors (SFs) at 30 °C. These SFs were higher than the corresponding values (∼5.2 CO2/CH4 SFs and ∼31 CO2/CH4 SFs) under dry conditions; such improvement could be ascribed to defect blocking by physisorbed water molecules. Finally, the contribution of molecular transport through zeolitic and nonzeolitic parts was quantitatively analyzed by combining information extracted from image processing of fluorescence confocal optical microscopy images with a one-dimensional permeation model. It appears that ∼19 and ∼20% of the total CO2 permeance for CHA-100 were reduced due to transport inhibition by the physisorbed water molecules on the membrane surface and defect, respectively.
AB - Chabazite (CHA)-type zeolites are promising for the separation of CO2 from larger molecules, such as N2 (relevant to postcombustion carbon capture) and CH4 (relevant to natural gas/biogas upgrading). In particular, the pore size of CHA zeolites (0.37 × 0.42 nm2) can recognize slight molecular size differences between CO2 (0.33 nm) and the larger N2 (0.364 nm) or CH4 (0.38 nm) molecules, thus allowing separation in favor of CO2 through CHA membranes. Furthermore, the siliceous constituents in the CHA zeolite can reduce the adsorption capacity toward the smaller H2O molecule (0.265 nm) and, thus, the H2O permeation rate. This is highly desirable for securing good molecular sieving ability with CO2 permselectivity in the presence of H2O vapor. Indeed, a siliceous CHA film obtained with a nominal Si/Al ratio of 100 (CHA-100) showed high CO2/N2 and CO2/CH4 separation performance, especially in the presence of H2O vapor; ∼13.4 CO2/N2 and ∼37 CO2/CH4 separation factors (SFs) at 30 °C. These SFs were higher than the corresponding values (∼5.2 CO2/CH4 SFs and ∼31 CO2/CH4 SFs) under dry conditions; such improvement could be ascribed to defect blocking by physisorbed water molecules. Finally, the contribution of molecular transport through zeolitic and nonzeolitic parts was quantitatively analyzed by combining information extracted from image processing of fluorescence confocal optical microscopy images with a one-dimensional permeation model. It appears that ∼19 and ∼20% of the total CO2 permeance for CHA-100 were reduced due to transport inhibition by the physisorbed water molecules on the membrane surface and defect, respectively.
KW - chabazite
KW - CO permselectivity
KW - defects
KW - hydrophobicity
KW - secondary growth
KW - siliceous zeolite film
UR - http://www.scopus.com/inward/record.url?scp=85060282250&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=85060282250&partnerID=8YFLogxK
U2 - 10.1021/acsami.8b18854
DO - 10.1021/acsami.8b18854
M3 - Article
C2 - 30614677
AN - SCOPUS:85060282250
VL - 11
SP - 3946
EP - 3960
JO - ACS applied materials & interfaces
JF - ACS applied materials & interfaces
SN - 1944-8244
IS - 4
ER -