Abstract
LTA (Linde Type A) type zeolites have been manufactured in a form of a continuous membrane and widely used for pervaporation-based dehydration of organic solvents. Despite the extremely high dehydration performances, the effects of parameters related to seed layer formation and, more importantly, water exposure of the resulting LTA membrane on the final membrane properties and, concomitant dehydration performances have not been investigated intensively. In this study, we examined how the immersion of as-synthesized LTA membranes in water (considering duration of water immersion) affected the membrane properties and dehydration performances. In addition, we focused on how to handle a LTA seed suspension (dependent on duration of precipitation) for forming proper seed layers on α-alumina tubes. We found that optimal preparation methods were necessary for securing a proper seed suspension and forming a seed layer that allowed for manufacturing high performance LTA membranes. In particular, when the disc-supported and tube-supported LTA membranes were immersed in water for ~12 h, they could show high dehydration performances with the H2O/CH3OH separation factors of ~860 ± 260 and ~910 ± 420, respectively, at 50 °C. However, after a critical time (~100–200 h), the corresponding dehydration performance was dramatically decreased, apparently due to the dissolution of LTA zeolites. Along with regular structural investigation with scanning electron microscopy and X-ray diffraction analyses, fluorescence confocal optical microscopy clearly revealed that the immersion of the LTA membranes in water resulted in forming almost defect-free membranes, but after some time, damaging the corresponding membrane structure. Nevertheless, the LTA membrane that did not contain non-zeolitic defects could preserve its aforementioned high dehydration performance with respect to a water-containing feed (~10 wt% H2O) up to ~102 h.
| Original language | English |
|---|---|
| Article number | 116493 |
| Journal | Separation and Purification Technology |
| Volume | 238 |
| DOIs | |
| Publication status | Published - 2020 May 1 |
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Keywords
- HO/CHOH separation performance
- LTA zeolite membranes
- Membrane deactivation
- Seed layer optimization
- Water immersion effect
ASJC Scopus subject areas
- Analytical Chemistry
- Filtration and Separation
Cite this
On the effects of water exposure of as-synthesized LTA membranes on their structural properties and dehydration performances. / Kim, Pyoseop; Hong, Sungwon; Nam, Seung Eun; Park, You In; Choi, Nakwon; Moon, Jong Ho; Choi, Jungkyu.
In: Separation and Purification Technology, Vol. 238, 116493, 01.05.2020.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - On the effects of water exposure of as-synthesized LTA membranes on their structural properties and dehydration performances
AU - Kim, Pyoseop
AU - Hong, Sungwon
AU - Nam, Seung Eun
AU - Park, You In
AU - Choi, Nakwon
AU - Moon, Jong Ho
AU - Choi, Jungkyu
PY - 2020/5/1
Y1 - 2020/5/1
N2 - LTA (Linde Type A) type zeolites have been manufactured in a form of a continuous membrane and widely used for pervaporation-based dehydration of organic solvents. Despite the extremely high dehydration performances, the effects of parameters related to seed layer formation and, more importantly, water exposure of the resulting LTA membrane on the final membrane properties and, concomitant dehydration performances have not been investigated intensively. In this study, we examined how the immersion of as-synthesized LTA membranes in water (considering duration of water immersion) affected the membrane properties and dehydration performances. In addition, we focused on how to handle a LTA seed suspension (dependent on duration of precipitation) for forming proper seed layers on α-alumina tubes. We found that optimal preparation methods were necessary for securing a proper seed suspension and forming a seed layer that allowed for manufacturing high performance LTA membranes. In particular, when the disc-supported and tube-supported LTA membranes were immersed in water for ~12 h, they could show high dehydration performances with the H2O/CH3OH separation factors of ~860 ± 260 and ~910 ± 420, respectively, at 50 °C. However, after a critical time (~100–200 h), the corresponding dehydration performance was dramatically decreased, apparently due to the dissolution of LTA zeolites. Along with regular structural investigation with scanning electron microscopy and X-ray diffraction analyses, fluorescence confocal optical microscopy clearly revealed that the immersion of the LTA membranes in water resulted in forming almost defect-free membranes, but after some time, damaging the corresponding membrane structure. Nevertheless, the LTA membrane that did not contain non-zeolitic defects could preserve its aforementioned high dehydration performance with respect to a water-containing feed (~10 wt% H2O) up to ~102 h.
AB - LTA (Linde Type A) type zeolites have been manufactured in a form of a continuous membrane and widely used for pervaporation-based dehydration of organic solvents. Despite the extremely high dehydration performances, the effects of parameters related to seed layer formation and, more importantly, water exposure of the resulting LTA membrane on the final membrane properties and, concomitant dehydration performances have not been investigated intensively. In this study, we examined how the immersion of as-synthesized LTA membranes in water (considering duration of water immersion) affected the membrane properties and dehydration performances. In addition, we focused on how to handle a LTA seed suspension (dependent on duration of precipitation) for forming proper seed layers on α-alumina tubes. We found that optimal preparation methods were necessary for securing a proper seed suspension and forming a seed layer that allowed for manufacturing high performance LTA membranes. In particular, when the disc-supported and tube-supported LTA membranes were immersed in water for ~12 h, they could show high dehydration performances with the H2O/CH3OH separation factors of ~860 ± 260 and ~910 ± 420, respectively, at 50 °C. However, after a critical time (~100–200 h), the corresponding dehydration performance was dramatically decreased, apparently due to the dissolution of LTA zeolites. Along with regular structural investigation with scanning electron microscopy and X-ray diffraction analyses, fluorescence confocal optical microscopy clearly revealed that the immersion of the LTA membranes in water resulted in forming almost defect-free membranes, but after some time, damaging the corresponding membrane structure. Nevertheless, the LTA membrane that did not contain non-zeolitic defects could preserve its aforementioned high dehydration performance with respect to a water-containing feed (~10 wt% H2O) up to ~102 h.
KW - HO/CHOH separation performance
KW - LTA zeolite membranes
KW - Membrane deactivation
KW - Seed layer optimization
KW - Water immersion effect
UR - http://www.scopus.com/inward/record.url?scp=85077216455&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=85077216455&partnerID=8YFLogxK
U2 - 10.1016/j.seppur.2019.116493
DO - 10.1016/j.seppur.2019.116493
M3 - Article
AN - SCOPUS:85077216455
VL - 238
JO - Separation and Purification Technology
JF - Separation and Purification Technology
SN - 1383-5866
M1 - 116493
ER -