Room temperature ionic liquid/ZIF-8 mixed-matrix membranes for natural gas sweetening and post-combustion CO2 capture

Lin Hao; Pei Li; Tingxu Yang; Tai Shung Chung

doi:10.1016/j.memsci.2013.02.034

Room temperature ionic liquid/ZIF-8 mixed-matrix membranes for natural gas sweetening and post-combustion CO₂ capture

Lin Hao, Pei Li, Tingxu Yang, Tai Shung Chung^*

^*Corresponding author for this work

Research output: Contribution to journal › Article › peer-review

181 Scopus citations

Abstract

We have investigated the effects of zeolite imidazolate framework-8 (ZIF-8) nanoparticles in miscible ionic liquid blend systems for natural gas sweetening and post-combustion CO₂ capture. The miscible blend systems consists of a polymerizable room temperature ionic liquid (poly(RTIL)) and a "free" room temperature ionic liquids (RTILs). The poly(RTIL) is 1-vinyl-3-butyl imidazolium-bis (trifluoromethylsulfonyl) imidate ([vbim][NTf₂]), while the RTIL is either (i) 1-ethyl-3-methylimidazolium tetrafluoroborate ([emim][BF₄]), (ii) 1-ethyl-3-methylimidazolium bis (trifluoromethanesulfonyl) imide ([emim][NTf₂]) or (iii) 1-ethyl-3-methylimidazolium tetracyanoborate ([emim][B(CN)₄]). Experimental results show that the free ionic liquids are miscible with poly(RTIL), while ZIF-8 are uniformly dispersed in the MMMs. The presence of ZIF-8 nanoparticles in the MMMs considerably improves gas permeability without much scarifying CO₂/N₂ and CO₂/CH₄ selectivities as compared to their poly(RTIL)/RTIL counterparts. The gas permeability of P[vbim][NTf₂]/[emim][B(CN)₄]/ZIF-8 comprising 25.8wt% ZIF-8 exhibits a threefold increase in gas permeability. Both the semi-logarithmic addition and Maxwell equations are employed to analyze the transport mechanisms across the newly developed MMMs. The permeability vs. ZIF-8 content of P[vbim][NTf₂]/ZIF-8, P[vbim][NTf₂]/[emim][NTf₂]/ZIF-8 follows exactly the Maxwell prediction, indicating these blend membranes are intrinsically heterogeneous with well dispersed ZIF-8 nanoparticles. However, an interesting phenomenon was observed in the P[vbim][NTf₂]/[emim][B(CN)₄]/ZIF-8 system where the homogeneous poly(RTIL)/RTIL phase turns into a more heterogeneous phase upon the adding of ZIF-8. As a result, a double employment of Maxwell equation is applied to analyze the enhanced gas permeability when a higher ZIF-8 loading is utilized. The P[vbim][NTf₂]/[emim][B(CN)₄]/ZIF-8 system with 25.8wt% ZIF-8 exhibits impressive performance for post-combustion CO₂/N₂ (50/50mol%) separation. It has a CO₂ permeability of 906.4×3.348×10^-19kmolm/(m²spa) (906.4barrer) and a CO₂/N₂ selectivity of 21 at 35°C and 3.5bar.

Original language	English (US)
Pages (from-to)	221-231
Number of pages	11
Journal	Journal of Membrane Science
Volume	436
DOIs	https://doi.org/10.1016/j.memsci.2013.02.034
State	Published - Jun 1 2013
Externally published	Yes

Keywords

Carbon dioxide
Ionic liquids
Maxwell model
Mixed-matrix membrane
Zeolitic imidazolate framework

ASJC Scopus subject areas

Biochemistry
General Materials Science
Physical and Theoretical Chemistry
Filtration and Separation

Access to Document

10.1016/j.memsci.2013.02.034

Cite this

@article{909692ab317d4d059504cf548be46dc8,

title = "Room temperature ionic liquid/ZIF-8 mixed-matrix membranes for natural gas sweetening and post-combustion CO2 capture",

abstract = "We have investigated the effects of zeolite imidazolate framework-8 (ZIF-8) nanoparticles in miscible ionic liquid blend systems for natural gas sweetening and post-combustion CO2 capture. The miscible blend systems consists of a polymerizable room temperature ionic liquid (poly(RTIL)) and a {"}free{"} room temperature ionic liquids (RTILs). The poly(RTIL) is 1-vinyl-3-butyl imidazolium-bis (trifluoromethylsulfonyl) imidate ([vbim][NTf2]), while the RTIL is either (i) 1-ethyl-3-methylimidazolium tetrafluoroborate ([emim][BF4]), (ii) 1-ethyl-3-methylimidazolium bis (trifluoromethanesulfonyl) imide ([emim][NTf2]) or (iii) 1-ethyl-3-methylimidazolium tetracyanoborate ([emim][B(CN)4]). Experimental results show that the free ionic liquids are miscible with poly(RTIL), while ZIF-8 are uniformly dispersed in the MMMs. The presence of ZIF-8 nanoparticles in the MMMs considerably improves gas permeability without much scarifying CO2/N2 and CO2/CH4 selectivities as compared to their poly(RTIL)/RTIL counterparts. The gas permeability of P[vbim][NTf2]/[emim][B(CN)4]/ZIF-8 comprising 25.8wt% ZIF-8 exhibits a threefold increase in gas permeability. Both the semi-logarithmic addition and Maxwell equations are employed to analyze the transport mechanisms across the newly developed MMMs. The permeability vs. ZIF-8 content of P[vbim][NTf2]/ZIF-8, P[vbim][NTf2]/[emim][NTf2]/ZIF-8 follows exactly the Maxwell prediction, indicating these blend membranes are intrinsically heterogeneous with well dispersed ZIF-8 nanoparticles. However, an interesting phenomenon was observed in the P[vbim][NTf2]/[emim][B(CN)4]/ZIF-8 system where the homogeneous poly(RTIL)/RTIL phase turns into a more heterogeneous phase upon the adding of ZIF-8. As a result, a double employment of Maxwell equation is applied to analyze the enhanced gas permeability when a higher ZIF-8 loading is utilized. The P[vbim][NTf2]/[emim][B(CN)4]/ZIF-8 system with 25.8wt% ZIF-8 exhibits impressive performance for post-combustion CO2/N2 (50/50mol%) separation. It has a CO2 permeability of 906.4×3.348×10-19kmolm/(m2spa) (906.4barrer) and a CO2/N2 selectivity of 21 at 35°C and 3.5bar.",

keywords = "Carbon dioxide, Ionic liquids, Maxwell model, Mixed-matrix membrane, Zeolitic imidazolate framework",

author = "Lin Hao and Pei Li and Tingxu Yang and Chung, {Tai Shung}",

year = "2013",

month = jun,

day = "1",

doi = "10.1016/j.memsci.2013.02.034",

language = "English (US)",

volume = "436",

pages = "221--231",

journal = "Journal of Membrane Science",

issn = "0376-7388",

publisher = "Elsevier",

}

TY - JOUR

T1 - Room temperature ionic liquid/ZIF-8 mixed-matrix membranes for natural gas sweetening and post-combustion CO2 capture

AU - Hao, Lin

AU - Li, Pei

AU - Yang, Tingxu

AU - Chung, Tai Shung

PY - 2013/6/1

Y1 - 2013/6/1

N2 - We have investigated the effects of zeolite imidazolate framework-8 (ZIF-8) nanoparticles in miscible ionic liquid blend systems for natural gas sweetening and post-combustion CO2 capture. The miscible blend systems consists of a polymerizable room temperature ionic liquid (poly(RTIL)) and a "free" room temperature ionic liquids (RTILs). The poly(RTIL) is 1-vinyl-3-butyl imidazolium-bis (trifluoromethylsulfonyl) imidate ([vbim][NTf2]), while the RTIL is either (i) 1-ethyl-3-methylimidazolium tetrafluoroborate ([emim][BF4]), (ii) 1-ethyl-3-methylimidazolium bis (trifluoromethanesulfonyl) imide ([emim][NTf2]) or (iii) 1-ethyl-3-methylimidazolium tetracyanoborate ([emim][B(CN)4]). Experimental results show that the free ionic liquids are miscible with poly(RTIL), while ZIF-8 are uniformly dispersed in the MMMs. The presence of ZIF-8 nanoparticles in the MMMs considerably improves gas permeability without much scarifying CO2/N2 and CO2/CH4 selectivities as compared to their poly(RTIL)/RTIL counterparts. The gas permeability of P[vbim][NTf2]/[emim][B(CN)4]/ZIF-8 comprising 25.8wt% ZIF-8 exhibits a threefold increase in gas permeability. Both the semi-logarithmic addition and Maxwell equations are employed to analyze the transport mechanisms across the newly developed MMMs. The permeability vs. ZIF-8 content of P[vbim][NTf2]/ZIF-8, P[vbim][NTf2]/[emim][NTf2]/ZIF-8 follows exactly the Maxwell prediction, indicating these blend membranes are intrinsically heterogeneous with well dispersed ZIF-8 nanoparticles. However, an interesting phenomenon was observed in the P[vbim][NTf2]/[emim][B(CN)4]/ZIF-8 system where the homogeneous poly(RTIL)/RTIL phase turns into a more heterogeneous phase upon the adding of ZIF-8. As a result, a double employment of Maxwell equation is applied to analyze the enhanced gas permeability when a higher ZIF-8 loading is utilized. The P[vbim][NTf2]/[emim][B(CN)4]/ZIF-8 system with 25.8wt% ZIF-8 exhibits impressive performance for post-combustion CO2/N2 (50/50mol%) separation. It has a CO2 permeability of 906.4×3.348×10-19kmolm/(m2spa) (906.4barrer) and a CO2/N2 selectivity of 21 at 35°C and 3.5bar.

AB - We have investigated the effects of zeolite imidazolate framework-8 (ZIF-8) nanoparticles in miscible ionic liquid blend systems for natural gas sweetening and post-combustion CO2 capture. The miscible blend systems consists of a polymerizable room temperature ionic liquid (poly(RTIL)) and a "free" room temperature ionic liquids (RTILs). The poly(RTIL) is 1-vinyl-3-butyl imidazolium-bis (trifluoromethylsulfonyl) imidate ([vbim][NTf2]), while the RTIL is either (i) 1-ethyl-3-methylimidazolium tetrafluoroborate ([emim][BF4]), (ii) 1-ethyl-3-methylimidazolium bis (trifluoromethanesulfonyl) imide ([emim][NTf2]) or (iii) 1-ethyl-3-methylimidazolium tetracyanoborate ([emim][B(CN)4]). Experimental results show that the free ionic liquids are miscible with poly(RTIL), while ZIF-8 are uniformly dispersed in the MMMs. The presence of ZIF-8 nanoparticles in the MMMs considerably improves gas permeability without much scarifying CO2/N2 and CO2/CH4 selectivities as compared to their poly(RTIL)/RTIL counterparts. The gas permeability of P[vbim][NTf2]/[emim][B(CN)4]/ZIF-8 comprising 25.8wt% ZIF-8 exhibits a threefold increase in gas permeability. Both the semi-logarithmic addition and Maxwell equations are employed to analyze the transport mechanisms across the newly developed MMMs. The permeability vs. ZIF-8 content of P[vbim][NTf2]/ZIF-8, P[vbim][NTf2]/[emim][NTf2]/ZIF-8 follows exactly the Maxwell prediction, indicating these blend membranes are intrinsically heterogeneous with well dispersed ZIF-8 nanoparticles. However, an interesting phenomenon was observed in the P[vbim][NTf2]/[emim][B(CN)4]/ZIF-8 system where the homogeneous poly(RTIL)/RTIL phase turns into a more heterogeneous phase upon the adding of ZIF-8. As a result, a double employment of Maxwell equation is applied to analyze the enhanced gas permeability when a higher ZIF-8 loading is utilized. The P[vbim][NTf2]/[emim][B(CN)4]/ZIF-8 system with 25.8wt% ZIF-8 exhibits impressive performance for post-combustion CO2/N2 (50/50mol%) separation. It has a CO2 permeability of 906.4×3.348×10-19kmolm/(m2spa) (906.4barrer) and a CO2/N2 selectivity of 21 at 35°C and 3.5bar.

KW - Carbon dioxide

KW - Ionic liquids

KW - Maxwell model

KW - Mixed-matrix membrane

KW - Zeolitic imidazolate framework

UR - http://www.scopus.com/inward/record.url?scp=84876050043&partnerID=8YFLogxK

U2 - 10.1016/j.memsci.2013.02.034

DO - 10.1016/j.memsci.2013.02.034

M3 - Article

AN - SCOPUS:84876050043

SN - 0376-7388

VL - 436

SP - 221

EP - 231

JO - Journal of Membrane Science

JF - Journal of Membrane Science

ER -