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Title: A Computational Study of Dicationic Ionic Liquids/CO 2 Interfaces

Abstract

Recent studies on CO2 capture using dicationic ionic liquids (DILs) demonstrated that DILs are promising absorbents for CO2 uptake especially compared with monocationic ionic liquids (MILs) analogues, in which each cation carries single positive charge in contrast to two unit charges of a dication. However, DILs/CO2 interfacial properties at the molecular level are still unknown. This work investigated the CO2 absorption properties of representative DILs, 1-alkyl-3-dimethylimidazolium bis(trifluoromethylsulfonyl)imide, [Cn(mim)2](Tf2N)2 (n = 3, 6, 12), using molecular dynamics (MD) simulations. The higher interfacial CO2 density at DIL than that at MIL interfaces suggests the increased CO2 interaction sites in DILs. The interfacial CO2 density also exhibits an alkyl chain length dependence which decreases with the elongation of alkyl chain and proportionally correlates with the content of fluorine atoms at interfaces. Different alkyl chain orientations in DILs were illustrated in contrast to those of MILs; both DILs and CO2 inside DILs exhibit lower diffusivity than MILs, in agreement with the stronger cation–anion binding energy of DILs. Moreover, DILs show a lower H2O and N2 uptake from flue gas compared with MILs, implicating the higher CO2/H2O and CO2/N2 selectivity.

Authors:
 [1];  [1];  [1];  [2]
  1. State Key Laboratory of Coal Combustion, School of Energy and Power Engineering, Huazhong University of Science and Technology, Wuhan 430074, China
  2. Department of Chemical and Biomolecular Engineering, Vanderbilt University, Nashville, Tennessee 37235, United States
Publication Date:
Research Org.:
Energy Frontier Research Centers (EFRC) (United States). Fluid Interface Reactions, Structures and Transport Center (FIRST)
Sponsoring Org.:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
OSTI Identifier:
1386364
DOE Contract Number:  
ERKCC61
Resource Type:
Journal Article
Resource Relation:
Journal Name: Langmuir; Journal Volume: 31; Journal Issue: 8; Related Information: FIRST partners with Oak Ridge National Laboratory (lead); Argonne National Laboratory; Drexel University; Georgia State University; Northwestern University; Pennsylvania State University; Suffolk University; Vanderbilt University; University of Virginia
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY; catalysis (heterogeneous), solar (fuels), energy storage (including batteries and capacitors), hydrogen and fuel cells, electrodes - solar, mechanical behavior, charge transport, materials and chemistry by design, synthesis (novel materials)

Citation Formats

Li, Song, Zhao, Wei, Feng, Guang, and Cummings, Peter T. A Computational Study of Dicationic Ionic Liquids/CO 2 Interfaces. United States: N. p., 2015. Web. doi:10.1021/la5048563.
Li, Song, Zhao, Wei, Feng, Guang, & Cummings, Peter T. A Computational Study of Dicationic Ionic Liquids/CO 2 Interfaces. United States. doi:10.1021/la5048563.
Li, Song, Zhao, Wei, Feng, Guang, and Cummings, Peter T. Thu . "A Computational Study of Dicationic Ionic Liquids/CO 2 Interfaces". United States. doi:10.1021/la5048563.
@article{osti_1386364,
title = {A Computational Study of Dicationic Ionic Liquids/CO 2 Interfaces},
author = {Li, Song and Zhao, Wei and Feng, Guang and Cummings, Peter T.},
abstractNote = {Recent studies on CO2 capture using dicationic ionic liquids (DILs) demonstrated that DILs are promising absorbents for CO2 uptake especially compared with monocationic ionic liquids (MILs) analogues, in which each cation carries single positive charge in contrast to two unit charges of a dication. However, DILs/CO2 interfacial properties at the molecular level are still unknown. This work investigated the CO2 absorption properties of representative DILs, 1-alkyl-3-dimethylimidazolium bis(trifluoromethylsulfonyl)imide, [Cn(mim)2](Tf2N)2 (n = 3, 6, 12), using molecular dynamics (MD) simulations. The higher interfacial CO2 density at DIL than that at MIL interfaces suggests the increased CO2 interaction sites in DILs. The interfacial CO2 density also exhibits an alkyl chain length dependence which decreases with the elongation of alkyl chain and proportionally correlates with the content of fluorine atoms at interfaces. Different alkyl chain orientations in DILs were illustrated in contrast to those of MILs; both DILs and CO2 inside DILs exhibit lower diffusivity than MILs, in agreement with the stronger cation–anion binding energy of DILs. Moreover, DILs show a lower H2O and N2 uptake from flue gas compared with MILs, implicating the higher CO2/H2O and CO2/N2 selectivity.},
doi = {10.1021/la5048563},
journal = {Langmuir},
number = 8,
volume = 31,
place = {United States},
year = {Thu Feb 19 00:00:00 EST 2015},
month = {Thu Feb 19 00:00:00 EST 2015}
}