abstract
Ionic liquids have been explored as attractive alternative media for CO2 separation not only due to their low volatility but also due to their highly tuneable nature. Aiming at designing highly efficient liquid phases for flue gas separation and natural gas purification, this work focuses on the use of binary ionic liquid mixtures containing sulfate and/or cyano-functionalized anions. Several mixtures were prepared and their gas transport properties through supported ionic liquid membranes (SILMs) were investigated. The thermophysical properties of these mixtures, namely viscosity and density (data presented and discussed in ESI), were also measured so that trends between transport properties and thermophysical properties could be evaluated. The results obtained indicate that depending on the anions mixed, membranes with fine-tuned gas permeabilities, diffusivities and solubilities can be obtained. Additionally, SILMs prepared with these ionic liquid mixtures are on the upper bound of the CO2/N-2 separation, or even may surpass it, indicating their potential for separating CO2 in low-pressure post-combustion processes. Overall, the use of ionic liquid mixtures combining the most selective anions with the least viscous anions is a highly promising strategy to design advanced engineered liquid phases for CO2 separation membranes.
keywords
CARBON-DIOXIDE SEPARATION; GAS SEPARATIONS; CO2/N-2 SEPARATION; HYDROCARBON SOLUBILITIES; FACILITATED TRANSPORT; LONG-TERM; MIXED-GAS; TEMPERATURE; IMIDAZOLIUM; CAPTURE
subject category
Chemistry; Physics
authors
Tome, LC; Florindo, C; Freire, CSR; Rebelo, LPN; Marrucho, IM
our authors
Carmen Sofia da Rocha Freire Barros
Coordinating Researcher
Liliana C. Tomé
PhD StudentProjects
acknowledgements
Liliana C. Tome would like to thank the FCT (Fundacao para a Ciencia e Tecnologia) for her PhD research grant (SFRH/BD/72830/2010). Isabel M. Marrucho and Carmen S.R. Freire acknowledge FCT/MCTES (Portugal) for contracts under Investigador FCT 2012. This work was partially supported by FCT through the projects PTDC/QUI-QUI/121520/2010, PTDC/QEQ-FTT/168612012, Pest-OE/EQB/LA0004/2013 (ITQB) and Pest-C/CTM/LA0011/2013 (CICECO).