Selective extraction of CO 2 from simulated flue gas using polymeric ionic liquid sorbent coatings in solid-phase microextraction gas chromatography

Abstract

The CO 2 selectivity of two polymeric task-specific ionic liquid sorbent coatings, poly(1-vinyl-3-hexylimidazolium) bis[(trifluoromethyl)sulfonyl]imide [poly(VHIM-NTf 2)] and poly(1-vinyl-3-hexylimidazolium) taurate [poly(VHIM-taurate)], was examined using solid-phase microextraction (SPME) for the determination of CO 2 in simulated flue gas. For comparison purposes, a commercial SPME fiber, Carboxen™-PDMS, was also studied. A study into the effect of humidity revealed that the poly(VHIM-taurate) fiber exhibited enhanced resistance to water, presumably due to the unique mechanism of CO 2 capture. The effect of temperature on the performance of the PIL-based and Carboxen fibers was examined by generating calibration curves under various temperatures. The sensitivity, linearity, and linear range of the three fibers were evaluated. The extraction of CH 4 and N 2 was performed and the selectivities of the PIL-based and Carboxen fibers were compared. The poly(VHIM-NTf 2) fiber was found to possess superior CO 2/CH 4 and CO 2/N 2 selectivities compared to the Carboxen fiber, despite the smaller film thicknesses of the PIL-based fibers. A scanning electron microscopy study suggests that the amine group of the poly(VHIM-taurate) is capable of selectively reacting with CO 2 but not CH 4 or N 2, resulting in a significant surface morphology change of the sorbent coating.