CO2 sorption using encapsulated imidazolium-based fluorinated ionic liquids

Abstract

The development and testing of new sorbents for the efficient removal of CO2 from flue gases is essential. Encapsulated room-temperature ionic liquids (RTILs) can be potentially employed in CO2 capture. In this work, we report the preparation and characterization of encapsulated imidazolium-based fluorinated RTILs for CO2 capture. [Emim][TF2N], [Bmim][TF2N], and [Hmim][TF2N] RTILS were encapsulated in polysulfone (PSF) using an emulsification method and characterized by several techniques. The pressure-decay technique was used to assess the CO2 sorption capacity and reusability. Encapsulated RTILs showed improved utility for CO2 capture processes compared with non-encapsulated RTILs, including higher CO2 sorption capacity and faster CO2 sorption/desorption. The CO2 absorption/desorption cycles demonstrated the reuse capacity of all microcapsules under mild conditions. The highest CO2 sorption capacity was noted for encapsulated [Emim][TF2N] (39.5 mg CO2 g−1 at 298.15 K and 1 bar; 62.7 mg CO2 g−1 at 298.15 K and 10 bar). It is worth emphasizing that the encapsulated [Emim][TF2N] contained a lower ionic liquid (IL) content (37.5. ± 0.6) when compared to other encapsulated samples. Moreover, encapsulated [Emim][TF2N] presented a higher CO2 affinity than the encapsulated ILs reported in the literature.

Keywords

• CO2 capture
• Encapsulated ionic liquid
• Microcapsules
• Ionic liquid