A study of porous support amine-RTILs binary system for CO₂ capture

In this work, room temperature ionic liquids (RTILs) 1-butyl-3-methylimidazolium tetrafluoroborate ([BMIM]BF₄) and 1-butyl-3-ethylimidazolium tetrafluoroborate ([BEIM]BF₄) are synthesized. The cation structure of ionic liquids is confirmed by NMR spectroscopy. The thermal decomposition temperature of synthesized ionic liquids is measured and both ionic liquids show good thermal stability. The viscosity of ionic liquids is determined over the temperature range of 298 K to 353 K. A mixed system made by blending amine and ionic liquid is proposed for CO₂ capture. Investigation of the performance of this binary system on a porous support medium for CO₂ absorption shows that amine is able to greatly intensify the ionic liquids' ability to absorb CO₂. Furthermore, when blending tertiary amine and ionic liquids to absorb CO₂, it was found that only physical absorption takes place and that the viscosity of the absorbent increases slightly after CO₂ absorption. Based on the results of this work, the binary system of tertiary amine and RTILs is proven to be an alternative absorbent for CO₂ capture.