CO₂ Adsorption Studies in Supported Amino Functionalized Ionic Liquids

In this paper, in order to study the potential impact of supported ionic liquids on CO₂ adsorption, the specific ionic liquids (NH₂p-mimX：X= Br^-，PF₆^-，BF₄^-，NTf₂^-) were immobilized in different supports, such as active carbon (AC), silica(SiO₂) and alumina(Al₂O₃) via an impregnation-vaporization method. The supported ionic liquids were characterized by flourier transform infrared(FT-IR) spectrometry,elemental analysis(EA),thermogravimetry-differential thermal analysis(TG-DTA) and so on. The performance of supported ionic liquids for CO₂ adsorption were investigated,and the The effects of using supports with different chemical structures and different anions on the CO₂ adsorption capacity of supported ionic liquids have been studied. The results show that the supported ionic liquids prepared with Al₂O₃ exhibits a high affinity for CO₂ compared with those on SiO₂ and AC. FT-IR analysis indicates that this behavior is due to the excellent dispersing effect of supports on the ionic liquids and the weak interaction between ionic liquids and supports, the latter increases the active sites of ionic liquids for CO₂ adsorption after being loaded. The supported ionic liquids prepared with Al₂O₃ have a relatively large electron density of atomic N of amino, which is favourable to the reaction of CO₂ with –NH₂ of NH₂p-mimBr/Al₂O₃. The CO₂ adsorption performance of supported ionic liquids increases with the increase of the viscosity of ionic liquids and reduces with the increase of volume of ionic liquids.