CO2 absorption and kinetic study in ionic liquid amine blends

Carbon dioxide emissions are the main cause of global warming, rise in sea level and ocean acidification. Currently, post-combustion CO2 capture is the most matured technology that is employed by most of the industries. This paper investigated the ways to enhance the CO2 capture ability of the ILs. For this purpose, two ionic liquids 1-butyl-3-methyl-imidiazolium tetrafluoroborate ([Bmim]+[BF4]−) and 1-butyl-3-methyl-imidiazolium hexafluorophosphate ([Bmim]+[PF6]−) were selected and compared with conventional amine (MEA and MDEA) solvents. Experimental results showed that conventional amines have larger CO2 loadings as compared to both the ILs because of the reactive nature of amines with CO2. Therefore, it was proposed to prepare the blends of IL-Amine to exploit the reactive nature of amine combined with non-volatile nature of the ILs. It was observed that the [Bmim]+[BF4]− blends with amine, have high CO2 loading as compared to pure IL as well as aqueous amine solution. Further, it was found that maximum CO2 loading results for 80% [Bmim]+[BF4]−-20% MEA blend. Piperazine (PZ) was further added to the blend as the promoter and it significantly enhanced the CO2 loading. Finally, the kinetic studies of various blends were performed and the kinetic parameters were evaluated.