Experimental study on the effects of an ionic liquid for CO2 capture using hollow fiber membrane contactors

Ionic liquids are considered as new absorbents with high solubility for separation of CO2 from flue gases. In this study, the effect of an ionic liquid ([Bmim][BF4]) on the absorption of CO2 using polypropylene hollow fiber membrane contactors was studied. Aqueous solutions of ionic liquid and mixture of ionic liquid with methyldiethanolamine were applied as physical and chemical absorbents, respectively. The effects of different parameters including concentration of ionic liquid in water and aqueous solution of methyldiethanolamine as base fluids, liquid and gas flow rates, and flow direction were investigated. The results showed that a 25 wt% solution of ionic liquid can increase the absorption efficiency about 20% and 15% compared to pure water in co-current and counter-current flows, respectively. It was also observed that a mixture containing 20 wt% of ionic liquid and 10 wt% of methyldiethanolamine can improve the absorption capacity about 10% compared to a 10 wt% MDEA aqueous solution without ionic liquid.