Towards the potential of absorbing pervaporation based on ionic liquids for gas mixture separation

摘要

A separation of a CH4/CO2 mixture was performed via absorbing pervaporation using ionic liquids as absorbent, using membrane gas separation as a comparator. Three factors were determined: the individual gas permeability through a poly(dimethyl-siloxane) membrane; the influence of the ionic liquid 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([bmim][Tf2N]); and the stage cut value on separation factor. Both experiments were carried out at three different flux ratios. The separation factor was determined with different stage-cut values for both absorbing pervaporation and membrane gas separation. The results show a directly proportional dependence of the separation factor from stage cut. Due to higher CO2 solubility in [bmim][Tf2N] in comparison with CH4, the ionic liquid separation factor using absorbing pervaporation is higher than for the comparable membrane gas separation. The superior performance of absorbing pervaporation vs. membrane gas separation in CH4/CO2 separation applications was observed.