(437e) Permeability of Carbon Dioxide Through Ionic Liquid Membrane With Polyvinylidene Fluoride

Membrane separation is expected to be candidate for carbon dioxide capture. Several materials, such as organic polymer, ceramics and hybrid of organic – inorganic, have been used for the membrane separation of carbon dioxide. A supported liquid membrane is a porous membrane filled with liquid. For carbon dioxide separation, amine solvents are often used as the liquid for the liquid membrane, but there is a problem of the low membrane stability due to the evaporation of the solvent. Ionic liquid can be suitable for the liquid membrane solvent more than the amines because their vapor pressure is ultra low. It is important for the process design of the membrane separation to understand the permeability of carbon dioxide through ionic liquid membrane. In this work, the permeabilities of carbon dioxide through ionic liquid membranes were investigated. Polyvinylidene fluoride (PVDF) was used as the porous membrane. Six species of ionic liquid were used as follows: 1-ethyl-3-methylimidazolium tetrafluoroborate ([emim][BF4]), 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl) imide ([bmim][Tf2N]), 1-butyl-3-methylimidazolium tetrafluoroborate ([bmim][BF4]), 1-butyl-3-methylimidazolium hexafluorophosphate ([bmim][PF6]), 1-butyl-3-methylimidazolium  trifluoromethanesulfonate ([bmim][OTf]) and 1-butyl-3-methylimidazolium dicyanamide ([bmim][dca]). The carbon dioxide permeabilities were measured by a sweep gas method at 303 to 343 K. Nitrogen gas was used as the sweep gas. The effects of temperature, anion species on carbon dioxide permeability though ionic liquid membrane were studied. The permeabilities of carbon dioxide increase with temperatures. The ionic liquid membrane with [bmim][Tf2N] results in the highest permeability of carbon dioxide of all the species in this work. The permeabilities of carbon dioxide through [bmim][PF6] and [bmim][Tf2N] membranes with water vapor were also measured at 303 to 333 K. It is found that the addition of water vapor at feed and permeate sides makes an enhancement of the permeabilities of carbon dioxide through ionic liquid membranes.