(771g) Mechanically Robust, Ionic Liquid Containing Hollow Fiber Membranes for CO2 Separation Applications

The inherent properties of ionic liquids (ILs), such as insignificant vapor pressure, thermal stability above 200^oC, functional diversity, and the high selectivity and permeability for CO₂, make them ideal candidates for separation of CO₂ from H₂, N₂, O_2, and CH₄. Several research groups have successfully demonstrated the application of ionic liquids in the form of supported ionic liquid membranes (SILMs) in which an IL is suspended within the pores of a membrane support and serves as the active gas transport medium of the membrane. The efficiency of SILMs can be further enhanced by spinning into hollow fiber geometry.  However, because of the small outer diameter of hollow fibers and its highly porous substructure, even relatively robust polymers such as Matrimid can have a low overall tensile strength. In particular, the addition of ionic liquid and increasing porosity both cause a decrease in the mechanical integrity of the fibers. The scope of this investigation is to fabricate mechanically robust IL containing hollow fiber membranes that can be used in industrial applications. Preliminary work was carried out using a well known and characterized IL, 1-hexyl-3-methyl-imidazolium bis(trifluoromethyl-sulfonyl)imide ([hmim][Tf₂N]) with  Matrimid^®_, and Torlon as the polymeric support material. The mechanical properties were characterized using a Dynamic Mechanical Analyzer (DMA). The CO₂ transport properties were recorded for the IL containing membranes with enhanced morphological features from 37 to 200 °C.