Block Copolymer Ion Gels for Gas Separation Applications

Carbon dioxide removal from light gases (eg. N₂, CH₄, and H₂) is an important technology for applications such as natural gas sweetening, CO₂ recovery from coal-fire power plant exhausts and hydrogen production.  In recent years, ionic liquids have received increasing interest in this area because of their highly selective solubility for CO₂ and essentially non-volatility. However, ionic liquid itself cannot stand the high pressure for a gas separation membrane. We report here the development and gas separation performances of physically crosslinked ion gels prepared through self-assembly of ABA-type triblock copolymers in ionic liquids. Three different types of block copolymers have been used to achieve gelation in ionic liquids. These ion gels generally shows a fast gas transportation and improved selectivity for gas separation. Specifically, an triblock copolymer ion gel with a polymerized ionic liquid (PIL) mid-block shows good performances higher than the upper bound of well-known "Robeson Plot" for CO₂/N₂. This presentation will discuss the development of these ion gel materials and compare their separation performances for CO₂/N₂ and CO₂/CH₄ gas pairs.