High-efficiency technology for lithium isotope separation using an ionic-liquid impregnated organic membrane

The tritium needed as a fuel for fusion reactors is produced by the neutron capture reaction of lithium-6 (6Li) in tritium breeding materials. New lithium isotope separation technique using ionic-liquid impregnated organic membranes (Ionic-Liquid-i-OMs) have been developed. Lithium ions are able to move by electrodialysis through certain Ionic-Liquid-i-OMs between the cathode and the anode in lithium solutions. s report, the effects of protection cover and membrane thickness on the durability of membrane and the efficiency of isotope separation were evaluated. In order to improve the durability of the Ionic-Liquid-i-OM, we developed highly-durable Ionic-Liquid-i-OM. Both surfaces of the Ionic-Liquid-i-OM were covered by a nafion 324 overcoat or a cation exchange membrane (SELEMION™ CMD) to prevent the outflow of the ionic liquid. It was observed that the durability of the Ionic-Liquid-i-OM was improved by a nafion 324 overcoat. other hand, the organic membrane selected was 1, 2 or 3 mm highly-porous Teflon film, in order to efficiently impregnate the ionic liquid. The 6Li isotope separation factor by electrodialysis using highly-porous Teflon film of 3 mm thickness was larger than using that of 1 or 2 mm thickness.