Development of CO2 separation membranes (2) facilitated transport membrane

With the aim of developing technologies for separating and recovering CO2 from exhaust gases amid the ongoing problem of global warming, Sumitomo Electric participated in the chemical CO2 fixation project undertaken by the Research Institute of Innovative Technology for the Earth (RITE). Our participation involved the development of facilitated support membranes, which are liquid membranes that include solvents of a material identified as a carrier that reacts specifically with the CO2 in exhaust gases. Compared with the already commercialized polymer membranes, facilitated support membranes have the advantages of a greater ratio of COy membrane permeation in relation to N2 (CO2/N2 separation factor) as well as the capacity to separate the feed stream at low power. On the other hand, employing a liquid membrane has the drawbacks of low CO2 permeation speed and limited durability. By applying a PVA-PAA copolymer gel layer on top of hydrophobic PTFE, we have developed a water-swollen gel membrane whose gel layer is to be impregnated with a carrier water solution. We have confirmed that the new membrane maintains its durability for at least six months. By using as the carrier agent a water solution that combines cesium carbonate and 2, 3 diaminopropionic acid, we have also developed a facilitated transport membrane that successfully balances the contradictory characteristics of permeation speed and separation factor, achieving the world's highest separation performance.