Polysulfone membranes for CO2/CH4 separation: State of the art

The world market for CO2/CH4 separation using membrane technology is getting bigger and polysulfone (PSf) is one of the most widely investigated polymer membrane materials. However, the existing PSf membranes performances are insufficient to fully exploit these opportunities. Therefore, modification that would produce membrane that fit the needs of target separation performances is a main issue. Firstly, various manufacturing processes to achieve best CO2/CH4 separation performance are discussed, including important post-treatments. The formulation of polymer solution and effects of manufacturing parameters on the resulting membranes are presented. Other modifications, which involved PSf structure modification, PSf-based copolymer, mixed matrix membrane and facilitated transport membrane, are also discussed. Performances of those modified membranes are compared with the Robeson’s upper bound and some modifications give satisfying results. Finally, commercial application of PSf membranes for CO2/CH4 separation is discussed.