Recent advance of membranes for gas separation.

Recent advance of polymeric membranes for gas separation was reviewed. The polymeric membranes were classified as follows : membranes for (1) oxygen/nitrogen separation, (2) hydrogen separation, (3) carbon dioxide separation, and (4) other gas separation. In the field of oxygen/nitrogen separation, new polymeric membranes containing trimethylsilyl group showed the highest gas permeability. In the field of hydrogen separation, a new polyimide membrane containing cyclic hydrocarbon rings in the main chain showed both high permeabilities and separation factors. In membranes which have permselectivity for carbon dioxide, sulfoxide-modified poly (vinyl alcohol) membranes are very attractive. The speciality polymeric membranes containing carriers in which a facilitated transport took place were also introduced.