"However, in lieu of polycarbonate the substrate 30 may be alternatively constructed of cellulose derivatives such as cellulose acetate, as well as polyolefins, (e.g. polyethylene, polypropylene, etc.), gels, or other porous materials. [0093] It is a particular feature of this embodiment of the present invention that membranes 13 have a high affi" . . . .