Possible air separations with superconducting membranes

Permeabilities of oxygen, nitrogen and helium across porous, superconducting membranes with 5-μm pores are consistent with those across nonsuperconducting membranes with well-defined pores of similar sizes. This is true both at ambient and superconducting temperatures. Transport can occur by Knudsen diffusion, Poiseuille flow, capillary condensation, and turbulent flow. There is no evidence of surface diffusion. Theoretical considerations of superconducting membranes are consistent with these results, indicating when superconductivity might play a role. However, past reports concerning air separation with superconducting membranes with these micrometer-sized pores are questionable.