In a process for the separation and purification of oxygen and nitrogen solutions of oxygen carriers (3) are utilised to selectively absorb oxygen from a gaseous stream. In the process, an oxygen carrier capable of reversibly binding molecular oxygen is dissolved in a solvent solution, which absorbs oxygen from an oxygen-containing gaseous feed stream such as atmospheric air and desorbs oxygen to a gaseous product stream, leaving nitrogen as a byproduct. The feed stream is maintained at a sufficiently high oxygen pressure to keep the oxygen carrier in its oxygenated form during absorption (1), while the product stream is maintained at a sufficiently low oxygen pressure to keep the carrier in its deoxygenated form during desorption (4), or the carrier solution is maintained at a sufficiently low temperature and high oxygen pressure to keep the oxygen carrier in its oxygenated form during absorption and at a sufficiently high temperature to keep the carrier in its deoxygenated form during desorption. Under such conditions, exceptionally high oxygen concentrations of the order of 95% to 99% are obtained, as well as a long carrier lifetime in excess of 3 months, making the process commerically feasible.
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