Lithium-based zeolites containing silver and copper and use thereof for selective absorption

摘要

The invention provides new methods for separating nitrogen from a mixture. The invention provides adsorbents specifically for accomplishing nitrogen separation. The adsorbents and separation methods are particularly useful for the selective adsorption of nitrogen from air. In one aspect, the adsorbent comprises an ion exchange zeolite X and preferably zeolite LSX (low silica zeolite X). The zeolite is most preferably a lithium-based zeolite. Further, the zeolite has exchangeable cationic sites, with silver cation or copper cation occupying at least some of the exchangeable cationic sites. The Ag/Cu exchanged zeolite is heat-treated under specific conditions as per the invention. The presence of the silver cation or copper cation at any of the sites will provide an improvement over the non-exchanged zeolite.