Recent advances have been made in research on carbon molecular sieve and zeolite adsorbents used in the non-cryogenic production of nitrogen and oxygen. Preparation methods that allow stringent control of porosity, density, and surface properties have resulted in carbon molecular sieve adsorbents with higher capacity and selectivity for nitrogen production. Recently, a new generation of mixed-cation zeolite adsorbents with high N 2 /O 2 selectivity and improved stability has been developed for oxygen production.