What is an alternative to zeolite for oxygen concentrator?

An alternative to zeolite for oxygen concentrators is carbon molecular sieves (CMS) or membranes. CMS can also be used in gas separation processes, but zeolite is more commonly preferred for oxygen generation due to its higher efficiency and cost-effectiveness in nitrogen adsorption. Membrane-based systems are used in some oxygen generation applications, but they are typically less efficient than PSA systems with zeolite.