Separation of oxygen and nitrogen from air by molecular sieve adsorbents

Central Salt and Marine Chemicals Research Institute, G. B. Marg, Bhavnagar-364 002, India

E-mail : salt@csir.res.in  Fax : 91-0278-567562

Manuscript received 10 November 2000

Oxygen and nitrogen gases, which find commercial applications in many industries, are totally produced from air. During the last two decades, pressure swing adsorption based processes for separating these gases from air are being increasingly used and have become competitive to conventional low temperature fractionation processes. In the present review, brief idea about the adsorption principle, and adsorption process employed for separation of these gases from air is given. Microporous solids like zeolites and carbon molecular sieves used as adsorbents arc central to this separation. The intrinsic equilibrium and kinetic properties of these solids can strongly influence the efficiency and economics of a particular separation process. Therefore, review has mainly focused on the developments on the adsorbents used for oxygen and nitrogen separation. Zeolites, carbon molecular sieves and inorganic metal complexes that show adsorption selectivity towards oxygen or nitrogen are discussed at length.