The Use of Metal-Organic Frameworks as Adsorbents for Hydrogen Purification

Metal-organic frameworks of the family M2 (2,5-dioxido-1,4-benzenedicarboxylate) wherein M=Mg, Mn, Fe, Co, Cu, Ni or Zn are a group of porous crystalline materials formed of metal cations or clusters joined by multitopic organic linkers that can be used to isolate individual gases from a stream of combined gases. This group of adsorbant materials incorporates a high density of coordinatively-unsaturated MII centers lining the pore surfaces. These adsorbents are particularly suited for selective carbon dioxide/monoxide adsorption via pressure swing adsorption near temperatures of 313 K since they selectively adsorb carbon dioxide at high pressures in the presence of hydrogen, and desorb carbon dioxide upon a pressure decrease. The redox-active FeII centers in Fe2(dobdc) can be used for the separation of O2 from N2 and other separations based on selective, reversible electron transfer reactions. Gas storage, such as acetylene storage, and catalysis, such as oxidation, are also useful applications of these materials