Multi-Component Adsorption Behavior of Hydrogen Isotopes on Zeolite 5A and 13X at 77.4 K

Equilibrium isotherms for the adsorption of H₂, HD, HT, D₂, DT and T₂ on synthetic zeolite type 5A or 13X at 77.4 K are estimated by using a theoretical formula, where the isotopic difference in adsorption depends on the zero-point energy difference between hydrogen isotopes. The formula agrees with the experimental isotherms for H₂ and D₂ on the zeolites. Adsorption of H₂-D₂ and H₂-HD-D₂ mixtures on the same adsorbents is experimentally examined. The experiments are performed using a volumetric apparatus and a quadra-pole-type mass spectrograph. The experimental adsorption behavior of H₂, D₂ and HD shows agreement of separation factors with results calculated according to the ideal adsorbed solution theory describing multi-component behavior, where the equilibrium isotherms estimated for H₂, HD and D₂ are used. Based on the theoretical adsorption model, the multi-component behavior of HT, DT and T₂ is predicted here.