Apparatus for studying the adsorption of H2-D2 gas mixtures

Intrinsic D2/H2 Selectivity of NaX Zeolite: Interplay between Adsorption and Kinetic Factors

“…The adsorption selectivity computed at zero pressure of 1.49 in favor of D 2 is in good agreement with PI-GCMC results (see Table ). Furthermore, the reported experimental adsorption D 2 /H 2 selectivity of 1.6 − is in good agreement with our theoretical calculations considering the intrinsic heterogeneities of NaX zeolite at the atomistic scale (e.g., variation of Si:Al ratio and long-range-ordering, Na cation occupancy of the crystallographic positions, defects, presence of impurities, and others) . The kinetic energy of adsorbed hydrogen isotopes converges to its classical value for low pore concentrations, as is expected from theory (see Figure c).…”

“…In this work, we studied the microscopic mechanism of D 2 permselective separation from D 2 /H 2 mixtures in NaX at 77 K. The adsorption D 2 /H 2 selectivity of 1.49 ± 0.01 computed at zero coverage is in good agreement with finite-pressure path integral Monte Carlo simulations of equimolar H 2 /D 2 mixture adsorption in NaX (1.46 ± 0.2) and the reported experimental value of 1.6. − Higher solubility of D 2 results from lower quantum fluctuations (i.e., higher solid–fluid interactions) of a heavier isotope in NaX. The maximum of adsorption selectivity is predicted at infinite dilution of adsorbed mixtures, where the most attractive adsorption centers (narrow windows interconnecting the NaX cages) are preferentially occupied.…”