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The equilibrium adsorption amounts of hydrogen isotope gas and the Brunauer−Emmett−Teller (BET) surface area were measured at 77 K with different microporous and mesoporous molecular sieves. The results indicate that good linear relationships are observed between the amount adsorbed and the BET surface area at (0.02, 0.04 0.06, 0.08, 0.10, and 0.12) MPa for microporous or mesoporous adsorbents, which provide proof of the monolayer adsorption mechanism for hydrogen isotopes at supercritical temperatures. Effects of specific surface area and pore size are more important than the surface properties of adsorbents for hydrogen isotope storage with the physical adsorption method. The equilibrium adsorption difference between hydrogen and deuterium is increased with a decrease of pressure. Moreover, the adsorption capacity of hydrogen isotopes on mesoporous molecular sieves is smaller than that on microporous molecular sieves at the same temperature, pressure, and BET surface area. [ABSTRACT FROM AUTHOR]

Abstract: The equilibrium and kinetic adsorption data of H2 and D2 on the micropore molecular sieve Y were collected at 77K with the volumetric setup, and adsorption rate constants of deuterium evaluated from kinetic adsorption isotherms are larger than that of hydrogen at low pressure. In order to further study the influence factor of hydrogen isotope separation, the breakthrough curves of H2 and D2 mixture on this adsorbent were measured with the single column adsorption apparatus. Effects of different flow rate and pressure on separation efficiency were investigated, and up to 1.52 of the separation factor is obtained at the total gas pressure of 0.4MPa and flow rate of 129.79cm3/min with the adsorption bed length of 1.0m. However, the ratios of the adsorbed amount of deuterium over hydrogen are only 1.18 and 1.17 at 0.0139 and 0.0175MPa, respectively. Based on the difference between equilibrium adsorption and dynamic adsorption in the column, the key factor of separating H2 and D2 mixture depends on their dynamic difference. Lastly, a model for the fixed adsorption bed was built to simulate the concentration distribution of H2 and D2, and the simulation results agree well with experimental results. [Copyright &y& Elsevier]