Ortho-para-hydrogen and para-ortho-deuterium separation factors on LiX zeolite at 50-112 K

The paper reports on a comprehensive set of experimentally measured orthopara- H2 and para-ortho-D2 separation factors at low temperature adsorption on an especially prepared sample of X type zeolite. The zeolite was investigated in its lithium cationic form by a new version of the gas solid chromatographic technique ECMA (Elution Chromatography with Modifying Adsorbates). Six types of eluents were used: four pure gases He, Ne, H2, D2, and two mixed eluents – He-H2 and He- D2 various compositions. The new ECMA version gives results of high precision. At easily attainable temperatures 77-50 K and practically suitable fractional coverages 0.6-0.8, the selectivity of adsorbent LiX ranges from 1.45 to 2.0 for ortho-para-H2, and 1.108 - 1.254 for para-ortho-D2. A low ortho-para-conversion catalytic activity and high selectivity of new sorbent LiX allow separation of orthopara- isomers of dihydrogens by Moving Temperature Gradient Adsorption technique

Cryoadsorption as universal route to dihydrogens of high and ultrahigh individual purity

The paper describes a new efficient cryoadsorptive method of dihydrogens p-H2, o-H2, HD, o-D2, p-D2, HT, DT, T2 separation with moving temperature gradient on the adsorbent fixed bed. The method was developed at the Department of Chemistry, Moscow State University, as a result of many years’ experimental and theoretical investigations. The separation method, and corresponding periodical action apparatus named MTGA (Moving Temperature Gradient Adsorption), and MGU DETRA (Multispecious Gas Separator-Upgrader: DEuterium, TRitium, Adsorption), respectively, are applied to prepare individual dihydrogens in very pure isotopic or nuclear-spin forms. In this paper, the basic design and possibilities of a typical three – stage laboratory adsorption separative cascade are given. The cascade was used to prepare two gases of ultrahigh isotopic purity (99.9998 mol.% deuterium and 99.98 mol.% deuterium hydride HD) for the first time. Moreover, the paper presents the results of successful studies on enriching microquantities of tritium-containing molecules HT, DT, T2 from macrocomponents H2 and D2