Preparation Of Gas Chromatographic Packing MnCl₂@MOFs@?-Al₂O₃ And There Performance On Separation Of H₂/D₂

As a mature separation and analysis method, gas chromatography has made some progress in the separation of hydrogen isotope H2/D2. The key point in H2/D2 separation on GC is the separating material. Research shows that MOFs have high selective separation of H2/D2 in liquid nitrogen temperature. In this paper, MOFs with good quantum sieving on hydrogen isotope H2/D2 were studied. MOFs@y-Al2O3 composite materials were obtained from MOFs loading to ?-Al2O3 which has hydrogen isotope H2/D2 separation selectivity by chemical method. MOFs@?-Al2O3 was modified by transition metal salt MnCl2, then MnCl2@MOFs@?-Al2O3 composite materials were obtained. The performances of hydrogen isotope H2/D2 separation were studied with the composite materials as gas chromatographic packing. The main research results of this paper as follows:(1) Metal-organic frameworks CPL-1 and Ni-MOF-74 were loaded on ?-Al2O3 successfully with the method of in situ crystallizrtion and layer-by-layer forming CPL-1@?-Al2O3 and Ni-MOF-74@?-Al2O3, then MnCl2@CPL-1@?-Al2O3 and MnCl2@Ni-MOF-74@?-Al2O3 composites materials were obtained using transition metal salt MnCl2 by dipping method. The composite materials were characterized by IR, XRD, SEM, EDS, TGA and N2 adsorption isotherm.(2) The performances of hydrogen isotope H2/D2 separation were studied on CPL-1@?-Al2O3, Ni-MOF-74@?-Al2O3?MnCl2@CPL-1@?-Al2O3 and MnCl2@Ni-MOF-74@?-Al2O3 column under the chromatographic conditions of detector temperature 100?, bridge current 160 mA, sample volume 50 ?L and column temperature 77 K. The experimental results show that hydrogen isotope H2/D2 can be separated effectively on CPL-1@y-Al2O3 and Ni-MOF-74@Y-Al2O3 column. The resolutions of H2 and D2 were up to 1.8 and 1.9, more than ?-Al2O3 and MnCl2@?-Al2O3. But peak retention time was long and trailing phenomenon was serious on CPL-1@?-A12O3 and Ni-MOF-74@?-Al2O3 column, which is not good for quantitative analysis of H2/D2. Peak retention time and tailing phenomenon were solved by MnCl2@CPL-1@?-Al2O3 and MnCl2@Ni-MOF-74@?-Al2O3 column. And the effects of MnCl2 loading amountand carrier gas flow rate on the separation performance of H2/D2 were studied. The results show that the resolutions of MnCl2@CPL-1@?-Al2O3 and MnCl2@Ni-MOF-74@?-Al2O3 were 1.61 and 1.80, respectively separation time were 6.5 min and 10 min under the optimal separation conditions. H2/D2 mixed components were quantitatively analyzed by these two composite materials under the optimal separation conditions.The results show that the RSD of retention time and peak area was less than 1% and 5% which showed good accuracy and reproducibility.The RSD of each component was less than 3%, and the relative error between measured content and actual content was less than 0.05.