Preparation Of Three New Types Of Elution Chromatographic Packing And Their Research Of Separation/Analysis Properties For Hydrogen Isotope H₂/D₂

In this paper,the separation of hydrogen isotope H2/D2 was studied by using elution chromatography to place the column in a liquid nitrogen cup(77K).This paper has made the following research progress:1.This paper prepared three new composite materials MnCl2@8-Ni-MOF-74@NH2-γ-Al2O3、MnCl2@2-Ni/Co-MOF-74@γ-Al203 and MnCl2@2-Co-MOF-74/Ni-MOF-74@γ-Al2O3,using the following characterization methods of infrared spectroscopy,powder X-ray diffraction spectroscopy,scanning electron microscopy,EDS spectroscopy,N2 adsorption-desorption isotherm,and thermogravimetry-difference analysis to characterize the three composites.2.The three composite materials of MnCl2@8-Ni-MOF-74@NH2-γ-Al2O3、MnCl2@2-Ni/Co-MOF-74@γ-Al2O3 and MnCl2@2-Co-MOF-74/Ni-MOF-74@γ-Al2O3 were loaded into a stainless steel column with a length of 1.0 m and an internal diameter of 2.0 mm as an elution chr-omatographic packing,using for analytical study of the separation of hydrogen isotope H2/D2.The following experimental conditions were fixed:the temperature of the thermal conductivity detector(TCD)was 100℃,the column temperature was 77K(the stainless steel column was immersed in the liquid nitrogen cup),the bridge current of the chromatograph was 150mA,and the helium gas was selected as the carrier gas.By changing the cycle loading times of Ni-MOF-74、Ni/Co-MOF-74 and Co-MOF-74/Ni-MOF-74,the loading amounts of MnCl2,carrier gas flow rates and injection volumes to explore the best experimental conditions for separation of hydrogen isotope H2/D2.The research shows that the optimum experimental conditions for MnCl2@8-Ni-MOF-74@NH2-γ-Al2O3 is as follow:the cycle loading times of Ni-MOF-74 is 8,the loading amounts of MnCl2is 20wt%,carrier gas flow rate is 30 mL/min,and injection volume is 100 μL.Under this condition,the separation selectivity is the best,the resolution R is 2.13,and the separation time is 4.04min.The research shows that the optimum experimental conditions for MnCl2@2-Ni/Co-MOF-74@γ-Al2O3 and MnCl2@2-Co-MOF-74/Ni-MOF-74@γ-Al2O3 are as follow:the cycle loading times of Ni/Co-MOF-74 and Co-MOF-74/Ni-MOF-74 are 2,the loading amounts of MnCl2 are 25wt%and 20wt%,carrier gas flow rate is 60 mL/min,and injection volume is 100 μL.Under this condition,the separation selectivity is the best,the resolution R are 2.75 and 2.11,and the separation time are 3.95min and 4.81 min,respectively.MnCl2@8-Ni-MOF-74@NH2-γ-Al2O3 composites were used as chromatographic packings to separate hydrogen isotopes H2/D2,solving the problems of lower chromatographic peak efficiency,lower resolution and longer separation time by 8-Ni-MOF-74@NH2-γ-Al2O3 effectively.MnCl2@2-Ni/Co-MOF-74@γ-Al2O3 and MnCl2@2-Co-MOF-74/Ni-MOF-74@γ-Al2O3 composites were used as chromatographic packings to separate hydrogen isotopes H2/D2,solving the problems of lower chromatographic peak efficiency and chromatographic peak tailing,in addition,the retention time of H2/D2 components in the chromatogram is reduced,and the separation efficiency is improved.3.Quantitative analysis of the separation of hydrogen isotope H2/D2(volume ratio 1:1)by MnCl2@8-Ni-MOF-74@NH2-γ-Al2O3,MnCl2@2-Ni/Co-MOF-74@γ-Al2O3 and MnCl2@2-Co-MOF-74/Ni-MOF-74@γ-Al2O3 chromatographic packings.The results prove that the relative standard deviations of the retention times of pure and mixed components of H2 and D2 are all less than 1%,the relative standard deviations of peak areas are all no more than 5%,the relative error of the respective volume percentages of the mixed components H2 and D2 between after the injecting samples and before the injecting samples is not more than ±0.10,therefore,the columns filled with the chromatographic packings synthesized in this dissertation have good repeatability and accuracy,and the quantitative results are accurate.