Preparation Of Series ZIF-67@ Carrier Chromatographic Stationary Phase Materials And Their Separation Performance For Hydrogen Isotopes

In this paper,layer-by-layer self-assembly method,in-situ sacrificial template method and in situ crystallization method are used to realize Al-NDC with kinetic quantum sieving effect,as well as kinetic quantum sieving and chemical affinity quantum sieving effect.The combination of ZIF-67 and carrier materials successfully prepared n-ZIF-67@NH2-SiO2(n=1,2,3,4),m-Al-NDC@y-AlOOH composites(m=1.02%),1.12%,2.61%,4.35%,6.63%),n-ZIF-67@1.12%-Al-NDC@y-AlOOH composite(n=1,2,3,4),n-ZIF-67@y-AlOOH(n=2,4,6,8)composites of these series.The(pH=p)Na2Cr207@2-ZIF-67@y-AlOOH(p=5.25,5.50,6.00,6.50,7.00)composite was then successfully prepared by impregnation-spin evaporation.These composite materials were used as gas chromatography stationary phases for hydrogen isotope separation.And got the following research results:(1)ZIF-67 with excellent separation performance for hydrogen isotope is loaded onto amino-modified SiO2 by layer-by-layer self-assembly method to obtain n-ZIF-67@NH2-SiO2(n=l,2,3,4)series of composite materials.The composites were characterized by IR,XRD,SEM,TG-DTA and BET total analysis.Use helium as the carrier gas and pre-purify the gas before testing;then set the machine parameters,the thermal conductivity detector temperature is set to 100℃,the bridge current is set to 160 mA;the final packed column is placed in liquid nitrogen(77)K is used as the experimental temperature;the injection method is a gas injection needle(H2:D2=1:1)injection.The n-ZIF-67@NH2-SiO2 composite(n=1,2,3,4)was used as a chromatographic packing for separating hydrogen isotopes.The optimum conditions for the separation of hydrogen isotope mixture gas H2/D2 are ZIF-67 loading times of 3 times,carrier gas flow rate of 20 mL·min-1,and injection volume of 50 μL.The separation selectivity is optimal,and the separation degree is R.The ratio was 1.52 and the separation time was 10.15 min.Under these conditions,the 3-ZIF-67@NH2-Si02 composite was used as a chromatographic stationary phase material to separate H2/D2 for repeatability verification and quantitative analysis.(2)The in-situ sacrificial template method was used to synthesize m-Al-NDC@y-AlOOH(m=1.02%,1.12%,2.61%,4.35%,6.63%)composite as a carrier,and then by in-situ crystallization ZIF-67 with excellent separation performance of hydrogen isotope was loaded onto 1.12%-Al-NDC@y-AlOOH to obtain n-ZIF-67@1.12%-Al-NDC@y-AlOOH composite(n=1,2,3,4).The composites were characterized by a series of characterization methods.The composite material was used as a chromatographic packing material to study the separation/analytical performance of H2/D2 by gas chromatography at liquid nitrogen temperature.The optimum conditions for n-ZIF-67@1.12%-Al-NDC@y-AlOOH as a chromatographic packing for hydrogen isotope separation are:1.12%for Al-NDC and 2 times for ZIF-67.The separation rate was 30 mL·min-1,and the injection selectivity was 50 L.The separation selectivity was the best,the resolution R was 2.02,and the separation time was 7.72 min.Under the optimal conditions,the 2-ZIF-67@1.12%-Al-NDC@y-AlOOH composite was investigated as a chromatographic stationary phase material to separate H2/D2 for repeatability verification and quantitative analysis.(3)The γ-AlOOH material was synthesized by hydrothermal method as a carrier,and then ZIF-67 with good separation effect on hydrogen isotope was loaded onto y-AlOOH by in-situ crystallization method to obtain n-ZIF-67@γ-AlOOH(n=2,4,6,8)composite.The(pH=p)Na2Cr207@2-ZIF-67@γ-AlOOH(p=5.25,5.50,6.00,6.50,7.00)composite was then successfully prepared by impregnation-spin evaporation.Under certain chromatographic conditions:the thermal conductivity detector(TCD)temperature is set to 100 ℃,the column temperature is 77 K,the chromatograph bridge current is 160 mA,and helium is used as the carrier gas.(pH=p)Na2Cr207@2-ZIF-67@γ-AlOOH(p=5.25,5.50,6.00,6.50,7.00)When the composite is used as a chromatographic stationary phase,the optimal experimental conditions are ZIF-67 loading.The number of times is 2,the pH of the Na2Cr2O7 synthetic mother liquor is 5.50,the carrier gas flow rate is 20 mL·min-1,and the injection volume is 50 μL.The separation selectivity is the best,the resolution R is 2.15,and the separation time is 2 times.It is 8.81 min.Under these conditions,the(pH=5.50)Na2Cr2O7@2-ZIF-67@γ-AlOOH composite was used as a chromatographic stationary phase material to separate H2/D2 for repeatability verification and quantitative analysis.