Study On Precise Regulation Strategy Of Metal-organic Framework Channel And Application In Gas Adsorption And Separation

The separation and purification of light hydrocarbon compounds（LHs）mixtures mainly rely on expensive and energy intensive low-temperature distillation.Solid adsorbent adsorption and separation technology has been favored in recent years due to its high efficiency and low energy consumption.On the other hand,the capture and storage of carbon dioxide gas in fossil fuels is one of the ways to meet carbon peak carbon neutrality.Metal-organic framework（MOF）is a new type of crystalline porous material,which has broad application prospects in hydrocarbon separation,carbon dioxide capture and storage due to its adjustability and designability.Based on the structural designability of MOF materials,a channel regulation strategy is adopted to introduce functional elements into their channels and cavities,enhancing the binding affinity of the framework to different guest molecules,thereby improving adsorption selectivity.In this thesis,several novel MOF materials have been designed and synthesized based on pore control strategies,and their potential applications in the separation of olefins/alkanes from CO₂/N₂ have been explored.This provides a new idea for the design and synthesis of MOF materials based on pore control strategies.A new type of Co OF material MOF-1 was synthesized by in-situ solvothermal method,and its structure characterization and adsorption performance were tested.The crystal structure analysis shows that there are octahedral cages and segmented channels within the MOF-1 framework.Single component adsorption tests show that although the framework has a large internal pore size,its adsorption selectivity is low.A novel NiOF material FJUT-4 was synthesized in situ based on solvothermal method using a channel regulation strategy,and its structure characterization and adsorption performance were tested.The experimental results show that FJUT-4 has interconnected twisted cages.The dimethylamine introduced in situ and decomposed by DMF can coordinate with Ni,both as an adsorption site within the cage and as a size regulator for pore size.The appropriate pore size enables the framework to screen CO₂and N₂.Penetration testing further indicates that FJUT-4 can effectively separate CO₂from the CO₂/N₂（15:85）mixture.In the existing NiOF[Ni₂^ⅡNi^Ⅲ-（μ₃-OH）（INA）₃（BDC）_1.5],its isomorphic Co OF Co-1was designed and synthesized,and Co-2 and Co-3 were designed and synthesized on the basis of Co-1 using a channel regulation strategy.The structural characterization and adsorption performance tests of the series were conducted.The test results show that the C₂H₆ selectivity of Co-2 obtained by introducing Cl functional elements into the Co-1channel is as high as 1.7,realizing the adsorption inversion of C₂H₆/C₂H₄,and obtaining C₂H₄ in one step.Co-3,which simultaneously introduces Cl and F functional units,not only maintains C₂H₆ selectivity,but also improves C₂H₂ selectivity.High purity C₂H₄ can be obtained in one step from C₂H₂/C₂H₄/C₂H₆ mixed gas,which has potential application value in the purification of C₂H₄.