Preparation Of Amine-Modified Metal-Organic Framework Materials And Their Carbon Dioxide Adsorption Properties

According to the statistics of the International Energy Agency,the current global energy consumption is mainly coal,oil,natural gas and other fossil fuels.With the rapid growth of the global economy and population,the consumption of fossil energy also shows a trend of rapid growth,which will inevitably lead to the emission of a large amount of carbon dioxide into the atmosphere,and also cause serious environmental problems to the earth,such as global warming,Ocean acidification,extreme weather and species extinction,etc.In recent years,many countries,including China,have proposed carbon neutrality goals,and carbon capture and storage（CCS）technology has been regarded as an important technical means for countries to achieve carbon neutrality goals.Metal-organic frameworks（MOFs）are relatively new crystalline porous materials considered as the most promising carbon capture and sequestration technology candidates due to their unique structural features,high specific surface area,and chemical tunability.Because MOFs are highly compatible with other materials,they can be used as precursors or templates to synthesize MOFs derivatives with desired properties with other materials with special properties.The purpose of this thesis is to use MIL-101（Cr）and Cu-BTC as the base materials to load organic amine molecules onto the MOFs framework by post-synthesis modification of MOFs.Using the two-solvent method to coordinate the organic amine molecules with the open metal sites in the pores of the MOFs,and by adding different amounts of diethylenetriamine（DETA）to the solution,the MIL-101（Cr）derivative,n-DETA-MIL,was prepared.（n=0.01,0.03,0.05 and 0.07 ml）,the effects of different amounts of DETA on the structure and CO₂adsorption properties of MIL-101（Cr）derivatives were systematically investigated.When the addition amount of DETA is 0.03 ml,the improvement of CO₂adsorption effect is the most significant,and its crystal structure is basically the same as that of MIL-101（Cr）,With the increase of the amount of DETA added,the BET test results showed that the BET specific surface area of the derivative gradually decreased,and the crystal morphology also changed significantly,and some crystal grains appeared collapse and agglomeration.The CO₂gas adsorption test results showed that with the increase of DETA addition,the CO₂adsorption increased first and then decreased.Organic alkylamines with different chain lengths were loaded onto MIL-101（Cr）and Cu-BTC frameworks by post-synthesis modification of MOFs,and the same amount of organic amines（ethylenediamine:EDA;Diethylenetriamine:DETA;triethylenetetramine:TETA）was added to the solution by a two-solvent method,prepared a series of MIL-101（Cr）derivatives namely 0.03-M-MIL-101（Cr）and0.03-M-Cu-BTC（M=EDA,ETA and TETA）to study the effect of organic amines with different chain lengths on the structures and adsorption properties of derivatives.Compared with the unmodified MIL-101（Cr）,the CO₂adsorption performance of the three organic amines modified MIL-101（Cr）was significantly improved,among which the EDA modified CO₂adsorption performance improved the most significantly.The CO₂adsorption performance after Cu-BTC modification was also improved most significantly.In this paper,a series of organic amine-modified MOFs materials with different chain lengths and different loadings were prepared,the preparation process of MOFs materials with the desired properties was explored,and the effects of the loading of amine groups and pore structure on the CO₂adsorption performance were studied.The experimental results in this paper are as follows:Adsorbent materials to improve CO₂adsorption performance provided experimental and theoretical basis.