Study on decarbonization properties and mechanism of composite adsorbent with modified biochar based on MOFs
In order to further explore high performance MOFs-based CO2 composite adsorbents,firstly,biochar was modified by doping Ce,Cu,Mn,and Co multi-metals,and on the basis of exploring the optimal preparation method,Mg-MOF-74modified biochar composite adsorbents were prepared by structural design based on the basic properties that biochar and Mg-MOF-74 contain unsaturated metal sites and oxygen-containing functional groups together.On the basis of obtaining the composite adsorption properties of Mg-MOF-74 modified biochar,the coupling and synergistic mechanisms among the loaded multi-metals,MOFs materials and biochar were investigated,and the microscopic properties such as pore structure,surface functional groups and crystalline structure of the samples were studied by various characterization methods.The decarbonization mechanism of the composite adsorbent was also investigated by combining adsorption kinetics,adsorption thermodynamics and elemental valence changes.It was found that the sol-gel method is favorable for the preparation of modified biochar.The loaded multi-metals existed as metal oxides in the modified biochar,and the oxidized edge lattice defects introduced oxygen-containing functional groups to the modified biochar,and the best results were obtained for the 10％Fe+4％Ce+2％Cu sample with an adsorption capacity of 1.53mmol/g.The adsorption of CO2 by the composite adsorbent was the result of the combined effect of physical and chemical adsorption,and the MOFs material optimized the pore structure of the composite adsorbent.The pore structure of the composite adsorbent was optimized by the MOFs material,and the chemisorption occurred on the surface of the modified biochar due to its graphite microcrystalline structure and doped multi-metal modification,the composite of the two played a mutually promoting and synergistic role in the decarbonization process,so that the adsorption performance of the composite adsorbent was significantly improved.The improvement was 230.7％and 75.7％compared to modified biochar and Mg-MOF-74,respectively.
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维普
