Selective Adsorption Desulfurization Performance Of Multi-Metal Ions In Cu-BTC

The key problem of metal-organic frameworks（MOFs）applied in adsorptive desulfurization is to improve its selectivity and adsorption capacity.In this work,Cu-BTC（one of the typical MOFs）is utilized as the substrate,it was optimized of the adsorption performance of benzothiophene（BT）by metal ions doping and magnetic modification.The research contents majorly include:1.Using 1,3,5-benzotricarboxylic acid as the organic ligand,Cu（II）as the metal precursor,the second metal V（III）was doped by in-situ hydrothermal method to generated bimetal V/Cu-BTC.The N₂ adsorption-desorption characterization substantiated that V/Cu-BTC still possesses large volume in its structure though the BET specific areas dropped by 45%compared with Cu-BTC（Cu-BTC 1242 m²/g,V/Cu-BTC 682m²/g）.XRD,SEM and FT-IR showed that V/Cu-BTC still maintain octahedral crystal structure,unique crystal diffraction peaks and functional groups.XPS results revealed that the structure of Cu（I）exists in V/Cu-BTC,indicating V-Cu redox happened during the hydrothermal synthesis process.Batch results show that the adsorption capacity of BT over V/Cu-BTC reaches 75 mg/g,superior than that of Cu-BTC by 25%.The adsorption processes are in well accordance with Langmuir isotherms model and Pseudo-second kinetics model.2.Using 1,3,5-benzotricarboxylic acid as the organic ligand,Cu（II）,Zn（II）,and Ni（II）as the metal node,mono-metal Cu-BTC,bimetal Zn/Cu-BTC and tri-metal Zn/Ni/Cu-BTC were accordingly synthesized through in-situ hydrothermal method.Metal Ag was introduced into the MOFs mentioned above to generate Ag@Cu-BTC,Ag@Zn/Cu-BTC and Ag@Zn/Ni/Cu-BTC,respectively.The structural information,crystal morphology and elemental content were characterized by N₂adsorption-desorption,XRD,SEM,XPS and FT-IR.The BT uptake capacity over the MOFs was tested under different model fuels system（aliphatic,aromatic and mixed model fuels）.The results confirm that the introduction of multi-metals is favorable for improving the adsorption performance with Ag@Zn/Ni/Cu-BTC possesses the highest uptake amount（105mg/g）3.Using Fe₃O₄ nano-spheres（200nm）,1,3,5-benzotricarboxylic acid,Cu（II）and Zn（II）as the raw materials,magnetic multi-metal materials Fe₃O₄@MOFs was synthesized through one-pot hydrothermal method.The properties and structural information of the material were characterized using N₂ adsorption-desorption,XRD,SEM,XPS and FT-IR.Results substantiate that Fe₃O₄ was coated around the surface of the MOFs.The composite material possesses a mesopor-micropore structure.Compared with Cu-BTC,the BT uptake（91mg/g）over Fe₃O₄@Cu-BTC increases by52%.The adsorption process conforms to the Langmuir isotherms model and Pseudo-second kinetics model.