Study On The Surface Functionalization Of MOFs And Their Selective Adsorption To Heavy Metal Ions And Organic Target Molecules

With the rapid development of economy,wastewater caused by pollutants such as dyes,phenols and metal ions is becoming more and more serious.How to efficient removal of pollutants from wastewater is an important subject.Metal-organic frameworks(MOFs)have the advantages of large specific surface area,high porosity,adjustable pore structure,etc.,and have good application prospects in the field of adsorption and removal of pollutants in wastewater,which has aroused people’s extensive attention to the design,development and application of MOFs materials.Three kinds of surface functional MOFs with excellent properties have been prepared for the adsorption of water pollutants,and the possible mechanism in the adsorption process was explored.The main research contents are as follows:(1)A new nanocomposite NH2-mSiO2@MIL-101(Cr)with a core-shell structure has been synthesized.The adsorption/separation ability of NH2-mSiO2@MIL-101(Cr)for Pb(Ⅱ)and Cr(Ⅵ)under different conditions was investigated.NH2-mSiO2@MIL-101(Cr)has excellent adsorption activity and selective adsorption of Pb(Ⅱ).In addition,adsorption kinetics and thermodynamics,as well as the mechanism of selective adsorption,were also analyzed.(2)The incorporation of polyethyleneimine(PEI)into Cu-BTC composites has been used for the first time to effectively remove Congo red(CR).FESEM,XRD,FT-IR,TG and Zeta potential measurements have been used to characterize these Cu-BTC composites.PEI modified Cu-BTC showed the best adsorption selectivity for CR,and its maximum adsorption capacity was 2578.6 mg/g.In addition,adsorption kinetics,adsorption thermodynamics,and adsorption mechanisms were also investigated.(3)A new complex of NH2-MIL-53(Al)@CNT was successfully constructed by combining NH2-MIL-53(Al)with carbon nanotubes(CNT)synthesized by ZIF-67.It was found that due to the synergistic effect,the heterojunction produced between CNT and NH2-MIL-53(Al)as well as the increased BET surface area and total volume were proved to be advantageous for enhancing the adsorption activity.The adsorption kinetics,isotherm and thermodynamics,and adsorption mechanism were analyzed in detail with BPAF and metribuzin as removal targets.