Study On Adsorption Properties Of Magnetic Graphene Based Composites For Several Typical Water Pollutants

It is regarded as the basic construction unit of various carbon materials.Monolayer graphene has only one carbon atom layer thickness（0.35 nm）,and the outer three electrons of carbon atoms are formed by SP² hybridizationσBond,each lattice contains threeσBond,forming a stable hexagon,the bond angle is 120^°,and the C-C bond length is about 0.142nm.SP in each carbon atom The porbitals perpendicular to the hybrid plane form large delocalizedπbonds side by side,which run through the whole graphene plane.Its specific surface area is 2630 m²·g^-1,much higher than graphene and carbon nanotubes have.Graphene materials are good absorbers.However,go has strong hydrophilicity,which leads to difficulties in recycling and secondary pollution:Theπ-πinteraction between graphene layers leads to the stacking agglomeration and the reduction of adsorption performance,which hinders the practical application of graphene based adsorption materials.Compounding is an effective solution to these issues.In this thesis,GO was prepared using the improved Hummers method.With go as the precursor,the graphene based materials of r GO-Fe₃O₄ and GO-Ni Fe₂O₄-CS composites were prepared,which were used to adsorb a variety of heavy metals and organic dyes in aqueous solution.XRD,FESEM/EDX,TEM/SAED,FTIR,Raman,TG,XPS and magnetization curves were used to characterize these graphene-based materials Based on the comprehensive consideration of comparison of adsorption experiment and sample spectra before and after adsorption,The mechanism of adsorption is proposed.The main findings and conclusions were as follows:（1）r GO-Fe₃O₄ was prepared by in-situ hydrothermal method.When the dosage of r GO-Fe₃O₄is 750 mg·L^-1,500 mg·L^-1 and 500 mg·L^-1 respectively,the adsorption equilibrium of the above three adsorbents with initial concentrations of 50 mg·L^-1,50 mg·L^-1 and 50mg·L^-1 is reached in 150 min,60 min and 90 min respectively,and the equilibrium adsorption rate and adsorption capacity are 81.46%/54.31 mg·g^-1,93.46%/93.46 mg·g^-1 and 95.49%/95.49 mg·g^-1 respectively.It shows efficient adsorption performance:After five cycles of adsorption,the adsorption rate and adsorption capacity of r GO-Fe₃O₄ for PO₄^3-,Mo and R6are 70.61%/47.07 mg·g^-1,84.49%/84.49 mg·g^-1 and 86.94%/86.94 mg·g^-1 respectively,showing good recycling performance.（2）GO-Ni Fe₂O₄-CS was prepared by in-situ hydrothermal method.When the dosage of GO-Ni Fe₂O₄-CS is 500 mg·L^-1,650 mg·L^-1 and 500 mg·L^-1 respectively,the adsorption equilibrium of the above three adsorbents with initial concentrations of 50 mg·L^-1,50mg·L^-1 and 20 mg·L^-1is reached in 90 min,120 min and 120 min respectively,and the equilibrium adsorption rate and adsorption capacity are 90.91%/90.91 mg·g^-1,85.13%/65.48 mg·g^-1 and 80.13%/35.97 mg·g^-1 respectively.It shows efficient adsorption performance:After five cycles of adsorption,the adsorption rate and adsorption capacity of GO-Ni Fe₂O₄-CS for NR,PO₄^3-and Cr（VI）are 81.17%/81.17 mg·g^-1,71.63%/55.09mg·g^-1 and 68.29%/27.32 mg·g^-1 respectively,showing good recycling performance.