Synthesis And Properties Of CMBs/ferrite Composite Materials

Today,wastewater origining from industrial printing discharge has brought great harm on production and life of people.Therefore,remediation of environmental pollution becomes one of the important questions.Carbon microbeads（CMBs）as a representative of the carbon materials have the advantages of large specific surface area,high chemical stability,non-toxic,etc.So it is often used as an adsorbent for water or air treatment.However,small size and good dispersion result in difficult to separation from the water,which generates the secondary pollution.Spinel ferrite has excellent ferromagnetic propertie and it can be separated easily from wastewater.Ferrites can serve as multi-functional water purification materials due to their good adsorption performance and light catalytic properties.In this thesis,we synthesized successfully the composite materials with the twice hydrothermal method.Because of the synergy effect of ferrite and carbon microball on water purification,the absorption properties of the composite materials of CMBs/MFe₂O₄（M=Ni,Co,Mg,Zn）would be improved and it can be separated under an external magnet.First,CMBs were synthesised by hydrothermal method.The optimization synthesis condition of the carbon microbeads was studied by changing temperature,time and concentration.The best reaction temperature is 180℃,the best reaction temperature is 4 h and the best concentration of glucose is 0.5 mol/L.Sencond,a certain concentration of Fe³⁺and Ni²⁺solutions were added in carbon microbeads suspension solution without any processing after hydrothermal treatment,and then a second hydrothermal process carries on to obtain CMBs/NiFe₂O₄.We found that the composite material had excellent adsorption ability for methylene blue solution.The adsorption ability of the CMBs/NiFe₂O₄ is the best when the reaction temperature is 200℃,the reaction time is 24h and the ratio of the amount of substance between glucose and NiFe₂O₄ is 20:2.The removal rate of the CMBs/NiFe₂O₄obtained with optimization condition was 96.9%for methylene blue solution of 50 mg/L.The adsorption kinetics of sample is researched,which shows that the kind of adsorption is quasi level two dynamic model,it belongs to chemical adsorption.The maximum adsorption capacity of CMBs/NiFe₂O₄ is 75.643 mg/g by researching Langmuir adsorption isotherm.Also,it could be separated under the effect of magnetic field.Extending the Ni Fe₂O₄ to other ferrite,we also had successfully synthesized CMBs/CoFe₂O₄,CMBs/ZnFe₂O₄,CMBs/MgFe₂O₄ composite materials.We also found that the three kinds of composite materials had excellent adsorption ability for methylene blue solution.The removal rate of the CMBs/CoFe₂O₄,CMBs/ZnFe₂O₄,CMBs/MgFe₂O₄obtained with optimization condition was 88.3%,66.2%,82.3%for methylene blue solution of 100 mg/L.Also,it could be separated under the effect of magnetic field.The CMBs/ferrite composites can be obtained by the simple method,mainly due to CMBs were synthesized at the first hydrothermal process and contain many oxygen-bonds on the surface.The oxygen-bonds can directly react with metal ions and ensure the iron ions effectively contact with divalent metal cations to form spinel ferrite on the surface of the CMBs at high temperature and pressure.