摘要
Magnetic Fe3O4 nanoparticles were prepared by means of coprecipitation using NH3-H2O in water and in alcohol, and using NaOH in water. A series of instruments such as SEM, TEM, HRTEM, FT-IR, XRD and VSM were used to characterize the properties of the magnetic nanoparticles. The results indicated that the magnetism of Fe3O4 nanoparticles synthesized using NH3.H2O in water was the highest, although the reaction time was the longest. The process using NaOH in water was the simplest and the reaction time was the shortest, but the particle characteristics were inferior to those of the other two methods. The mean size of magnetic Fe3O4 nanoparticles prepared by coprecipitation in alcohol was the smallest among the three, but the nanoparticles aggregated severely. The magnetic Fe3O4 nanoparticles were coated with oleic acid using saturated sodium oleate, and the polarity of the surface-modified nanoparticles was measured. Fe3O4 nanoparticles prepared using NH3.H2O, not NaOH, could be coated successfully and thoroughly.
Magnetic Fe3O4 nanoparticles were prepared by means of coprecipitation using NH3-H2O in water and in alcohol, and using NaOH in water. A series of instruments such as SEM, TEM, HRTEM, FT-IR, XRD and VSM were used to characterize the properties of the magnetic nanoparticles. The results indicated that the magnetism of Fe3O4 nanoparticles synthesized using NH3.H2O in water was the highest, although the reaction time was the longest. The process using NaOH in water was the simplest and the reaction time was the shortest, but the particle characteristics were inferior to those of the other two methods. The mean size of magnetic Fe3O4 nanoparticles prepared by coprecipitation in alcohol was the smallest among the three, but the nanoparticles aggregated severely. The magnetic Fe3O4 nanoparticles were coated with oleic acid using saturated sodium oleate, and the polarity of the surface-modified nanoparticles was measured. Fe3O4 nanoparticles prepared using NH3.H2O, not NaOH, could be coated successfully and thoroughly.
基金
The project was supported by the National Natural Science Foundation of China （NNSFC, No. 20476065）
the Scientific Research Foundation for Returned 0verseas Chinese Scholars of the State Education Ministry （SRF for R0CS, SEM）
the Key Lab. of Multiphase Reaction of the Chinese Academy of Sciences （No. 2003-5）
the State Key Lab. of Coal Conversion of CAS, the Key Lab. of 0rganic Synthesis of Jiangsu Prov., Foundation of Chemical Experiment Center of Soochow Univ. and R＆D Foundation of Nanjing Medical Univ. （NY0586）.
