纳米Fe_3O_4粒子的制备及表面包覆

采用化学共沉淀法和氧化沉淀法制备磁性纳米Fe3O4粒子,并用柠檬酸三钠为表面活性剂包覆制备纳米Fe3O4粒子,同时利用包覆磁性粒子制备水基纳米磁性液体。对两种方法制备的纳米Fe3O4粒子的晶体结构、微观形貌及化学共沉淀法制备的Fe3O4在包覆前后等电点的变化进行了表征。结果表明,化学共沉淀法制备的纳米Fe3O4粒子平均粒径约为20 nm且分布比较均匀,表面活性剂包覆后,等电点由原来的pH=6.70移向pH=2.35,证实了Fe3O4粒子表面被柠檬酸离子所包覆,且制得的磁性液体的稳定性比较高;而氧化沉淀法制备Fe3O4纳米粒子粒径分布是从几十纳米到上百纳米,制得的磁性液体出现很明显的团聚。

Preparation and Surfaces Modification of Magnetic Fe3O4 Nanoparticles

Magnetic Fe3O4 nanoparticles were prepared by the chemical co-precipitation and oxidation precipitation methods, and the water-base magnetic fluids were obtained by dispersing sodium citrate-coated nanoparticles into water. The morphologies and sizes of the Fe3O4 particles were investigated and the isoelectric points of Fe3O4 prepared by chemical co-precipitation method after modification with/without sodium citrate were determined. The results showed that the average size of Fe3O4 nanoparticles prepared by chemical co-precipitation method was about 20 nm, which was much smaller than that of the particles prepared by the oxidation precipitation method. The isoelectric points of Fe3O4 particles prepared by chemical co-precipitation method before and after modification with sodium citrate were at pH=6.70 and pH = 2. 35, respectively.