FeCl2×4H2O和FeCl3×6H2O为原料、NaOH为沉淀剂，采用撞击流-旋转填料床制备Fe3O4纳米颗粒，考察了超重力因子、液体流量和反应物浓度对Fe3O4颗粒粒径的影响及其对Pb(II)和Cd(II)的吸附性能. 结果表明，随超重力因子、液体流量及反应物浓度增加，Fe3O4颗粒的粒径减小，最佳制备条件为超重力因子65.32、液体流量60 L/h及FeCl3×6H2O浓度0.321 mol/L，该条件下所制超顺磁性单分散Fe3O4纳米颗粒的平均粒径约为10 nm，饱和磁化强度为60.5 emu/g. Fe3O4纳米颗粒对Pb(II)和Cd(II)吸附过程符合Langmuir吸附等温模型，计算的最大吸附容量分别为30.47和13.04 mg/g.

A novel impinging stream-rotating packed bed was used to prepare Fe3O4 nanoparticles with aqueous solutions of FeCl3/FeCl2 and NaOH as raw materials. The effects of high gravity factor, liquid flow rate and reactant concentrations on the particle size of Fe3O4 were examined. Moreover, the adsorption property of Fe3O4 nanoparticles to Pb(II) and Cd(II) was evaluated. The results showed that higher high gravity factor, larger liquid flow rate and higher concentration of reactants were associated with smaller size of Fe3O4 nanoparticles. Fe3O4 nanoparticles were quasi-spherical with the average diameter of about 10 nm and showed superparamagnetic behavior with the saturation magnetization of 60.5 emu/g under the optimal operation conditions, which were high gravity factor of 65.32, liquid flow rate of 60 L/h and FeCl3×6H2O concentration of 0.321 mol/L. The adsorption of Fe3O4 nanoparticles to Pb(II) and Cd(II) well fitted to the Langmuir isothermal model, and their maximum adsorption capacities calculated were 30.47 and 13.04 mg/g for at pH value 6.0, respectively.