Fe_3O_4/SiO_2复合粒子的制备及对Cd^(2+)的吸附性能研究

Preparation of Fe_3O_4/SiO_2 Composite Particles for Cadmium(Ⅱ) Adsorption from Aqueous Solution

采用共沉淀法制备出粒径为10nm左右、具有超顺磁性的Fe3O4纳米粒子,在Fe3O4纳米粒子外包覆SiO2合成了磁性Fe3O4/SiO2复合粒子,研究了该复合粒子对水溶液中Cd2+离子的吸附性能.利用透射电子显微镜(TEM)、X射线衍射仪(XRD)、红外光谱(FTIR)、振动样品磁强计(VSM)和原子吸收分光光度计(AAS)对样品进行表征,考察了SiO2不同包覆量对吸附剂吸附性能的影响.结果表明:随着SiO2包覆量的增大,SiO2壳层厚度增大,内核中包埋的Fe3O4粒子数量增多,Fe3O4/SiO2复合粒子尺寸随着增大,由50nm左右增大到300 nm左右;Fe3O4纳米粒子表现出了良好的磁性能,比饱和磁化强度达73.6A·m2·kg-1,Fe3O4/SiO2复合粒子的比饱和磁化强度随SiO2包覆量的增大而逐渐减小;Fe3O4/SiO2复合粒子的吸附率随着SiO2包覆量的增多而逐渐增大,最大吸附率为91.0%.

The superparamagnetic Fe3O4 nanoparticles with the size of about 10 nm were prepared by coprecipitation method.The magnetic Fe3O4/SiO2 composite particles were synthesized by coating SiO2 on Fe3O4 nanoparticles for the adsorption of Cd2＋ions from aqueous solution.The samples were characterized by transmission electron microscope（TEM）,X-ray diffraction（XRD）,Fourier transform infrared（FTIR）,vibrating sample magnetometer（VSM）and atomic absorption spectrophotometer（AAS）.The effect of the different coating amount of SiO2 on the adsorption properties of the Fe3O4/SiO2 composite particles was investigated.The results show that with the coating amount of SiO2 increasing,the thickness of SiO2 shell increases,the number of Fe3O4 nanoparticles in the core increases,the size of Fe3O4/SiO2 composite particles increases from about 50 nm to about 300 nm.The as-prepared Fe3O4/SiO2 composite particles exhibit an excellent magnetic property with the saturation magnetization of 73.6A·m2·kg-1.The saturation magnetization of Fe3O4/SiO2 composite particles decreases with the increase of the coating amount of SiO2.The adsorption efficiency of Fe3O4/SiO2 composite particles gradually increases with the coating amount of SiO2 increasing,and the maximum absorption efficiency is 91.0%.