Preparation and characterization of Fe/SiO_2 core/shell nanocomposites

In a simple ethanol-water system,the magnetic α-Fe nanoparticles(with an average diameter of 10-40 nm)were prepared by reduction of Fe2 +using potassium borohydride in the presence of surfactant.Then the shell was formed by hydrolysis-condensation polymerization of tetraethylorthosilicate(TEOS)on the surface of the Fe particles.The samples were characterized by XRD,TEM,SAED,TG-DSC and VSM.The results indicate that a thin film of silica is coated on the surface of Fe particles through a Si-O-Fe bond.The coated shell of silica can effectively protect the Fe cores from being oxidized.     

磁性X沸石的合成及其性能

采用水热合成法,在X型沸石的晶化原料液中加入磁核合成了磁性沸石,对合成产物进行了结构性能测试. 结果表明,产物为X型沸石结构,具有较好的磁性能和吸附性能. 饱和磁化强度为3.7 emu/g,在磁场作用下,磁性沸石在30 min内完成与母液的分离,产物的比表面积为571.5 m2/g,铅离子吸附量为196.8 mg/g.     

磁性沸石的制备与表征及其对Pb2+的吸附性能

通过氨基甲酸乙酯的粘结作用使天然沸石与Fe3O4结合,制备了具有吸附和磁性能的沸石复合体. 利用XRD, SEM, 氮吸附等温线和振动样品磁强计等对所制磁性沸石进行了表征. 结果表明,与钠型沸石相比,磁性沸石的结构没有发生明显改变,比表面积由25.13 m2/g增至38.01 m2/g. 磁性沸石和钠型沸石对模拟废水中Pb2+的平衡吸附量分别为54.53和66.99 mg/g,两者对Pb2+的吸附符合Langmuir型液相吸附,其单层饱和吸附量分别为50.89和65.92 mg/g.