Adsorption and separation studies of lanthanide ions on the magnetic adsorbents are presented.The synthesis of SiO2 coated magnetic particle has been the focus for adsorption of lanthanide ions and magnetic separation due to the outstanding ability for selective adsorption of the target ions on functionalized ligand,and separation of adsorbent materials by external magnetic field.Magnetic adsorbents for lanthanide ions were prepared through synthesis of Fe3O4/SiO2 core/shell nanoclusters by modified Stober method,and surface modification process.As magnetic adsorbents,the Fe3O4/SiO2 core/shell nanoclusters are prepared by silica growth on magnetic aggregation which is encapsulation of the hydrophobic magnetic nanoparticles in amphiphilic polymer(pluronic F-127).The magnetic aggregation provides hydroxide functionality as a growth point of silica shell on the magnetic nanoparticles.Also,it is applied for the high Fe3O4 loading efficiency in the homogeneous core/shell nanoclusters.The surface properties of the nanoclusters were modified to various lengths of amine,and carboxy groups in order to provide the functionality for lanthanide ions.These nanoclusters can be removed conveniently from water with an external magnetic field because of their exceptional magnetic properties from Fe3O4 core.The prepared nanoclusters adsorb lanthanide ions on the surface functional groups by chealating coordinations with lanthanide ions.It results from the Energy Dispersive Spectrometer(EDS) studies of the adsorbent surface,and the theoretical description of the adsorption isotherm,and adsorption kinetics.The adsorption amounts are increased as longer chain length of the functional groups,and adsorption times,and depending on the experimental results,theoretical descriptions are explained by Langmuir adsorption isotherm model and 1st order adsorption kinetic model due to their 1st ordered chemical,and monolayed adsorption uptake on the functional groups.The interaction between functional groups and lanthanide ions is reversible,which means that those ions can be separated from functional groups in basic deionized water because of the reduction of lanthanide ions in alkali conditions.The competitive adsorptions between lanthanide ions and transition metal ions are studied.Adsorption tendency is highly related to the forming cage complex on the surface functionality,which is based on the thermodynamic values.[1-4] On the basis of the reasons referred to above,synthesized magnetic nanoclusters were used as a useful recyclable tool for lanthanide ion removal.The recyclability is studied in 10 times recycle experiments,which show stable adsorption properties.This work provides a potential platform for developing a unique route for lanthanide ion removal from dilute solutions.In this study,it indicates that the adsorption for separation of lanthanide ions in dilute metal ion solutions has several advantages including stable compositions,easy preparation,high and selective adsorption abilities,easy desorption using pH conditions,and rapid separation of the adsorbents on external magnetic field in the aqueous phase.