Preparation of magnetic nanoclusters for adsorption and separation system of lanthanide

Abstract

The preparation of Fe3O4/SiO2 core/shell nanostructure and surface functionalization have been the focus for adsorption of lanthanide ions and magnetic separation due to the outstanding ability for selective adsorption of the target ions on funcionalized ligand, and separation of adsorbent materials via external magnetic field. Magnetic adsorbents were prepared with fabricating colloidal crystals by using monodisperse SiO2 coated magnetic nanoparticle (Fe3O4/SiO2) nanosphere with a core-shell structure to remove lanthanide ions from aqueous media.

In chapter 2, monodisperse superparamgnetic nanoparticles for magnetic materials in absorbents are prepared by phase-transfer synthetic method. A phase transfer synthetic process for realizing monodisperse and size-controllable magnetite nanoparticles in a 2.5-30nm range by reducing iron chlorides with sodium oleate, hydrazine (N2H4), and sodium hydroxide (NaOH) in a water/ethanol/toluene solution is proposed. The particle size depends on the ratio of sodium oleate to iron ions in a phase transfer reaction and the additional growth step of the second phase transfer reaction. Smaller nanoparticles are obtained at a higher ratio of sodium oleate to iron ions through phase transfer reaction, while, the average diameter of particles dramatically increases with the second phase transfer reaction.

In chapter 3, magnetic adsorbents were prepared in the basic condition with hydrophilic magnetic aggregation, which is eancapulated the hydrophobic magnetic nanoparticles in amphiphlic polymer(F-127), tetraethyl orthosilicate(TEOS) and ammonium hydroxide via two main steps by a modified Stober process and the layer-by-layer(LbL) assembly technique in order to modify the hydrophobic surface property of magnetic nanoparticles which is stabilized with oleic acid into hydroxide functionality as a growth point of silica on the magnetic nanoparticle, also in order to provide the uniform ratio of magnetic nanoparticle to silica, the ...