Synthesis and characterization of novel γ-Fe2O3-NH4OH@SiO2(APTMS) nanoparticles for dysprosium adsorption

This paper deals with synthesis and characterization of novel γ-Fe2O3-NH4OH@SiO2(APTMS) nanoparticles formed from magnetic γ-Fe2O3 core, stabilized electrostatically in basic media NH4OH, doped with SiO2 shell and functionalized with 3-aminopropyltrimethoxysilane. The gradually synthesized nanoparticles are characterized in order to analyze their structural, morphology, thermogravimetry, surface area and charge, and magnetic properties. The novel synthesized γ-Fe2O3-NH4OH@SiO2(APTMS) nanoparticles are suitable to adsorb dysprosium ions (Dy3+), as one of the most critical rare earth elements, from aqueous solution. The Dy3+ adsorption from aqueous solution follows a pseudo-second order kinetic model and the adsorption equilibrium data fits well to the Temkin isotherm. Thermodynamic studies imply that the adsorption process is endothermic and spontaneous in nature. The maximum adsorption efficiency for Dy3+ from aqueous solution with 2·10−6M concentration of Dy3+ is over 90% at pH 7.