Silica-Coated Magnetite Nanoparticles Modified with 3-Aminopropyl Groups for Solid-Phase Extraction of Pd(II) Ions from Aqueous Solutions

Abstract

Here we report a simple two-step synthesis of magnetite nanoparticles (NPs) coated with silica shell functionalized with 3-aminopropyl groups. The content of surface amino groups within the range of 0.7–2.8 mmol g −1 was established by elemental analysis and acid–base titration. The materials obtained are hydrolytically stable in acidic medium and are rapidly separated from the solution using an external magnetic field. It was shown that the prepared NPs efficiently extract palladium(II) ions in the form of [PdCl 4 ] 2– from the solution. The kinetics of adsorption was well described by the second-order model with the rate constant of approximately 0.76 g mmol −1 minute −1 . The isotherm of adsorption is fitted by the Langmuir model with the maximum [PdCl 4 ] 2– adsorption capacity of 0.158 mmol g −1 .