Synthesis and characterization of DTPA and DOTA modified Fe3O4@SiO2 core-shell nanoparticles

Abstract

Chelation is a type of ions/ molecules bonding to metal ions. Due to the excellent chelating properties of aminopolycarboxylic acids such as diethylenetriamine-pentaacetic acid (DTPA) and 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacet-ic acid (DOTA), this study focuses on the synthesis of these compounds. Few investigations have been carried out on the comparison of desorption rate and amount of heavy metals extracted successively by organic acid mixtures. DTPA and DOTA as chelating agents were grafted on the metal nanoparticles (MNPs). They are convenient compounds for the removal of heavy metals ions from wastewater. Magnetic iron oxide nanoparticles with narrow size distribution were synthesized by a simple and high-yielded co-precipitation technique using ferrous salts with molar ratio of Fe³⁺/Fe²⁺=2. After preparation of silica-coated iron oxide nanoparticles by Stöber method (wet chemistry), the nanoparticles were functionalized via amine residues of ligands. The synthesis of Fe₃O₄@SiO₂ core-shell nanoparticles, as well as their structural and magnetic properties, were characterized by X-ray diffraction (XRD), tramsition electron microscopy (TEM), Fourier-transform infrared (FT-IR) spectroscopy, Brunauer-Emmett-Teller (BET), and thermogravimetric analysis techniques.