Co-precipitation in aqueous solution synthesis of magnetite nanoparticles using iron(III) salts as precursors

An innovative quantitative synthetic method for preparing magnetite nanoparticles was achieved by co-precipitation in aqueous solution using only one single iron(III) salt as a precursor. A 2 Fe(III):1 Fe(II) mole ratio was first attained in solution by reducing iron(III) using KI solution, followed by filtering the iodine formed and hydrolyzing the filtrate by 25% ammonium hydroxide solution at pH 9–11. A high selectivity and atom economy percents were achieved indicating that the method is environmentally benign and green. The as-synthesized nanoparticles were characterized by fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), field emission transmission electron microscopy (FETEM), selected area electron diffraction (SAED), and 57Fe Mössbauer spectroscopy. Magnetite nanocrystals (d: 7.84 ± 0.05 nm) and nanorods (d: 6.3 ± 0.2 nm; l: 46.2 ± 0.9) formation was evident.