Nanocomposites and nanomaterials

Synthesis of magnetite nanoparticles by co-precipitation method under the influence of microwave radiation 
O. Ye. Lipatov1, T.S. Antonenko2, N.O. Dudchenko2, A.B. Brik2, V.V. Ovsienko2, Yu.I. Cherevko2
1 Educational and Scientific Institute “Institute of Geology” of Taras Shevchenko National University of Kyiv, Vasylkivska street, 90, Kyiv-03033, Ukraine.
E-mail: tetyana_savchenko@ukr.net

2 M.P. Semenenko Institute of Geochemistry, Mineralogy and Ore Formation of Natl. Acad. of Sci. of Ukraine, Palladina prosp, 34, Kyiv-03142, Ukraine. 

The aim of this work was to synthesize highly magnetized magnetite particles using different temperature, pressure, and alkali under the influence of microwave radiation. 
For magnetite synthesis, iron (II) chloride tetrahydrate (FeCl2·4H2O), iron (III) chloride hexahydrate (FeCl3·6H2O) and hydrochloric acid (HCl) have been used. The following alkaline reagents were used: potassium hydroxide (KOH), sodium hydroxide (NaOH), ammonium hydroxide (NH4OH). Magnetite nanoparticles were prepared by method of co-precipitation of Fe3+ and Fe2+ salts in alkaline medium. Investigations of magnetite synthesis was carried-out at six temperature points: 100 °С, 120 °С, 160 °С, 200 °С and 260 °С. The preparation of the reagents was performed as follows: 2M FeCl2·4H2O and 1M FeCl3·6H2O was dissolved in 1M HCl. After that, the reaction was started by adding of 40 ml of 3M alkali. The solution was incubated using Microwave Reaction System (Anton Paar Multiwave PRO) for 30 min. The formed samples were washed three times with distilled water and dried in a thermostat at 90 °С for 1 h. The obtained samples were investigated by X-ray diffraction and magnetometry methods. Characteristic peaks in XRD pattern of obtained samples (for example, 4,85Å, 2,96Å, 2,53Å, 2,09Å, 1,71Å, 1,61Å, 1,47Å) were attributed to magnetite. The saturation magnetization of the sample, obtained using sodium hydroxide was 10 Am2/kg; using potassium hydroxide – 7 Am2/kg; using ammonium hydroxide – 62 Am2/kg. We could conclude that the reaction using potassium hydroxide and sodium hydroxide occurs with the absorption of heat, which is not favorable for the production of particles with high magnetization. The dependence of the saturation magnetization values on the temperature was investigated. The saturation magnetization increased with the temperature rapidly in the temperature range of 100-120 °C with no further increasing in the temperature range of 120-260 °C.