Thermal behavior of MnFe2O4 and MnFe2O4/C nanocomposite synthesized by a solvothermal method

A new solvothermal method for MnFe2O4 nanoparticles and MnFe2O4/C nanocomposite synthesis is reported. Manganese ferrite nanoparticles thus sinthesized are not stable at thermal treatment in oxidizing atmosphere, due to Mn(II) oxidation to Mn(III), evidenced at 640 degrees C by thermal analysis. The FTIR spectroscopy also confirmed the oxidation of Mn(II) to Mn(III). XRD analysis has revealed the complete decomposition of manganese ferrite around 700 degrees C. The specific surface area of the composite with activated carbon was much higher (253 m(2) g(-1)), in comparison with that of the naked ferrite (65 m(2) g(-1)). Scanning electron microscopy and transmission electron microscopy images evidenced the obtaining of nearly spherical ferrite nanoparticles, with diameters within the range 10 nm - 30 nm, loaded on the surface of activated carbon in case of the composite. The magnetization of the synthesized composite (30 emu g(-1)) was below the one of naked manganese ferrite (40 emu g(-1)), but sufficient to insure a facile magnetic separation of the composite from aqueous solution, in case of its use as adsorbent for pollutant removal. (C) 2017 Elsevier B.V. All rights reserved.