Solvothermal synthesis of monodisperse iron oxides with various morphologies and their applications in removal of Cr(vi)

Monodisperse iron oxide micro-, nanospindles and nanospheres with controlled sizes were synthesized through a facile solvothermal process. The products are characterized by X-ray diffraction, X-ray photoelectron spectroscopy, BET surface area measurements, scanning electron microscopy and high-resolution transmission electron microscopy. The growth mechanism of spindle-like or spherical iron oxides with controlled size is discussed. Different content of Cl− in the reaction medium can also influence the nucleation rate through the decomposition of Fe8O8(OH)8Cl1.35 and thus control the particle sizes. The as-prepared iron oxides exhibit size dependence in their physical properties such as UV-vis absorption spectra and IR spectra. In addition, the removal capacities of Cr(VI) of the as-prepared iron oxides are investigated. The better performances of the as-prepared iron oxides than commercial iron oxides could be attributed to the larger surface area and rough surface structure.