Environmentally Compatible Synthesis of Superparamagnetic Magnetite (Fe3O4) Nanoparticles with Prehydrolysate from Corn Stover

An environmentally compatible and size-controlled method has been employed for synthesis of superparamagnetic magnetite nanoparticles with prehydrolysate from corn stover. Various characterizations involving X-ray diffraction (XRD), standard and high-resolution transmission electron microscopy (TEM and HRTEM), selected area electron diffraction (SAED), and thermogravimetric analysis (TGA) have integrally confirmed the formation of magnetite nanoparticles with homogeneous morphology and the formation mechanism of magnetite only from ferric precursor. Organic materials in the prehydrolysate act as a bifunctional agent: (1) a reducing agent to reduce ferric ions to prepare magnetite with the coexistence of ferric and ferrous ions; and (2) a coating agent to prevent particle growth and agglomeration and to promote the formation of nanoscale and superparamagnetic magnetite. The size of the magnetite nanoparticles can be easily controlled by tailoring the reducing sugar concentration, reaction time, or hydrothermal temperature.