Synthesis of ferrites obtained from heavy metal solutions using wet method

Wet method was employed to the treatment of heavy metal-contaminated wastewater, and ZnxFe3−xO4, NixFe3−xO4 and CrxFe3−xO4 (0 < x < 1) were synthesized. Phase identification of the prepared samples was done by X-ray diffraction (XRD), which indicates that the products are spinel-structured; transmission electron microscopy (TEM) images show that crystal size of the ferrite products synthesized is 0.1-0.4 μm. Thermostability of the products was characterized by differential thermal analysis (DTA) and thermal gravimetric analysis (TGA). It was found that when the doped ferrite is qualified, the highest content of doped ion (Zn2+, Ni2+ and Cr3+) that could enter ferrite lattice is: 0.08, 0.049 and 0.02, respectively. At low concentration the capability of doped ions entering ferrite product is Ni2+ ≈ Zn2+ > Cr3+ and the influence of the three ions on sample thermostability is Zn2+ > Ni2+ > Cr3+.