Mechanosynthesis of MFe₂O₄ (M = Co, Ni, and Zn) Magnetic Nanoparticles for Pb Removal from Aqueous Solution

Abstract

Adsorption of Pb(II) from aqueous solution using MFe 2 O 4 nanoferrites (M = Co, Ni, and Zn) was studied. Nanoferrite samples were prepared via the mechanochemical method and were characterized by X-ray powder diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), micro-Raman, and vibrating sample magnetometry (VSM). XRD analysis confirms the formation of pure single phases of cubic ferrites with average crystallite sizes of 23.8, 19.4, and 19.2 nm for CoFe 2 O 4 , NiFe 2 O 4 , and ZnFe 2 O 4 , respectively. Only NiFe 2 O 4 and ZnFe 2 O 4 samples show superparamagnetic behavior at room temperature, whereas CoFe 2 O 4 is ferromagnetic. Kinetics and isotherm adsorption studies for adsorption of Pb(II) were carried out. A pseudo-second-order kinetic describes the sorption behavior. The experimental data of the isotherms were well fitted to the Langmuir isotherm model. The maximum adsorption capacity of Pb(II) on the nanoferrites was found to be 20.58, 17.76, and 9.34 mg·g −1 for M = Co, Ni, and Zn, respectively.