The Effect of EDTA Functionalization on Fe₃O₄ Thermal Behavior

Abstract

The surface of Fe₃O₄ nanoparticles is very reactive and can oxidize to γ-Fe₂O₃ (maghemite) and α-Fe₂O₃ (hematite) structures. Based on this, the oxidation process of Fe₃O₄ nanoparticles must be prevented, and one of the strategies is surface functionalization with organic or inorganic molecules. Thus, this study analyzed the thermal behavior of Fe₃O₄ and Fe₃O₄-EDTA nanoparticles using X-ray diffraction (XRD), simultaneous thermogravimetry-differential thermal analysis (TG-DTA), differential scanning calorimetry (DSC). Results showed that γ- Fe₂O₃ was obtained as an intermediate in Fe₃O₄ and Fe₃O₄-EDTA decomposition, as confirmed by TG-DTA and DSC curves. Moreover, Fe₃O₄-EDTA exhibited a temperature peak (T_p = 573.5°C) of phase transformation (γ-Fe₂O₃ → α-Fe₂O₃) higher than that of Fe₃O₄ (T_p = 533.0°C), confirming that EDTA molecules stabilized the nanoparticles efficiently. The kinetic behavior of samples changed, and the activation energy for functionalized samples decreased.

Keywords:
Magnetite; Maghemite; Hematite; Non-isothermal kinetics