Estudo das Propriedades Físicas de Nanocompósitos α − Fe2O3/Fe3O4 Obtidos em Meio Bioquelante

Abstract

This study investigates the physical properties of Hematite/Magnetite (! →Fe2O3/Fe3O4) nanocomposites synthesized using Maytenus rigida Mart. extract as a biochelating agent. The research explores the influence of calcination temperature (400, 500, and 600 °C) on the size, morphology, and magnetic properties of the nanoparticles. FTIR analysis of the precursor xerogel revealed the presence of several functional groups, indicating a favorable environment for the formation of an amorphous Fe–OH complex. Thermogravimetric analysis showed that at 400 °C, 41% of the xerogel’s initial weight was lost due to the extensive decomposition of organic compounds, highlighting optimal calcination conditions. FTIR, Raman, and TEM analyses of the nanocomposites confirmed the formation of ! →Fe2O3 and Fe3O4 nanoparticles with average sizes of 8.9 ± 1.1 nm (Fe3O4) and 24 ± 2.5 nm ! →Fe2O3 at 400 °C, increasing to 79 ± 2.2 nm Fe3O4 and 133 ± 4.4 nm !→Fe2O3 at 600 °C. Magnetic hysteresis curves showed a reduction in saturation magnetization from 29.79 emu/g (400 °C) to 12.51 emu/g (600 °C), while coercivity increased due to a higher proportion of (! →Fe2O3 . This study demonstrates that the use of Maytenus rigida promotes a sustainable and effective synthesis of (! →Fe2O3/Fe3O4) nanomaterials. Furthermore, the materials exhibited physical properties dependent on calcination temperature, which may be useful for environmental applications, such as the remediation of contaminated water and pollutant removal.