A facile one-pot hydrothermal synthesis of hematite (α-Fe2O3) nanostructures and cephalexin antibiotic sorptive removal from polluted aqueous media

Abstract

We herein report a facile approach for a one-pot hydrothermal preparation of pure α-Fe2O3 nanoparticles with an average crystallite size of 21 nm. The preparation was carried out by a hydrothermal treatment of iron sulfate aqueous solution in the presence of H2O2 at pH 9 and 160 °C for 4 h. The produced phases were controlled by varying different reaction parameters such as reaction time, reaction temperature, H2O2 concentration, and pH of the reaction media. Different analytical tools were used to investigate the products such as Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), field-emission scanning electron microscopy (FE-SEM), energy-dispersive X-ray spectroscopy (EDS), and transmission electron microscopy (TEM). The as-fabricated α-Fe2O3 nanoparticles evinced a high adsorption capacity (ca. 70 mg/g) for the removal of cephalexin antibiotic (CEX) from aqueous media. The pseudo-second-order and Langmuir isotherm models described well the adsorption kinetic and adsorption isotherm data, respectively. The estimated thermodynamic parameters: ΔG° (from −3.761 to −4.278 kJ/mol), ΔH° (1.375 kJ/mol), and Ea (29.10 kJ/mol), indicated the spontaneous, endothermic, and physisorption nature of the adsorption process, respectively. Besides, the excellent reusability and adsorption capacity for the α-Fe2O3 nanostructure indicated its high efficiency for the removal of CEX antibiotic from aqueous media.