Microwave‐assisted synthesis of mesoporous γ‐Fe ₂ O ₃ for dye removal

The synthesis of mesoporous γ‐Fe ₂ O ₃ nanoparticles by eco‐friendly one‐step microwave irradiation method in ambient atmospheres without surfactants as described in this Letter. Characterisation of synthesised nanoparticles was performed by X‐ray diffraction, X‐ray photoelectron spectroscopy, Brunauer–Emmett–Teller surface area & pore volume analyser, field emission scanning electron microscopy, high‐resolution transmission electron microscopy, and superconducting quantum interference device. The adsorption behaviour of nanoparticles towards methyl orange, an azo dye, was examined in aqueous solutions under various operational conditions like pH, temperature, contact time, and adsorbent weight. Results suggest that as‐synthesised γ‐Fe ₂ O ₃ nanoparticles are mesoporous and superparamagnetic at room temperature. Some characteristics of γ‐Fe ₂ O ₃ nanoparticles, for example, saturation magnetisation, pore diameters, specific surface areas, and pore volumes are 72.0 emu g ⁻¹ , 7.11 nm, 189.35 m ² g ⁻¹ , and 0.52 cm ³ g ⁻¹ , respectively. The experimental data of adsorption study fitted with the Langmuir isotherm model and maximum adsorption capacity is 403.23 mg g ⁻¹ . The reusability of the γ‐Fe ₂ O ₃ nanomaterials was examined, and it can be recycled for ten cycles. In sum, this simple eco‐friendly synthesis method of magnetic mesoporous adsorbent is suitable for large scale production without any template or surfactant or inert atmosphere.