Synthesis, Characterization, and Activity of Maghemite (γ-Fe2O3) Nanoparticles through a Facile Solvent Hydrothermal Phase Transformation of Fe2O3

A facile solvent hydrothermal phase transformation (HPT) of iron oxide (Fe2O3, 1.5 μm) into γ-Fe2O3 nanoparticles (NPs) is investigated through calcination. The synthesis does not involve complex chemistry like pH adjustment or interference of other chemicals, as only ethanol and iron precursor are used. The HPT showed pure γ-Fe2O3 NPs with uniform morphology and good adsorptive properties in comparison to their precursor. The morphologies of NPs are characterized by Scanning Electron Microscopy (SEM), Energy Dispersive Spectrometry (EDS), and Fourier Transform Infrared Spectroscopy (FTIR). SEM images showed the γ-Fe2O3 cubical nanorod-like structure (74.5–97.6 nm). EDS scan showed facade morphology free from contamination. Congo red (CR) dye adsorption capacity of γ-Fe2O3 reaches 93.60% and the data is fitted to Langmuir Lagergren adsorption isotherm model, with pseudo-second-order kinetics. Recovered NPs are subjected to SEM, EDS, and FTIR analysis. The size of recycled NPs was found to be similar (78.8–99.4 nm), and were effective for reuse for least four times.