Enhanced Catalyst Recovery and Photocatalytic Degradation of Rhodamine B and Methylene Blue Using a ZnO/TiO2/Fe3O4 Nanocomposite: Physicochemical Characteristics and Environmental Implications

A facile wet chemical approach was adopted to synthesize zinc oxide, titanium dioxide, and iron (II, III) oxide, followed by the synthesis of ZnO–TiO₂–Fe₃O₄ nanocomposite via physical mixing. The synthesized nanoparticles were characterized using X-ray diffraction, UV–visible spectroscopy, vibrating sample magnetometry, transmission electron microscopy, and energy-dispersive X-ray spectroscopy to investigate various physical and chemical characteristics of the prepared samples. Furthermore, the catalytic reduction of methylene blue (MB) and rhodamine B (Rh B) dyes was carried out using prepared nanomaterials as catalysts under UV–visible light illumination. It was observed that the degradation efficiency of the nanocomposite was equivalent to or slightly better than TiO₂ nanoparticles and higher than ZnO nanoparticles against both dye solutions. Its removal efficiency using an external magnetic field is much higher than that of the constituent nanoparticles, owing to its higher saturation magnetization. So, the obtained results suggest that the produced nanocomposite can be employed as a high-potential catalyst for reducing organic dyes and pollutants in wastewater treatments.