فاطمه اسلامي

In recent decades, contamination of water resources by azo organic dyes such as methylene blue has posed a significant challenge. Titanium dioxide is recognized as an efficient semiconductor photocatalyst; however, the difficult separation of its nanoparticles an‎d the restriction of its activity to the ultraviolet region constitute the primary barriers to industrial applications. Combining this material with magnetic iron oxide offers a viable solution for developing recyclable catalysts.In the present study, the magnetic nanocomposite TiO₂/Fe₃O₄ was synthesized via a mechanothermal method. The process involved high-energy ball milling of the precursor powders in a 1:1 weight ratio for 3.5 hours, followed by heat treatment at 450 °C. Parameter optimization was conducted through systematic experiments varying milling time an‎d heat treatment temperature to achieve a hybrid structure with adequate phase adhesion. The properties of the optimal sample were characterized using X-ray diffraction, field-emission scanning electron microscopy, diffuse reflectance spectroscopy, vibrating sample magnetometry, an‎d photoluminescence techniques. Photocatalytic performance was eva‎luated under natural sunlight irradiation.The results revealed that the optimal sample retained the anatase an‎d magnetite phases, exhibiting an average crystallite size of 544 Å an‎d a ban‎d gap of 3.12 eV. A saturation magnetization of 12.9 emu/g enabled rapid separation under an external magnetic field, while the electron-hole recombination rate was substantially reduced. The nanocomposite degraded methylene blue (at an initial concentration of 10 mg/L) by 95% within 40 minutes an‎d maintained stability above 90% during magnetic recovery cycles.

نانوكامپوزيت مغناطيسي، TiO₂/Fe₃O₄، روش مكانيوشيميايي، روش مكانوترمال، فتوكاتاليزگر، متيلن بلو

Magnetic nanocomposite, TiO₂/Fe₃O₄, Mechanochemical method, Photocatalyst, Methylene blue

Fateme Eslami

Dr. Rezvane Amrollahi