Synthesis and Optimization of Iron and Manganese Oxide Nanoparticles for Environmental Applications

Abstract

Hematite, maghemite, and hausmannite play significant roles in various technological and environmental applications due to their distinct properties. Hematite is valued for its excellent adsorption capabilities, suitable bandgap for solar applications, and versatility in sensors and environmental remediation, while maghemite’s unique magnetic properties make it indispensable in superparamagnetic applications, drug delivery, and imaging. Additionally, manganese oxide (Mn₃O₄) stands out for its catalytic efficiency, affordability, and biocompatibility, making it a promising material for both catalytic processes and biomedical applications. Hematite (α-Fe₂O₃), maghemite (γ-Fe2O3) and hausmannite (Mn₃O₄) nanoparticles were synthesized via the chemical coprecipitation method; a technique favored for its cost-effectiveness, simplicity, and scalability. A systematic optimization study of key synthesis parameters, including precursor ratios, reaction temperature, synthesis time, and surfactant use, was done to produce nanoparticles with uniform morphology, high crystallinity, and excellent thermal stability. The optimized factors for the synthesis of metal oxide polymorphs were utilized in environmental remediation of water from azo dyes (Congo Red and Methylene Blue). The previous parameters were varied and quantified along with their effects using several microscopic and spectroscopic techniques, such as thermogravimetric technique, X-Ray diffraction, Scanning electron microscopy and UV-vis spectroscopy.