Synthesis of Fe2O3/TiO2 Photocatalytic Composites for Methylene Blue Degradation as a Novel Strategy for High-Value Utilisation of Iron Scales

In this study, novel Fe₂O₃/TiO₂ photocatalytic composites were synthesised by combining traditional oxidation roasting with the sol-gel method, using low-cost metallurgical waste (iron scales) as the raw material. The characterisation results revealed that the oxidised iron scales could be transformed into high-purity and porous Fe₂O₃ particles through oxidation roasting, thereby providing additional sites for the adsorption process and thus serving as an effective carrier for TiO₂-based photocatalytic materials. During the sol-gel process, TiO₂ was loaded onto the synthesised Fe₂O₃ particles, generating core-shell heterostructure Fe₂O₃/TiO₂ photocatalytic composites. Under visible light irradiation for 90 min, the Fe₂O₃/TiO₂ photocatalytic composites achieved a remarkable methylene blue removal rate (97.71%). This reaction process followed the quasi-first-order kinetic model with a rate constant of 0.038 min^-1. The results have demonstrated that this combination of various components in the Fe₂O₃/TiO₂ photocatalytic composites improved the adsorption, light utilisation, and charge separation effect of the photocatalysts. Moreover, the material exhibited favourable stability and recyclability, making it a decent candidate for the treatment of wastewater from the biochemical industry. Therefore, this study provides a new strategy for improving the photocatalytic activity of TiO₂ and expanding the high value-added utilisation of iron scales.