The production of titanium dioxide generates substantial quantities of wastes and by-products, especially spent acids. Conventional treatment methods require large amounts of alkalis, leading to the formation of secondary wastes such as red gypsum. This study aims to valorize titanium dioxide spent acids from India through the synthesis of value-added products, specifically nano-sized iron phosphate for energy-related applications. The process involves a comprehensive evaluation of the physical and chemical properties of the spent acids, the selective removal of impurities, the oxidation of Fe (II) to Fe (III), and the precipitation of iron as FePO₄ using an appropriate phosphoric source. Advanced characterization techniques, including XRF, XRD, SEM, TEM, and ICP-MS, were employed. TEM analysis confirmed that the synthesized iron phosphate exhibits a nanoscale particle size (below 200nm), while SEM revealed uniform particle morphology. ICP-MS results showed low levels of impurities in the final product, demonstrating its suitability for high-performance applications.
The TEM images collectively reveal the successful synthesis of nanoscale, plate-like or flake-like particles, with uniform shape, good dispersion, and thin morphology across multiple magnifications.
Morphology shows plate-like, flake-like, or nanosheet structures with polygonal shapes and varied orientations. Sharp and angular edges typically suggest a crystalline nature, while variations in contrast imply stacking or thickness differences.