Hydrothermal Synthesis of Mesoporous FeTiO3 for Photo-Fenton Degradation of Organic Pollutants and Fluoride Adsorption †

Abstract

Metal oxide semiconductor-based photocatalysis and advanced oxidation processes (AOPs) are effective in treating various recalcitrant pollutants such as organic dyes present in industrial wastewater streams. AOPs rely on the highly reactive hydroxyl radicals (OH•) that facilitate the non-selective destruction of most organic pollutants. Here, we present the novel synthesis of mesoporous FeTiO3 catalyst via a simple, hard template-free, aqueous-solution-based hydrothermal synthesis method. The surfactant, tetradecyltrimethylammonium bromide (TTAB), was used as the structure-directing agent, the removal of which led to the formation of the mesoporous structure. The catalyst was characterized by thermo-gravimetric analysis (TGA), Fourier transform infrared spectroscopy (FTIR), Branauer–Emette–Teller analysis (BET), X-ray diffraction (XRD), and scanning electron microscope (SEM) techniques. The obtained catalyst has been studied for its photocatalytic application in the presence of H2O2 towards the degradation of organic dyes as representative pollutants, namely, rhodamine B (RhB) and methylene blue (MB) under direct solar light irradiation. The various characterizations confirm the formation of mesoporous FeTiO3 with a pore size of ≈7.5 nm and a specific surface area of 65 ± 5 m2/g. The influence of H2O2 oxidant on the removal of the said dyes has also been studied at various concentrations in the presence of the synthesized catalyst to determine the optimum dosage of H2O2. The catalyst was efficient in the complete synergistic adsorption-led photo-Fenton-like removal of MB in just 30 min of irradiation time, while the 96% RhB was degraded in 240 min. Moreover, this catalyst has also shown potential for fluoride adsorption that reaches up to more than 50% in 90 min.