Blocking the formation of bromate in γ-Fe-Ti-Al2O3 catalytic ozonation of ibuprofen in bromide-containing water.

Iron and titanium doped γ-Al₂O₃ (γ-Fe-Ti-Al₂O₃) mesoporous catalysts were synthesized by evaporation-induced self-assembly using glucose as template, and applied to ozonation of ibuprofen in bromide-containing water. X-ray diffraction (XRD), nitrogen adsorption–desorption (BET), X-ray photoelectron spectroscopy (XPS) results showed that iron and titanium successfully doped into the skeleton of γ-Al₂O₃, uniform distribution, maintain the ordered mesoporous structure of γ-Al₂O₃, with larger specific surface area. The valence of titanium coexists with Ti⁴⁺ and Ti³⁺, and the valence of iron was Fe³⁺. Infrared spectra of chemisorbed pyridine (Py-FTIR) results showed that the doped titanium and iron into the framework position of γ-Al₂O₃ altered the surface acidity of the alumina surface, especially increasing the medium Lewis acid sites, which was conducive to the effective decomposition of ozone into active oxygen species. The γ-Fe-Ti-Al₂O₃ catalyst (Al/Fe = 25, Al/Ti = 75) enhanced the removal rate of ibuprofen in ozonation of bromide-containing water, and effectively blocked the formation of bromate. After the reaction of 60 min, the removal rate of TOC was increased from 54% of γ-Al₂O₃/O₃ to 86% with γ-Fe-Ti-Al₂O₃/O₃, while the ozonation alone was only 13%. Electron Paramagnetic Resonance (EPR) spectra showed that hydroxyl and superoxide radicals were reactive oxygen species, which was beneficial to the mineralization of organic matter. The capture experiment of Fe²⁺ ion confirmed that the electronic cycle of Fe²⁺ ion and Fe³⁺ ion was beneficial to block the formation of bromated. The addition of ibuprofen and humic acid can enhance the reduction of Fe³⁺ in the catalytic ozonation of γ-Fe-Ti-Al₂O₃, which further strengthened the blocking of bromate formation. [ABSTRACT FROM AUTHOR]