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

Iron and titanium doped gamma-Al2O3 (gamma-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 gamma-Al2O3, uniform distribution, maintain the ordered mesoporous structure of gamma-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 gamma-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 gamma-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 gamma-Al2O3/O-3 to 86% with gamma-Fe-Ti-Al2O3/O-3, 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 gamma-Fe-Ti-Al2O3, which further strengthened the blocking of bromate formation. [GRAPHICS] .

Automated summary

Iron and titanium doped gamma-Al2O3 mesoporous catalysts were synthesized by self-assembly, applied to ozonation of ibuprofen in bromide-containing water, effectively enhancing ibuprofen removal and blocking bromate formation.