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

ABSTRACT

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.

GRAPHICAL ABSTRACT

KEYWORDS:

• γ-Fe-Ti-Al₂O₃
• catalytic ozonation
• ibuprofen
• bromate
• humic acid

Acknowledgements

This work was supported by the National Natural Science Foundation of China (Grant No. 51538013) and Jiangsu postdoctoral fund (Grant No.2018K014A).

Disclosure statement

No potential conflict of interest was reported by the author(s).

Author contributions

Liqiang Yan carried out sample fabrication and measurements; Jishuai Bing conceived the idea; Hecheng Wu and Jishuai Bing supervised the project; Liqiang Yan and Jishuai Bing analysed simulation data and co-wrote the paper. All authors, including Liqiang Yan, Jishuai Bing and Hecheng Wu discussed the results and commented on and revised the manuscript.

Additional information

Funding

This work was supported by the National Natural Science Foundation of China [grant number 51538013] and Jiangsu postdoctoral fund [grant number 2018K014A].