Issue 9, 2023

Mechanism of catalytic ozonation in different surface acid sites of oxide aqueous suspensions

Abstract

The behaviour of ozone on the surface of different oxides, including MCM-41, γ-Al2O3, α-Fe2O3, α-FeOOH, Fe3O4, α-MnO2 and β-MnO2, was investigated for the degradation of ibuprofen, acyclovir and humic acid in water. According to the temperature-programmed desorption of NH3, Fourier transform infrared (FTIR) spectroscopy of adsorbed pyridine and in situ attenuated total reflection FTIR (ATR-FTIR) spectroscopy measurements, Brønsted acid sites from the isolated hydroxyl and hydrogen-bonded hydroxyl groups were predominant on MCM-41 and α-Fe2O3, both Brønsted and Lewis acid sites existed on Fe3O4 and β-MnO2 and Lewis acid sites were predominant on γ-Al2O3, α-FeOOH and α-MnO2. In situ ATR-FTIR, in situ Raman and electron spin resonance spectroscopy using isotopic ozone revealed that ozone was electrostatically adsorbed on the Brønsted acid sites and hardly decomposed; thus, ozone served as a direct oxidant for pollutant degradation over MCM-41 and α-Fe2O3 suspensions. However, ozone was adsorbed on the surface Lewis acid sites, competing with water, and decomposed into surface atomic oxygen species and ˙OH and O2˙ radicals in the γ-Al2O3 suspension. Thus, more ˙OH and O2˙ radicals were generated on the surface of multivalent oxides (α-FeOOH, Fe3O4, α-MnO2 and β-MnO2) due to their redox activity, which was enhanced by the formation of complexes of pollutants and by-products with multivalent metals. On the basis of the experimental results, a mechanism for the transformation of ozone on the different surface acid sites is proposed.

Graphical abstract: Mechanism of catalytic ozonation in different surface acid sites of oxide aqueous suspensions

Supplementary files

Article information

Article type
Paper
Submitted
24 Mud 2023
Accepted
26 Maw 2023
First published
08 Mha 2023

Environ. Sci.: Nano, 2023,10, 2312-2323

Mechanism of catalytic ozonation in different surface acid sites of oxide aqueous suspensions

J. Bing, Y. Xu, C. Wu, X. Lv, X. Xiao and L. Chen, Environ. Sci.: Nano, 2023, 10, 2312 DOI: 10.1039/D3EN00331K

To request permission to reproduce material from this article, please go to the Copyright Clearance Center request page.

If you are an author contributing to an RSC publication, you do not need to request permission provided correct acknowledgement is given.

If you are the author of this article, you do not need to request permission to reproduce figures and diagrams provided correct acknowledgement is given. If you want to reproduce the whole article in a third-party publication (excluding your thesis/dissertation for which permission is not required) please go to the Copyright Clearance Center request page.

Read more about how to correctly acknowledge RSC content.

Social activity

Spotlight

Advertisements