A1 Journal article (refereed)
Superoxide-driven autocatalytic dark production of hydroxyl radicals in the presence of complexes of natural dissolved organic matter and iron (2020)

Xiao, Y., Carena, L., Näsi, M.-T., & Vähätalo, A. V. (2020). Superoxide-driven autocatalytic dark production of hydroxyl radicals in the presence of complexes of natural dissolved organic matter and iron. Water Research, 177, Article 115782. https://doi.org/10.1016/j.watres.2020.115782

JYU authors or editors

Publication details

All authors or editors: Xiao, Yihua; Carena, Luca; Näsi, Marja-Terttu; Vähätalo, Anssi V.

Journal or series: Water Research

ISSN: 0043-1354

eISSN: 1879-2448

Publication year: 2020

Volume: 177

Article number: 115782

Publisher: Elsevier

Publication country: United Kingdom

Publication language: English

DOI: https://doi.org/10.1016/j.watres.2020.115782

Publication open access: Not open

Publication channel open access:

Publication is parallel published (JYX): https://jyx.jyu.fi/handle/123456789/68569

Abstract

We introduced superoxide as potassium superoxide (KO2) to artificial lake water containing dissolved organic matter (DOM) without or with introduced ferric iron complexes (DOM-Fe), and monitored the production rate of hydroxyl radicals as well as changes in the absorption and fluorescence properties of DOM. The introduction of KO2 decreased the absorption by DOM but increased the spectral slope coefficient of DOM more with complexed ferric Fe than without it. The introduction of KO2 increased the fluorescence of humic-like components in DOM without introduced ferric Fe but resulted in the loss of fluorescence in DOM with introduced ferric Fe. A single introduction of 13 μmol L−1 KO2 produced 10 μmol L−1 and 104 μmol L−1 hydroxyl radicals during a week-long experiment without and with the introduced DOM-Fe complexes, respectively. The production rate of hydroxyl radicals decreased exponentially with time but levelled off and continued several days in DOM with introduced ferric Fe. These findings suggest that in the presence of DOM-Fe complexes, superoxide can trigger an autocatalytic Fenton reaction that produces hydroxyl radicals and breaks down DOM.

Keywords: organic material; decomposition (chemistry); iron; oxides; catalysis; free radicals; absorption

Free keywords: dissolved organic matter; iron; superoxide; hydroxyl radicals; production rate; absorption

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Ministry reporting: Yes

Reporting Year: 2020

JUFO rating: 3