Production of a Surface-Localized Oxidant during Oxygenation of Mackinawite (FeS)
| Autor: | Dongsheng Wang, Richard N. Collins, Christopher J. Miller, Jie He, T. David Waite |
|---|---|
| Rok vydání: | 2019 |
| Předmět: |
Hydroxyl Radical
Iron Radical chemistry.chemical_element General Chemistry 010501 environmental sciences engineering.material Oxidants Photochemistry 01 natural sciences Sulfur 6. Clean water chemistry.chemical_compound Adsorption chemistry Hydroxybenzoate Mackinawite engineering Environmental Chemistry Hydroxyl radical Reactivity (chemistry) Ferrous Compounds Oxidation-Reduction 0105 earth and related environmental sciences Benzoic acid |
| Zdroj: | Environmental Science & Technology. 54:1167-1176 |
| ISSN: | 1520-5851 0013-936X |
| DOI: | 10.1021/acs.est.9b03975 |
| Popis: | The oxygenation of mackinawite (FeS) frequently occurs at anoxic-oxic interfaces in both natural and engineered systems such as intertidal sediment, in activated sludge in water treatment processes, and during sulfidized zero-valent iron particle corrosion. During reoxygenation events, FeS may drive a Fenton-like process leading to the production of strong oxidants though the details of this process are poorly understood. In this study, benzoic acid (BA) has been used to probe both the magnitude and identity of these strong oxidants under circumneutral pH conditions. The major product of BA oxidation during FeS oxygenation was found to be 2,5-dihydroxybenzoic acid (2,5-DHBA) rather than monohydroxybenzoic acids identified to be the major products in a range of hydroxyl radical (HO·)-dominated systems. Based upon relative reactivity with other competitive probes and nature of the hydroxybenzoate product distribution, it is hypothesized that the strong oxidant must be a surface-localized entity such as high-valent iron or surface-associated hydroxyl or sulfur-based radicals with reactivity differing from those formed in free solution. The importance of both the reactivity of the oxidant and adsorption of the substrate to the surface is demonstrated. |
| Databáze: | OpenAIRE |
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