Insights into the Photochemical Mechanism of Goethite: Roles of Different Types of Surface Hydroxyl Groups in Reactive Oxygen Species Generation and Fe(III) Reduction.
Environ Sci Technol
; 58(33): 14812-14822, 2024 Aug 20.
Article
em En
| MEDLINE
| ID: mdl-39118219
ABSTRACT
The surface photochemical activity of goethite, which occurs widely in surface soils and sediments, plays a crucial role in the environmental transformation of various pollutants and natural organic matter. This study systemically investigated the mechanism of different types of surface hydroxyl groups on goethite in generating reactive oxygen species (ROSs) and Fe(III) reduction under sunlight irradiation. Surface hydroxyl groups were found to induce photoreductive dissolution of Fe(III) at the goethite-water interface to produce Fe2+(aq), while promoting the production of ROSs. Substitution of the surface hydroxyl groups on goethite by fluoride significantly inhibited the photochemical activity of goethite, demonstrating their important role in photochemical activation of goethite. The results showed that the surface hydroxyl groups (especially the terminating hydroxyl groups, ≡FeOH) led to the formation of Fe(III)-hydroxyl complexes via ligand-metal charge transfer on the goethite surface upon photoexcitation, facilitating the production of Fe2+(aq) and â¢OH. The bridging hydroxyl groups (≡Fe2OH) were shown to mainly catalyze the production of H2O2, leading to the subsequent light-driven Fenton reaction to produce â¢OH. These findings provide important insights into the activation of molecular oxygen on the goethite surface driven by sunlight in the environment, and the corresponding degradation of anthropogenic and natural organic compounds caused by the generated ROSs.
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Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Espécies Reativas de Oxigênio
Idioma:
En
Revista:
Environ Sci Technol
Ano de publicação:
2024
Tipo de documento:
Article
País de afiliação:
China
País de publicação:
Estados Unidos