Photochemical generation of reactive intermediates from urban-waste bio-organic substances under UV and solar irradiation.
Environ Sci Pollut Res Int
; 24(22): 18470-18478, 2017 Aug.
Article
en En
| MEDLINE
| ID: mdl-28646308
ABSTRACT
Singlet oxygen (1O2), hydroxyl radicals (â¢OH), and excited triplet states of organic matter (3OM*) play a key role in the degradation of pollutants in aquatic environments. The formation rates and quantum yields (Φ) of these reactive intermediates (RI) through photosensitized reactions of dissolved organic matter (DOM) have been reported in the literature for decades. Urban biowaste-derived substances (UW-BOS), a form of organic matter derived from vegetative and urban waste, have recently been shown to be efficient sensitizers in the photo-degradation of different contaminants. Nevertheless, no quantitative measurements of photo-oxidant generation by UW-BOS have been reported. In this study, the formation quantum yields of 1O2 and â¢OH, as well as quantum yield coefficients of TMP degradation (indicative of 3OM* formation), were quantified for two UW-BOS samples, under 254-nm UV radiation or simulated sunlight and compared to a DOM standard from the Suwanee River (SRNOM). Values of Φ for UW-BOS samples ranged from Φ(+1O2) = 8.0 to 8.8 × 10-3, Φ(+â¢OH) = 4.1 to 4.3 × 10-6, and f TMP = 1.22 to 1.23 × 102 L Einstein-1 under simulated sunlight and from Φ(+1O2) = 1.4 to 2.3 × 10-2, Φ(+â¢OH) = 1.3 to 3.5 × 10-3, and f TMP = 3.3 to 3.9 × 102 L Einstein-1 under UV. Although UW-BOS are not necessarily better than natural DOM regarding photosensitizing properties, they do sensitize the production of RI and could potentially be used in engineered treatment systems.
Palabras clave
Texto completo:
1
Bases de datos:
MEDLINE
Asunto principal:
Luz Solar
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Rayos Ultravioleta
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Residuos
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Contaminantes Químicos del Agua
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Oxidantes
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Radical Hidroxilo
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Oxígeno Singlete
Idioma:
En
Revista:
Environ Sci Pollut Res Int
Asunto de la revista:
SAUDE AMBIENTAL
/
TOXICOLOGIA
Año:
2017
Tipo del documento:
Article
País de afiliación:
Brasil