Journal ArticleDOI
Transformation kinetics of phenols in water: photosensitization by dissolved natural organic material and aromatic ketones.
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TLDR
The results show that reactive excited triplet states are important photooxidants in natural waters and should be considered for assessing the abiotic degradation of chemicals.Abstract:
Different dissolved natural organic materials photosensitize the transformation of a series of methyl and methoxy phenols at pH 8 with a very similar high selectivity (reactivity range 50). This selectivity falls in the range of that achieved using the aromatic ketones benzophenone (BP), 3'-methoxyacetophenone (3'-MAP), and 2-acetonaphthone (2-AN) as model photosensitizers. For both natural and model sensitizers, the photooxidation at pH 8 is not controlled by singlet oxygen. Deuterium isotope effects (k H /k D ) of different phenols are 0.7-1.3 for humic and fulvic acids and 1.1-1.7 for BP, suggesting an electron transfer mechanism. In contrast, the isotope effect for 2-AN of 4 indicates an H-atom abstraction reaction. The results show that reactive excited triplet states are important photooxidants in natural waters and should be considered for assessing the abiotic degradation of chemicals. The reactive triplet state concentration is estimated to be 10 -14 M in the top meter of Lake Greifensee under summer noon sunlight, and this leads to a half-life of 7 h for 2,4,6-trimethylphenol. Further still uncharacterized photooxidants derived from the dissolved organic material are also involved in the phototransformation of the phenols.read more
Citations
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Looking at the overlooked hole oxidation: Photocatalytic transformation of organic contaminants on graphitic carbon nitride under visible light irradiation
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Indirect photodegradation of sulfathiazole and sulfamerazine: Influence of the CDOM components and seawater factors (salinity, pH, nitrate and bicarbonate).
TL;DR: This report is the first study of indirect photodegradation of ST and SM from the perspective of the CDOM components and simulated coastal waters and found exogenous components with high molecular weight and higher number of aromatic groups played a decisive role.
Journal ArticleDOI
Photolysis of atrazine: Role of triplet dissolved organic matter and limitations of sensitizers and quenchers.
TL;DR: Atrazine loss via reaction with 3DOM* will be relevant only in selected conditions, and this work provides a more comprehensive view on the use of model sensitizers to mimic triplet 3DOM*.
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Simulated solar UV-irradiation of endocrine disrupting chemical octylphenol.
TL;DR: The results indicate that the oxidation rate increases in the presence of H(2)O(2), nitrate and DNOM, while the disappearance of the estrogenic activity of octylphenol during irradiation using YES test was investigated.
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