The photosensitized processes significantly enhance photolysis of various chemicals in
the aqueous system with dissolved organic matter (DOM) as sensitizer. The excitation of
chromophores on the DOM molecule further generates reactive species as triplet states
DOM, singlet oxygen, hydroxyl radical, carbonate radical etc. We investigated the
photosensitization properties of Beaufort Fulvic Acid, Suwannee River Fulvic Acid,
South Platte River Fulvic Acid, and Jeddah wastewater treatment plant effluent organic
matter with a sunlight simulator. DOM photochemical properties were characterized by
observing their performances in 3DOM*, singlet oxygen, hydroxyl radical production
with indirect probing protocols. Sensitized degradation of 0.1 μM and 0.02 μM 2, 4, 6-
Trimethylphenol exhibited higher pseudo-first-order rate constant than that of 10 μM.
Pre-irradiated DOMs were found to be depressed in photochemical properties. Photolysis
of 5 different contaminants: ibuprofen, bisphenol A, acetaminophen, cimetidine, and
caffeine were found to be enhanced in the presence of sensitizers. The possible reaction
pathways were revealed. Long time irradiance induced change in contaminants
degradation kinetics in some DOM solutions, which was proposed to be due to the
irradiation initiated indirect transformation of DOMs.
Key Words: Photolysis Dissolved Organic Matter, Triplet State DOM, Singlet Oxygen,
Hydroxyl Radical, Contaminants Degradation.
| Date of Award | May 2013 |
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| Original language | English (US) |
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| Awarding Institution | - Biological, Environmental Sciences and Engineering
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| Supervisor | Jean-Philippe Croue (Supervisor) |
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- Photolysis Dissolved Organic Matter
- Triplet State DOM
- Singlet Oxygen
- Hydroxyl Radical
- Contaminants Degradation