Natural sunlight induced photooxidation of naphthalene in aqueous solution

• Published in: Water, air, and soil pollution Vol. 136; no. 1-4; pp. 347 - 359
• Main Authors: MCCONKEY, B. J, HEWITT, L. M, DIXON, D. G, GREENBERG, B. M
• Format: Journal Article
• Language: English
• Published: Dordrecht Springer 01-05-2002; Springer Nature B.V
• Subjects: Applied sciences; Biological and physicochemical phenomena; Catalysts; Earth sciences; Earth, ocean, space; Engineering and environment geology. Geothermics; Environmental monitoring; Exact sciences and technology; Hydrogen peroxide; Light sources; Naphthalene; Natural water pollution; Oxidation; Photooxidation; Pollution; Pollution, environment geology; Polycyclic aromatic hydrocarbons; Sunlight; Water treatment and pollution; Naphthalene; Hydrocarbon; Pollutant behavior; Reaction mechanism; Oxidation; Water pollution; Photochemical reaction; Polycyclic aromatic compound; Solar radiation; Photooxidation; Degradation product; Photochemical degradation
• ISSN: 0049-6979; 1573-2932
• DOI: 10.1023/a:1015223806182

There is surprisingly little data on the photooxidation of polycyclic aromatic hydrocarbons (PAHs) under environmentally relevant lighting conditions. The aqueous photooxidation reactions of naphthalene (the simplest and most water soluble PAH) were investigated using natural sunlight as a light source.Six of the major reaction products were identified, including 1-naphthol, coumarin, and two hydroxyquinones. The reactionproducts were consistent with initial [2,2] or [2,4] photocycloaddition reactions, with subsequent oxidations and/or rearrangements. The oxidation reactions in aqueous phase favoredproducts different from those observed in atmospheric oxidation reactions. However, similar photoproducts were observed withtitanium catalysts or in the presence of hydrogen peroxide. Theproducts from aqueous photooxidation were also similar to the products resulting from naphthalene metabolism. The observedphotooxidation products were generated by mechanisms that areexpected to occur with other PAHs as well, and thus naphthaleneoxidation provides a model for possible photoreactions of largerPAHs.[PUBLICATION ABSTRACT]