Sensitized photolysis of polychlorobiphenyls in alkaline 2-propanol: Dechlorination of Aroclor 1254 in soil samples by solar radiation
Journal Article
·
· Environmental Science and Technology; (United States)
- Biotechnology Research Institute, Montreal, Quebec (Canada)
Photodechlorination of Aroclor 1254 (1000 mg/L) in an alkaline 2-propanol solution at [lambda] = 254 nm proceeded with a high quantum yield ([Phi] = 35.0) as determined by Cl[sup [minus]] release. The Aroclor was completely dechlorinated in 30 min and gave predominantly biphenyl (BP). After 20 h of solar irradiation, only partial dechlorination (25%) was observed, and no BP was formed. In the presence of phenothiazine (PT) sensitizer (5 mM) Aroclor was completely dechlorinated to BP in 1 h at 350 nm ([Phi] = 2.33) and in 4 h by exposure to sunlight. Under the same conditions, Aroclor 1254 extracts of contaminated soil (730 mg/L) were dechlorinated in 2 h at 350 nm ([Phi] = 0.28) and in 20 h on exposure to sunlight. The photoreaction was completely quenched by oxygen and nitrobenzene (0.1 M). Moreover, Aroclor was thermally (ca. 80 [degrees]C) dechlorinated to BP using di-tert-butyl peroxide. A free-radical chain reaction was suggested in which the aryl radical anion, Ar[sup [sm bullet][minus]]-Cl, was a key intermediate in the dechlorination process. 30 refs., 2 figs., 2 tabs.
- OSTI ID:
- 6716538
- Journal Information:
- Environmental Science and Technology; (United States), Journal Name: Environmental Science and Technology; (United States) Vol. 26:10; ISSN ESTHAG; ISSN 0013-936X
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400201 -- Chemical & Physicochemical Properties
54 ENVIRONMENTAL SCIENCES
540220* -- Environment
Terrestrial-- Chemicals Monitoring & Transport-- (1990-)
ALCOHOLS
AROMATICS
CHEMICAL REACTIONS
CHLORINATED AROMATIC HYDROCARBONS
DECHLORINATION
DECOMPOSITION
DEHALOGENATION
HALOGENATED AROMATIC HYDROCARBONS
HYDROXY COMPOUNDS
ORGANIC CHLORINE COMPOUNDS
ORGANIC COMPOUNDS
ORGANIC HALOGEN COMPOUNDS
OXYGEN COMPOUNDS
PEROXIDES
PHOTOCHEMICAL REACTIONS
PHOTOLYSIS
POLYCHLORINATED BIPHENYLS
PROPANOLS
REMEDIAL ACTION
SOILS
400201 -- Chemical & Physicochemical Properties
54 ENVIRONMENTAL SCIENCES
540220* -- Environment
Terrestrial-- Chemicals Monitoring & Transport-- (1990-)
ALCOHOLS
AROMATICS
CHEMICAL REACTIONS
CHLORINATED AROMATIC HYDROCARBONS
DECHLORINATION
DECOMPOSITION
DEHALOGENATION
HALOGENATED AROMATIC HYDROCARBONS
HYDROXY COMPOUNDS
ORGANIC CHLORINE COMPOUNDS
ORGANIC COMPOUNDS
ORGANIC HALOGEN COMPOUNDS
OXYGEN COMPOUNDS
PEROXIDES
PHOTOCHEMICAL REACTIONS
PHOTOLYSIS
POLYCHLORINATED BIPHENYLS
PROPANOLS
REMEDIAL ACTION
SOILS