Comparative rates of photolysis of polychlorinated dibenzofurans in organic solvents and in aqueous solutions

Journal Article · Fri Apr 01 04:00:00 EST 1994 · Environmental Science and Technology; (United States)

DOI:https://doi.org/10.1021/es00053a004· OSTI ID:7019327

Dung, M H ^[1]; O'Keefe, P W ^[2]

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1. New York State Department of Health, Albany, NY (United States)
2. New York State Department of Health, Albany, NY (United States) State Univ. of New York, Albany, NY (United States)

A generator-column technique was used to prepare aqueous solutions of polychlorinated dibenzofurans (PCDFs). The photolysis rate constants of 2,7-di-, 2,3,7,8-tetra-, and 1,2,7,8-tetra-CDF in aqueous solution irradiated at 300 nm were 1.3, 0.45, and 0.36 h[sup [minus]1], respectively. These photolysis rates were 4-15 times faster than the photolysis rates in organic solutions and, in the cases of 2,7-di CDF and 1,2,7,8-tetra-CDF, 20 times faster than in 60% acetonitrile/water. Thus, a solvent mixture of acetonitrile and water should not be used to study the photolysis of PCDFs in aqueous solution. The contribution of dechlorination to the overall loss of the PCDF compounds was determined. It was found that 10%, 70%, and 50% of photodecomposed 2,7-di-, 1,2,7,8-tetra-, and 2,3,7,8-tetra-CDF, respectively, were dechlorinated under 300-nm irradiation in hexane, compared with <1%, 17%, and 20% in water. Dechlorination may therefore be a major process in the photodecomposition of higher chlorinated PCDFs in hydrocarbon solvents but not in water. These results suggest that the mechanism of photolysis of PCDFs in water differs from that in organic solvents. It was also found that the sunlight photolysis rates of PCDFs in natural water were enhanced by indirect or sensitized photoreactions of chemicals naturally occurring in water. 34 refs., 2 figs., 4 tabs.

• OSTI ID: 7019327
• Journal Information: Environmental Science and Technology; (United States), Journal Name: Environmental Science and Technology; (United States) Vol. 28:4; ISSN ESTHAG; ISSN 0013-936X
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400102 -- Chemical &amp; Spectral Procedures
400201 -- Chemical &amp; Physicochemical Properties
400500* -- Photochemistry
ACETONITRILE
ALKANES
AQUEOUS SOLUTIONS
CHEMICAL REACTION KINETICS
CHEMICAL REACTIONS
CHROMATOGRAPHY
COMPILED DATA
DATA
DECHLORINATION
DECOMPOSITION
DEHALOGENATION
DISPERSIONS
GAS CHROMATOGRAPHY
HEXANE
HYDROCARBONS
INFORMATION
KINETICS
MASS SPECTROSCOPY
MIXTURES
NITRILES
NUMERICAL DATA
ORGANIC CHLORINE COMPOUNDS
ORGANIC COMPOUNDS
ORGANIC HALOGEN COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
ORGANIC SOLVENTS
PHOTOCHEMICAL REACTIONS
PHOTOLYSIS
RADIATIONS
REACTION KINETICS
SEPARATION PROCESSES
SOLAR RADIATION
SOLUTIONS
SOLVENTS
SPECTRA
SPECTROSCOPY
STELLAR RADIATION
ULTRAVIOLET SPECTRA