Record Display for the EPA National Library Catalog


Main Title Comparison of Photochemical Behavior of Various Humic Substances in Water: II. Photosensitized Oxygenations.
Author Zepp, Richard G. ; Baughman, George L. ; Schlotzhauer, Patricia F. ;
CORP Author Environmental Research Lab., Athens, GA.
Year Published 1980
Report Number EPA-600/J-81-127;
Stock Number PB81-192098
Additional Subjects Photochemical reactions ; Humic acids ; Oxygenation ; Water pollution ; Reaction kinetics ; Concentration(Composition) ; Reprints ; Furan/dimethyl ; Numerical solution
Library Call Number Additional Info Location Last
NTIS  PB81-192098 Some EPA libraries have a fiche copy filed under the call number shown. 07/26/2022
Collation 10p
The photochemical oxygenation of 2, 5-dimethylfuran (DMF) in water was studied under a variety of reaction conditions employing various humic substances as photosensitizers. As predicted by theory, the reactions at low DMF concentrations were first order with respect to DMF, and the reaction rate constants were directly proportional to the average light intensity and to the concentration of humic substance. The rate of oxygenation photosensitized by the humic matter from a river was independent of hydrogen ion activity in the pH 5 to 9 range. Wavelength studies indicate that oxygenations photosensitized by humic substances are induced by ultraviolet and blue radiation. Rate constants computed for this photosensitized reaction in sunlight were in close agreement with experimental values. Calculations also show that the ratio of the sunlight rate constants to total visible solar irradiance (400 to 700 nm) is approximately constant. Therefore, it may be possible to calibrate rate constants for photosensitized reactions in terms of commonly measured units of visible light intensity such as foot candles.