Photochemical Degradation Of Hazardous Chemicals In Natural Water And Soil

摘要

The aquatic photochemistry of two high-energy compounds was investigated as a part of a larger study of their environmental fate. Ammonium dinitramide (ADN) absorbs light < 4OOnm and degrades rapidly upon exposure to sunlight. Half- lives for the photolysis of ADN at the surface of a body of water were calculated as six minutes for a location in Syracuse NY. However. much of the light that degrades ADN directly is absorbed in the top layer of water; the half-life at a depth of 2m was calculated as 15 years. A model of the absorption of light passing through the water column in combination with quantum yields was used in order to compare predicted and observed rates in Onondaga Lake, with good agreement. Dark solutions of ADN were stable indefinitely and indirect photolysis did not provide a significant decay mechanism. Although quadricyclane did not photolyze in distilled water it degraded if natural dissolved organic matter (DOM) was also present. This phenomenon was ascribed to the reaction of quadricyclane with hydroperoxy (HOO) and its conjugate base, superoxide (O2). The kinetics of this reaction were tested through the use of an alternative HOO/02 generator, xanthine-xanthine oxidase and a probe. ferricytochrome C.