Comparison of photochemical behavior of various humic substances in water: II. Photosensitized oxygenations

Zepp, Richard G.; Baughman, George L.; Schlotzhauer, Patricia F.

doi:10.1016/0045-6535(81)90175-2

Cited by 114 publications

(74 citation statements)

References 5 publications

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“…The experimental results consequently are inconsistent with a reaction in which photoproduction of X and reaction of it with mirex occur in a homogeneous solution. Figure 2a have been observed for the humic-mediated reductive dissolution of metal oxides complexed to HAs (29) and postulated for the HA-photosensitized reactions of pollutants bound to HAs (24,29). What distinguishes these reactions from the description in eq 8 is binding.…”

Section: Equation 8 Predicts That K X ′ Will Increase With [Doc] and mentioning

confidence: 85%

Binding Effects on Humic-Mediated Photoreaction: Intrahumic Dechlorination of Mirex in Water

Burns

Hassett

Rossi

1996

Environ. Sci. Technol.

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A kinetic model was developed describing the effects of hydrophobic partitioning to humics on second-order humic-mediated photoreactions in aqueous solution. Model development and evaluation were in terms of the humic-mediated dechlorination of the hydrophobic chlorocarbon, mirex. Mirex dechlorination in irradiated (λ g 290 nm) Aldrich humic acid (HA) solution was examined as a function of humic acid and scavenger concentration. Kinetic models in which HA solution is described as a homogeneous or single-phase solution were not able to describe the effects of HA and scavenger concentrations on mirex dechlorination rates. However, these effects were successfully described by including partitioning in the models to characterize the bound phase and dissolved phase mirex reactions separately. The resulting model uses homogeneous phase kinetics to describe reaction in the dissolved phase. Bound phase reaction is described as occurring within individual HA molecules with the distribution of scavengers within HA molecules following a Poisson distribution. Used to assess the relative reactivities of the bound and dissolved phases, the model indicated that the reaction of mirex in HA solution is confined to the humic phase. The general predictions and utility of the model are evaluated both in terms of experimental data and pollutant photodegradation.

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Section: Equation 8 Predicts That K X ′ Will Increase With [Doc] and mentioning

confidence: 85%

Binding Effects on Humic-Mediated Photoreaction: Intrahumic Dechlorination of Mirex in Water

Burns

Hassett

Rossi

1996

Environ. Sci. Technol.

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“…Kinetics of phenanthrene photodegradation: According to the photochemical theory (Zepp et al 1981: Kawaguchi 1993, in a well-mixed aqueous system containing a very low concentration of a chemical, both direct and photosensitized reactions can be described by first-order rate equation:…”

Section: Resultsmentioning

confidence: 99%

Photodegradation of phenanthrene in the presence of humic substances and hydrogen peroxide

Wangl

Yediler²,

et al. 1995

Chemosphere

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The photodegradation of phenanthrene in water was investigated for a variety of reaction conditions employing various fulvic acids (FAs) as photosensitizers and hydrogen peroxide as oxidant. All experiments were conducted by using artificial sunlight from Suntest apparatus (Hanau, Germany) as light source. The relative rates of phenanthrene photodegradation for the different experimental conditions were computed. Fulvic acids of different origins influenced the rate of sunlight-induced photodegradation of phenanthrene in different ways. Hydrogen peroxide vigorously enhanced the photodegradation rate of phenanthrene. The photoproducts identified were oxygenated products of aromatic ring, such as 9,10,-phenanthrenquinone, a group of hydroxyphenanthrene with hydroxyl at different position (1,3,4, and 9), 2,2'-biphenyldicarbonic acid, 2,2'-biphenyldialdehyde and 2-phenylbenzaldehyde. It can be consumed that the phenanthrene photodegraded via free radical mechanism.

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“…The significance of singlet oxygen in aquatic photochemistry was already recognized in the 1980s [45,46]. We refer the reader to the various reviews on indirect photochemical transformations for more detailed information [7-9, 12, 13].…”

Section: Singlet Oxygenmentioning

confidence: 99%

Aquatic Phototransformation of Organic Contaminants Induced by Coloured Dissolved Natural Organic Matter

Richard

Canonica

2005

The Handbook of Environmental Chemistry

129

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Comparison of photochemical behavior of various humic substances in water: II. Photosensitized oxygenations

Cited by 114 publications

References 5 publications

Binding Effects on Humic-Mediated Photoreaction: Intrahumic Dechlorination of Mirex in Water

Binding Effects on Humic-Mediated Photoreaction: Intrahumic Dechlorination of Mirex in Water

Photodegradation of phenanthrene in the presence of humic substances and hydrogen peroxide

Aquatic Phototransformation of Organic Contaminants Induced by Coloured Dissolved Natural Organic Matter

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