| Attributs | Valeurs |
|---|
| type
| |
| Is Part Of
| |
| Subject
| |
| Title
| - Effects of FeS on the TransformationKinetics ofγ-Hexachlorocyclohexane
|
| has manifestation of work
| |
| related by
| |
| Author
| |
| Abstract
| - Distinctly different rates and pathways were observed forabiotic transformation of γ-hexachlorocyclohexane (γ-HCH) between homogeneous systems and systems containingFeS solid. The observed half-lives of γ-HCH decreasefrom about 1136 and 126 d in homogeneous systems toabout 55 and 50 d in heterogeneous systems at pH ∼6.9and pH ∼8.3, respectively. While no appreciable differencein the measured rate was found between the two testedheterogeneous systems of pH 6.9 and pH 8.3, the observedhydrolysis rate constant for the homogeneous systems ishighly pH dependent, being constant at ∼0.0005 d-1 in pH2.26−6.73, and increased by an order of magnitude perpH unit from pH 6.73 to pH 12.02. A dehydrohalogenationpathway from γ-HCH to pentachlorocyclohexene followedby parallel reactions to three trichlorobenzenes is proposedfor the hydrolysis reaction in the homogeneous systems.For the heterogeneous systems, the reactions likely followboth the hydrolysis pathway and pathways from γ-HCHto tetrachlorocyclohexene (TeCCH) and to dichlorocyclohexadiene (DCCD) via dichloroelimination followed bydehydrohalogenation from TeCCH to dichlorobenzenes orfrom DCCD to chlorobenzene. This study suggests thatenvironmental modeling using hydrolysis rate data measuredin homogeneous systems may bear significant inaccuracyfor the predicted fate and transport of HCH isomers inhighly heterogeneous ecosystems at the regional or megascales.
|
| article type
| |
| is part of this journal
| |
