Kinetics of carbaryl degradation by anodic Fenton treatment in a humic-acid-amended artificial soil slurry.
A Fenton-based indirect electrochemical method, anodic Fenton treatment (AFT), developed for destroying and detoxifying pesticides in the aqueous environment, was evaluated for the degradation of a widely used pesticide, carbaryl, in an artificial soil slurry. More than 90% of carbaryl was removed in less than 20 minutes under given experimental conditions. The effect of initial slurry pH, humic acid content, initial carbaryl concentration, Fenton reagent delivery ratio, and soil/water ratio (w/v) were investigated. The results indicate that humic acid content is the key factor that slows down pesticide degradation, most probably because of its pH buffering and adsorption capacity. A kinetic model, which was shown to fit the experimental data quite well (R2 > 0.99), was developed to describe the carbaryl degradation in the soil slurry during the AFT process. In the presence of humic acid, carbaryl degradation kinetics was found to shift to a pseudo-first-order reaction after an "initiation" stage.
Ye
Peng
P
Graduate Field of Environmental Toxicology, Cornell University, Ithaca, New York 14853-4401, USA.
Kong
Lingjun
L
Lemley
Ann T
AT
D012721:Carbaryl / Q000737:chemistry*; D004563:Electrochemistry; D004566:Electrodes; D006812:Humic Substances / Q000032:analysis*; D006861:Hydrogen Peroxide; D006863:Hydrogen-Ion Concentration; D007501:Iron; D007616:Kaolin / Q000737:chemistry; D007700:Kinetics; D008956:Models, Chemical; D012822:Silicon Dioxide / Q000737:chemistry; D013997:Time Factors
C045076:Fenton's reagent; D006812:Humic Substances; D007616:Kaolin; D012822:Silicon Dioxide; D006861:Hydrogen Peroxide; D007501:Iron; D012721:Carbaryl