Degradation of Methomyl by Fenton Process in Neutral Environment

摘要

The purpose of this study aims to investigate the chemical degradation of aqueous methomyl by Fenton process in neutral environment The initial methomyl concentration was 20 ppm for the degradation experiments with different Fenton reagent dosages (i.e., molar concentration ratio of H2O2 to Fe2+). The results showed that Fenton process is effective to degrade methomyl around pH 7. The optimal dosage of Fenton reagent for best methomyl removal was equal to 1, which resulted in 80% methomyl removal. At the Fenton reagent dosages of 1 and 2, the methomyl degradation at the humic acid concentrations of 2.5, 5.0 and 10.0 ppm were evaluated as well. The presence of humic substances was found to have apparent enhancing effect for methomyl degradation due to the formation of locally-acid environment, which is more favorable for Fenton reaction. The mass spectrometry results showed that the hydroxyl radical may attack the single bonds to break the methomyl molecule into smaller fractions which are more easily to degrade either through physio-chemical or biological processes.