Kinetics study on degradation of herbicide ZJ0777 by Fenton reagent

To establish an efficient oxidation process for ZJ0777 degradation, the effects of operating parameters such as initial concentrations of ZJ0777, H2O2 and FeSO4·7H2O were examined during treatment with Fenton reagent. Firstly, the effect of initial ZJ0777 concentration was tested between 0.12 mmol/L and 0.48 mmol/L. More than 90% of ZJ0777 was degraded after 32 h with an initial concentration of 0.12 mmol/L and in 48 h with an initial concentration of 0.24 mmol/L. At an initial concentration of 0.48 mmol/L, only 87% conversion of ZJ0777 could be obtained in 84 h. And the influence of initial amount of H2O2 between 150 and 300 mmol/L was analyzed. The effective degradation of ZJ0777 was reached. The degradation rate was found to increase with increasing dosages of H2O2. Further, the effect of initial FeSO4·7H2O concentrations on the homogeneous degradation of ZJ0777 was also investigated. The increase of Fe2+ doses accelerated the degradation of ZJ0777 in the range of 5-20 mmol/L. Addition of Fe2+ became inefficient and unnecessary. Kinetic analysis indicated that ZJ0777 degradation by the homogeneous Fenton reaction could be described by a pseudo-first-order reaction model and the apparent activation energy was 75.34 kJ/mol.