Abstract:

CoFeMg oxide nanocrystals were prepared with solgel method and characterized as a catalyst. SEM and XRD were used to characterize the catalyst, methylene blue was used to study the synergistic degradation of the catalyst and H₂O₂, the dynamic process of oxidative degradation of methylene
blue was studied by the steadystate approximation method. Results show that CoFeMg Fenton reaction system composed of CoFeMg oxide nanocrystals used as a heterogeneous Fentonlike catalyst and H₂O₂ effectively degraded methylene blue. At pH≈7.15, a mass concentration of CoFeMg oxide nanocrystals of 0.8 g/L and concentration of H₂O₂ of 2 mmol/L, the degradation rate of methylene blue was evaluated to be 95%. Compared with that of traditional Fenton reaction system, the amount of leaching of iron was decreased to 0.2 mg/L under similar conditions. The dynamics results show that Fenton reaction system shows a hydroxyl radicals (·OH) oxidation degradation process of methylene blue, and the reaction was considered as secondary dynamics.

Key words: CoFeMg oxide nanocrystal, Fenton reaction, leaching of iron, steadystate approximation