Fe3O4 catalyst supported on spherical γ-Al2O3 was prepared with and without ultrasonic treatment during the impregnation step

and the heterogeneous catalytic oxidation of dimethoate wastewater was conducted with Fenton reagent.Then

the physical and chemical properties of the catalysts were analyzed by means of XRD

ICP-AES and SEM

especially the effect of Fe3O4 dispersity on γ-Al2O3.The results showed that the activity of the supported catalysts prepared with ultrasonic treatment for dimethoate was higher than those without ultrasonic treatment and the corresponding degradation rate doubled those of the catalyst obtained by impregnation.The probable cause was that for catalysts prepared with ultrasonic treatment

Fe3O4 was well dispersed on the catalyst surface with small particle size

or existed in non-crystalline amorphous state

and Fe content on the catalyst surface was higher than those without ultrasonic treatment.