The presence of phosphorus pesticides in the aquatic environment has raised concerns due to the poor degradation in conventional water treatment plants.In this study,sonolytic degradation of dimethoate in aqueous solution was investigated.The effects on its degradation rate by ultrasonic frequency and power, dimethoate’s initial concentration and initial pH value, and the concentration of humic acid and different ions are studied.The results indicate that at the conditions in question,600 kHz is the optimal frequency for dimethoate degradation and the degradation rate of dimethoate increased with enhancement of input power and decreasing initial concentration.The added inorganic ions can contribute diverse effects on the degradation.Carbonate and bicarbonate ions have negative effecst while bromonium and ferrous ions have positive effects.During the initial period,lower pH value is favorable,however,the constant of degradation rate decreases as the concentration of pre-existing humic acid increases.It is proved that sonolytic process has shown great potential for the removal of dimethoate.Besides,the mechanism of the degradation is also proposed.
