Improving sono-activated persulfate oxidation using mechanical mixing in a 35-kHz ultrasonic reactor: Persulfate activation mechanism and its application

This study investigated the degradation of ibuprofen (IBP), an activated persulfate (PS), when subjected to ultrasonic (US) irradiation and mechanical mixing (M). The effects of several critical factors were evaluated, including the effect of rpm on M, PS concentration, and initial pH, and that of temperature on IBP degradation kinetics and the PS activation mechanism. The resulting IBP oxidation rate constant was significantly higher at 400 rpm. As the PS load increased, the IBP oxidation rate constant increased. The value of the IBP reaction rate increased with decreasing pH; below pH 4.9, there was no significant difference in the IBP oxidation rate constant. The IBP oxidation activation energy when using the US/M-PS system was 18.84 kJ mol(−1). In the US/M-PS system, PS activation was the primary effect of temperature at the interface during the explosion of cavitation bubbles. These encouraging results suggest that the US-PS/M process is a promising strategy for the treatment of IBP-based water pollutants.