Removal of Ketoprofen from Water by Sono-Activated Persulfate Oxidation

In this study, we evaluated the feasibility of treating water contaminated with ketoprofen (KET) by ultrasound (US) and sono-activated persulfate (US/PS) systems. The effects of different reaction parameters, such as the initial pharmaceutical compound concentration (C₀), persulfate concentration, ultrasonic power, and initial pH of the solution (pH_i) on the KET removal and reaction kinetics were investigated. Tert-butyl alcohol (TBA) was used as a chemical probe to identify the predominant radicals in the US and US/PS systems. The results demonstrated that the persulfate oxidant can be activated by US under neutral and alkaline conditions. Moreover, KET was predominantly degraded by hydroxyl radicals (HO^.) generated by the activation of persulfate. Under alkaline conditions, the removal efficiency of KET improved with increasing amount of persulfate added. HO^. was the dominant radical at a more alkaline pH in both US and US/PS systems, which was verified by the tert-butyl alcohol probe. These results provide insights into the treatment of water contaminated with pharmaceutical compounds.