Ultrasonic degradation at 20 kHz and 500 kHz of atrazine and pentachlorophenol in aqueous solution: Preliminary results

Atrazine and pentachlorophenol degradation in aqueous solution by ultrasound has been performed at two frequencies: 20 kHz, 500 kHz. Using the same acoustical power determined through the calorimetic method, the treatment is much more efficient at the higher frequency. In comparison with an irradiation conducted at 20 kHz, the degradation proceeds 7.8 time more rapidly for atrazine, and 4.8 time more rapidly for pentachlorophenol at 500 kHz. Sonochemical degradation of atrazine is characterized by the formation of intermediates coming from dealkylation processes. Fast release of chloride is the main feature of the pentachlorophenol ultrasonic transformation. Total inhibition of the degradation by n-pentanol indicates that °OH are involved in the degradation pathway.