Ultrasonic decomposition of atrazine and alachlor in water.
Abstract The collapse of ultrasonically‐generated cavitation bubbles can result in sonochemical reactions. The kinetics of sonochemical decomposition of alachlor and atrazine in water were determined using a sonicator operating in the continuous mode at maximum output. Alachlor and atrazine solutions, 3.1 nmol L‐1, were kept at constant temperature during the sonication. Decomposition at 30°C followed first‐order kinetics: k = 8.01 × 10‐3 min‐1 and 2.10 × 10‐3 min‐1 for alachlor and atrazine, respectively. It is not clear from the product analysis whether the decomposition was due to a thermal or free radical reaction. However, regardless of the decomposition mechanisms, the extrapolated half‐lives (86 and 330 min for alachlor and atrazine, respectively) support the potential development of ultrasonic waves to decompose herbicides in contaminated water.