Ultrasonic treatment of arsenic species: Transformation kinetics analysis

Abstract A study on the transformation kinetics of arsenite (As(III)), arsenocholine (AsC) and arsenobetaine (AsB) was carried out in aqueous solution by ultrasonic treatment. High performance liquid chromatography-inductively coupled plasma-mass spectrometry (HPLC-ICP-MS) was used for this research under the condition of simulated ultrasound-assisted extraction. The results showed that the transformation of arsenic species accorded with the 1st-order kinetic equation at different ultrasonic water bath temperatures (0–80 °C) and ultrasonic powers (150–750 W). At the ultrasonic power of 300 W, the reaction rate constants of arsenic species at different ultrasonic water bath temperatures were as follows: k20 °C > k40 °C > k0 °C > k60 °C > k80 °C. At the ultrasonic water bath temperature of 60 °C, the reaction rate constants of arsenic species at different ultrasonic powers were as follows: k600 W > k450 W > k750 W > k300 W > k150 W. The study also provides a theoretical basis for the optimization of ultrasound-assisted extraction method without changing arsenic species.