Sonochemical oxidation of arsenite in aqueous phase

The objective of this research is to assess critically the experimental rate data for sonochemical oxidation of arsenite [As(III)] at different frequencies and powers in the aqueous phase. The oxidative conversion of As(III) into arsenate [As(V)] was >90% in the range of 283 to 450 kHz. With a power density of 69WL^-1, the oxidation of As(III) for 40min at 283kHz showed a second-order rate constant of 7:1 × 10² M^-1 s^-1, whereas it was 3:8 × 10³M^-1 s ^-1 at 450 kHz. As calculated by the calorimetric method, the power transferred into samples was in the range of 7-34.5 W with the two frequencies of 283 or 450 kHz. Approximately 100% oxidation efficiency was obtained with a frequency of 450 kHz and 34.5 W. As the pretreatment process, oxidation by sonication has potential applications to groundwater contaminated with both As(III) and As(V).