Sonochemical Oxidation of Arsenite in Aqueous Phase

Abstract

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 69 W L-1, the oxidation of As(III) for 40 min at 283 kHz showed a second-order rate constant of 7.1 x 10(2) M-1 s(-1), whereas it was 3.8 x 10(3) M-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). (C) 2011 The Japan Society of Applied Physics