Bromate (BrO 3 − ) is a potential carcinogenic compound that can form during the disinfection of drinking water. For the first time, the sonocatalytic reduction of BrO 3 − were studied through examining the effect of the important operational parameters such as ultrasound (US) frequency, TiO 2 loading, pH, temperature and other anions. By observing sonoluminescence (SL) at various frequencies and measuring H 2 production rates, a new reduction mechanism for BrO 3 − is also proposed. The kinetic results presented that the BrO 3 − reduction rates enlarged as the measured H 2 production rate increased for all parameters, and the slopes between the BrO 3 − reduction and H 2 production rates for sonocatalysis were much higher than those for sonolysis. Interestingly, sonolysis could be limited by the amount of H 2 production, but sonocatalysis could increase the BrO 3 − reduction rate because of additional electrons (e − ) from the surface of TiO 2 via SL. The highest SL intensities for H 2 production and BrO 3 − reduction rates occurred at an ultrasound frequency of 500 kHz, implying that an increase in SL intensity caused by ultrasound cavitation enhanced H 2 production and increased the e - released to the conduction band of TiO 2 . At 500 kHz, BrO 3 − reduction rate (6.84 × 10 −2 min −1 ) by sonophotocatalysis was 5.2 times higher than that (1.32 × 10 −2 min −1 ) of sonolysis. Investigation into the effect of anion species showed that BrO 3 − reduction was inhibited or enhanced depending on the type of anions present. In real application, sonocatalytic reduction of BrO 3 − could be advantageous, as it has higher reduction rates than those reported for photocatalysis.
ASJC Scopus subject areas
- Environmental Chemistry
- Chemical Engineering(all)
- Industrial and Manufacturing Engineering