Effect of carbon tetrachloride on sonochemical decomposition of methyl orange in water

Two types of sonicators were used for the sonochemical decomposition of methyl orange (MO) in the presence and absence of carbon tetrachloride (CCl(4)): One is a 45 kHz ultrasonic cleaning bath (a low intensity sonicator) and the other is a 200 kHz ultrasonic reactor (a high intensity sonicator). It was clearly confirmed that the rates of the sonochemical decomposition of MO increased with increasing the concentration Of CCl(4) in both sonicators. The enhancement effect Of CCl(4) was much higher in the high intensity sonicator than in the low intensity one: by the addition of 100 ppm of CCl(4), the decomposition ratio of MO with the high intensity sonicator became 41 times larger, while that with the low intensity sonicator became 4.8 times larger. Based on the obtained results, it was suggested that the formed cavitation phenomenon was different between sonicators. It was also suggested that the sonochemical decomposition of MO in the presence Of CCl(4) would be useful to evaluate the sonochemical efficiency, because the rate of MO decomposition can be effectively enhanced by the sonolysis Of CCl(4). (c) 2007 Elsevier Ltd. All rights reserved.