Frequency Effects on 2-Chlorobiphenyl Sonication

In order to better understand sonication, this paper studies the effect of sound frequency on the 2-chlorobiphenyl (2-CB) sonication and analyzes two prevailing hypotheses. Four frequencies 205, 358, 618, and 1071 kHz were tested. The 2-CB degradation kinetics, dechlorination, and inhibition by a free radical scavenger were examined. The results show that sonication effectively degrades 2-CB, and the first order rate constants using 0.4 W/cm3 sonication are 0.214, 0.508, 0.454, and 0.248 min1 at 205, 358, 618, and 1071 kHz, respectively. Good dechlorination was also achieved. 358 kHz frequency provided the most effi-cient 2-CB degradation, but the worst dechlorination, and was most sensitive to the free radical scavenger. Detailed analyses show that thermolysis is relatively stable at these frequencies while the free radical reac-tion depends strongly on the sound frequency.