Sonochemical removal of trihalomethanes from aqueous solutions

In this research, ultrasound irradiation was employed to degrade the trihalomethanes, THMs: CHCl3, CHBrCl2, CHBr2Cl, CHBr3, and CHI3. The kinetics reaction rates and removal efficiencies of the THMs compounds, as a sole component in the aqueous solutions, were studied. Batch experiments were conducted at an ultrasonic frequency of 20 kHz and acoustic intensity of 3.75 W/cm2. The first-order degradation rate constants and the sonolysis efficiencies followed the decreasing order of CHCl3 > CHBrCl2 > CHBr2Cl > CHBr3 > CHI3. Up to 100% of the CHCl3 was removed, while only 60% of the CHI3 was sonodegraded, after 180 min sonication. The THMs vapor pressure was found to be the most important parameter affecting the sonodegradation kinetics and efficiency, while the bond dissociation energy and hydrophilic/hydrophobic characteristics of the THMs compounds were found to be of secondary importance.