Abstract
Phenolic solution was decomposed by ultrasonic irradiation. The best frequency was found to be 400kHz. To examine the influence of the ultrasonic power, experiments using 11.4, 29.0 and 41.5 W were carried out and the initial decomposition rate of the phenol solution was measured; keeping the frequency constant, higher decomposition rates were obtained increasing the ultrasonic power. The concentrations of hydrogen peroxide, nitric acid and organic acids such as formic acid, propionic acid and oxalic acid were measured during the phenol solution decomposition process. We found that, in case of phenol (0.5 mM), complete decomposition was obtained after 3 h of ultrasonic irradiation (400kHz, 41.5 W), and in case of bisphenol A (0.215 mM), complete decomposition was obtained after 2 h of ultrasonic irradiation (400kHz, 41.5 W). Total organic carbon (TOC) was also measured before and after 10 h of ultrasonic irradiation. Phenol solution (0.5 mM) presented a TOC reduction at the order of 30 % for the process using 400kHz and 41.0 W indicating that although complete decomposition was achieved, some organic carbon still remained in solution as organic acids.
