Effects of hydrogen peroxide and frequency for the sonochemical degradation of aqueous phenol

The effect of hydrogen peroxide and frequency on the degradation of phenol was investigated in this study. The concentrations of phenol and hydrogen peroxide were 0.05 and 0.0018 mM, respectively. When a high frequency of sonication (1MHz) was irradiated to a phenol solution, the efficiency of decomposition of phenol was about 95% within 120 min. At a low frequency, the phenol degradation was slower than at a high frequency, while the degradation of the total organic carbon at a low frequency was nearly the same as that at a high frequency. Hydrogen peroxide was formed due to the dissipation of water. Through a comparison, it can be seen that the order of degradation rates of phenol and the formation rate of hydrogen peroxide were not the same. The relationship between the degradation rate of compounds and the formation rate of hydrogen peroxide was not clear. With the addition of hydrogen peroxide in phenol solution, the phenol concentration was almost completely degradable within 30 min. In the case of total organic carbon (TOC), the concentration was degraded by 50%. Therefore, for the decomposition of total organic carbon, the addition of hydrogen peroxide or other catalysts was required.