상수처리 : 초음파를 이용한 페놀의 분해에 오존의 초기 농도의 영향에 대한 연구 = The effect of initial concentration in ozone for the sonochemical degradation of phenol

다국어 초록 (Multilingual Abstract)

In this research, the combination of sonolysis and ozonolysis on degradation of phenol as an advanced oxidation process was investigated. Experiments were performed with a probe type ultrasonic system at frequency of 20kHz and power of 225W. Ozone was pre-saturated in distilled water by an ozone generator with different initial ozone concentrations (20mg/L, 39.1mg/L, 60.4mg/L). Compared to linear combination of US and O3, increments of approximately 1.8% and 9.7% of phenol reduction were observed under the US/O3 combination process. Besides, the reaction rate constants of US/O3 seemed to rise with increasing initial concentrations of aqueous ozone. From the kinetic study, the degradation was found to follow the pseudo-first-order kinetic law. And in each case with individual initial ozone concentration, the reaction rate constant of combined system was higher than that of the numeric addition of US and O3 separate system. So the addition of sonolysis had proved to have a synergetic effect on the degradation of phenol with ozonation alone. Both the direct reaction of phenol by O3 and reaction of phenol by hydroxyl radical were supposed to be the main mechanism in this combination process. In addition, an increase of the applied ozone dosage should increase ozone concentration in the liquid phase. At higher ozone concentration, the ozonation time to reach the same efficiency of total phenol removal was smaller than in the case of lower ozone concentration.