Removal of Phenol from Wastewater Using Ultrasound Cavitation

Ultrasound cavitation is an advanced oxidation process in which organic contaminants are degraded by thermal degradation and reaction with hydroxyl (OH∙) radicals. In the present study, a horn-type sonicator was used to treat the synthetic aqueous solution containing phenol, and the effect of various parameters such as ultrasonic power, initial solution pH, and tip or horn depth on the degradation of phenol in synthetic aqueous solution was investigated, and the optimum value of the parameters was determined. It was observed that the degradation of phenol increased with an increase in ultrasonic power. The degradation of phenol was higher in acidic solution pH compared with that in alkaline solution pH. Moreover, the degradation of phenol increased with an increase in tip depth until an optimum value was reached, beyond which the degradation of phenol decreased with an increase in tip depth. To enhance the phenol degradation, the ultrasound cavitation of synthetic aqueous solution containing phenol was performed by adding hydrogen peroxide and Fenton reagent to the synthetic aqueous solution, and an enhancement in phenol degradation was noticed. Furthermore, cavitation energy was determined, and an enhancement in the energy efficiency of the ultrasound cavitation in the presence of hydrogen peroxide and Fenton reagent was observed. The treatment of industrial effluent containing phenol was also performed, and a chemical oxygen demand reduction of 56.6% was obtained after 120 min. The cost of effluent treatment was determined.