Catalytic degradation of phenol in sonolysis by coal ash and H2O2/O3

This Study demonstrated that coal ash, as widely distributed solid waste disposal, would function as a media for organic pollutants removal in the presence or absence of H2O2/O-3 under ultrasonic radiation. Coal ash could act as a catalyst to generate (OH)-O-center dot radicals with the presence of H2O2/O-3 and consequently enhance the phenol degradation. Experimental results showed that when using coal ash as a catalyst under ultrasonic irradiation, 83.4% and 88.8% of phenol was degraded in the presence of H2O2 or O-3, respectively. The degradation rate of phenol would increase with increasing amount of O-3, while there was an optimal concentration of H2O2 (1.5 mM) for phenol degradation. Higher dosage of coal ash could result in higher phenol degradation rates. H2O2/coal ash/ultrasonic system could achieve better performance for phenol degradation under more acidic conditions, while more alkaline condition in O-3/coal ash/ultrasonic system favored phenol degradation. This study provides a new approach for wastewater treatment especially when contaminated with phenolic pollutants. (C) 2009 Elsevier B.V. All rights reserved.