1. College of Chemical Engineering and Materials Science, Zhejiang University of Technology, Hangzhou 310032, China; 2. W. M. Keck Laboratories, California Institute of Technology, Pasadena, CA 91125, USA
发布日期：
2011-03-05
摘要
Aqueous solutions of phenol were oxidized by hydrogen peroxide assisted by microwave (MW) irradiation. A simple kinetic model for the overall degradation of phenol in the presence of excess H O is proposed in which the degradation rate of phenol is expressed as a linear function of the concentrations of phenol and H O . A detailed parametric study showed that the degradation rate of phenol increased with increasing [H O ] until saturation was observed. Phenol degradation followed apparent zero-order kinetics under MW radiation or H O oxidation. However, after 90 min of irradiation, the observed kinetics shifted to pseudo first order. The overall reaction rates were significantly enhanced in the combined MW/H O system, mainly because microwave could accelerate H O to generate hydroxyl radical ( OH) and other reactive oxygen intermediates. The observed synergetic effects of the MW/H O process resulted in an increased in the net reaction rate by a factor of 5.75. When hydrogen peroxide is present in a large stoichiometric excess, the time required to achieve complete mineralization is reduced significantly.
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