tailieunhanh - Chemical Degradation Methods for Wastes and Pollutants - Chapter 4

Fenton Fenton và thay đổi phương pháp suy thoái ô nhiễm Bản chất biorefractory của nhiều chất ô nhiễm hữu cơ bền đã dẫn đến những nỗ lực để đưa ra các phương pháp hóa học và vật lý của chất gây ô nhiễm làm giảm dòng thải hoặc trong các trang web bị nhiễm bẩn như đất, trầm tích và nước ngầm. Thuốc thử Fenton đã được áp dụng cho sự xuống cấp của một loạt các chất gây ô nhiễm, chủ yếu là các chất ô nhiễm hữu cơ dai dẳng. Những lợi ích chính của thuốc thử Fenton. | 4 Fenton and Modified Fenton Methods for Pollutant Degradation Matthew A. Tarr University of New Orleans New Orleans Louisiana . I. INTRODUCTION The biorefractory nature of many persistent organic pollutants has resulted in efforts to devise chemical and physical methods of degrading pollutants in waste streams or in contaminated sites such as soils sediments and groundwater. Fenton reagent has been applied to the degradation of a wide range of contaminants predominantly persistent organic pollutants. The primary benefits of the Fenton reagent are its ability to convert a broad range of pollutants to harmless or biodegradable products its benign nature residual reagents do not pose an environmental threat and the relatively low cost of the reagents. The major drawbacks to utilization of Fenton reagent are interferences from nonpollutant species difficulty in application to the subsurface generation of excessive or explosive heat under aggressive conditions and wasted reagent costs due to inefficient application or inefficient pollutant degradation in the subsurface. This chapter will detail the fundamental chemistry of Fenton reagent discuss the kinetics and mechanisms of pollutant degradation illustrate the advantages and disadvantages of its application to subsurface remediation and evaluate recent advances that may improve the utility and efficiency of Fenton reagent for pollutant degradation and subsurface remediation. The term Fenton reagent refers to aqueous mixtures of Fe II and hydrogen peroxide. The Fenton reagent was first reported by Fenton 1 2 in 1876. Although Fenton did not elucidate the mechanism of the reaction Copyright 2003 by Marcel Dekker Inc. All Rights Reserved. named after him subsequent research has indicated the following net reaction as the predominant process Fe2 H2O2 Fe3 HO- OH 1 where Fe2 and Fe3 represent the hydrated species Fe H2O 62 and Fe H2O 63 respectively. Reaction 1 is often referred to as the Fenton reaction although many