Use of High-Energy Radiation for Degradation of Environmental Pollutants

Abstract

The purpose of the project was to explore the advantages and/or limitations of high-energy radiation treatment as a method for degrading organic pollutants, particularly aryl halides, in an aqueous medium. The authors have done analyses of (60) Co-irradiated samples and kinetic studies using pulsed electron beams. For aryl halides containing no more than two fused rings, the main products detected are those of simple halogen replacement by hydrogen, although the amount of aryl halide destroyed was always greater than the total amount of products detected. To accomplish halogen replacement by H, the reaction solvent may not be pure water but must contain a hydrogen source such as an aliphatic alcohol. The absence of such an additive, results in products of aryl radical addition to aryl halide. The necessary amount of additive required is quite small for halobenzenes. With aryl halides of three (and presumably more than three) fused rings, the radical-anion intermediates either undergo conversion to halogen-containing dihydroarenes, or lose halogen to form radicals which resist reaction with H-donating additive and thus form dimers. When aryl halides are solubilized in micelle-forming detergent solutions, the detergent molecules serve as hydrogen atom sources. Conversions are highest with cationic detergents.