Removal of volatile organic compounds in water using low-energy electron beam

Abstract

This paper presents the experimental results concerning removal of organic contaminants in water using low energy electron beam radiation. A laboratory scale apparatus for electron beam irradiation of water is described. The absorbed dose of radiation was controlled by water circulation time (1 to 10 min), accelerating voltage (100 to 170 kV), and electron beam current (0.5 to 1.2 mA) for a constant flow rate of 2 kg/min. The volume of the treated water was 1 dm/sup 3/. The electron beam was generated in vacuum (p<10/sup -5/ Pa), and electrons were injected into the water through the electron transparent window made of titanium foil with a thickness of 25 /spl mu/m TCE (trichloroethylene) and chloroform dissolved in deionized water were used in the experiment. The dependency of the relative concentration c=C/C/sub 0/; where C is the weight content of compound after electron irradiation and C/sub 0/ the initial contaminant concentration, on radiation energy density and the absorbed dose are presented. Although the initial contents of the compounds were higher than those occurring in real water sources, it has been found that it is possible to decompose both of the chemicals with high efficiency (total decomposition of TCE, and up to 90% reduction of chloroform) using a relatively low accelerating voltage (<200 kV). The results have indicated that the removal of TCE and chloroform mainly depended on the absorbed dose of electron radiation.