Destruction of Halogenated Aliphatics by Ultraviolet Catalyzed Oxidation with Hydrogen Peroxide

Abstract

Hazardous compounds are often present in water at low concentration levels, which can make their removal difficult and costly by conventional treatment processes. This project investigated the destruction of hazardous compounds in water by ultraviolet catalyzed oxidation using hydrogen peroxide as the oxidizing agent. The effectiveness of this process was determined for typical halogenated aliphatics, including trichloroethylene, tetrachloroethylene, tetrachloroethane, dichloromethane, chloroform, carbon tetrachloride and ethylene dibromide. The reactions were conducted in a batch reactor equipped with a low pressure ultraviolet lamp. The rates of decomposition increased with increasing hydrogen peroxide concentration and temperature, and were highly dependent on chemical structure. With trichloroethylene, for example, the concentration was reduced from 50 ppm to less than 1 ppm in 50 min at 20°C and in 10 min. at 40°C. All of the reacted chlorine was converted to chloride ion, indicating that the chlorinated structures were destroyed by UV catalyzed oxidation.