VACUUM-UV-OXIDATION OF CHLOROORGANIC COMPOUNDS IN AN EXCIMER FLOW-THROUGH PHOTOREACTOR

The application of a novel vacuum-UV excimer now through photoreactor (lambda = 172 nm) to the degradation of chloroorganic compounds in water is presented. A sample of ground water, contaminated with trichloroethene (Tri), 1,2-dichloroethene (1,2-DCE) and tetrachloroethene (Per), was purified successfully without the addition of oxidizing agents like H2O2 or O-3. During the VUV-oxidation the intermediary formation of 1,1,2-trichloroethane (1,1,2-Tri) was established by GC-MS analysis. Over 93 % of the organically bound chlorine atoms were transformed to inorganic chlorine ions (Cl-). The photomineralization of 2,4-dichlorophenol (2,4-DCP) is presented on the basis of 2,4-DCP, Cl- and TOC analyses. In few of technical applications the volume-corrected energy efficiencies Phi(-s) of the degradation of 2,4-DCP were determined for different intensities of irradiation and different now rates (e.g. Phi(-s)(142 W, 48 l/min) = 16200 mg/kWh).