Vacuum - UV - oxidation of chloroorganic compounds in an excimer flow through photoreactor

The application of a novel vacuum-UV excimer flow through photoreactor (Λ = 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 O3. 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 −s of the degradation of 2,4-DCP were determined for different intensities of irradiation and different flow rates (e.g. −s(142 W, 481/min) = 16200 mg/kWh).