MINERALIZATION OF CYCLIC ORGANIC-WATER CONTAMINANTS BY THE PHOTO-FENTON REACTION - INFLUENCE OF STRUCTURE AND SUBSTITUENTS

Photochemical degradation of different aromatic and saturated cyclic organic substances (each containing six carbon atoms per molecule) in aqueous solution by the Photo-Fenton reaction has been studied by monitoring TOC (Total Organic Carbon), UV-absorbance at 254 nm and consumption of H2O2. Mineralization of phenol, hydroquinone, 4-chlorophenol and 4-chloroaniline reached between 92% and 98% after 5 hours of illumination with a 250 W tungsten lamp. TOC-reduction of 3-nitroaniline and 4-nitroaniline was 76% and 74%, respectively. Cyclohexanol and cyclohexanone showed only a very slight removal of TOC after this time. UV-absorbance (254 nm) of solutions containing aromatic substrates decreased very rapidly at the beginning of the reaction suggesting a partial destruction of the aromatic structure. Reasons especially for the selectivity of TOC-degradation are discussed.