HETEROGENEOUS PHOTOCATALYTIC DECOMPOSITION OF POLYAROMATIC HYDROCARBONS OVER TITANIUM-DIOXIDE

The photocatalytic degradation of a mixture of 16 polyaromatic hydroca rbons (PAHs) was investigated in aqueous suspensions of high surface a rea TiO2 illuminated with 310-380 nm ultraviolet light. Triethylamine was utilized for extraction of PAH compounds from motor oil contaminat ed soil and subsequently to increase PAH solubilities in TiO2/water sl urries. Minimum steady-state hydroxyl radical (HO .) concentrations ge nerated during photocatalysis were determined directly by electrospray ionization mass spectrometry analysis of a stable spin-trapped HO . a dduct. In contrast to organic Compounds like trichloroethylene which a re readily mineralized over TiO2, the PAHs investigated here were rela tively slow to degrade although several compounds (acenaphthylene, ant hracene, benzo(a)pyrene, and dibenzo(a,h)anthracene) displayed excepti onal decomposition kinetics.