抄録
Model compounds (benzoic acid or phenol: 1.25×10^<-6> mol/l) as organic pollutants of water were added to the aqueous solution contained titanium dioxide (0.1〜0.8g) and hydrogen peroxide (0.0423 mol/l). The solution was continuously stirred during degradation treatments (1〜4days) by means of a magnetic stirrer in the dark place. At the end of reaction, sodium hydrogen sulfite was added to the mixture to reduce the excess hydrogen peroxide. The remained phenol was extracted from the reaction mixture with ethyl acetate. The extracts were analyzed by FID-GC. For remained benzoic acid and both oxidation products, an aliquot of the reaction mixture was evaporated to dryness under a nitrogen gas and esterified with 15% BF_3/n-butanol at 100℃ for 60 min. The derivatives were analyzed by FID-GC and GC/MS. Each of substrates were decreased with treatment times, the remained amounts of them after 4 days treatment were about 40%. The results of oxidative reaction confirmed cleavage and hydroxylation of the aromatic rings. When benzoic acid was used as a model compound, the major oxidation products (about 20%) consist of aliphatic C_2-C_4 α,ω-dicarboxylic acids, C_4 unsaturated dicarboxylic acids (maleic and fumaric) and hydroxy benzoic acids. While, in the case of phenol, was little. In addition, when ultrasound (40kHz) was simultaneously irradiated (1〜10 hr) into the solution, the rates of the disappearance of each substrates was exponentially accelerated. On the other hand, amounts of the degradation products were less rather than without ultrasonic irradiation.
