EFFECTS OF METHANOL, FORMAMIDE, ACETONE AND ACETATE IONS ON PHENOL DISAPPEARANCE RATE AND AROMATIC PRODUCTS IN UV-IRRADIATED TIO2 AQUEOUS SUSPENSIONS

Effects of methanol, formamide, acetone and acetate ions on the TiO2 p hotocatalytic degradation of phenol in water at equal initial concentr ations (similar to 1 mmol L-1) have been studied. The amount of phenol adsorbed in the dark and the apparent first-order rate constant of ph enol disappearance remained the same within experimental accuracy. The temporal variations in the concentrations of hydroquinone and catecho l, the two main primary intermediate products, were not significantly affected either, except by acetate ions which increased these concentr ations, particularly that of catechol. In the presence of each of the aliphatic additives, the phenol-phenol coupling products were less num erous and their lifetime was decreased. Traces of products showing rea ctions between phenol and acetate were found. Interpretations are tent atively presented for these observations. Overall, the absence of mark ed effects of these aliphatic pollutants upon phenol degradation are o f great interest for the photocatalytic treatment of water, since thes e aliphatics represent intermediate products in the mineralization of organic matter. (C) 1997 Elsevier Science Ltd.