PHOTOMINERALISATION ON TITANIUM-DIOXIDE O F URACIL AND 5-HALOGENOURACILS - INFLUENCE OF PH AND SOME ANIONS ON THE PHOTODEGRADATION OF URACIL

In oxygenated aqueous solutions, the photocatalytic degradation of ura cil and its halogenated homologous is achieved on irradiated titanium dioxide. The kinetics of disappearance and mineralisation in carbon di oxide, ammonium, and nitrate ions are established. In presence of chlo ride, carbonate, sulphate and nitrate ions, photodisappearance of urac il is inhibited. This can be due to a partial blockage of catalyst act ive sites by these ions or their reaction with the oxidizing radicals such as HO30 or OH0. It is reported that, at pH lower than 6, disappea rance kinetics of this pollutant is reduced.