The decrease of fluorescence emission of phenol was studied in the presence of photoactive oxides (TiO2, ZnO and Fe2O3) irradiated with a sodium lamp, direct sunlight (I sun) and concentrated sunlight (40-50 suns) in aqueous solutions. As expected photodegradation of phenol was seen to be faster for all of the oxides irradiated by concentrated sunlight. The photodegradation capacity of titanium dioxide (TiO2) is superior to that of zinc oxide (ZnO) and ferric oxide (Fe2O3) under a sodium lamp and direct sunlight, but ZnO is found to be as reactive as TiO2 under concentrated sunlight. It has been shown that ZnO is a low cost alternative solar photocatalyst to TiO2 for degradation of organics in aqueous solutions. (C) 2001 Elsevier Science B.V. All rights reserved.