In this work, the activities of selected photocatalysts during the degradation process of sulfanilamide were compared. Experiments were carried out in the presence of homogeneous Fe-salts (FeCl 3 , Fe(NO 3 ) 3 , Fe 2 (SO 4 ) 3 , FeSO 4 ), heterogeneous compounds (TiO 2 ) and a mixture of catalysts (TiO 2 /FeCl 3 ) under UV-A and solar irradiation. Based on the comparison of several factors such as initial degradation rate and quantum yields, as well as economic and ecological aspects, FeCl 3 is proposed as the optimal catalyst.