Novel photocatalytic system Fe-complex/TiO2 for efficient degradation of phenol and norfloxacin in water

Photocatalysis is one of the effective strategies to eliminate various organic pollutants in water body. In this paper we have prepared a series of new composite photocatalysts to degrade phenol and norfloxacin under visible light irradiation. They were [FeII(dpbpy)2(H2O)2]/TiO2, [FeII(dpbpy)(phen)2]/TiO2 and [FeII(dpbpy)(bpy)2]/TiO2 (dpbpy: 2,2'-bipyridine-4,4'-diphosphoric acid, phen: 1,10-phenanthroline, bpy: 2,2-bipyridyl). The results show that their photocatalytic performance and cyclic stability are much better than that of pure TiO2 or P25. Phenol can be degraded almost completely and the active groups or substituents of norfloxacin (NOR) can be destroyed also, which greatly reduced the biological toxicity of phenol and norfloxacin in water. The possible mechanisms of improving the photocatalytic activity and stability of TiO2 by using Fe-complex are proposed based on free radical capture test and density functional theory calculation. It is clearly that the interfacial interaction between Fe-complex and titanium dioxide directly affects the photocatalytic activity and stability of the composite photocatalyst. The conjugated structure of the complexes plays a crucial role.