In this paper the recent work of the author’s research group on photocatalysis is reviewed. Special emphasis is made on the application of the redox photocatalysis using semiconductor powders to the elimination of toxic species in solution. The most relevant results obtained by the author’s group about the photorecovery of noble metals and the photodeposition of toxic metals are reported. On the other hand, the degradation of organic and inorganic pollutants by photocatalytic oxidation at different experimental conditions and using different photocatalysts are also reported. Finally, a flow system for a continous mode of depuration based on this photocatalytic method is described.