Vis-active photocatalytic composite thin films for advanced wastewater treatment

Conventional wastewater treatment processes are preparing the water for discharge thus it still contains small amounts of pollutants. For re-use, advanced wastewater treatment is required and heterogeneous photocatalysis represent a viable path for removing organic pollutants at very low concentrations but still above the discharge limit. The mostly investigated photocatalyst is TiO2 that is a wide band gap semiconductor that can be activated only using UV radiation. However, for large-scale implementation of advanced wastewater treatment, there are required efficient and affordable processes, thus Vis- or solar-activated photocatalysts. Attempts on extending the photocatalytic response towards Vis are under intensive research including the development of composite structures with TiO2 matrix and various fillers that are discussed through this paper. The latest results involving carbon-based fillers are presented along with the extended use of the composites acting also as self-cleaning coatings.