Nano-photocatalysis in water and wastewater treatment

Industrial development, civilization growth and climate changes make water pollution a global critical issue. The efficient removal of contaminants from aquatic environment urgently requires the use of novel techniques. Among them, photocatalysis is undoubtedly one of the most promising method of mitigation of water pollution issues, especially if it is combined with the use of nano-catalysts and other nanomaterials. Despite intensive research on various photocatalysts (e.g., ZnO, ZnS, graphene based semiconducting composites, MoS 2 , WO 3 and Fe 2 O 3 ) , it is titanium dioxide (TiO 2 ), which remains the most commonly used photocatalyst due to its low price, nontoxicity and high oxidation potential. Moreover, TiO 2 based photocatalysts can be easily activated on various surfaces, what enhances their industrial scale application. The presented paper is focused on the review of the latest achievements in the field of photocatalysis, especially regarding the application of nano-catalysts in water and wastewater treatment technologies. The use of the process to degradation of such harmful substances like endocrine disruptors (pesticides, pharmaceuticals, phenols, etc.), dyes, pathogenic microorganisms and heavy metals is also discussed.