Nanostructured photocatalysis in the visible spectrum for the decontamination of air and water

Photocatalytic remediation aligns with the zero waste schemes of waste and wastewater industries with low cost, environment-friendly and sustainable treatment technologies. Efforts are made to increase the photocatalytic activity of photocatalysts (titanium oxide (TiO2), zinc oxide (ZnO) and tungsten oxide (WO3)) by altering their shape (nanowires, nanotubes, nanoparticles, etc.), size and doping (nitrogen, metal and carbon). The photocatalytic properties of various photocatalysts in visible light radiation have been reviewed critically. The nanostructure, doping and composite formation of photocatalysts have profound impact on the remediation of various organics in both air and water. The article also emphasises on attempts to enhance the contact of insoluble pollutants by the use of surfactants and biosurfactants in photocatalytic remediation methods. The comparative photocatalytic activities using doping, surfactants and biosurfactants have been discussed to show the effective remediation of organics under visible light. This review depicts, as the first attempt, organic remediation in visible light using various photocatalytic materials.