Photocatalysis: An emerging route for waste water treatment

Waste water pollution is increasing all over the globe at a rapid pace. Various pollutants are regularly discharged through the effluents of the chemical based industries into nearby water resources; such as rivers, ponds, lakes, sea, etc. These pollutants can affect the life of human beings, vegetation and aquatic animals adversely. Therefore, it is necessary to degrade or mineralize these pollutants completely in eco-friendly manner. Photocatalysis has emerged as an eco-friendly method for waste water treatment, but it has several disadvantages; fast recombination of electron and hole pairs and minimum or low adsorption in the visible light. These two problems can be overcome, by modifications of existing photocatalysts such as sensitization, doping by metal and non-metals, using cocatalyst, formation of composite, formation of Z-, S-, and double Z-Schemes.