Methodologies of Removal of Dyes from Wastewater: A Review

Dyes have been used in several industries, like paper-making, textiles, plastic, leather tanning, cosmetic and foods industries since Eighteenth century. Effluents containing dyes reduce the penetration of sunlight into natural bodies of water, thus leading to a decrease of both photosynthetic activity and the concentration of dissolved oxygen. The presence of dyes in watercourses is both aesthetically unacceptable and also toxic to aquatic ecosystem and human health. The effluent treatment technologies being used now a days for removal of dyes from wastewater includes coagulation, biological methods, adsorption, advanced oxidation processes, membrane technology, electrochemical methods, nano technology etc. In this review, extensive information is presented with regard to different techniques adopted for dyes removal from the available literature.