Adsorption of Metals onto Tea Factory Waste: a Review

Industrial waste constitutes the major source of various kinds of metal pollution in natural water. There are at least 20 metals which cannot be degraded or destroyed. The important toxic metals are Cd, Zn, Pb, Cr, Cu, and Ni. There are numerous methods currently employed to remove and recover the metals from our environment and many physico-chemical methods have been proposed for their removal from wastewater. Adsorption is one of the alternatives for such cases and is an effective purification and separa0tion technique used in industry especially in water and wastewater treatments. Cost is an important parameter for comparing the adsorbent materials. Therefore, there is increasing research interest in using alternative low-cost adsorbents. In recent years, tea factory waste (TFW) is also gaining grounds due to its potential to overcome heavy metal pollutants. Insoluble cell walls of tea leaves are largely made up of cellulose and hemicelluloses, lignin, condensed tannins and structural proteins. In present paper a review on potential of TFW as an adsorbent for the removal of toxic metals were discussed. Characterization of various type of TFW, equilibrium studies, kinetic studies, thermodynamic studies and batch studies for the removal of toxic metals by adsorption were presented.