Efficiency Evaluation of Tea Waste for Adsorption of Hexavalent Chromium from Industrial Effluent

Water used in industries creates a wastewater that has a potential hazard for our environment because of introducing various contaminants such as heavy metals into soil and water resources. There are atleast 20 metals which cannot be degraded or destroyed. In this study, removal of Chromium (VI) from the industrial effluent has been investigated by using activated waste tea (AWT) as a useful natural adsorbent. The study was performed using batch experiments with chemical industry effluent having Cr (VI) in higher concentration. The adsorption experiments were carried out under different conditions of solution pH and AWT dose. The results indicated that the AWT has good removal efficiency. About 88 % and 98 % Cr removal was achieved by using 0.5 gm and 2 gm adsorbent for wastewater initial concentration of 250 mg/l. The adsorption process reached equilibrium within 40 minutes of the contact time with maximum adsorption at neutral pH. The equilibrium data were fitted to Langmuir and Freundlich isotherms. The adsorption behaviour followed both Langmuir and Freundlich isotherm model. Higher sorption capacity of this sorbent indicates that the waste tea can be used for the treatment of effluent containing Cr (VI).