Comparative studies of zinc, cadmium, lead and copper on economically viable adsorbents

Lead and cadmium are very important metals even at trace levels because many health hazards are associated with them. Whereas, zinc and copper are toxic only when these are present at higher concentrations. Their removal from the contaminated samples is of utmost importance. The technique of adsorption using various economically viable adsorbents such as bagasse, bottom ash, rice husk ash, sawdust, and used tea leaves has been applied for their removal from aqueous solutions. Various parameters such as contact time, adsorbent dose, and metal concentrations were studied, optimized and applied to the present study. The equilibrium data obtained were analyzed in the light of Freundlich and Langmuir isotherms. Results revealed that rice husk ash is most efficient in removing lead and copper from aqueous solutions in comparison to the other adsorbents. Whereas in the case of cadmium, bottom ash was found to be of maximum efficiency. Bagasse was of maximum efficiency in removing zinc.