Bioremediation of Lead and Cadmium by Tea Waste

Heavy metals released by a number of industrial processes are major pollutants in marine, ground, industrial and even treated waste waters. Biosorption is a process that utilizes biological materials as adsorbents and several researchers have studied this method as an alternative technique to conventional methods for heavy metal removal from wastewaters. In this study, the efficiency of tea waste has been determined in the process of heavy metal removing from single metal ion solution and mixed metal ion solutions. Metals of interest are lead and cadmium. The research is bench scale experiment type and analyses have performed by using fixed amount of adsorbent in solution with four different concentrations (5mgs/L, 10mgs/L, 15mgs/L and 30mgs/L) of each metal and also in a mixed combination. Since the pH plays a major role in adsorption, it should be maintained at 4.5 throughout the experiment. Result indicates the removal efficiency is highest for lead than for cadmium. The adsorption data fit well with the Langmiur isotherm model. Though tea waste could adsorb 80 +2% cadmium in single metal ion solution, but its adsorption of cadmium get increased to 90+2 % in mixed ion solution. This indicates that lead acts as the stimulator for cadmium. Comprehensive parameters indicate tea waste to be excellent parameters for Biosorption of lead and cadmium to treat waste waters containing low concentration of metals.