American Journal of Biochemistry and Biotechnology 5 (2): 75-83, 2009 ISSN 1553-3468 © 2009 Science Publications Corresponding Author: Modher A. Hussain, Phycology Laboratory, Institute of Biological Science, Faculty of Science, University of Malaya, Kuala Lumpur 50603, Malaysia Tel: +603-7967-4356 Fax: +603-7967-4178 75 Characterization of the Adsorption of the Lead (II) by the Nonliving Biomass Spirogyra neglecta (Hasall) Kützing Modher A. Hussain, Aishah Salleh and Pozi Milow Phycology Laboratory, Institute of Biological Sciences, Faculty of Science, University of Malaya, Kuala Lumpur 50603, Malaysia Abstract: Problem statement: Conventional techniques for removing dissolved heavy metals are only practical and cost-effective when applied to high strength wastes with heavy metal ion concentrations greater than 100 ppm. The possibility of using a nonliving algal biomass to solve this problem was carried in this study. Lead (II) was used in this study because it had been reported to cause several disorders in human. Approach: The nonliving algal biomass was obtained from a filamentous green alga Spirogyra neglecta. The effects of initial concentration and contact time, pH and temperature on the biosorption of lead (II) by the nonliving algal biomass were studied. The equilibrium isotherms and kinetics were obtained from batch adsorption experiments. The surface characteristics of the nonliving algal biomass were examined using scanning electron microscope and Fourier Transformed Infrared. The maximum adsorption capacity of the nonliving algal biomass was also determined. Results: Maximum adsorption capacity of lead (II) was affected by its initial concentration. Adsorption capacity of lead (II) increased with the pH and temperature of lead (II) solution. Langmuir isothermic model fitted the equilibrium data better than the Freundlich isothermic model. The adsorption kinetics followed the pseudo-second-order kinetic model. The nonliving algal biomass exhibited acaves-like, uneven surface texture along with lot of irregular surface. FTIR analysis of the alga biomass revealed the presence of carboyl, amine and carboxyl group which were responsible for adsorption of lead (II). The maximum adsorption capacity (q max ) of lead (II) by the nonliving biomass of Spirogyra neglecta was 132 mg g -1 . Conclusion: The maximum adsorption capacity for lead (II) by the nonliving biomass of Spirogyra neglecta was higher than reported for other biosorbents. Therefore, it had a great potential for removing lead (II) from polluted water. Its use will also need to consider the various factors that affect biosorption process. Key word: Adsorption, kinetics, Spirogyra neglecta, Langmuir model, second order model INTRODUCTION The presence of heavy metals in water systems has become a problem due to their harmful effects on human health even at low concentration in the environment. Lead (II) is among the most toxic heavy metal ion affecting the environment [1] . The current EPA and WHO drinking water standard for lead (II) is 0.05 mg L -1 and 10 g L -1 , respectively. Lead (II) accumulates mainly in bones, brain, kidney and muscles and may cause many serious disorders like anemia, kidney diseases, nervous disorders and sickness even death [2] . It is therefore, essential to remove lead (II) from wastewater before disposal. Conventional techniques for removing dissolved heavy metals such as chemical precipitation, carbon adsorption, ion exchange, evaporation and membrane processes [3] , are only practical and cost-effective when applied to high strength wastes with heavy metal ion concentrations greater than 100 ppm [4] . Low strength heavy metal containing wastewaters generally cannot be treated successfully with such methods. Adsorbent materials (biosorbents) derived from suitable biomass, on the other hand, has been shown to remove and recover of heavy metal ions from wastewater streams even at low concentrations. The phenomena of adsorption has been described in a wide range of living biomass like fungi [5] , bacteria [6,7] , yeast [8] , moss [9] , aquatic plants [10] and algae [11,12] . Algae is one of the most promising biosorbents [13] . Different algal species often had different sorption characteristics. The sorption characteristics have shown to be influenced by pH, metal ion concentration, temperature, other metal ions [3] .