Development of technology and industrial uses of metals and their salts has caused fast growth of environment pollution by pollutant industrial wastewaters. A major group of pollutants present in industrial wastewater is heavy metals, which should be removed from wastewater by using proper methods before discharging them to the environment. From conventional methods used for this group of metals are reverse osmosis and evaporation, sedimentation, clarification, active carbon method and ion exchange. In recent years biological adsorption method has been introduced and considered as one of most effective methods for heavy metal removal from aqueous solutions. In this research work adsorption capability of biomass MGL 75(1390) for batch adsorption of lead and cadmium cations from aqueous solutions, and effects of different parameters such as initial metal ion concentration, pH, temperature and process time on the adsorption percentage were investigated. Results showed increasing pH and initial concentration and reduction of temperature enhance metal adsorption by biomass. Also results of kinetic studies proved that almost 85% of metals was adsorbed very rapidly in the first 5 minutes and process reached to equilibrium after about 1 hour. Different type of sugar was used in the medium of the biomass producing bacteria and it was seen that despite change in the amount of produced biomass the type of sugar has no considerable effect on the amount of metal adsorption. Experimental results were in good agreement with Langmuir and Freundlich models, however the latter showed a better agreement for both cations. Maximum adsorption was found by applying Langmuir model equal to 91.74 (mg adsorption/gr dry adsorbent) for Cd 2+ and 158.73 for Pb 2+ . Finally obtained results proved that biomass MGL 75(1390) could be used as an effective and promising adsorbent for removal of Cd 2+ and Pb 2+ cations from aqueous wastes.
