BIOSORPTION OF HEAVY METALS BY USING FREE AND IMMOBILIZED CELLS OF HALOBACTERIUM CUTIRUBRUM

摘要

Water pollution is of great concern to scientists as the water is the prime necessity of life. Heavy metals are one of the major classes of pollutants in marine, lake and in ground waters. Conventional treatment technologies for removal of heavy metals from aqueous solution are not economical and generate sludge in huge quantity. Biosorption is an effective and attractive technology to accumulate heavy metals from aqueous solutions. Large number of microorganisms viz., bacteria, fungi, yeasts were found to be successful in binding variety of heavy metals to different extents. The Immobilization of cells on a suitable support simplify the treatment of liquid waste as the entrapment of living cells increases the retention time of cells on contaminatedwater. In the present work the free and immobilized cells of Halobacterium Cutirubrum were studied as biosorbent material for the removal of Cu, Cd, Ba, Mg, Zn and Pb from aqueous solutions. The experimental data highlight that the sorption of metals isboth metabolic and non-metabolic dependent. Removal of metals is drastic under immobilized conditions than with free cells of Halobacterium Cutirubrum. The influence of various factors pH, incubation time, initial concentration of biomass and temperature were verified to optimize the process. The selected microorganism exhibited maximum removal at an optimum concentration of 1 mg/mL, optimal time of 180 min, optimal temperature of 35°C and pH 4-7. The mechanism for sorption of metals by the biomass is discussed.