Effect of pH and Temperature on the Biosorption of Heavy Metals by Bacillus licheniformis

Among all the pollutants, heavy metals are most dangerous one as these are non biodegradable and persist in environment. Human activities, such as mining operations and the discharge of industrial wastes, have resulted in accumulation of heavy metals in the environment. Removal of metals and their recovery is one of the major concerns in sewage and industrial effluent treatment. This paper attempts to present a brief summary of the role of bacterial biomass in heavy metal removal from aqueous solutions. Biosorption has emerged as a low-cost technological option for removal or recovery of base metals from aqueous wastes. Screened Bacillus licheniformis was evaluated for biosorption ability for copper and iron ions. Bacteria were grown at different pH (3, 4, 5, 6, 7 and 8) and temperature (30C, 35C, 40C, 45C, 50C and 55C). It was found that bacteria were able to decontaminate with good efficacy for Fe and Cu ions at pH 8 with 92 % and 93 % respectively. For Fe ions 92 % removal was seen at 30C and for Cu ions 94 % of removal was seen at 45C. This will be advantageous for effluent treatment plant to recover important heavy metals with low cost.