摘要
This work aimed to investigate the biosorption of lead by free and immobilized bacterial cell. Twenty four samples were collected from the wastewater of batteries factory in AL-Waziria district for the period from June to Sept. 2004, three species of bacteria have been isolated from this wastewater： Enterobacter agglomerans, E. gergoviae, and E. sakazakii. The results revealed a high variation in the ability of these bacteria for lead biosorption, the bacteria E. agglomerans （ES） was the most efficient compared to the other bacterial species. A laboratory plant with continuous flow system was designed for lead ions removal from standards aqueous solutions, as the cells were immobilized using： white sand, charcoal, agar and calcium alginate. However, the cells immobilized to calcium alginate were the most efficient in removal of lead ions （98%）. Present study also determined the optimal conditions for the biosorptJon of lead ions which were temperature 40℃ and pH 4 with one hour contiguity between the immobilized bacteria and solution. Different washing solutions were used fo~： recovering the lead ions that have been biosorbed on the bacterial walls, 0.1 M EDTA was the most efficient. Preferential biosorption by E. agglomerans （E5） to copper and cadmium was determined, result showed that the order of this preferential capability was： Cu 〉 Pb 〉 Cd. No significant differences were found in the biosorption of lead ions by alive and dead E. agglomerans （E5）. The designed lab plant containing bacterial cells binding on calcium alginate was able to uptake all lead ions from all samples of industrial wastewater of batteries factory.
