BIOLOGICAL MATERIALS FOR REMOVING AND RECOVERING HEAVY METALS

摘要

After being isolated from river sludge and industrial effluents, the bacteria of the genera Bacillus and Enterobacter showed resistance to heavy metals and capacity to sorb lead (Ⅱ), chromium (Ⅵ), cadmium (Ⅱ), nickel (Ⅱ), copper (Ⅱ) and zinc (Ⅱ). Their bacterial biomass was tested with different metal loads, bdth free and immobilized in calcium alginate, to study its possible use in removing and recovering those metals. The tested biomaterials showed 83% to 97% sorption of lead, 65% to78% sorption of cadmium, copper and nickel, 41% to 45% sorption of zinc, and 30% to 61% sorption of chrome. The recovery of the materials analyzed was possible in synthetic water, with quantities varying from 40 mg/l to 323 mg/l. And the biomass could be reused 4 to 8 times both free and immobilized in calcium alginate. The results of this research show that the tested biosorbents may be a great alternative for the secondary treatment of the waterwaste, from an economic, ecological and technological point of view.