CHELATING PROPERTIES OF BACTERIAL EXOPOLYSACCHARIDES FROM DEEP-SEA HYDROTHERMAL VENTS

The metal-binding properties of four bacterial exopolysaccharides orig inating from deep-sea hydrothermal vents were investigated in batch ex periments. The effect of pH on ion uptake was also investigated. Remov al of toxic elements such as lead, cadmium and zinc occurred according to a chemical, equilibrated and saturable mechanism, following the ty pical Langmuir model. The sorption isotherms were plotted to obtain th e maximum of uptake capacities and apparent dissociation constants. Ma ximum uptake capacities reached 316 mg g(-1), 154 mg g(-1) and 77 mg g (-1) for lead, cadmium and zinc respectively. The strong chelating pro perties of all polymers for the three selected metals make their use a s biosorbents in wastewater treatment as a possible alternative to oth er physical or chemical methods. (C) 1998 Published by Elsevier Scienc e Limited. All rights reserved.