Effect of the presence of lead on the biosorption of copper, cadmium and zinc by activated sludge

The effect of the presence of Pb on the biosorption efficiency of Cu, Cd and Zn by activated sludge was investigated. To evaluate the two-metal sorption system efficiency, simple isotherm curves had to be replaced by three-dimensional sorption isotherm surfaces. In order to describe the isotherm surfaces mathematically, three Langmuir-type models were evaluated. The isotherms indicated a competitive uptake of the different metals with Pb that was preferentially adsorbed.