Copper and cadmium biosorption onto Sphaerotilus natans:: Application and discrimination of commonly used adsorption models

In this paper, the experimental data of copper and cadmium biosorption onto Sphaerotilus natans obtained under different operating conditions of pH (3divided by6 units) and biomass concentration (0.5divided by2 g/L) were reported. These experimental data, showing the good separative performances of S. natans and the strong effect of the selected operative factors, were represented by three different empirical models: Langmuir. Freundlich, and Redlich-Peterson isotherms. A statistical representation of the characteristic model parameters (parameter standard deviation and regression coefficient) along with a model discrimination analysis (model residual variance, F-test and residual analysis) were proposed in order to suggest a standardized procedure for treating the biosorption data.