Evaluating the adsorption of Ni(II) and Cu(II) on spirulina biomass by statistical physics formalism

Statistical physics formalism is used for modeling and interpreting the adsorption isotherms of the ions Cu(II) and Ni(II)-Spirulina system. Numerical modeling is performed at three temperatures (298, 318 and 338 K) and pH = 6. Cu and Ni adsorption isotherms were fitted by multilayer model and Hill model with two energies, respectively. The interpretations were based on the numbers of ions per site (n, n1, n2), the densities of receptor sites (Sm, S1m, S2m), the number of adsorbed layers N2 and the energetic parameters (C1, C2). The thermodynamic study indicated that the adsorption was spontaneous, exothermic for Cu and endothermic for Ni.