Biosorption of Cr(VI) and Cu(II) by waste tea fungal biomass

The biosorption of Cr(VI) and Cu(II) ions from aqueous solution by waste tea fungus was studied in a batch biosorption system as a function of pH, contact time and absorbent dosage. The biosorption capacities and adsorption rates of Cr(VI) and Cu(II) ions onto live and dried tea fungal biomass were evaluated. In the experiments, the optimum pH values for Cr(VI) and Cu(II) were 2.0 and 4.0, respectively. The Langmuir, Freundlich, BET and Temkin adsorption models were applied to describe adsorption. Based on the coefficient of determination R-2, Freundlich, BET and Temkin equations produced the very good models for Cr(VI) and Cu(II) biosorption onto waste tea fungal biomass. The kinetics of adsorption of Cr(VI) and Cu(II) have been discussed using two kinetic models, i.e. the Lagergren pseudo-first-order model and Elovich equation. It was shown that both kinetic models could describe the adsorption kinetics very successfully. (C) 2008 Elsevier B.V. All rights reserved.