BIOSORPTION OF Cu AND Zn BY IMMOBILIZED ALGAE BIOMASS OF CHLORELLA KESSLERI

Biosorption of heavy metals from aqueous solution can be considered as an alternative technology in industrial wastewaters treatment. This innovative process uses biomaterials which are either abundant in nature such as algae, fungus, bacteria, moss or wastes coming from industrial production and biological processes such as fermentation. The paper presents results of studies carried out on biosorption of heavy metals from aquaeous solutions by algae as a low cost biosorbents. The biosorption of Cu and Zn ions from aqueous solutions by algae was studied in a batch biosorption system as a function of a contact time. Chlorella kessleri, an unicellular green algae were immobilized in alginate. The biosorption capacities and adsorption rates of Cu and Zn ions onto algal powder and immobilized algal biomass were evaluated. The Langmuir, Freundlich, Redlich-Peterson adsorption models were applied to describe biosorption. Based on the coefficient of determination R, models equations produced Acta Metallurgica Slovaca, Vol. 15, 2009, No. 4, p. 255-263 256 the very good models for Cu and Zn biosorption onto algae biomass. The maximum biosorption capacity (qmax) of immobilized and non-immobilized algae were 37.24 and 24.6 mg for Cu and 40.23 and 35.38 for Zn per gram of dry biosorbents, respectively.