Biosorption of Copper Ions by Caustic Treated Waste Baker's Yeast Biomass

Authors: YEKTA GÖKSUNGUR, SİBEL ÜREN, ULGAR GÜVENÇ

Abstract: Waste baker's yeast (Saccharomyces cerevisiae) was used as a biosorbent for Cu^{+2} biosorption. The yeast cells were treated with caustic soda, ethanol and heat to increase their biosorption capacity. Among the treatment methods used, the highest copper uptake (21.1 mg g^{-1}) was obtained with the caustic treatment of baker's yeast. The effect of initial copper concentration and pH on biosorption for caustic treated yeast was studied. The highest Cu^{+2} uptake (120.7 mg g^{-1}) was obtained at pH 4.0, for 198.2 mg I^{-1} initial copper ion concentration. The Langmuir model and Freundlich equation were applied to the experimental data and the Langmuir model was found to be in better correlation with the experimental data. The Langmuir constants were q_{max} (mg g^{-1}) = 181.8 and b (l mg^{-1}) = 0.0312. In packed bed column studies with calcium alginate immobilized caustic treated yeast, it was found that the real biosorption capacity came from the alginate gel and immobilizing caustic treated yeast particles in the gel only slightly increased the biosorption capacity of the gel.

Keywords: copper, biosorption, Saccharomyces cerevisiae, adsorption isotherms, calcium alginate, immobilization

Full Text: PDF