Removal of Copper and Lead Ions from Aqueous Solution Using Brewer Yeast as Biosorbent

Biosorption is an effective procedure of heavy metal ions removal from wastewater. Brewer yeast, a byproduct of brewing industry could be a low cost and promising adsorbent for copper and lead ions from aqueous solutions. In this work the removal of these ions from water solutions by brewer yeast was performed as function of key parameters such pH, contact time, yeast dose and initial metal ions concentrations. Results demonstrate that the highest equilibrium adsorption capacity was reached at the pH=6 for both metal ions. It was found that the adsorptive capacity q(e) of both copper and lead ions on brewer yeast increase with the increasing of the contact time until the equilibrium stage was obtained. The biosorption process was rapid in the first 15 min. and the equilibrium was reached after 60 min. Results showed that the percent of metal removal increase as yeast dosage increase up to 1 g/100 mL solution for metal ions. The increase in metal uptake with yeast dosage confirms the increase in binding sites for metal ions. The metal uptake decrease with the increasing of yeast dosage over 1 g/100 mL due to aggregation of the yeast. Biosorption experiment was carried out at different initial concentrations of Cu(II) and Pb(II) ions, ranged between 1 mg L-1 to 10 mg L-1. The removal efficiency increase with the increasing of metal ions concentrations until 7 mg L(-)1 for Pb(II) ions and 8 mg L-1 for copper ions. The sorption equilibrium data were analyzed using the Langmuir adsorption isotherms. The data obtained represent a favorable adsorption in the case of adsorption of Cu(II) and Pb(II) ions. The maximum loading capacities of beer yeast was obtained as 20.6 mg g(-1) for Cu(II) ions and 22.9 mg g(-1) for Pb(II) ions, so the ability of lead adsorption is higher than copper ions.