COMPETITIVE BIOSORPTION OF Cu2+ AND Cd2+ ONTO INACTIVE Saccharomyces cerevisiae CELLS

In this study, the competitive removal of copper and cadmium from aqueous solutions by biosorption onto inactive S. cerevisiae cells was investigated under batch conditions, at laboratory scale. The influence of metal ions speciation, properties and solution pH on Cu2+ and Cd2+ removal was studied. The speciation distribution of the metal ions in solution was calculated using PHREEQC program. The maximum competitive adsorption capacity and removal efficiency of Cu2+ (7.016 mg/g and respectively 70.16%) and Cd2+ (6.414 mg/g and respectively 64.14%) ions were obtained at pH 5.5, initial metal concentration of 50 mg/l, biosorbent dosage -0.5 % w/v, agitation rate 200 pm, contact time 30 min and temperature 20 degrees C. The order of the adsorption capacity and removal efficiency was found as Cu2+ > Cd2+ for all pH values. The obtained results suggest that the inactive S. cerevisiae cells can be used as biosorbent in competitive conditions for heavy metals (i.e. Cu2+, Cd2+) removal from aqueous solutions.