Selective biosorption of heavy metals by algae

Thirty strains of algae were examined for their biosorption abilities for the uptake of cadmium, lead, nickel and zinc from aqueous solutions. A wide range of adsorption capacities was observed between the different strains of algae and between the four metals. The cyanophyceae Lyngbya taylorii exhibited high uptake capacities for the four metals. It was confirmed by using instrumental analysis including EDX that the resulting capsules of the immobilization process are pervious to the lead. In simultaneous sorption processes of the four metals lead, cadmium, zinc and nickel, the following order of selective sorption was observed: Pb > Ni > Cd > Zn. In contrast to a commercial ion-exchange material, the alkaline metal ions Na, Ca, K, and Mg showed only a small competitive effect on the adsorption abilities of the immobilized L. taylorii