The potential use of blank alginate beads, free (non-immobilized) live and dead and immobilized dead algal cells for the removal of nickel ions from aqueous solutions was investigated. Immobilization enhanced the sorption of nickel and repetitive use of the sorbent could be achieved. Increasing initial pH or initial nickel ions concentration resulted in an increase in nickel uptake. The experimental results were fitted satisfactory to the Langmuir and Freundlich isotherm models. The results of the kinetic studies showed that the sorption of nickel ions on blank alginate beads, free live, dead and alginate immobilized dead algal cells followed pseudo-second order kinetics. (C) 2003 Elsevier Ltd. All rights reserved.