The adsorption of copper ions on Spirulina platensis was studied as a function of contact time, initial metal ion concentration, and initial pH regimes. Characterization of this adsorbent was confirmed by FTIR spectrum. Modified Gompertz and Logistic models have not been previously applied for the adsorption of copper. Logistic was the best model to describe experimental kinetic data. This adsorption could be explained by the intra-particle diffusion, which was composed of more than one sorption processes. Langmuir, Freundlich, and Redlich-Peterson were fitted to equilibrium data models. According to values of error functions and correlation coefficient, the Langmuir and Redlich-Peterson models were more appropriate to describe the adsorption of copper ions on S. platensis. The monolayer maximum adsorption capacity of copper ions was determined as 67.93 mg g(-1). Results indicated that this adsorbent had a great potential for removing of copper as an eco-friendly process. (C) 2009 Elsevier B.V. All rights reserved.