Immobilized Saccharomyces cerevisiae on the surface of chitosan-coated magnetic nanoparticles (SICCM) was applied as a new magnetic adsorbent for the adsorption of Cu(II) from aqueous solution. The prepared magnetic adsorbent was characterized by TEM, XRD and FTIR. TEM images indicated that S. cerevisiae was immobilized on the surface of chitosan-coated magnetic nanoparticles (CCM) successfully, and conglobation was not observed. The XRD pictures suggested that the Fe3O4 nanoparticles were pure Fe3O4 with a spinel structure and that the immobilizing process did not result in the phase change of Fe3O4. Factors that influence the adsorption of Cu(II) were investigated, which included the initial pH of Cu(II) solution, initial concentration of Cu(II) solution and contact time. The optimum pH for Cu(II) absorption was 4.5. The highest removal efficiency of 96.8% was reached when the initial Cu(II) concentration was 60 mg L-1, and the adsorption capacity was increased with the increase of initial concentration of Cu(II). In particular, SICCM was highly efficient for the fast adsorption of Cu(II) within the first 10 min, and adsorption equilibrium could be achieved in 1 h. Equilibrium studies show that the data of Cu(II) adsorption follow the Langmuir model. The maximum adsorption capacity for Cu(II) was estimated to be 144.9 mg g(-1) with a Langmuir adsorption equilibrium constant of 0.0719 L mg(-1) at 301 K. (C) 2009 Elsevier B.V. All rights reserved.