Here we report a separation of a cationic dye, acridine orange (AO), by use of magnetic nanoparticles (gamma-Fe2O3). The particles were showed to capture 98% of the dye within the first 20 min of contact time. The maximum sorption capacity of the magnetic nanoparticles (MNPs) for AO was 59 mg/g. The sorption isotherms fit well with the Freundlich model. The sorption kinetics fits well the pseudo-second-order rate equation model. 60-90% dye recovery was achieved by rotary evaporating the dye bearing nanoparticles in acetone. The nanoparticles were recycled for additional dye removal. (C) 2009 Elsevier B.V. All rights reserved.