The thiourea-modified magnetic chitosan (CS) Fe3O4@Al2O3-CS with high adsorption capacity and separation efficiency for Cr(VI) was prepared successfully, and its physicochemical properties were characterized via XRD, SEM, TEM, N-2 adsorption-desorption, FT-IR, TGA-DSC, Zeta-potential and VSM, respectively. The batch adsorption results show that its kinetic data match the pseudo-second order well, and the equilibrium data are well depicted by the Langmuir adsorption isotherm with the maximum adsorption capacity of 327.8 mg/g. The thermodynamic parameters of the adsorption process reveal its spontaneous and endothermic characteristic. Most importantly, the Fe3O4@Al2O3-CS shows good selective and recyclable performance for Cr(VI), indicating that it has a good application prospect to remove heavy metals ions from wastewater. (C) 2019 Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.