In this study, thiolated magnetic iron oxide nanoparticles (Fe3O4-SH) were prepared and characterized in detail, which exhibited benign superparamagnetism and magnetic recoverability. And the adsorption and desorption processes for various heavy metals, including Pb2+, Ni2+, Zn2+ and Cu2+, had been investigated comprehensively both in single and mixed systems using the Fe3O4-SH nanoparticles as adsorbents. The results showed that heavy metal ions could be removed rapidly depending on the complexation with the SH-groups on the Fe3O4-SH surface. Besides, the adsorption was all sensitive to pH and ionic strength while the nano-adsorbents had the highest adsorption capacity and rate for Ni2+ according to the adsorption kinetics and thermodynamics. In addition, the corresponding competitive adsorption processes and desorption experiments reflected that Fe3O4-SH had the strongest affinity and adsorption selectivity for Pb2+, followed by Ni2+ and finally by Cu2+ and Zn2+. Generally, the present study might provide a serviceable direction for the future efforts towards the application of Fe3O4-SH nano-adsorbents in industrial wastewater treatments involving multiple heavy metal contaminants. (C) 2017 Published by Elsevier B.V. on behalf of Institution of Chemical Engineers.