Liquid-phase　adsorption　of　Cu2+　ions　onto　magnetic　Fe3O4@graphene　oxide　(GO)　composites,　prepared　by　a　co-precipitation　approach,　has　been　investigated.　This　synthesis　method　is　capable　of　depositing　highly　crystalline　Fe3O4　nanoparticles　onto　GO　sheets.　The　adsorption　temperature　and　the　weight　ratio　of　Fe3O4　nanoparticles　to　GO　sheets　are　found　to　be　crucial　factors　affecting　the　adsorption　performance.　The　pH　value　of　the　aqueous　solution　has　a　strong　influence　on　the　adsorption　capacity　of　Cu2+　ions.　The　Langmuir,　Freundlich,　and　Dubinin-Radushkevich　(D-R)　adsorption　models　were　adopted　to　fit　the　adsorption　isotherms.　The　deposition　of　magnetite　enhances　the　equilibrium　rate　constant　(Langmuir　model)　and　the　adsorption　energy　(D-R　model).　The　analysis　of　thermodynamic　parameters　reveals　that　the　adsorption　of　Cu2+　ions　is　a　favorable　and　spontaneous　process.　However,　a　moderate　density　of　magnetite　onto　GO　substrate　is　essential　for　the　design　of　Fe3O4@GO　adsorbents　for　efficient　removal　of　metal　ions　from　an　aqueous　solution.　©　2018　Elsevier　B.V.