3D　graphene　macroscopic　gel　synthesized　via　self-assembly　of　GO　nanosheets　under　basic　conditions　at　low　temperature　is　modified　with　polydopamine　and　Fe3O4　nanoparticles.　The　modification　of　polydopamine　can　not　only　strengthen　the　3D　graphene-based　macroscopic　architecture　but　also　enhance　the　loadage　and　binding　ability　of　Fe3O4　nanoparticles.　The　synthesized　3D　Fe3O4-graphene　macroscopic　composites　are　characterized　by　SEM,　XRD,　XPS,　BET,　Raman　and　magnetic　property　and　used　as　a　versatile　adsorbent　for　sub-ppm　concentration　of　As(III)　and　As(V)　removal　from　aqueous　solutions.　The　experimental　results　suggest　that　the　synthesized　3D　Fe3O4-graphene　macroscopic　composites　are　promising　for　treating　low　concentration　of　arsenic　contaminated　water.　(C)　2015　Elsevier　B.V.　All　rights　reserved.