Controlled assembly of Fe3O4 magnetic nanoparticles on graphene oxide.

We describe a facile approach to controllable assembly of monodisperse Fe(3)O(4) nanoparticles (NPs) on chemically reduced graphene oxide (rGO). First, reduction and functionalization of GO by polyetheylenimine (PEI) were achieved simultaneously by simply heating the PEI and GO mixture at 60 °C for 12 h. The process is environmentally friendly and convenient compared with previously reported methods. Meso-2,3-dimercaptosuccinnic acid (DMSA)-modified Fe(3)O(4) NPs were then conjugated to the PEI moiety which is located on the periphery of the GO sheets via formation of amide bonds between COOH groups of DMSA molecules bound on the surface of the Fe(3)O(4) NPs and amine groups of PEI. The magnetic GO composites were characterized by means of TEM, AFM, UV-vis, FTIR, Raman, TGA, and VSM measurements. Finally, preliminary results of using the Fe(3)O(4)-rGO composites for efficient removal of tetracycline, an antibiotic that is often found as a contaminant in the environment, are reported.