Graphene manganese ferrite (MnFe 2 O 4 -G) composite was prepared by a solvothermal process. The as-prepared graphene manganese ferrite composite was tested for the adsorption of lead (Pb(II)) and cadmium (Cd(II)) ions by analytical methods under diverse experimental parameters. With respect to contact time measurements, the adsorption of Pb and Cd ions increased and reached equilibrium within 120 and 180 min at 37°C with a maximum adsorption at pH 5 and 7 respectively. The Langmuir model correlates to the experimental data showing an adsorption capacity of 100 for Pb(II) and 76.90 mg g -1 for Cd(II) ions. Thermodynamic studies revealed that the adsorption of Pb and Cd ions onto MnFe 2 O 4 -G was spontaneous, exothermic and feasible in the range of 27-47°C. Cytotoxicity behavior of graphene against bacterial cell membrane is well known. To better understand its antimicrobial mechanism, the antibacterial activity of graphene and MnFe 2 O 4 -G nanocomposite was compared. Under similar concentration and incubation conditions, nanocomposite MnFe 2 O 4 -G dispersion showed the highest antibacterial activity of 82%, as compared to graphene showing 37% cell loss. Results showed that the prepared composite possess good adsorption efficiency and thus could be considered as an excellent material for removal of toxic heavy metal ions as explained by adsorption isotherm. Hence MnFe 2 O 4 -G can be used as an adsorbent as well as an antimicrobial agent. © 2014 Elsevier B.V. All rights reserved.