A novel ternary magnetic manganese dioxide/graphene compound (Fe3O4/MnO2@G) was fabricated by a facile and eco-friendly co-blending method with ultrasound assistance. Characterizations show Fe3O4 nanoparticles and MnO2 nano branches were assembled with graphene flakes without any phase change. High degradation activity is observed with a discoloration efficiency of 71.67% after 10 min after using this compound in the degradation of methylene blue dye at room temperature. Furthermore, magnetic property of the compound is helpful in the separation process and recycling of the material. (C) 2015 Elsevier Ltd. All rights reserved.