The FTIR spectrum of RGO-M was evidenced by the dramatically weakening of the peak at 3450 cm−1. It implied that heat treatment in the presence of EG removed the oxygen from the hydroxyl groups so that the peak became weaker compared to GO. A vibrational band at around 1440 cm−1 can be assigned to the formation of complex between the carboxyl group and Fe on the surface of the magnetic particles, indicating that the Fe3O4 microspheres are covalently bonded to RGO