▎ 摘　　要

Magnetic nanoparticles were integrated with graphene oxide sheets modified by metformin to introduce polyamine functionality in structure. Modified magnetic graphene oxide by metformin (MMGO) adsorption ability was studied for removal of methyl violet (MV) and acid red 88 (AR88) at different pH, initial concentration, and contact time. The successful preparation of magnetic nanoparticles supported with modified graphene oxide sheets is evident from FTIR spectra, TGA, zeta-potential and magnetic measurements. Morphology and chemical structure of the prepared MMGO nanocomposite was studied by TEM, SEM, XPS and EDS analyses. Surface area measurement of the MMGO composite revealed high BET surface area of 226 m(2) g(-1). Equilibrium isotherms were employed to evaluate the experimental data and calculate the isotherms' parameters. Results showed that adsorption process is based on Langmuir isotherm (R-2 > 0.99) and adsorption capacity of fabricated nano-composite was found to be 243 mg g(-1) for MV and 303 mg g(-1) for AR88. Kinetical results were based on pseudo-second order (R-2 > 0.99) and physisorption was main process in the rate-controlling step. (C) 2019 Elsevier B.V. All rights reserved.