Magnetite/graphene/polyaniline composite for removal of aqueous hexavalent chromium

Here, we report the synthesis of Fe₃O₄/G/PANI composite containing magnetite nanoparticles (Fe₃O₄), graphene sheets (G), and polyaniline (PANI) via chemical route for removal of toxic Cr (VI) from water. TEM image shows the formation of uniformly distributed magnetite nanoparticles on graphene/PANI composite. HRTEM images shows the formation of crystalline magnetite nanoparticles showing lattice fringes with inter‐planner distance 0.21 nm. The magnetic measurement shows magnetization 22 emu/g and ferromagnetic property of the adsorbent. The equilibrium adsorptions were well‐described by the Langmuir isotherm model and shows maximum adsorption capacity 153.54 mg/g at pH 6.5 and temperature 30 °C. The kinetics data well fitted by pseudo‐second‐order model and around 86% Cr (VI) removal completed within 20 min. The Cr (VI) removal capacitive decreases with increase in pH and ionic strength. The adsorbent shows leaching of iron nanoparticles at pH 1 whereas stable in solution having pH 2 and more. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 44002.