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 degrees 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. (c) 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 44002.