Magnetic graphene oxide functionalized by poly dimethyl diallyl ammonium chloride for efficient removal of Cr(VI)

A novel adsorbent was prepared in this work by introducing the poly dimethyl diallyl ammonium chloride (PDMDAAC) onto the magnetic graphene oxide (GO/Fe3O4) for removal of Cr(VI) from aqueous solutions. The PDMDAAC modified magnetic graphene oxide (PMGO) exhibited high adsorption capacity towards Cr(VI) via electrostatic attraction by quaternary amine. The equilibrium isotherm was fit well with the Langmuir model and the maximum Cr(VI) capacity of the adsorbent calculated from the Langmuir model was found to be 95.2 mg/g, which was about twice higher than that of magnetic graphene oxide. The characteristics of the adsorbent indicated that some required functional groups (e.g. C-N and N-H groups) have been grafted on the magnetic graphene oxide. Regeneration tests were conducted by five successive sorption-desorption processes, and the results indicated that the regenerated PMGO still retained high adsorption capacity towards Cr(VI). All these results identified that PMGO could be employed as an efficient adsorbent for Cr(VI) collection from aqueous solution, which is of high practical value. (C) 2018 Taiwan Institute of Chemical Engineers. Published by Elsevier B.V. All rights reserved.