One step synthesis of polyacrylamide functionalized graphene and its application in Pb(II) removal

Polyacrylamide grafted graphene (PAM-g-graphene) from graphite oxide (GO) was successfully prepared by gamma-ray irradiation with acrylamide monomers in aqueous at room temperature in this paper. Our strategy involves the PAM chains graft on the surface and between the layers of GO by in situ radical polymerization which led to the exfoliation of GO into individual sheets. Results show that the degree of grafting of PAM-g-graphene samples is 24.2%, and the thickness is measured to be 2.59 nm. Moreover, the as-prepared PAM-g-graphene with some amino from PAM and little oxygen functional groups exhibit superior adsorption of Pb(II) ions. The adsorption processes reach equilibrium in just 30 min and the adsorption isotherms are described well by Langmuir and Freundlich classical isotherms models. The determined adsorption capacity of PAM-g-graphene is 819.67 mg g(-1) (pH 6) for Pb(II), which is 20 times and 8 times capacities of that for graphene nanosheets and carbon nanotubes according to reports, respectively. This chemically modified graphene synthesized by this fast one-step approach, featuring a good versatility and adaptability, excellent adsorption capacity and rapid extraction, may provide a new idea for the global problem of heavy metal pollutants' removal in water. (C) 2014 Elsevier B.V. All rights reserved.