Fast and enhanced removal of mercury from aqueous solutions by magnetic starch-g-poly(acryl amide)/graphene oxide nanocomposite superabsorbents

In this study, we developed a novel magnetic nanocomposite superabsorbent (MNS) for effective removal of mercury ions from aqueous solutions. The preparation method of MNS is easy, fast, simple, effective, and safe. The MNSs were synthesized via the simultaneous formation of magnetic iron oxide nanoparticles (MIONs) and in situ radical solution polymerization of superabsorbents based on poly(acryl amide) grafted onto starch backbones in the presence of graphene oxide (GO) nanosheets. The chemical structure, morphology and phase composition of the obtained MSNs were characterized using FTIR, SEM, TEM, XRD, and VSM techniques. The effects of parameters and also the morphology of MNSs on the adsorption of Hg 2+ were investigated in detail through batch experiments. Furthermore, the adsorption kinetics fits well with the pseudosecond- order model. The equilibrium data also fitted the Langmuir sorption isotherms well. Moreover, the thermodynamic parameters shown that the sorption process was feasible, spontaneous and endothermic.