Reduced graphene oxide/iron nanoparticles used for the removal of Pb (II) by one step green synthesis

While nanomaterials are increasingly being proposed for contaminant remediation, a major challenge is how to develop high removal functionality while maintaining low cost and environmental friendliness. In this study, a hybrid reduced graphene oxide/iron nanoparticle (rGO/Fe NPs) was prepared via the in situ reduction of GO and FeCl3 by eucalyptus leaf extract in one-pot. The obtained rGO/Fe NPs could rapidly remove 72.7% of Pb(II) from aqueous solution in 10 mins and remove up to the maximum removal efficiency of 82.4%. Electron microscopy, XPS and BET showed that the irregular Fe3O4 nanoparticles, sized between 20 and 40 nm, were disorderly dispersed on rGO sheets, which constituted a mesoporous material. FTIR and XRD indicated that the surface of rGO/Fe NPs was capped by many active organic constituents from the eucalyptus leaf extract. rGO/Fe NPs also showed a high selectivity for Pb(II) with minimal interference from either calcium or magnesium ions in the solution. Finally, GC–MS separated 13 significant active organic constituents from the eucalyptus leaf extract that possibly contributed to the reduction of rGO/Fe NPs. Overall, eucalyptus leaf extracts, acted efficiently as green reducing agents and impacted reactivity of the final material by determining the components and surface properties of rGO/Fe NPs.