Graphene oxide decorated nanoscale iron sulfide for highly efficient scavenging of hexavalent chromium from aqueous solutions

In this paper, a novel graphene oxide (GO) decorated nanoscale FeS composite (GO/FeS) combining both advantages of GO and FeS was synthesized and tested for the highly efficient scavenging of Cr(VI) from aqueous solutions. The as- synthesized materials were characterized by scanning electron microscopy-energy dispersive spectrometer (SEM-EDS), transmission electron microscopy (TEM), atomic force microscopy (AFM), Raman spectra and X-ray photoelectron spectroscopy (XPS) in detail. The results indicated that FeS nanoparticles were effectively decorated onto the surface of GO through -OH, C-O, C=O, and O=C-O functional groups, resulting in larger specific surface area and higher reactivity The nanocomposites displayed an enhanced Cr(VI) scavenging capacity, and the acidic conditions favored the Cr(VI) scavenging by GO/FeS. The kinetics of Cr(VI) scavenging on GO/FeS nanoparticles was in accordance with the pseudo-second order kinetic model, suggesting that chemical interaction is mainly responsible for Cr(VI) scavenging on GO/FeS. Furthermore, the Langmuir model fit the best, and q_max, i.e. the maximum scavenging capacity of Cr(VI) obtained from the Langmuir model reached 138.5 mg/g, Surface sorption and reduction were the dominant scavenging mechanisms for Cr(VI) by GO/FeS. The present study demonstrated the promise of GO/FeS as an effective scavenger for the remediation of Cr(VI) in groundwater environment.