Efficient removal of lead (II) ions from aqueous solutions using methyl-β-cyclodextrin modified graphene oxide

Abstract

Graphene oxide (GO) and graphene oxide modified with methyl-β-cyclodextrin denoted as GO-mβCD were prepared and applied as adsorbents to determine the adsorption characteristics of Pb(II) from aqueous solutions. The characteristic results of Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), Raman spectroscopy, and scanning electron microscopy (SEM) showed that mβCD was successfully physically attached to GO to form the GO-mβCD nanocomposite. The adsorption equilibrium and kinetics of the adsorbents were well described by Langmuir isotherm and pseudo-second-order models, respectively. The maximum Pb(II) adsorption capacity of GO-mβCD (at pH = 6 and room temperature) was determined as 312.5 mg/g which was significantly higher than that of GO (217.39 mg/g). This indicates that the modification of GO with mβCD enhances the adsorption capacity of GO. The desorption studies show that the adsorbent GO-mβCD can be used for at least five cycles with non-significant loss of its initial adsorption capacity for Pb(II) ions.