▎ 摘　　要

Cr (VI) is one of the most toxic contaminants recognized as a carcinogenic and mutagenic agent and needs complete removal from wastewater before disposal. In the present study, a novel graphene based adsorbent was synthesized from sugar and sand using green chemistry approach and adsorption of Cr (VI) ions from aqueous solution was studied by batch adsorption technique under varying experimental conditions like contact time, pH, adsorbent dose, initial Cr (VI) concentration and temperature. The characterization of the prepared graphene sand composite (GSC) was accomplished by Fourier transform infrared (FTIR) spectroscopy, transmission electron microscopy (TEM), X-ray diffraction(XRD) analysis, Raman spectroscopy, electron diffraction measurements, X-ray photoelectron spectroscopy, energy dispersive X-ray spectroscopy (EDX) and surface area measurements. The specific surface area of the GSC before and after activation was determined to be 100 m(2)/g and 157 m(2)/g, respectively. The optimum adsorption of Cr (VI) by the new adsorbent, coined as GSC, was observed at pH 1.5 The maximum adsorption capacity of GSC for Cr (VI) was found to be 2859.38 mg/g at room temperature which is claimed to be one of the exceptionally high values reported so far in the literature. The equilibrium sorption data were fitted satisfactorily to the Langmuir adsorption model with R-2 value of 0.99108. The progress of the adsorption process was found to follow the second order kinetics. The results obtained in this study illustrated that the prepared graphenic material could be an effective and economically viable adsorbent for removal of Cr (VI) ions. (C) 2015 Elsevier Ltd. All rights reserved.