Preparation of α-zirconium phosphate-pillared reduced graphene oxide with increased adsorption towards methylene blue

In order to prevent the reunion of reduced graphene oxide (rGO) during storage, a-zirconium phosphate (ZrP) was used as the modifier, and a peculiar adsorbent of ZrP-pillared rGO (rGO-ZrP) was prepared. The features of rGO-ZrP were characterized by using Fourier transform infrared (FTIR), scanning electron microscope (SEM), transmission electron microscopy (TEM), energy dispersion X-ray (EDX) spectrometer, atomic force microscopy (AFM) and X-ray diffraction (XRD) measurements. Then, rGO-ZrP was employed as the adsorbent and the adsorption characteristics of rGO-ZrP toward methylene blue (MB) were evaluated under laboratory conditions. The results showed that rGO-ZrP possessed a higher BET specific surface area relative to rGO. The maximum adsorption quantity of MB onto the new prepared rGO-ZrP was similar to 1.38 g/g at 30 degrees C. With the increase of storage day, the BET specific surface area and the maximum adsorption capacity of rGO-ZrP approximately remained unchanged. Under the maximum adsorption capacity, the adsorption quantity of MB onto rGO-ZrP was dependent on the initial concentration of MB, and higher temperature could facilitate the adsorption process. The efficiency of rGO-ZrP almost remained constant during the first six cycles of adsorption-desorption process. In addition, the fluorescence spectra implied that the adsorption of MB onto rGO-ZrP was a pi-pi stacking adsorption process, and the pillared structure of rGO-ZrP greatly enhanced the noncovalent adhesion. In conclusion, rGO-ZrP could serve as a promising adsorbent for the removal of MB in waste water. Crown Copyright (C) 2014 Published by Elsevier B.V. All rights reserved.