Graphene oxide nanosheet: characterization, modification, and dye removal

Among various methods that have been developed for removal of heavy metal ions and dyes from wastewater including ions exchange, electrodialization, biodegradation, and coagulation, adsorption becomes most popular due to its high efficiency and simplicity [1]. The adsorption process is mainly dependent on different parameters such as pH, temperature, the type and concentration of adsorbent [2]. nano GO flakes [3] have numerous hydrophilic functional groups on its surface that make it dispersible in aqueous media [4]; indeed GO high surface area provide an ideal platform for immobilization of different molecules. However, GO nano flakes tend to become aggregated in the presence of different ions. In order to overcome such screen effect the surface chemistry should be considered wisely. Galactose as a common carbohydrate with multiple hydrophilic functional groups could not only enhance GO dispersibility but also could provide more active sites for interaction with heavy metal ions and dyes [5]. Graphene-based hybrid materials were fabricated through chemical modification of graphene oxide surface by Galactose and it has been characterized by Fourier transform infrared spectroscopy (FT-IR), X-ray powder diffraction (XRD), Ultraviolet-visible spectroscopy (UV-Vis) and Scanning electron microscope (SEM). 5 mg/L of Synthesized composite has been used for the treatment of methylene blue (15 mg/L) at pH 6. The results indicate 49% degradation efficiency in first 10 min compared to the 19% of the pure GO, verifying the modification of the GO has a positive effect on removal efficiency.