Functional graphene sheets-TiO2 nanocomposites and their photocatalytic performance for wastewater treatment

In this paper, a powerful photocatalyst based on carbon nanocomposite is developed in order to obtain a new material applicable in water treatment and especially for the discoloration of effluents used in the textile industry. For that, TiO2-graphene nanocomposites have been successfully synthesized by a mixture of Functionalized Graphene Sheet (FGS) and tetrachlorotitanium complexes to form FGS-TiO2 nanocomposite. In the presence of an anionic surfactant, we used a new chemical process to functionalize graphene sheets in order to make them an excellent medium for blocking and preventing the aggregation of TiO2 nanoparticles. The components of these nanocomposites are characterized by means of X-ray diffraction (XRD), Fourier Transform Infrared Spectroscopy (FT-IR), Scanning Electron Microscopy (SEM) and Transmission Electron Microscopy (TEM), which confirms the successful formation of the FGS-TiO2 nanocomposite. It was found that the TiO2 nanoparticles were dispersed uniformly on the graphene plane which possesses better charge separation capability than pure TiO2. The FGS-TiO2 nanocomposites exhibited higher photocatalytic activity compared to pure TiO2 for the removal of three dyes: such as Methylene Blue (MB), Bromophenol Blue (BB) and Alizarin Red-S (AR) in water. The removal process was fast and more efficient with FGS-TiO2 nanocomposite in daylight (in the absence of UV irradiation) compared to pure TiO2 nanoparticles without and under UV in all pH range.