▎ 摘　　要

In this work, titanium dioxide (TiO2), TiO2/graphene (TiO2/GO) and polyaniline-TiO2/graphene (polyaniline-TiO2/GO) catalysts were prepared and characterized by different analysis methods such as X-ray diffractometer, transmission electron microscope, scanning electron microscope, energy-dispersive X-ray spectroscopy, Brunauer-Emmett-Teller and diffuse reflectance spectra. The photocatalytic activity and adsorption capacity of prepared samples were investigated by the removal of methyl orange as an anionic dye from aqueous solutions. Polyaniline-TiO2/GO nanocomposite presented high photocatalytic activity, which is partly due to the sensitizing effect of polyaniline and the low recombination rate due to the graphene oxide electron scavenging property. In order to study the nature of adsorption procedure, the equilibrium adsorption isotherms were investigated. The linear correlation coefficients of Langmuir and Freundlich isotherms were obtained. Based on results, Langmuir isotherm model fitted the experimental data better than Freundlich isotherm model. According to the Langmuir isotherm model, the maximum adsorption capacity of Polyaniline-TiO2/GO nanocomposite for sequestering methyl orange was about 69.23 mg g(-1). Furthermore, negative free energy change (AG) and enthalpy change (AH) values resulted from thermodynamic investigation suggested that the adsorption of methyl orange onto polyaniline-TiO2/GO nanocomposite was spontaneous and exothermic in nature, respectively.