Synthesis of novel Bi2O3-montmorillonite nanocomposite with enhanced hotocatalytic performance in dye degradation

Novel Bi2O3-montmorillonite nanocomposite photocatalyst was synthesized and characterized by scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS) and X-ray diffraction (XRD). Effect of Bi2O3 intercalation with montmorillonite clay on photocatalytic performance of Bi2O3-montmorillonite under visible light irradiation was systematically investigated. The results indicate that Bi2O3-montmorillonite shows enhanced adsorption and photocatalytic performance for Congo red (CR) removal under visible light irradiation. Higher rate of light absorption and lower rate electron-hole pair recombination are responsible for the increase in photocatalytic efficiency. Adsorption of CR on Bi2O3-montmorillonite follows pseudo-second-order kinetics and the adsorption isotherm follows Freundlich isotherm. The monolayer capacity was observed to be 500 mg g(-1). The maximum percentage removal achieved upto 86.4% at pH 9 for 2 g L-1 photocatalyst dose. Photocatalytic degradation of CR by Bi2O3-montmorillonite proceeds via advanced oxidative process. (C) 2015 Elsevier Ltd. All rights reserved.