CdS nanocrystals/TiO2/crosslinked chitosan composite: Facile preparation, characterization and adsorption-photocatalytic properties

Abstract CdS nanocrystals deposited on TiO 2 /crosslinked chitosan composite (CdS/TiO 2 /CSC) were prepared in an attempt to photocatalyze decolorization of water soluble azo dye in aqueous solution under simulated solar light irradiation. CdS/TiO 2 /CSC was characterized by X-ray diffraction (XRD), energy-dispersive spectroscopy (EDS), and scanning electron microscopy (SEM). The characterization results proved that CdS nanocrystals has successfully been deposited on/in TiO 2 /crosslinked chitosan composite. The adsorption ability of CdS/TiO 2 /CSC was approximately 2.66 mg methyl orange (a typical water soluble azo dye) per gram. The photocatalytic decolorization of methyl orange solution reached 99.1% by CdS/TiO 2 /CSC after simulated solar light irradiation for 210 min. Kinetics analysis indicated that photocatalytic decolorization of methyl orange solution by CdS/TiO 2 /CSC obeyed first-order kinetic Langmuir-Hinshelwood mechanism ( R 2  > 0.997). CdS/TiO 2 /CSC exhibited enhanced photocatalytic activity under simulated solar light irradiation compared with photocatalysts reported before and the photocatalytic activity of CdS/TiO 2 /CSC maintained at 89.0% of initial decolorization rate after five batch reactions. The presence of NO 3 − accelerated the decolorization of methyl orange solution by CdS/TiO 2 /CSC, while SO 4 2− and Cl − had an inhibitory effect on the decolorization of methyl orange. Therefore, present experimental results indicated to assess the applicability of CdS/TiO 2 /CSC as a suitable and promising photocatalyst for effective decolorization treatment of dye-containing effluents.