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

CdS nanocrystals deposited on TiO2/crosslinked chitosan composite (CdS/TiO2/CSC) were prepared in an attempt to photocatalyze decolorization of water soluble azo dye in aqueous solution under simulated solar light irradiation. CdS/TiO2/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 TiO2/crosslinked chitosan composite. The adsorption ability of CdS/TiO2/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/TiO2/CSC after simulated solar light irradiation for 210 min. Kinetics analysis indicated that photocatalytic decolorization of methyl orange solution by CdS/TiO2/CSC obeyed first-order kinetic Langmuir-Hinshelwood mechanism (R2 > 0.997). CdS/TiO2/CSC exhibited enhanced photocatalytic activity under simulated solar light irradiation compared with photocatalysts reported before and the photocatalytic activity of CdS/TiO2/CSC maintained at 89.0% of initial decolorization rate after five batch reactions. The presence of NO3− accelerated the decolorization of methyl orange solution by CdS/TiO2/CSC, while SO42− and Cl− had an inhibitory effect on the decolorization of methyl orange. Therefore, present experimental results indicated to assess the applicability of CdS/TiO2/CSC as a suitable and promising photocatalyst for effective decolorization treatment of dye-containing effluents.