Effect of key operational factors on decolorization of methyl orange during H 2O 2 assisted CdS/TiO 2/ploymer nanocomposite thin films under simulated solar light irradiation

Abstract

CdS/TiO 2/polymer nanocomposite thin films (CdS/TiO 2/polymer NTFs) as photocatalyst were prepared and characterized by wide angle X-ray diffraction (WXRD). The effect of key operational factors, i.e. catalyst amount, H 2O 2 dosage, solution pH, initial dye concentration, coexisting anions and reuse of catalyst on decolorization of methyl orange (MO) was investigated systematically. WXRD results indicated that CdS/TiO 2/polymer NTFs presented a mixture of anatase TiO 2 and hexagonal CdS nanocrystals. 99.5% of MO was successfully decolorized after 130 min simulated solar light irradiation at 3.9 mmol L −1 H 2O 2, 1.0 g L −1 CdS/TiO 2/polymer NTFs and pH 6.0 for 15 mg L −1 MO aqueous solution. All examined anions (Cl −, NO 3 −, SO 4 2−, CO 3 2− and PO 4 3−) had an inhibitory effect on the decolorization of MO. When the photocatalyst was used for the fifth time, decolorization efficiency was still about 99% after 130 min irradiation. These results demonstrated that H 2O 2 assisted CdS/TiO 2/polymer NTFs under simulated solar light irradiation was an effective and promising process for decolorization of dye-containing wastewater.