Keywords: 
• nano-CdS /
• chitosan /
• biebrich red dye /
• photocatalytic decolourization /
• amplified sunlight

Abstract: The chitosan/nano CdS composite particle was prepared successfully by simulating biomineralization process.The photocatalytic decolourization of biebrich red using the catalyst was investigated under amplified sunlight illumination. The influences of initial concentrations of biebrich red, initial pH of the reaction system, dose of catalyst, different anions and the reusability of the catalyst on biebrich red decolorization efficiency were investigated. The experimental results indicated that the decolorization of 20 mg/L biebrich red reached above 96% within 60 min,under the condition of pH 30,catalysts dosage of 0.7 g/L. The dye could be more efficiently decolorized in an acid media than in a basic media. All of the anions tested had a stimulative effect on the decoloration of biebrich red, of which the effect of NO-3 was the most pronounced compared with Br-，SO2-4 and Cl-.UVVis spectra were analyzed to indicate that the decoloration of the dye by cross-linked chitosan/nano CdS photolysis treatment was the degradation of dye actually.After the catalyst was reused for 5 times,dye decolorization efficiency was still about 80.7%.