Photodegradation study of congo red, methyl orange, methyl red and methylene blue under simulated solar irradiation catalyzed by ZnS/CdS nanocomposite

The nanocomposites of Zn(X)Cd(1-X)S were synthesized via controlled co-precipitation. The X-ray diffraction pattern, transmission electron microscopy image and BET method were used to characterize the synthesized nanocomposites. The cubic structure of nanocomposites were confirmed using X-ray diffraction pattern. The photodegradation of congo red, methyl orange, methyl red and methylene blue catalyzed by prepared nanocomposites was studied under simulated solar irradiation. The Zn(0.4)Cd(0.6) S show the highest photoactivity among nanocomposites. The effect of samples pH and Zn(0.4)Cd(0.6)S dosage were adjusted to optimize the photodegradation process of dyes. The degradation efficiency of 95% were obtained within 20 min for congo red and 60 min for other dyes with initial concentration of 10 mg/l. The Zn(0.4)Cd(0.6)S indicate the stability in samples with pH of 3-11. The mineralization of dyes was confirmed using determination of chemical oxygen demand of solutions after photodegradation process.