Spectroscopic investigations on the photodegradation of toluidine blue dye using cadmium sulphide nanoparticles prepared by a novel method.

A novel method to prepare cadmium sulphide nanoparticles (CdS NPs) possessing nearly uniform size was adopted using eggshell membrane (ESM), under different pH conditions. Significant yield of CdS NPs with smallest possible size was obtained by increasing the pH of the reaction medium from acidic to alkaline. The above prepared CdS NPs have been characterized by UV-vis absorption as well as emission spectra, powder X-ray diffraction, scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The efficiency of the above prepared CdS NPs as a catalyst for the photodegradation of toluidine blue (TB) dye, as a function of pH as well as the ratio between the catalyst and the substrate was studied after irradiation with UV light. The results showed that an efficient interaction took place between the catalyst and the substrate to cause degradation of the selected dye. A maximum degradation of toluidine blue dye (90%) was observed at pH 8 which is higher than that of the efficiencies at pH 4 and pH 6.