Preparation And Photocatalytic Performance Of Metal Sulfide/ESM Composites

Eggshell membrane(ESM) is one of waste from the kitchens and industry. It exhibits outstanding superiority such as abundant source, high ability of adsorption, easy recycling and high performance of suspending. In this paper, we prepared CuS/ESM composite and CuS-ZnS/ESM composite employing eggshell membrane as biological carrier. The new composites were characterized by various means and methods and the effect of different factors on the photocatalytic performance of the new composite were investigated, which would provide a theoretical basis and experiment foundation for the practical use of the new composites as photocatalyst. Our main works and results are given as follows:CuS/ESM composite was successfully synthesized though liquid impregnation method and the CuS-ZnS/ESM composite was prepared by ion-exchange method using ZnS/ESM composite and CuSO4 as precursor. The prepared composites were characterized by X-ray diffraction(XRD), Fourier transform infrared(FT-IR), Field emission scanning electron microscope(FE-SEM) and UV-vis diffuse reflectance(UV-DRS). The influence of cycle index of the impregnation, copper precursor and the temperature of the solution on the photocatalytic performance of the CuS/ESM composite have been investigated. In addition, the mechanism of the formation and catalysis process of the CuS/ESM composite were proposed. The change of properties and photocatalytic performance of the CuS-ZnS/ESM composite as the increase of the ratio of Cu:Zn was analyzed. The possible mechanism of the degradation of dyes by the CuS-ZnS/ESM composite was proposed.The results showed that the increase of cycle indexes of the impregnation would improve the amount and the crystallinity of CuS on the ESM surface, which was bad for the catalytic performance. The anion in the copper precursor could also participate in the formation and growth of CuS particles. The ability of adsorption of the prepared CuS/ESM composites towards MB was improved with the increase of the impregnation temperature. ESM not only acted as the biological carrier but also play a role in the process of formation of CuS, which made the CuS particle distributed uniformly. The inatial pH of the MB solution has great impact on the catalytic performance. The formation of heterostructured CuS-ZnS would improve the absorption of visible light and the diameter of the particle on the ESM surface did not change after the ion-exchange. The degradation efficiency of dyes by the CuS-ZnS/ESM composites was related with the ratio of Zn: Cu.