Biogenic synthesis of photocatalytically active ZnS/ESM composites

The ZnS/ESM composites have been successfully fabricated using ESM (eggshell membrane), sodium sulfide and zinc sulfate as the main raw materials through an environmental and economical liquid impregnation method. The obtained samples were characterized via X-ray diffraction, scanning electron microscopy, energy dispersive spectroscopy, UV-vis diffuse reflectance spectra and Fourier-transform infrared spectra. The results demonstrated that the formed ZnS nanoparticles uniformly distributed on the surface of the egg membrane fibers, and the crystallinity and the amount of the ZnS loaded on the ESM fibers could be adjusted by changing the cycle indices of the impregnation. Furthermore, we tested the photocatalytic effects and analyzed the mechanism of the resulting ZnS/ESM composites as photocatalysts to degrade the harmful organic pollutant methyl orange under UV light irradiation. The results showed that the ESM support made it easy to recover the photocatalysts and enhanced the intensity of light absorption and the stability of the ZnS/ESM composites as photocatalysts. Based on the high photocatalytic activity and good stability, the ZnS/ESM composites with 4 cycle indices of the impregnation can be expected to be a practical photocatalyst.