Biogenic synthesis and photocatalytic activity of CdS nanoparticles

The present work demonstrates the photocatalytic activity of biologically synthesized cadmium sulfide (CdS) nanoparticles, using the fungal biomass of Trichoderma harzianum. The photocatalytic activity of the nanoparticles was determined upon the degradation of methylene blue (M.B.) in a photocatalytic reactor and the residual concentration was monitored using UV-Vis spectroscopy. The mechanism behind the photocatalytic activity was discussed with a diagrammatic representation. The synthesized CdS nanoparticles were characterized by UV-Vis spectroscopy, Transmission electron microscopy (TEM), X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR). The UV-Vis spectrum of the CdS nanoparticles suspension showed an absorption peak at 332 nm. The photocatalytic activity of the CdS nanoparticles was evaluated using reaction kinetics. The energy band gap of the synthesized CdS nanoparticles was estimated by absorbance spectra. TEM analysis showed that the particles are formed on the nano scale and have a spherical morphology. X-ray diffraction analysis showed intense peaks which correspond to the crystalline nature of CdS. Fourier transform infrared spectroscopy provided clear evidence of the presence of proteins as probable biomolecules responsible for the stabilization of the CdS nanoparticles.