Cadmium sulfide (CdS), with a large direct band gap of 2.4eV, has been recognized as one of the most important semiconductors and CdS nanoparticles exhibited important applications in the field of photocatalytic degradation of organic pollutants. However, CdS nanoparticles are easy to aggregate in aqueous solution during preparation process, leading to synthesize big-sized CdS crystals, which accordingly results in rather lower efficiency for photocatalytic activity.  In this study, CdS nanoparticles were prepared using in situ synthesizing method in chitosan hydrogel films. The resulting chitosan/CdS nanoparticles composite films were characterized by FTIR and TEM. The results indicate that crosslinked chitosan films provided a confined matrix for CdS nanoparticles growth through chelation between cadmium ions and �NH2 groups in C2, �OH groups in C3 in chitosan chains. Methyl Orange (MO) was used to study the photocatalytic activity of the composite film under a 50 W Hg lamp irradiation. The influences of catalyst amount, initial MO concentrations, pH and the recycle of the catalyst were investigated in details. The kinetics of photocatalytic decolourization was found to follow a pseudo-first-order according to Langmiur-Hinshelwood (L-H) model. The figure below shows the UV-vis spectra changes of MO solutions under the irradiation. The results indicate that the aromatic rings at 270.0 nm and azo bonds at 463.0 nm of MO were broken under the irradiation in the presence of 0.7 g L-1 chitosan/CdS nanoparticles composite film.

Preparation of chitosan/CdS nanoparticles composite films and their photocatalytic degradation activities

248th National Meeting (2014)

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