L-cysteine caped ZnS QDs on the surface of chitosan: preparation, characterization, and application of sonophotocatalyst for decomposition of methyl violet dye

Recently, Quantum dots (QDs) as nano-scale luminescent inorganic semiconductor nanocrystals have been attention by the researchers due to the their unique electrooptical properties of QDs, size-tunable light emission, long-term photostability[۱]. Moreover, by surface modifications of QDs and the loading of these QDs on biocompatable compounds can make QDs available for interactions with target analytes, for various applications[۲]. So, in this study, Zinc sulfide (ZnS) quantum dots (QDs) were prepared by a simple, fast and water based chemical precipitation method, in the presence L-cysteine- hydrocloride. ZnS QDs were loading on chitosan (Ch) in various rations and then, the obtained QDs have been characterized by XRD, SEM-EDAX, FT-IR, and UV–visible absorption spectroscopy. The results revealed that the optical absorption band of ZnS nanostructures varied by chitosan and percent of QD. Photodecolorization of methyl violet (MV) as a model molecule was investigated by prepared QD by photocatalytic and sonophotocatalytic. Influence of affecting parameters on the decolorization efficiency of QDs was studied and optimized. The results indicated that the prepared QDs can effectively remove different concentrations of MV dye at alkaline pH, in the presence of low concentrations of QDs via sonophotocatalytic by ۹۹%. According to the photocatalytic results, the presented method can be considered as a green, quick and efficient strategy for photobleaching of organic pollutants.

کلیدواژه ها:

Zinc sulfide ، Quantum dot ، Sonophotocatalytic ، Chitosan