Investigation of the crystalline structure and photoluminescence, photocatalytic and antibacterial properties of the nanocrystals (Ag2-2xZnX)WO4 with (x = 0, 0.25, 0.50, 0.75 and 1) incorporated in chitosan

Abstract

The goal of this proposed postdoctoral project is to investigate the preparation and modification of nanosized compounds Ag2-2xZnxWO4 with (x = 0, 0.25, 0.50, 0.75 and 1) and their inclusion in the polymer matrix chitosan (CS) for the formation of nanocomposites (CS/Ag2-2xZnxWO4) by co-precipitation method. These modifications can enhance or even induce new chemical, physical, optical, photocatalytic and anti-microbial properties that are superior to polymer matrices and pure nanocrystals. In order to create the nanocomposites, first the (Ag2-2xZnX)WO4 nanocrystals will be synthesized from salts diluted in aqueous solutions per the various concentration of ions Zn2+ and Ag+. Then the (Ag2-2xZnX)WO4 nanocrystals will be dispersed in the CS matrix at various mass ratios of the nanocrystal relative to the CS. The obtained materials will be characterized structurally by X-ray diffraction (XRD), Raman and Infrared spectroscopies. To study the thermal stability of the material will be accomplished by thermal gravimetric analysis (TG). For better structural characterization of the nanocrystals and nanocomposites, X-ray scattering at low angle (SAXS) will also be performed. The morphological characteristics of the nanocrystals and nanocomposites will be verified by field emission gun scanning electron microscopy (FEG-SEM) and transmission electron microscopy (TEM). The optical properties of these materials will be investigated by ultraviolet visible (UV-vis) spectroscopy and photoluminescence measurements. The photocatalytic properties of the nanocrystals and nanocomposites will be characterized for the degradation of organic dyes (Rhodamine B and methyl orange) dispersed in aqueous solution exposed to UV illumination and by analyzing total organic carbon (TOC), which will be assessed the actual mineralization of dyes.. The photodegradation of these dyes will be quantified by monitoring the intensity of the absorption band. Moreover, the potential of these nanocrystals and nanocomposite materials to combat common bacteria in contaminated water (Salmonella typhi and Escherichia coli) will also be assessed. (AU)