A liquid precipitation method was used to prepare zinc oxide nanoparticles in three diverse media: water, methanol, and ethylene glycol. The studied materials were examined by scanning electron microscopy, X-ray diffraction, Fourier transform infrared spectroscopy, and ultraviolet-visible spectroscopy. X-ray diffraction patterns showed a hexagonal Wurtzite structure of zinc oxide with a nanocrystalline size. Acquired powders showed different morphologies (rod, star, and spherical structures), which were affected by the nature of the solvent in the reaction. The different zinc oxide powders have varied optical band gaps. Scanning electron microscopy examinations confirmed the arrangement of nano-zinc oxide on the surfaces of the materials. The zinc oxide-covering procedure was carried out on cotton, polyester, and 50/50 wt% polyester/cotton blended fabrics using a simple dip and curing system. The cotton fabric treated with nanorod zinc oxide exhibited the highest ultraviolet protection factor with a value of 247.2. The antimicrobial properties of untreated and treated fabrics with nano-zinc oxide were measured against Gram-negative bacteria (Escherichia coli), Gram-positive bacteria (Staphylococcus aureus), and diploid fungus (Candida albicans). The results showed the antimicrobial action relies on the morphological structure and the particle size of zinc oxide and that it increases with a reduced particle size. The cotton fabric treated with 26 nm nonspherical zinc oxide particles showed the highest antimicrobial efficiency with values of 91.4%, 86.8%, and 84.7% for Staphylococcus aureus, Escherichia coli, and Candida albicans, respectively. The mechanical properties of treated fabrics were studied. The results confirm that nano-zinc oxide is highly useful for improving the performance of defense textile products because of its biocompatibility, environmental friendliness, and nontoxicity.
Cadmium sulfide (CdS)
quantum dots (QDs) were homogeneously embedded
into chitosan (CTS), denoted as CdS@CTS, via an in situ hydrothermal
method. The intact structure of the synthesized materials was preserved
using freeze-drying. The materials were characterized using X-ray
diffraction (XRD), X-ray photoelectron spectroscopy, transmission
electron microscopy, high-resolution TEM, scanning TEM, dispersive
energy X-ray (EDX) for elemental analysis and mapping, Fourier transform
infrared spectroscopy, nitrogen adsorption–desorption isotherms,
thermogravimetric analysis, UV–vis spectroscopy, and diffuse
reflectance spectroscopy (DRS). The synthesis procedure offered CdS
QDs of 1–7 nm (average particle size of 3.2 nm). The functional
groups of CTS modulate the in situ growth of CdS QDs and prevent the
agglomeration of CdS QDs, offering homogenous distribution inside
CTS. CdS@CTS QDs can also be used for naked-eye detection of heavy
metals with high selectivity toward copper (Cu
2+
) ions.
The mechanism of interactions between Cu
2+
ions and CdS@CTS
QDs were further studied.
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