Synthesis, characterization, and dispersion behavior of ZnO/Ag nanocomposites

Physicochemical and photocatalytic properties of biogenic ZnO and its chitosan nanocomposites for UV-protection and antibacterial activity on coated textiles

The textiles for medical use and the purification of textile factory effluents have become the most crucial part of the human healthcare sector. In this study bioactive compounds produced by four distinct plant extracts were used for the synthesis of zinc oxide nanoparticles. The four different ZnO nanoparticles were comprehensively characterized by different analytical techniques. XRD analysis revealed the crystalline nature and phase purity of the ZnO nanoparticles. FTIR spectra provided information on the function of plant extracts in the stabilization or capping process. The size distribution and morphological diversity of the nanoparticles were further clarified by SEM and TEM images. The photocatalytic degradation activity of the four ZnO nanoparticles on two different dyes showed that ZnO nanoparticles prepared from A. indica were most effective for the degradation of 98 % and 91 % of Rhodamine B and Alizarin red dye respectively. The selected ZnO nanoparticles from A. indica were used to prepare ZnO-chitosan nanocomposites before coating on cotton fabrics. The hydrophobicity, UV protection factor, and antibacterial activity of ZnO-chitosan nanocomposites, when coated on cotton fabrics, were also examined. The overall results demonstrated the ZnO and ZnO-chitosan nanocomposite prepared in the present study as a promising material for environmental remediation application.

Effect of preparation conditions on the properties of nano ZnO powders during ultrasonic assisted direct precipitation process

Transparent conductive thin films (TCO) are widely used for their excellent photoelectric properties. To prepare high-quality ZnO targets, starting with the original ZnO powder is necessary. This paper aims to explore the basic technology and method of ultrasonic-assisted direct precipitation for mass production of ZnO powder and to analyze the effects of factors such as precipitating agent, surfactant, calcination temperature, and solvent on the powder's morphology, particle size, and crystallinity. The study found that the type and amount of precipitants and surfactants affect the powder's morphology and dispersibility, while calcination temperature mainly affects the powder's morphology and crystallinity. The ethanol content in the solvent mainly affects the grain size. After testing different variables, the optimal conditions for preparing spherical ZnO powder were found to be using (NH4)2·CO3 as the precipitant, adding 3% wt of PEG-400 and 3% wt of TEA at a calcination temperature of 320°C and a 60% ethanol solvent. This resulted in a smooth surface, uniform particle size distribution, good dispersibility, high crystallinity, and particle sizes between 26-32nm.