Search Results (5)

Zinc oxide-modified tourmaline-based negative ion polyester fiber (ZnO/TM/PET), as a new functional fiber with excellent negative ion emission characteristics, is of great significance to human health, and its industrial application needs to be expanded and promoted. In this paper, using zinc oxide, tourmaline, and polyethylene terephthalate as the main raw materials, ZnO/TM/PET negative ion functional fiber with 5% ZnO/TM composites was prepared. Then, it was blended with cotton fiber and interknitted with wool yarn and spandex yarn, from which we developed five kinds of negative ion polyester/cotton-blended yarn and four different kinds of knitted double-sided fabric using different equipment and process parameters. The micromorphology of the fiber samples, the basic properties of the blended yarns, and the wearability and functional properties of the knitted fabrics were tested. The results show that the ZnO/TM negative ion additive is randomly dispersed in the polymer matrix without visible conglobation and the fiber has a good appearance. The blending ratio has an important effect on the properties of functional polyester/cotton blended yarn. The higher the ratio of negative ion polyester fiber in the blended yarn, the better the mechanical index of the blended yarn, the higher the negative ion emission, and the lower the hairiness index. The performances of fabric are influenced by the comprehensive action of fiber raw material type, yarn ratio, fabric tightness, and structure. The mechanical properties of the fabric knitted from negative ion polyester/cotton-blended yarn are lower than those made from negative ion polyester filament yarn. In the case of the same fabric structure, the negative ion emission performance, far-infrared emission performance, and antibacterial property of the fabric with a higher ratio of negative ion functional fiber is better than the lower ratio. With the same yarn composition, the negative ion emission performance and air permeability of the fabric with a loose structure are better than that of the fabric with a tight structure, but the moisture permeability, far-infrared emission properties, and antibacterial properties show little difference. Full article

Using zinc oxide (ZnO), tourmaline (TM), and polyethylene terephthalate (PET) as main raw materials, a novel ZnO/TM/PET negative ion functional fiber was created. The rheological properties of a ZnO/TM/PET masterbatch were investigated; the morphology, XRD, and FT-IR of the fibers were observed; and the mechanical properties, thermal properties, and negative ion release properties of the new fiber were tested. The results showed that the average particle size of the ZnO/TM composite is nearly 365 nm, with an increase in negative ion emission efficiency by nearly 50% compared to the original TM. The apparent viscosity of fiber masterbatch decreases with the increase in the addition of the ZnO/TM composite, and the rheological properties of the PET fiber masterbatch are not significantly effected, still showing shear thinning characteristics when the amount of addition reaches 10%. The ZnO/TM composite disperses well in the interior and surface of the ZnO/TM/PET fiber matrix. The prepared ZnO/TM/PET fiber has excellent properties, such as fineness of 1.54 dtex, glass transition temperature of 122.4 °C, fracture strength of 3.31 cN/dtex, and negative ion release of 1640/cm³, which shows great industrialization potential. Full article

In this study, we tested the biosorption capacity of trimethyl chitosan (TMC)-ZnO nanocomposite (NC) for the adsorptive removal of Escherichia coli (E. coli) in aqueous suspension. For the formation of ZnO NPs, we followed the green synthesis route involving Terminalia mantaly (TM) aqueous leaf extract as a reducing agent, and the formed ZnO particles were surface-coated with TMC biopolymer. On testing of the physicochemical characteristics, the TM@ZnO/TMC (NC) hydrogel showed a random spherical morphology with an average size of 31.8 ± 2.6 nm and a crystal size of 28.0 ± 7.7 nm. The zeta potential of the composite was measured to be 23.5 mV with a BET surface area of 3.01 m² g⁻¹. The spectral profiles of TM@ZnO/TMC NC hydrogel on interaction with Escherichia coli (E. coli) revealed some conformational changes to the functional groups assigned to the stretching vibrations of N-H, C-O-C, C-O ring, and C=O bonds. The adsorption kinetics of TM@ZnO/TMC NC hydrogel revealed the pseudo-second-order as the best fit mechanism for the E. coli biosorption. The surface homogeneity and monolayer adsorption of the TM@ZnO/TMC NC hydrogel reflects majorly the entire adsorption mechanism, observed to display the highest correlation for Jovanovic, Redlich–Peterson, and Langmuir’s isotherm models. Further, with the use of TM@ZnO/TMC NC hydrogel, we measured the highest adsorption capacity of E. coli to be 4.90 × 10 mg g⁻¹, where an in-depth mechanistic pathway was proposed by making use of the FTIR analysis. Full article

We performed a comparative spectroscopic analysis on three novel Tm³⁺:tellurite-based glasses with the following compositions Tm₂O₃:TeO₂-ZnO (TeZnTm), Tm₂O₃:TeO₂-Nb₂O₅ (TeNbTm), and Tm³⁺:TeO₂-K₂O-Nb₂O₅ (TeNbKTm), primarily for 2-μm laser applications. Tellurite glasses were prepared at different doping concentrations in order to investigate the effect of Tm³⁺ ion concentration as well as host composition on the stimulated emission cross sections and the luminescence quantum efficiencies. By performing Judd–Ofelt analysis, we determined the average radiative lifetimes of the ³H₄ level to be 2.55 ± 0.07 ms, 2.76 ± 0.03 ms and 2.57 ± 0.20 ms for the TeZnTm, TeNbTm and TeNbKTm samples, respectively. We clearly observed the effect of the cross-relaxation, which becomes significant at higher Tm₂O₃ concentrations, leading to the quenching of 1460-nm emission and enhancement of 1860-nm emission. Furthermore, with increasing Tm₂O₃ concentrations, we observed a decrease in the fluorescence lifetimes as a result of the onset of non-radiative decay. For the ³H₄ level, the highest obtained quantum efficiency was 32% for the samples with the lowest Tm₂O₃ ion concentration. For the 1860-nm emission band, the average emission cross section was determined to measure around 6.33 ± 0.34 × 10⁻²¹ cm², revealing the potential of thulium-doped tellurite gain media for 2-μm laser applications in bulk and fiber configurations. Full article

Taking the adsorption of CO, NO, O₂ and O as probes, we investigated the electronic structure of transition metal atoms (TM, TM = Fe, Co, Ni, Cu and Zn) embedded in graphene by first-principles-based calculations. We showed that these TM atoms can be effectively stabilized on monovacancy defects on graphene by forming plausible interactions with the C atoms associated with dangling bonds. These interactions not only give rise to high energy barriers for the diffusion and aggregation of the embedded TM atoms to withstand the interference of reaction environments, but also shift the energy levels of TM-d states and regulate the reactivity of the embedded TM atoms. The adsorption of CO, NO, O₂ and O correlates well with the weight averaged energy level of TM-d states, showing the crucial role of interfacial TM-C interactions on manipulating the reactivity of embedded TM atoms. These findings pave the way for the developments of effective monodispersed atomic TM composites with high stability and desired performance for gas sensing and catalytic applications. Full article