ZnO Content Research Articles

Impact of incremental zinc-oxide incorporation on optical, magnetic, mechanical and photon transmission properties of K2O, SrF2, PbO containing borate-glasses

This study examines the radiation shielding properties of borate glass systems, with a focus on the simultaneous enhancement of optical, mechanical, and magnetic characteristics. The glass composition is represented by formula (55-x)B2O3+25PbO+10SrF2+10K2O + xZnO (where x: 0.0–10.0 mol%). By manipulating the ZnO concentration, we aimed to investigate its role as a radiation attenuator and its effects on the glass's optical, mechanical, and magnetic properties. Using traditional melt-quenching techniques, we produced the glass samples and examined their density, molar volume, linear attenuation coefficients (GLAC), mean free paths (GMFP), half-value layers (GHVL), and optical and magnetic properties. Our findings demonstrate that higher ZnO concentrations lead to a significant increase in density and a corresponding decrease in molar volume, thereby enhancing the glasses' ability to shield against gamma radiation. The radiation attenuation analysis revealed that increasing ZnO content substantially improves GLAC values across the energy range of 356–1333 keV. Additionally, ZnO incorporation decreases the optical bandgap, shifting the UV absorption edge to shorter wavelengths and enhancing UV dielectric capacity. Magnetic properties were assessed using vibrating sample magnetometer (VSM) measurements, showing a strong correlation between ZnO content and the effective atomic number (Zeff). It can be concluded that ZnO not only contributes to radiation shielding but also modifies the electronic structure of the glass, impacting its optical absorption properties.

Deciphering the Nd3+ environment and energy-transfer mechanisms in thermally stable novel calcium aluminate glasses: elucidation of broadband high-gain performance for laser applications

Rare-earth-doped barium calcium aluminate (BCA) glasses, having extended infrared (IR) transmission (6 μm), are attractive materials for near IR (NIR) photonic applications. Nd2O3-doped BCA glasses display broadband emission at 1.07 µm, but they are limited, with poor glass-forming ability (GFA) and low emission cross sections. In the present study, four different barium zinc calcium aluminate (BZCA) glasses are synthesized with varied ZnO concentrations (from 9.5 to 24.5 mol%) and doped with 0.5 mol% Nd2O3 to decipher the effect on GFA and spectroscopic properties. The addition of ZnO enhances the GFA, and the NdBZCA20 glass shows the maximum GFA. Ultraviolet (UV)–visible (Vis)–NIR absorption spectra reveal a decreasing trend in the nephelauxetic effect, while J–O parameters, emission, and gain properties lead to no significant alteration with increasing ZnO, and the structure–properties correlation is established accordingly. However, the emission cross sections for all ZnO concentrations are found ∼4.5 × 10−20 cm2 accompanied by broadband emission (Δλ eff ∼ 40 nm), which ensures the potentiality of these glasses for low-threshold high-gain laser applications as well as ultrashort pulse laser applications. Furthermore, a thorough analysis of 1.06 µm emission as a function of Nd concentration in the BZCA20 glass is reported here. The emission spectra and decay time indicate that 0.5 mol% is the optimized doping concentration. Inokuti–Hirayama and Burshtein equations are adopted to study the decay kinetics and energy-transfer mechanisms, which confirm that the energy-transfer process due to cross-relaxation is dominant up to 0.5 mol% concentration, whereas, beyond that concentration, excitation energy migration via the hopping mechanism supersedes.

A comprehensive review on active chain density evaluation from swelling and insights for better accounting for insoluble particles

AbstractThe present study provides a state of the art on methods for evaluating active chain density of rubbers from swelling experiments. This review focuses more particularly on the effects of components that are known to limit the swelling, and which typically results in an overestimation of the active chain density. These components are commonly considered as insoluble. Different corrections dealing with the two principal insoluble components, namely zinc oxide (Zn0) and carbon black (CB) filler, are thoroughly investigated. A comparative study on the same natural rubber (NR), either filled and unfilled, vulcanized with three different vulcanization systems, is performed to evaluate the relevance of each predictive approach. The results obtained highlight their respective limitations. In particular, it is shown that the swelling ratio of unfilled and filled natural rubbers are linearly related, suggesting that fillers have no significant effect on the overall number of cross‐links formed during vulcanization. As a result, we propose a unified approach for correcting the ZnO content for unfilled NR and both the ZnO and CB contents for filled NR. By comparing with results issued from uniaxial tensile tests, it is shown that the use of a mechanical response is a relevant alternative for determining the active chain density.

Bio-based materials in tribology: New salicylate ionic liquid+ZnO nanolubricant of PLA and PLA nanocomposite

ZnO nanoparticles have been dispersed (in 0.05; 0.5 and 1.0 wt% proportions) in the protic ionic liquid bis(2-hydroxyethyl) ammonium salicylate (DSa) to obtain new (DSa+ZnO) nanofluids. A non-Newtonian behavior was found for ZnO concentrations lower than 1 wt%. The Newtonian DSa+ 1 wt%ZnO nanofluid was selected as lubricant of polylactic acid (PLA) and as 5 wt% additive to obtain the new PLA+ (DSa+ZnO) nanocomposite. PLA+ZnO was also studied as a reference. The excellent friction-reducing and antiwear behavior of PLA+ (DSa+ZnO) is attributed to the porosity that promotes self-lubrication and to synergy due to interactions between the salicylate anion in DSa and the surface of ZnO nanoparticles. Electron microscopy (SEM and TEM), Raman spectroscopy, thermal analysis (DSC and TGA) and profilometry techniques were used.

Structural, microstructural and optical characteristics of rGO-ZnO nanocomposites via hydrothermal approach

This paper describes the production and characterizations of reduced graphene oxide-zinc oxide (rGO-ZnO) nanocomposites fabricated via hydrothermal approach. Firstly, rGO powder was produced via modified Hummers' method and ZnO nanoparticles using chemical co-precipitation. The nanocomposites structural, microstructural and optical characteristics were determined using X-ray diffraction (XRD), infrared spectroscopy (FTIR), Raman spectroscopy and Ultraviolet–visible (UV–Vis) spectroscopy. The findings demonstrated the effective synthesis of rGO-ZnO nanocomposites with evenly distributed ZnO nanoparticles on the surface of reduced graphene oxide sheets. rGO-ZnO nanocomposites with different concentrations ratio rGO:ZnO in composition of 10:0. 7.5:2.5, 5:5, 2.5:7.5, and 0:10 (weight percentage) were formed. An average crystallite size (Davg) was observed to be decreasing with an increasing concentration of ZnO in to rGO from ∼13.96 nm to ∼21.36 nm which is supported by Williamson-Hall (W–H) extrapolation. The FTIR spectra showed the functional groups belongs to intrinsic and extrinsic vibrations v1 and v2 at ∼410 cm−1 for rGO and metal‒oxygen (Zn–O) stretching vibrations ∼400 cm−1 to ∼500 cm−1 for rGO-ZnO nanocomposites. On rising ZnO content in the rGO-ZnO nanocomposites, a slight variation in band positions was caused due to the microstructural changes. Raman spectroscopy revealed certain peaks (D, G, for rGO; E2, A1 (TO), LO for ZnO) in various compositions. The research demonstrates how the composition of a material affects its vibrational characteristics, which is crucial for customizing the material for certain applications. The optical energy band gap of rGO-ZnO 75 % was recorded to be ∼4.94 eV, and highest for rGO with 5.44 eV. The optical energy band gap decreased from 5.44 eV to 4.94 eV. This decrease can be attributed to the influence of the smaller crystallite size and fluctuations in microstructural properties caused by the rGO-ZnO nanocomposite. The obtained rGO-ZnO nanocomposites can be utilized for opto-electronic device applications.

Enhanced photoluminescence properties and stability of CsPbBr3 quantum dots borosilicate glasses modified by ZnO

Halide perovskite quantum dots (QDs) glass has attracted much attention in the field of optoelectronics, but its photoluminescence (PL) properties and water stability still need further improvement. In this work, the melt-quenching method is used to successfully precipitate CsPbBr3 QDs in borosilicate glass. By increasing the concentration of ZnO, the photoluminescence quantum yield (PLQY) of CsPbBr3 QDs glass is enhanced up to 30 times from 1.91 % to 65.87 %. The results demonstrate that the introduction of ZnO loosens the glass network structure, which contributes to the QDs to precipitate. In addition, it can be found that the PL intensity maintains 91.68 % of the initial PL intensity after 30 days of immersion, which is attributed to ZnO delays the corrosion of borosilicate glass by water. The effect of ZnO-modified borosilicate glass structure on PL and stability provides a certain reference value for further research on QDs glass, and the good PLQY and water stability make ZnO-modified CsPbBr3 QDs glass a potential material in the field of WLEDs.

Design and synthesis of chitosan/alginate/zinc oxide nanocomposite hydrogel beads as carrier for metformin hydrochloride

In the current study, nanocomposite hydrogel beads were prepared from chitosan, alginate and zinc oxide nanoparticles using sodium tripolyphosphate as the crosslinking agent by ionotropic gelation method. The resulting nanocomposite hydrogel beads were characterized by FT-IR, XRD, TGA and UV methods and the beads were found to be an effective delivery system for the regulated release of the antidiabetic drug metformin. The swelling properties, drug loading and encapsulation efficiencies of the metformin loaded nanocomposite beads were evaluated and these parameters were found to be influenced by the concentrations of chitosan, alginate and ZnO nanoparticles. The rate of release of the drug from the nanocomposite beads was determined by UV spectroscopic method at λmax 233 nm. An increase in the concentration of ZnO enhances the swelling properties but lowers the release rate. Swelling indices of the prepared formulations were in the range 5–150. Maximum swelling index of 150 was observed for the formulation with 3 % chitosan, 2 % alginate and 15 % zinc oxide NPs. However, a maximum release rate of 83.23 % was observed for the formulation without ZnO and with 3 % chitosan, 2 % alginate. Controlled drug release was observed for the drug loaded chitosan/alginate/ZnO, hydrogel beads. The zinc oxide nanoparticles improved the in vitro α-glucosidase inhibitory activity of the formulations and the formulation with 5 % ZnO exhibited a maximum α-glucosidase inhibition rate of 62.92 %. The incorporation of ZnO nanoparticles enhanced the antioxidant properties of the formulations. The cell viability values of the samples were evaluated using L929 mouse fibroblast cells which confirmed the nontoxic nature of the samples. Dinitrosalicylic acid (DNS) studies proved that the prepared nanocomposites are biodegradable.

Tailoring glass radiation shielding properties through the Integration of ZnO and CaO

In this study, borate glasses with a general formula of (80-x-y)B2O3–10BaO–10Na2O-xZnO-yCaO, where x = 10, 15, 20 and 25 mol %, and y = 5, 10, 15 and 20 mol % were prepared. The radiation shielding capabilities of the prepared glass system were investigated at a wide energy range of 0.015 MeV–15 MeV. The data reveal that, the values of the mass attenuation coefficient (MAC) vaired between 20.043 and 32.435 cm2/g at 0.015 MeV. The MAC demonstrated that the increase of the ZnO and CaO content within the glasses leads to increase the MAC values, and improve the absorption ability of the glasses. The relation between the density of the glasses and their linear attenuation coefficients (LAC) were studied. A positive linear relationship between LAC and density has been fond. At 0.150 MeV, the LAC values are 0.804, 0.874, 0.945, and 1.020 cm−1 for the glass with 5, 10, 15 and 20 mol % of CaO in the order, respectively. We also evaluated the ratio of half value layer (HVL) for all prepared glass samples with lowest and highest density. The results revealed that the calculated ratio of HVL is always >1. This means that the Zn25Ca20 sample requires a smaller thickness to attenuate the same number of photons as betweenZn10Ca5. This is desirable in situations where space is a constraints well as costs as a smaller material can be used. This study uniquely highlights the combined impact of ZnO and CaO on enhancing the radiation shielding performance of borate glasses, offering a novel approach to developing more efficient materials.

The Effects of Different Zn Forms on Sintering Basic Characteristics of Iron Ore.

The micro-sintering method was used to determine the sintering basic characteristics of iron ore with Zn contents from 0 to 4%, the influence mechanism of Zn on sintering basic characteristics of iron ore was clarified by means of thermodynamic analysis and first-principles calculations. The results showed that (1) increasing the ZnO and ZnFe2O4 content increased the lowest assimilation temperature (LAT) but decreased the index of liquid phase fluidity (ILF) of iron ore. The addition of ZnS had no obvious effect on LAT but increased the LIF of iron ore. (2) ZnO and ZnFe2O4 reacted with Fe2O3 and CaO, respectively, during sintering, which inhibited the formation of silico-ferrite of calcium and aluminum (SFCA). The addition of ZnS accelerated the decomposition of Fe2O3 in the N2 atmosphere; however, the high decomposition temperature limited the oxidation of ZnS, so the presence of ZnS had a slight inhibitory effect on the formation of SFCA. (3) The Zn concentrated in hematite or silicate and less distributed in SFCA and magnetite in the form of solid solution; meanwhile, the microhardness of the mineral phase decreased with the increase in Zn-containing solid solution content. As the adsorption of Zn on the SFCA crystal surface was more stable, the microhardness of SFCA decreased more. The decrease in microhardness and content of the SFCA bonding phase resulted in a decrease in the compressive strength of the sinter.

Neutron Shielding Properties of Cellulose Acetate CdO-ZnO Polymer Composites

In this work, the neutron shielding ability of Cellulose Acetate-CdO-ZnO Polymer Composites of different concentrations of CdO and ZnO were investigated. Cellulose acetate is a biodegradable good matrix and the used metal oxides are good for absorbing radiation. The neutron attenuation coefficient was calculated by Phy-X computer code for all the samples.

In-vitro biocompatibility, antibacterial activity, and corrosion resistance of HA-TiO2/ZnO coating fabricated by plasma electrolytic oxidation on Ti6Al4V

The hydroxyapatite/Zinc Oxide (HA-TiO2/ZnO) coatings were grown on the Ti6Al4V substrate by plasma electrolyte oxidation from the CaP-based electrolyte containing 1, 3, and 6 g/L ZnO nanoparticles. XRD results confirmed the presence of ZnO, HA, and rutile phases in all coatings. According to SEM observations, coatings presented the porous morphology as a result of micro-arc discharges during the PEO process, whereas some of the pores in the composite coatings were filled by ZnO proportional to its content. After 7 days of immersion in SBF solution, accumulations of bone-like clusters were visible on the surface, demonstrating a promising bio-mineralization ability for all coatings, although the higher amount of 6 g/L ZnO had partially an inhibitory effect on the apatite nucleation. In-vitro studies demonstrated a time and concentration-dependent impact of ZnO on the viability of MG-63 osteoblast-like cells so that the concentration of 3 and 6 g/L caused the death of some cells after 7 days. The antibacterial tests also showcased that the presence of ZnO decreased the activity of gram-negative bacteria (E. coli) and gram-positive bacteria (S. aureus), while the higher concentration of ZnO particles led to more antibacterial activity of the coating. Finally, evaluating the corrosion behavior of PEO coatings through a potentiodynamic polarization test in Ringer's solution manifested a better protection against corrosion by increasing the ZnO content in the coating, mainly owing to the blocking of the pores by the ZnO particles, and as a result, the greater difficulty of electrolyte to reach the titanium substrate.

The role of ZnO in the radiation shielding performance of newly developed B2O3–PbO–ZnO–CaO glass systems

Glasses with varying compositions were prepared using the melt-quenching process within the 40B2O3–20PbO-xZnO-(40-x)CaO system, where x = 20, 25, 30 and 35 mol%. ZnO's influence on the prepared glasses' radiation shielding properties was studied in the 0.015–15 MeV energy range. The results demonstrated that ZnO has a significant shielding effect at low energies, where there is an increased in the linear attenuation coefficient from 279.96 to 319.17 cm−1 at 0.015 MeV due to the 20-to-35 mol% increase in ZnO. The values of the mean free path (MFP) for the prepared glasses are very small when the energy is less than 0.1 MeV, in the order of 0.013–0.015 cm at 0.03 MeV, 0.051–0.055 cm at 0.05 MeV and 3.051–3.248 cm at 1 MeV, which revealed an enhanced attenuation efficiency with increasing ZnO content. According to the MFP results, the Zn35Ca5 sample (which contains 35 mol% ZnO) offers the best shielding performance. The half value layer (HVL) was also evaluated, and we found that the HVL is in order of 1.5 cm at 0.6 MeV, and in order of 3 cm at 2 MeV, while at 15 MeV, the HVL is 4.30 cm for Zn20Ca20 and 3.74 cm for Zn35Ca5.

Influence of ZnO and Pr6O11 incorporation on the structural, thermal, optical, mechanical, and magnetic properties of calcium lithium borate glasses

A new glass of calcium lithium borate with the chemical formula (62.75-x)B2O3 + 20CaO + 0.25Pr6O11 + 17Li2O + xZnO, where x = 0, 2.5, 5, 10, 20 (mol%) have been prepared by conventional melt-quenching process. The amorphous character has been confirmed by the very short-range ordering structural matrices demonstrated through X-ray diffraction.The Raman spectra of the prepared glass revealed an enhancement of host lattice distortions. Differential scanning calorimetry (DSC) estimated the glass transition temperature (Tg), the onset temperature of crystallization (Tc), and the melting temperature (Tm). The glass transition decreased from 441 °C to 431 °C with increasing ZnO content up to 10 mol%. The criteria of glass samples up to 10 % ZnO have higher strength, rigidity and higher level of thermal stability. The physical quantities as density, molar volume, inter-atomic distance, polaron radius, packing density, and oxygen packing density were calculated. The glass density increases while the molar volume decreases with ZnO content. The optical properties of glasses were investigated using UV–Vis spectrophotometer. The addition of ZnO enhances the light absorption in UV–Vis. The results of the calculated direct and indirect optical band gaps decrease from 3.663 eV to 3.233 eV for and from 3.167 eV to 2.648 eV for direct and indirect transitions respectively with the increment of ZnO addition. Additionally, the dispersion energy and static refractive index clearly increase while the oscillator energy declines. The Makishima-Mackenzie’s (M−M) method was employed to ascertain mechanical parameters, including elastic moduli, and Poisson’s ratio. The study revealed an enhancement to the mechanical properties as the content of ZnO increased. Vibrating sample magnetometer (VSM) was used to investigate the magnetic properties of the prepared glass and all samples exhibited a ferromagnetic behavior. The incorporation of ZnO act as glass modifier controlling their physical, optical and mechanical properties making the investigated glasses suitable for various applications.

Correlation between biomedical and structural properties of Zn/Sr modified calcium phosphates.

This study investigates the correlation between the biomedical and structural properties of Zn/Sr-modified Calcium Phosphates (ZnSr-CaPs) synthesized via the sol-gel combustion method. X-ray diffraction (XRD) analysis revealed the presence of Ca10(PO4)6(OH)2 (HAp), CaCO3, and Ca(OH)2 phases in the undoped sample, while the additional phase, Ca3(PO4)2 (β-TCP) was formed in modified samples. X-ray absorption near-edge structure (XANES) analysis demonstrated the incorporation of Sr into the lattice, with a preference for occupying the Ca1 sites in the HAp matrix. The introduction of Zn, furthermore, led to the formation of ZnO and CaZnO2 species. The ZnSr-CaPs exhibited significant antibacterial activity attributed to the generation of reactive oxygen species by ZnO, the oxidation reaction of CaZnO2, and the presence of Sr ions. Cytotoxicity tests revealed a correlation between the variation in ZnO content and cellular viability, with lower ZnO concentrations corresponding to higher cell viability. Additionally, the cooperative effects of Zn and Sr ions were found to enhance the bioactivity of CaPs, despite ZnO hindering the apatite formation process. These findings contribute to the deep understanding of the diverse role in modulating the antibacterial, cytotoxic, and bioactive properties of ZnSr-CaPs, offering potential applications in the field of biomaterials.

Tuning ZnO-based piezoelectric nanogenerator efficiency through n-ZnO/p-NiO bulk interfacing

ZnO based piezoelectric nanogenerators (PENG) hold immense potential for harvesting ambient vibrational mechanical energy into electrical energy, offering sustainable solutions in the field of self-powered sensors, wearable electronics, human–machine interactions etc. In this study, we have developed flexible ZnO-based PENGs by incorporating ZnO microparticles into PDMS matrix, with ZnO concentration ranging from 5 to 25 wt%. Among these, the PENG containing 15 wt% ZnO exhibited the best performance with an open-circuit output voltage/short-circuit current of ~ 42.4 V/2.4 µA. To further enhance the output performance of PENG, p-type NiO was interfaced with ZnO in a bulk hetero-junction geometry. The concentration of NiO was varied from 5 to 20 wt% with respect to ZnO and incorporated into the PDMS matrix to fabricate the PENGs. The PENG containing 10 wt% NiO exhibits the best performance with an open-circuit output voltage/short-circuit current of ~ 65 V/4.1 µA under loading conditions of 30 N and 4 Hz. The PENG exhibiting the best performance demonstrates a maximum instantaneous output power density ~ 37.9 µW/cm2 across a load resistance of 20 MΩ under loading conditions of 30 N and 4 Hz, with a power density per unit force and Hertz of about ~ 0.32 µW/cm2·N·Hz. The enhanced output performance of the PENG is attributed to the reduction in free electron concentration, which suppresses the internal screening effect of the piezopotential. To assess the practical utility of the optimized PENG, we tested the powering capability by charging various commercial capacitors and used the stored energy to illuminate 10 LEDs and to power a stopwatch displays. This work not only presents a straightforward, cost-effective, and scalable technique for enhancing the output performance of ZnO-based PENGs but also sheds light on its underlying mechanism.

Band Gap Modulation in Zn2TiO4 Spinels for Efficient UV-A Persistent Luminescence

Spinels are important materials for an application in bioimaging. The key advantage with spinel-type hosts is the presence of antisite defects, which act as charge reservoirs for trapping electrons and holes at complementary defect sites. This makes them a host system similar to a molecular system. Herein, we present a systematic approach to modulating the band gap of an inverse Zn2TiO4 spinel. With a change in ZnO concentration, the absorption band at 375 nm diminishes and disappears at a ZnO:TiO2 concentration of 1.40:1.00. The band gap of the material is modified from 3.30 to 4.40 eV. The crystal structure of the sample does not change drastically as determined using X-ray diffraction and Rietveld refinement. The Zn2TiO4 emits in the UV-A region with a lifetime in the time domain of `ns’. The sample also shows persistent luminescence of at least 15 min upon excitation with 254 nm with prominent emission in the UV-A region (300–390 nm). The present results open a new avenue for the synthesis of spinel hosts where the band gap can be modified with ease. The UV emission thus observed is expected to find usage in interesting applications like photocatalysis, anti-counterfeiting, water disinfecting, etc.

Morphology, physical, and structural aspects of copper nanoparticles induced- metal phosphate nanocompounds for gamma ray shielding and magnetic sensing applications

The inorganic nanocompounds were synthesized by solid state reaction with the composition 10Li2O+(30-x)Sb2O3 + xZnO + 59.5P2O5 + 0.5Cu (in mol%). SEM morphographs of the samples confirmed the grain size ≈0.5–2.5 μm. The EDAX spectra of the samples confirmed presence of copper (Cu) nanoparticles (<2 wt%) in the composition. The EDAX studies showed energy dispersion of Kα- photons by reactivity of elements P, Cu, and Zn, while the element Sb has shown dispersion of Lα- photons up to 10 keV. Mass attenuation coefficient (MAC) has exhibited a few discontinuities (bumps) at low energies (<10 keV) due to K, L- absorption edges of various elements (such as P, Cu, Zn, and Sb) presented in the samples. The shrinking of Phosphorous-Phosphorous separation (dP-P) from 4.716 Ao to 3.990 Ao indicated the greater solidity (or density) of the prepared nanocompounds at higher content of ZnO. XRD spectra showed the presence of major crystallites such as LiPO3, Li3PO4, Li6P6018, SbPO4, Cu3PO4, Cu2P2O7, Cu3[PO4]2, Zn[PO3]2, Zn2P2O7, ZnP4O11, and LiZnPO4 in the prepared nanocompounds. The average crystallite size was determined in the range of 35–83 nm. FTIR spectra of these compounds displayed the [PO2]−, [PO3]−, [PO4]3−, and [ZnO4] units along with linkages P─O─P, O─P─O, Sb─O─Sb, Cu─O─Cu, etc. A band due to vibrations of Cu─O bond has been observed in the range of 466–478 cm−1, which endorses the contribution of copper nanoparticles in the solid state reaction of the metal phosphate nanocompounds. A partially resolved hyperfine structure of magnetic resonance signals corresponding to g|| ≈2.4 and g⊥ ≈2.05 were observed due to the presence of an anisotropic hyperfine interaction of the electron spin (S = 1/2) with the nuclear spin (I = 3/2) of copper isotopes (63Cu and 65Cu) in the samples.

Role of GO content in ZnO/@ x wt% GO NCs for the reduction of Cr(VI) pollutant from wastewater stream

Role of GO content in ZnO/@ x wt% GO NCs for the reduction of Cr(VI) pollutant from wastewater stream

Optimizing Synergistic Silica–Zinc Oxide Coating for Enhanced Flammability Resistance in Cotton Protective Clothing

This study reports process optimization studies of silica and zinc oxide-based flame-retardant (FR) coatings on cotton fabric for protective clothing and enhanced flammability properties. The experiments were designed by central composite design (CCD) using response surface methodology (RSM) to assess the synergistic protective effects of silica and zinc oxide FR coating. These prepared sols were coated on cotton fabrics by a simple dip dry cure process. The resulting FR-finished fabrics were characterized by SEM, mechanical properties, flame retardancy, and air permeability. SEM results confirmed the homogenous spreading of particles on cotton fabrics. From TGA results, it was noticed that the incorporation of silica and ZnO in the prepared nano-sols results in improved thermal stability of the FR-finished fabrics. These sol–gel-treated FR cotton fabrics showed excellent comfort properties, which shows their suitability for fire-retardant protective clothing. RSM analysis proved that the predicted values are in good agreement with the experimental values since R2 values for time to ignite, flame spread time, and air permeability were greater than 0.90. The optimized concentration of silica and ZnO in FR-finished fabrics was found to be 0.302% and 0.353%, respectively, which was further confirmed by confirmatory experiments. The optimization analysis successfully optimized the process for synergistic coating of silica and zinc oxide nanoparticles for enhanced flammability properties of FR cotton fabric for protective clothing.

Tailoring of dielectric, ferroelectric, and optical properties of Bi0.99Nd0.1Fe2O3/ZnO nanocomposite at room temperature

We observe the fine-tuning of electrical and optical properties in a composite nanoparticle system consisting of varying weight fractions of semiconducting ZnO grains (x) embedded into Nd-doped multiferroic Bi0.99Nd0.1Fe2O3 matrix and annealed at 500 °C. X-ray diffraction (XRD) is used to validate the phase which further reveals the existence of cubic ZnO phases and rhombohedral BFO with some impurity phases. With the aid of SEM and EDX, the morphological and elemental composition of grains are found to be affected by ZnO nanoparticles. To understand the nature of dielectric response impedance analysis is performed which reveals the presence of large resistance offered by a composite maximum of 46.8 KΩ at x = 10 %. The enhancement in dielectric constant and dielectric loss is observed at higher concentrations for (x = 5 %). The Ferroelectric investigation shows that the maximum polarization achieved at low frequency for x = 10 % is 22.13 μc/cm2. The optical band gap in the composite sample exhibits significant dependence on ZnO concentrations, thus indicating potential application in optoelectronic devices.