Search Results (713)

The formation of phosphate conversion coatings on St20 low-carbon steel was studied in order to evaluate the effect of organic accelerators on coating formation and protective performance. The influence of pH, temperature, treatment time, and stirring rate on coating formation was studied by gravimetry and SEM-EDS, the influence of accelerators was studied by Raman spectroscopy, salt spray testing, polarization measurements, EIS, and dynamic LPR monitoring. Efficient coating formation was achieved at an initial pH of 3.0, elevated temperature, and intensive stirring; the process showed diffusion-controlled behavior with an apparent activation energy of 28 kJ/mol. Sodium nitrite accelerated coating formation but did not increase the limiting coating mass. Among the organic additives, catechol provided the most pronounced improvement in corrosion resistance, which was attributed to lower effective porosity and possible incorporation of catechol-derived oxidized fragments into the phosphate layer. The catechol-modified coating also improved electrochemical resistance and did not impair the adhesion of subsequent acrylic paint. These results indicate that catechol is a promising organic modifier for zinc phosphate intermediate pretreatment layers. Full article

Aging of Styrene–butadiene–styrene (SBS)-modified asphalt accelerates the degradation of both the SBS polymer network and asphalt components, resulting in deterioration of the durability of asphalt concrete. This study investigates the use of zinc diethyldithiocarbamate (ZDC), a multifunctional antioxidant, in SBS-modified asphalt to improve its aging resistance. Physical property tests, dynamic rheological analysis, multiple stress creep recovery (MSCR) and Fourier transform infrared spectroscopy (FTIR) assays were conducted to evaluate the rheological and chemical properties of asphalt binders before and after thermo-oxidative and UV aging. The results indicate that the incorporation of ZDC improved the deformation resistance and elastic recovery of SBS-modified asphalt. After aging, the ZDC/SBS composite-modified asphalt exhibited lower performance change rate than conventional SBS-modified asphalt, indicating enhanced resistance to permanent deformation and aging-induced damage. FTIR analysis demonstrated that ZDC effectively inhibited the formation of oxygen-containing functional groups during aging, suggesting suppressed oxidative reactions within the asphalt binder. The 5% ZDC dosage reduces the carbonyl index of SBS-modified asphalt by 36.48% after thermo-oxidative aging, and by 21.89% after UV aging, showing a stronger chemical inhibition effect on thermo-oxidative reactions. From the perspective of rheological performance stability, ZDC lowers the variation amplitude of non-recoverable creep compliance by 35.32% before and after thermo-oxidative aging and 41.46% before and after UV aging, and delivers a more prominent mitigating effect on property fluctuations triggered by UV aging. This indicates that ZDC exerts differentiated anti-aging mechanisms on thermo-oxidative and UV aging, with considerable potential to improve the comprehensive aging resistance of polymer-modified asphalt binders. Full article

Epoxy resins are widely used in advanced engineering applications, including coatings, adhesives, and electronics. Therefore, improving their flame resistance is important for enhancing fire safety and extending their range of applications. A series of flame retardants based on melamine phosphate derivatives, such as melamine phosphate (MP), melamine dibutyl phosphate, and melamine bis(2-ethylhexyl) phosphate, as well as a zinc borate-modified system (ZnB-MP) has been incorporated into commercially available epoxy resin (Epidian® 601). The blends were characterized using Fourier transform infrared spectroscopy (FTIR) to confirm their chemical structure. Thermal behaviour was investigated using differential scanning calorimetry and thermogravimetry coupled with FTIR gas analysis (TG-FTIR). The flammability performance of the epoxy blends was evaluated using pyrolysis combustion flow calorimetry, which allowed parameters such as heat release rate, total heat release, and heat release capacity to be determined. The incorporation of melamine phosphate-based flame retardants was found to significantly reduce the flammability of epoxy blends, leading to substantial decreases in heat release rate, total heat release, and heat release capacity. The most pronounced effect was observed in systems containing higher concentrations of MP and in cooperative ZnB-MP formulations. Full article

Wastewater contamination with synthetic organic dyes is a significant environmental challenge. Zinc oxide (ZnO) has attracted considerable attention as a non-toxic, multifunctional material for electronics, optics, piezoelectric devices, and photocatalysis, where its performance is strongly governed by morphology. In this work, we investigate the effect of hexamethylenetetramine (HMTA) on the formation and photocatalytic behavior of ZnO nanostructures synthesized from different zinc precursors, namely zinc acetate and zinc nitrate, via a one-step sol–gel process at low temperature without any post-treatment. All samples crystallize in the hexagonal wurtzite phase without detectable impurities, and the incorporation of HMTA leads to smaller, more uniform rod- and flake-like nanostructures. Although ZnO derived from zinc acetate without HMTA exhibits the highest specific surface area, ZnO synthesized in the presence of HMTA shows more favorable crystallinity, morphology, and pore connectivity, which together enhance charge separation and reactive oxygen species generation. As a result, ZnO samples synthesized with HMTA exhibit improved photocatalytic degradation of rhodamine B under UV irradiation. Full article

Zinc oxide (ZnO) nanoparticles are semiconductor nanomaterials widely used in biomedical, environmental, and catalytic applications due to their unique physicochemical properties. However, their increasing environmental release has raised concerns regarding potential toxicity in aquatic ecosystems. In this study, pure ZnO, 1% Au-modified ZnO, and 5% Au-modified ZnO nanoparticles were synthesized via a reflux-assisted method to evaluate the effects of Au incorporation on morphology, crystallinity, optical behavior, surface chemistry, and ecotoxicological responses, using Artemia salina as a marine bioindicator. Structural characterization was performed using high-resolution transmission electron microscopy (HRTEM), electron diffraction, high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM), and energy-dispersive X ray spectroscopy (EDS) elemental mapping, while optical and surface analyses were conducted using UV–Vis and Fourier-transform infrared (FT-IR) spectroscopy. Although Au-rich domains were identified, the available data do not allow definitive determination of whether Au is incorporated into the ZnO lattice or present as surface-associated metallic Au. Increasing Au content promoted greater nanoparticle agglomeration and broader particle size distributions while preserving the hexagonal wurtzite ZnO crystalline structure. UV-Vis and FT-IR analyses demonstrated that Au modification altered the optical response and surface chemical environment of the nanoparticles. Toxicological evaluations revealed concentration- and time-dependent toxicity. Pure ZnO nanoparticles exhibited LC₅₀ values of 531.25 ppm after 24 h and 65.15 ppm after 48 h exposure. In contrast, 1% Au-modified ZnO nanoparticles showed reduced toxicity, whereas 5% Au-modified ZnO nanoparticles exhibited increased toxicity after prolonged exposure. These findings demonstrate that Au modification significantly influences the physicochemical properties and biological interactions of ZnO nanoparticles. Full article

Zinc processing generates large volumes of tailings enriched with potentially toxic elements such as zinc, lead, arsenic, and antimony, creating environmental challenges. Conventional disposal in tailings dams is associated with land occupation, contamination risks, and geotechnical concerns, reinforcing the need for more sustainable management strategies. This study presents a bibliometric and semi-systematic review of alkali-activated binders for the stabilization and solidification of zinc mine tailings, based on nine studies published between 2019 and 2026. The results indicate that this is a recent and expanding research field, with a marked concentration of studies in China. Current research mainly focuses on the links between microstructure, heavy metal immobilization, and mechanical performance. Alkali-activated systems, commonly based on blast furnace slag, fly ash, and coal gangue, can produce dense matrices with compressive strengths of up to 100.77 MPa and high immobilization efficiency. Their performance is largely governed by the type of reaction products formed, particularly calcium silicate hydrate, calcium aluminosilicate hydrate, and sodium aluminosilicate hydrate gels, which control microstructural development and stabilization mechanisms such as encapsulation, structural incorporation, and secondary phase formation. Overall, the reviewed studies suggest that alkali-activated binders have potential as alternative binders to Portland cement for the management and valorization of zinc mine tailings. Full article

In this study, a water-based epoxy curing agent was prepared using polyamines (mixed amines), and epoxy coatings were formulated by blending this with a polyurethane-toughened water-based epoxy curing agent in specific proportions. By testing the tensile properties of the water-based epoxy coatings, the curing agent ratio was adjusted and the curing process optimised. A layer of water-based epoxy coating was applied to both the rebar electrodes and the rebar surfaces. Through electrochemical testing, coating thickness measurement, and coating continuity testing, the effects of filler type, particle size, and content on coating performance were investigated. On this basis, steel bars coated with a water-based epoxy coating containing 0.3% graphene–polyaniline composite nanomaterials were used as the control group, whilst a water-based epoxy coating incorporating a silane solution served as the primer. Based on the results of the preliminary screening, a water-based epoxy coating containing 1% silane coupling agent and 10% zinc phosphate was selected as the intermediate coat, whilst a water-based epoxy coating containing fly ash microspheres and polystyrene microspheres was selected as the top coat. Through cold bending tests and tensile strain tests on the coated reinforcing bars, the study investigated the effects of zinc phosphate, fly ash microspheres, and polystyrene microspheres on the cold bending performance and deformation combination performance of the water-based epoxy-coated reinforcing bars. By optimising the curing process, the tensile strength of the coating reached 40.11 MPa, with an elongation at break of 19.94%; the corrosion resistance of the zinc phosphate composite coating (corrosion current density: 0.00589 μA/cm²) was comparable to that of the 0.3% graphene/polyaniline coating; and the fly ash microsphere top coat significantly improved the deformation compatibility between the reinforcing bars and the coating. The high-performance, cost-competitive water-based epoxy coating system developed in this study offers a new technical approach to the durability protection of reinforced concrete structures in marine environments. Full article

The present study investigates the effect of whey powder incorporation on the nutritional composition, structural characteristics, and functional properties of rice flour-based gluten-free systems. Composite flours and biscuits were formulated by substituting rice flour with 5%, 10%, and 15% whey powder. Proximate composition, mineral profile, and structural modifications were evaluated using standard analytical methods, complemented by Fourier Transform Infrared Spectroscopy (FTIR) and Small-Angle X-ray Scattering (SAXS). The results showed that whey addition significantly improved the protein content of both flours and biscuits, increasing from 8.45% in the control to 15.06% at the highest enrichment level. Whey powder showed elevated phosphorus (912 mg/kg), sodium (434.65 mg/kg), and calcium (526.49 mg/kg) contents compared to rice flour. Consequently, mineral levels increased progressively in the composite flours, with phosphorus rising from 528 mg/kg to 647 mg/kg, sodium from 105.66 mg/kg to 132.81 mg/kg, and calcium from 102.15 mg/kg to 137.33 mg/kg as the whey incorporation level increased. Iron content showed minor variations among the gluten-free biscuit formulations (76.01–95.16 mg/kg). Whey incorporation led to a progressive increase in copper content, from 8.91 mg/kg in the control biscuits to 15.50 mg/kg, while zinc levels decreased from 27.47 mg/kg to 18.47 mg/kg with increasing whey addition. FTIR analysis revealed clear structural changes associated with whey addition, including the progressive intensification of amide I and II bands and a reduction in starch-specific signals, confirming the incorporation of whey proteins into the starch matrix and the formation of protein–starch interactions. These findings were supported by SAXS analysis, which indicated modifications in the internal structural organization of the systems. Sensory evaluation indicated good overall acceptability of the fortified biscuits at moderate whey incorporation levels, while higher whey addition slightly reduced taste scores due to the characteristic salty flavor associated with acid whey. Overall, the study demonstrates that whey powder is an effective functional ingredient for enhancing the nutritional and structural properties of gluten-free products. However, achieving an optimal balance between improved nutritional quality, technological performance, and mineral composition remains essential for the development of high-quality gluten-free formulations. Full article

Zinc oxide (ZnO) nanoparticles have attracted increasing attention in wood science due to their multifunctional properties, including antimicrobial activity, UV absorption, and photocatalytic behavior. Water-based deposition protocols offer clear advantages yet typically struggle with nanoparticle aggregation and limited adhesion to lignocellulosic substrates. This work introduces a rapid and scalable waterborne protocol combining catalyst-free aqueous seeding with microwave-assisted (MWA) growth under mild conditions. Pinus pinaster veneer samples were treated via dip-coating and spraying, with single and double seeding cycles, followed by MWA growth. Protocol efficiency was assessed through ZnO retention, SEM, and EDS analysis, while the impact of the substrate was assessed via mechanical testing, ATR-FTIR spectroscopy, and colorimetry. Dip-coating achieves significantly higher precursor uptake than spraying, while repeated seeding cycles further increase ZnO loading. Results suggest that incorporation may proceed through zinc–carboxylate bonds within the wood matrix, followed by localized ZnO nanostructures development. The effective integration did not weaken the mechanical properties, while color changes were significant for dip-coated samples and noticeable for sprayed ones. Overall, this methodology provides a fast, water-based, and minimally invasive route for ZnO incorporation into wood and a scalable pathway with retained mechanical and chemical properties and limited visual impact. Full article

Hierarchical ZnO–SiO₂/carbon composites (C-Zn1, C-Zn2, C-Zn3) were synthesised via the carbonisation of resorcinol–formaldehyde gels in the presence of ZnO-modified fumed silica, and characterised by N₂ adsorption–desorption, FTIR, XRD, SEM, and zeta potential analysis. The composites exhibited hierarchical micro–mesoporous structures with BET surface areas of 467–499 m² g⁻¹; the non-microporous volume fraction increased from 0.09 (reference carbon RFC, 545 m² g⁻¹) to 0.54–0.63 upon ZnO–SiO₂ incorporation. Adsorption of methylene blue (MB), crystal violet (CV), and rhodamine 6G (R6G) followed the Marczewski–Jaroniec isotherm model. Maximum adsorption capacities for the best-performing composite (C-Zn1) reached 1.22 mmol g⁻¹ for MB, 1.04 mmol g⁻¹ for CV, and 0.63 mmol g⁻¹ for R6G, compared to 1.32, 1.17, and 0.67 mmol g⁻¹ for unmodified RFC. Kinetic analysis revealed up to 3.5-fold faster adsorption rates for C-Zn1 relative to RFC (for CV and R6G), attributed to enhanced diffusion through mesoporous channels while preserving the micropore-driven capacity. Agar well-diffusion assays against four bacterial strains showed no inhibition zones for any composite, indicating that no biologically active concentration of zinc species was released under the assay conditions. The proposed approach yields composites with enhanced adsorption kinetics, preserved capacity, and confirmed non-leaching character, positioning them as effective candidates for water purification. Full article

New lacunary Keggin-type polyoxometalate salts with the formula Cs₅PMMo₁₁(H₂O)O₃₉ (M = Cu, Zn) were synthesized via the inorganic solution condensation method. X-ray diffraction and FT-IR spectroscopy confirmed the preservation of the Keggin structure. The surface morphology and elemental composition were characterized using scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy. Thermal analysis, performed by differential scanning calorimetry coupled with thermogravimetry, demonstrated a significant enhancement in thermal stability upon the incorporation of the transition metals into the heteropolyacid framework. Specifically, the substitution of protons by cesium and of molybdenum by copper or zinc positively influenced the crystallographic configuration of the salts, raising their thermal resistance (up to 526 °C). Furthermore, optical and dielectric measurements revealed promising electronic properties in the synthesized lacunary salts. Notably, the compound Cs₅PZnMo₁₁(H₂O)O₃₉ exhibited a substantially increased dielectric constant at low frequency, underscoring the synergistic effect of zinc addition on its dielectric performance. Full article

Background: Pelvic inflammatory disease (PID) is a prevalent chronic inflammatory condition among women. The Composite Dietary Antioxidant Index (CDAI), a measure of dietary antioxidant capacity, has been associated with various inflammatory diseases, but evidence concerning its association with PID remains limited. Methods: The final analytic sample included 4539 women. CDAI was calculated from six dietary antioxidant components: vitamin A, vitamin C, vitamin E, carotenoids, zinc, and selenium. Survey-weighted multivariable logistic regression models were used to evaluate the association between CDAI and self-reported history of treated PID, incorporating the sampling weights, strata, and primary sampling units of NHANES. Restricted cubic spline (RCS) analysis was used to assess both linear and non-linear associations. Subgroup analyses and a machine learning model based on random forest, combined with SHapley Additive exPlanations (SHAP) value ranking, were conducted to evaluate the relative importance of individual components of CDAI. Results: In the fully adjusted spline model including smoking status, CDAI was inversely associated with the odds of self-reported history of treated PID, with no statistical evidence of nonlinearity. Compared with the lowest quartile (Q1), the odds ratios (ORs) for self-reported history of treated PID across higher quartiles of CDAI were as follows: Q2 (OR = 0.682, 95% CI: 0.485–0.959, p = 0.036), Q3 (OR = 0.524, 95% CI: 0.334–0.819, p = 0.009), and Q4 (OR = 0.666, 95% CI: 0.380–1.167, p = 0.167). Among the components of CDAI, vitamin E intake showed an independent inverse association with the odds of self-reported history of treated PID. The SHAP value interpretation indicated that vitamin A, vitamin C, and carotenoids were the three components in CDAI with the highest predictive contribution. Furthermore, subgroup analysis demonstrated a significant interaction effect of age on the association between CDAI and PID. Conclusions: This cross-sectional study suggests an inverse association between CDAI and self-reported history of treated PID, particularly in spline analyses; however, the quartile-based fully adjusted results were non-monotonic and attenuated after adjustment for smoking status. These findings provide hypothesis-generating evidence for future longitudinal and mechanistic studies on antioxidant-related dietary patterns and PID-related reproductive health. Full article

Developing zinc oxide-based nano-bactericides as alternatives to conventional chemical bactericides for controlling rice bacterial diseases has become a major research focus. In this study, ZnO nanoparticles were initially surface-modified and subsequently covalently conjugated with chitooligosaccharide (COS) via imine bonds to get a pH-responsive zinc oxide–chitooligosaccharide (ZnO–COS) delivery system. A series of physicochemical characterizations, including FTIR, UV-vis, XRD, and TGA, confirmed the successful synthesis of ZnO–COS NPs. Building on this foundation, the pH-responsive release behavior, foliar deposition performance, antibacterial activity, and biosafety of the nanoparticles were systematically investigated. The prepared ZnO–COS NPs exhibited pronounced acid-triggered Zn²⁺ release, together with enhanced wettability, spreadability, and retention on rice leaf surfaces, owing to COS incorporation. In both in vitro and in vivo assays against Xanthomonas oryzae pv. oryzae (Xoo), ZnO–COS NPs demonstrated effective antibacterial activity associated with bacterial cell damage and the activation of antioxidant defense responses in plants. Consequently, ZnO–COS NPs achieved a preventive efficacy of 56.0% against rice bacterial blight, surpassing those of ZnO (33.3%) and COS (14.3%). Furthermore, safety assessment confirmed the good biocompatibility of ZnO–COS NPs towards rice seed germination and seedling growth. In summary, the synthesised ZnO–COS NPs integrated pH-responsive release, improved foliar deposition, and enhanced antioxidant capacity of rice, offering a promising strategy for mitigating bacterial diseases in rice. Full article

Moisture-induced damage is one of the primary causes of premature distress in asphalt pavements, leading to reduced service life and increased maintenance costs. Although nanomaterials have shown potential in enhancing asphalt performance, the underlying composite interaction mechanisms among nanomaterials, asphalt binder, and aggregate phases under moisture exposure are still not fully understood. In addition, comparative evaluations under consistent experimental conditions remain limited. This study investigates the influence of five nanomaterials: nano-silica (NS), nano-alumina (NA), nano-titanium dioxide (NT), nano-zinc oxide (NZ), and carbon nanotubes (CNT) on the physical and mechanical properties of asphalt binders and mixtures, with particular emphasis on moisture damage resistance. The nanomaterials were incorporated at dosages of 1.5%, 3.0%, 4.5%, and 6.0% by binder weight. Binder performance was evaluated using conventional and performance grading (PG) tests, while mixture performance was assessed through Marshall properties and moisture susceptibility indicators, including the tensile strength ratio (TSR) and the index of retained strength (IRS). Fluorescence microscopy (FM), scanning electron microscopy (SEM), and Fourier transform infrared spectroscopy (FTIR) were employed to investigate nanomaterial dispersion characteristics, microstructural morphology, and physicochemical interactions within the asphalt composite system. The results indicate that nanomaterial modification reduced penetration and increased softening point and Marshall stability, reflecting enhanced stiffness and thermal resistance, although ductility decreased at higher dosages. Significant improvements in moisture resistance were observed, particularly under conditioned states. The TSR increased from 81.2% for the control mixture to 92.4% for NS and 91.7% for NA, while the IRS improved from 72.7% to 88.5% for NS. Statistical analysis indicated that both nanomaterial type and dosage significantly affected TSR and IRS performance, with dosage exhibiting comparatively greater influence on moisture resistance improvement. FM and SEM analyses revealed comparatively better dispersion and lower agglomeration tendency for NS and NA, which corresponded to their superior moisture resistance performance. FTIR analysis indicated that the modification process was predominantly physical, with no major formation of new chemical functional groups. Among the investigated nano materials, NS at 6% dosage exhibited the most pronounced improvement, followed by NA at similar dosage levels. Overall, the findings suggest that nanomaterial modification can considerably improve the moisture resistance and mechanical performance of asphalt mixtures under laboratory conditions. However, higher nanomaterial dosages may adversely affect binder workability due to increased viscosity, particularly in CNT-modified binders. Full article

The present study investigates the development of antimicrobial textile coatings by encapsulating zinc oxide (ZnO) particles within electrospun polylactic acid (PLA) fibers. Electrospinning was used to produce uniform fibrous coatings with effective incorporation of ZnO. ZnO reduced solution viscosity and increased conductivity, resulting in thinner and more homogeneous fibers. Thermogravimetric analysis confirmed high encapsulation efficiency (up to 95%) and a significant loading capacity (47.71 ± 1 mg ZnO/g fiber), while scanning electron microscopy revealed uniform fiber structures with high-contrast regions that are qualitatively consistent with the presence of ZnO-rich domains. The release behavior of ZnO was assessed under simulated washing and perspiration conditions. Results showed limited release under sweat conditions (R < 0.07), indicating strong ZnO retention under perspiration-related exposure, whereas washing increased release from the free-standing coatings (up to 0.32), indicating partial ZnO retention under more aggressive aqueous surfactant conditions. Kinetic modeling using first-order, Higuchi, and Korsmeyer–Peppas models indicated that ZnO release was predominantly diffusion-controlled, with the Higuchi and Korsmeyer–Peppas models showing the best fit to the experimental data. Following thermal bonding onto textile substrates, the coatings achieved successful macroscopic integration; however, washing simulation of the bonded coatings resulted in more pronounced ZnO loss, while sweat exposure caused only limited release. The antimicrobial activity of the coatings was assessed against Staphylococcus aureus and Klebsiella pneumoniae (ISO 20743:2021). The PLA/ZnO (5% w/v) system showed strong broad-spectrum antibacterial activity, with values of 4.71 and 3.37, respectively. Overall, electrospun PLA/ZnO coatings show potential as antimicrobial textile coatings, offering controlled release behavior, strong antibacterial activity, and condition-dependent ZnO retention. Full article