Search Results (351)

To address the low-value recycling dilemma of waste polyvinyl butyral (PVB) and cater to the demand for sustainable multifunctional active food packaging, this study developed a facile and cost-effective solution blow spinning approach. Continuous, smooth, and bead-free nanofiber membranes were prepared by optimizing the solution blow spinning process parameters. Zinc oxide nanoparticles (ZnO NPs) were incorporated into the PVB nanofiber membrane with vacuum impregnation. The results demonstrated that ZnO NPs significantly enhanced the tensile strength, thermal stability, and the UV absorption of PVB fiber membranes. ZnO/PVB fiber membranes exhibited antibacterial activity against Staphylococcus aureus, Escherichia coli, and Pseudomonas aeruginosa. Practical preservation tests showed that ZnO/PVB fiber membranes effectively inhibited cherry tomatoes’ microbial spoilage and water loss, extending the shelf life of tomatoes to 13 days. These findings validate the potential of ZnO/PVB composite nanofiber membranes as active food packaging and provide a feasible technical pathway for the low-cost, efficient utilization of recycled PVB. Full article

Infected wounds form a complex microenvironment that creates difficulties for drug delivery. In this study, a composite fiber membrane based on polyethylene oxide (PEO) was prepared. The intention was to achieve on-demand drug release and integrate multiple functions by adjusting the material composition. The membrane uses PEO as the main framework and contains chitosan (CS) and ascorbic acid (Asc). CS leads to an increase in fiber diameter, while Asc makes the fibers thinner. The two components act together to influence the microstructure. In vitro drug release experiments showed that changing the CS content in the PEO matrix can affect the initial release rate and the duration of sustained release. The membrane also shows sensitivity to pH. Under slightly acidic conditions, drug release becomes faster, which is similar to the state of infected wounds. In addition, the membrane maintains antioxidant activity and can inhibit Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus). These results suggest that PEO-based composite fibers may be useful in drug delivery and tissue repair. Full article

Membrane separation is a promising, low-energy technology for purifying turquoise hydrogen from methane pyrolysis streams. However, there is a critical knowledge gap between the performance of membrane materials and the practical application of large-scale modules under realistic process conditions. This study evaluates commercial polyimide and polysulfone hollow fiber membranes for H₂/CH₄ separation. The effect of feed composition and pressure on the membrane separation performance were studied, revealing that the separation efficiency is overwhelmingly dominated by concentration polarization, which reduced the H₂/CH₄ separation factor by up to 80% compared to ideal values. Despite this, by optimizing process conditions, we successfully achieved a permeate purity of 99.3% H₂ at 85% recovery. Furthermore, Aspen Plus simulations of an integrated pyrolysis reactor with the membrane unit and a recycle stream demonstrate significant process benefits. The integration increased the H₂ production rate from 10.3 to 17.6 kmol/h and substantially reduced the specific energy consumption from 40.3 to 24.9 kJ/g H₂ compared to non-integrated systems. This work shows that a membrane process can improve not only the product H₂ purity but also the overall energy efficiency of a turquoise hydrogen production process. Full article

Contaminated water detoxification remains difficult due to the presence of persistent halo-organic contaminants, such as perfluorooctanoic acid (PFOA) and chlorophenols, which are chemically stable and resist conventional purification methods. Functionalized membrane-based separation and decontamination have garnered immense attention in recent years. Commercially available microfiltration membrane (PVDF) and polymeric non-woven fiber filters (glass and composite) are functionalized with poly(methacrylic acid) (PMAA) that shows outstanding pH-responsive performance and tunable water permeability under ambient conditions perfect for environmental applications. Polymer loading based on weight gain measurements on PMAA–microglass composite fibers (137%) and microglass fibers (116%) confirmed their extent of functionalization, which was significantly greater than that of PVDF (25%) due to its widely effective pore diameter. Presence of chemically active hydrogel within PVDF matrix was validated by FTIR (hydroxyl/carbonyl) stretch peak, substantial decrease in contact angle (68.8° ± 0.5° to 30.8° ± 1.9°), and decrease in pure water flux from 509 to 148 LMH/bar. Nanoparticles are generated both in solution and within PVDF using simple redox reactions. This strategy is extended to PVDF-PMAA membranes, which are loaded with Fe/Pd nanoparticles for catalytic conversion of 4-chlorophenol and PFOA, forming Fe/Pd-PVDF-PMAA systems. A total of 0.25 mg/L Fe/Pd nanoparticles synthesized in solution displayed alloy-type structures and demonstrated a strong catalytic performance, achieving complete hydrogenation of 4-chlorophenol to phenol and 67% hydrogenation of PFOA to its reduced form at 22–23 °C with ultrapure hydrogen gas supply at pH 5.7. These results underscore the potential of hybrid polymer–nanoparticle systems as a novel remediation strategy, integrating tunable separation with catalytic degradation to overcome the limitations of conventional water treatment methods. Full article

Silicone rubber from decommissioned composite insulators has become one of the major environmental challenges in the power industry due to its non-degradable nature. Therefore, the recycling and reuse of silicone rubber are of great environmental and economic significance. In this work, a method for preparing silica microspheres based on stepwise pyrolysis combined with post-treatment particle size fractionation is proposed. First, highly spherical silica microspheres were obtained by stepwise pyrolysis. Subsequently, glass fiber membrane filtration and aga-rose gel electrophoresis were employed as post-treatment methods to achieve particle size fractionation and enhanced uniformity. The results indicate that the post-treated silica microspheres exhibit high uniformity, high sphericity, and good dispersibility. This method significantly improves the structural uniformity and microscopic characteristics of the microspheres, making them promising high-value fillers for epoxy resin insulation modification. Comparative analysis with commercial nanosilica used as epoxy fillers shows that the recycled and fractionated silica microspheres achieve comparable improvements in breakdown strength and dielectric performance, confirming their potential for recycling and reuse in high-voltage insulation and electronic packaging applications. Full article

Composite fiber membranes fabricated via rotational-force spinning have become widely applied in biomedicine, energy, and environmental fields owing to their excellent properties. Improving their functional performance and fabrication quality has therefore become a key research focus. Rotational-force spinning is a simple and efficient technique in which high-speed motor rotation ejects polymer solutions from a nozzle to form fibers. However, the influence of polymer flow behavior within the nozzle on fiber formation remains insufficiently understood. In this study, the flow characteristics within the micro-triangle and the liquid–liquid slip phenomenon were investigated using a core–shell spinning device. Numerical simulations were conducted to analyze velocity differences between two polymer solutions under varying motor speeds and polyoxyethylene (PEO) concentrations. The results demonstrate that increasing PEO concentration and motor speed decreases slip velocity, thereby stabilizing the flow. Complementary experiments were performed using PEO and hydroxyethyl cellulose (HEC) solutions under controlled conditions. Mechanical testing, scanning electron microscopy (SEM), and thermogravimetric analysis (TG) were employed to assess the mechanical performance, thermal stability, morphology, and fiber diameter distribution of the composite membranes. Overall, the findings highlight the critical role of liquid–liquid slip in fiber formation and provide valuable insights for the controlled fabrication of high-quality composite fibers, offering a foundation for future research. Full article

The contamination of water bodies by dye effluents from micro-scale in-house denim laundries remains a significant environmental concern in central México, particularly in the Atoyac River, where conventional treatment methods are not economically viable. This study develops and evaluates Nylon-6/pumice powder (PPw) nonwoven composites as hybrid adsorptive membranes for the removal of methylene blue (MB) from aqueous solutions. Pumice, a locally abundant siliceous mineral, was incorporated into Nylon-6 through melt-compounding and melt-blown fiber processing at 1 wt% and 5 wt% loadings. SEM, XRD, and TGA confirmed even filler distribution, structural stability, and the development of a porous, layered structure. Batch adsorption tests revealed a rapid initial dye adsorption, followed by a slower diffusion-controlled phase, with equilibrium achieved within 15 min for PPw and within 30 min for the composites. The data fitted both Langmuir and Freundlich isotherms, indicating that MB adsorption involved a combined mechanism: monolayer adsorption on uniform silanol/aluminol sites and multilayer physical adsorption at the polymer–mineral interfaces. Higher PPw content increased adsorption capacity (q_max = 1.1460 mg/g) and surface uniformity, resulting in favorable Freundlich exponents (n = 2). Finally, it was found that adsorption proceeds via chemisorption, where the pumice powder provides reactive sites. These findings demonstrate that Nylon-6/PPw nonwoven composites combine the strength of a synthetic material with the surface reactivity of a natural mineral, providing an effective and scalable Nature-Based Solution for decentralized dye removal, aligned with Sustainable Development Goals 6 and 12. Full article

Omniphobic membranes have gained extensive attention for mitigating membrane wetting in robust membrane separation owing to the super-repulsion toward water and oil. In this study, a Teflon/PAI composite membrane with omniphobic characteristics was prepared by a vacuum-assisted dip-coating strategy on the PAI hollow fiber membrane. A series of characterizations on morphological structure, surface chemical composition, wettability, permeability, mechanical properties, and stability were systematically investigated for pristine PAI and Teflon/PAI composite membranes. Subsequently, the experiment was conducted to explore the oil–gas separation performance of membranes, with standard transformer oil containing dissolved gas as the feed. The results showed that the Teflon AF2400 functional layer was modified, and C-F covalent bonds were introduced on the composite membrane surface. The Teflon/PAI composite membrane exhibited excellent contact angles of 156.3 ± 1.8° and 123.0 ± 2.5° toward DI water and mineral insulating oil, respectively, indicating omniphobicity. After modification, the membrane tensile stress at break increased by 23.0% and the mechanical performance of the composite membrane was significantly improved. In addition, the Teflon/PAI composite membrane presented satisfactory thermal and ultrasonic stability. Compared to the previous membranes, the Teflon/PAI composite membrane presented a thinner Teflon AF2400 separation layer. Furthermore, the omniphobic membrane demonstrated anti-wetting performance by reaching the dynamic equilibrium within 2 h for the dissolved gases separated from the insulating oil. This suggests an omniphobic membrane as a promising alternative for oil–gas separation in monitoring the operating condition of oil-filled electrical equipment online. Full article

Wax apple (Syzygium samarangense) is highly perishable postharvest. Even under refrigerated storage conditions, its shelf life typically lasts only about one week. This study developed a novel antibacterial food packaging membrane to extend its shelf life and explored the underlying preservation mechanisms. A composite fiber membrane was fabricated via solution blow spinning (SBS) using polyethylene oxide (PEO) and oxidized sesbania gum (OSG) incorporated with ε-polylysine (ε-PL). The composite membrane demonstrated exceptional antibacterial activity against both E. coli and S. aureus by disrupting cell wall and membrane integrity, as evidenced by increased protein leakage, alkaline phosphatase activity, and electrical conductivity. Morphological observations through scanning electron microscopy confirmed extensive cellular damage and bactericidal effects. During nine days of ambient storage, the PEO/OSG/PL membrane significantly maintained the postharvest quality of wax apples. This was evidenced by a lower decay index (2.22 ± 0.19) and weight loss rate (5.32 ± 0.16%) compared to the control group, alongside better preservation of firmness (4.11 ± 0.08 N) and color stability. The treatment suppressed respiratory rate and delayed the degradation of soluble solids and titratable acidity. Furthermore, it enhanced antioxidant capacity through higher peroxidase activity and reduced malondialdehyde accumulation, indicating attenuated oxidative stress. Non-targeted metabolomics analysis revealed that the membrane treatment modulated critical metabolic pathways, particularly phenylalanine metabolism and linoleic acid metabolism. These metabolic adjustments contributed to enhanced defense responses and delayed senescence. The results show that the PEO/OSG/ε-PL fiber membrane acts as an effective active packaging material by inhibiting microbial growth and regulating metabolism. This provides a potential method to extend the shelf life of perishable fruits. Full article

This study aimed to achieve efficient capture of phthalate esters (PAEs) and bisphenol A (BPA) from pear samples collected in the northern Anhui Province. A novel polystyrene–pyridine (PS/PD) composite nanofiber membrane was fabricated via electrospinning and employed as a filter in the sampling process. Following sample collection, PAEs and BPA were extracted with acetonitrile (ACN). Then, 100 μL of the extract was further concentrated using packed-fiber solid-phase extraction (PFSPE), with PS/PD nanofibers as the sorbent, and subsequently analyzed by gas chromatography–mass spectrometry (GC-MS). Under the optimized procedure, satisfactory recoveries of 87.0–109.9% were obtained for pear samples, with relative standard deviations (RSDs) ranging from 0.6% to 11.9%. Limits of detection (LOD) and limits of quantification (LOQ) were 0.03–0.10 μg/L and 0.034–0.34 μg/L, respectively. Analysis of pear samples from local markets and the native region was performed, and the detected concentrations of five PAEs and BPA ranged from 0.037 to 0.079 μg/L. Matrix effects were also evaluated. These findings demonstrate that the developed packed-nanofiber solid-phase extraction (PFSPE)-GC-MS method is reliable and effective for the determination of PAEs and BPA in pear samples. Full article

The demand for effective antibacterial materials is growing rapidly in today’s world. Both metallic and metal oxide nanoparticles have been widely used as antibacterial agents against various bacterial species due to their unique mechanisms of destroying bacterial membrane cells. The current study explores the antibacterial activity of centrifugally spun fibers prepared from copper acetate polyvinylpyrrolidone (PVP) ethanol precursor solutions against both Gram-negative and Gram-positive bacteria. During the synthesis of the composite fibers, the physical and chemical conditions were optimized. The structure and morphology of the PVP/Cu-Ac fibers were analyzed using scanning electron microscopy (SEM), X-ray diffraction (XRD), energy-dispersive X-ray spectroscopy (EDS), and thermogravimetric analysis (TGA). The antibacterial activity of PVP/copper acetate fibers was tested against Gram-positive Staphylococcus aureus and Gram-negative Escherichia coli. The PVP/Copper acetate fibers demonstrated bactericidal activity against both bacterial strains, making the PVP/copper acetate composite fibers an effective material for biomedical applications. Full article

Membrane separation is a promising technology for emulsified wastewater treatment. However, conventional membrane often suffer from limitations such as low mechanical strength, the inherent “trade-off” effect between flux and separation efficiency, and poor antifouling properties. To address these challenges, we report a novel composite membrane (CFM-UiO-66-(COOH)₂) fabricated by in situ growth of functionalized UiO-66-(COOH)₂ on a mechanically robust collagen fiber membrane (CFM) substrate. The resulting composite leverages the inherent properties of the CFM, along with the controlled generation of charge-neutralization demulsification sites and size-sieving filtration layers from the UiO-66-(COOH)₂. This CFM-UiO-66-(COOH)₂ exhibited superwetting behavior and achieved efficient separation of cationic surfactant-stabilized oil-in-water micro- and nano-emulsions. Specifically, the CFM-UiO-66-(COOH)₂ achieved separation efficiencies exceeding 99.85% for various cationic O/W emulsions, with permeation fluxes ranging from 178.9 to 225.9 L·m⁻²·h⁻¹. The membrane also demonstrated robust antifouling properties, excellent acid/alkali resistance, high abrasion durability, and good biocompatibility. Importantly, stable performance was maintained over six consecutive separation cycles. These characteristics, combined with the electrostatic interactions between carboxyl groups on the UiO-66-(COOH)₂ and cationic contaminants, suggest that CFM-UiO-66-(COOH)₂ holds significant potential for practical and sustainable wastewater treatment applications. Full article

L-arginine, a basic amino acid, exhibits high biocompatibility, reactivity, and absorbability. It was selected as the co-polymer modification monomer for L-lactic acid with the objective of enhancing the hydrophilicity of poly(lactic acid) (PLA), neutralizing the acidity of PLA degradation products, and regulating the degradation cycle. The copolymer poly(lactic acid-co-arginine) (PLAA) was synthesized by direct melting polycondensation of L-arginine and L-lactic acid, and the structures and properties of PLAA were characterized. The results indicated the presence of –NH₂, –NH–, and NH= in the molecular chain of the copolymer PLAA. Furthermore, the PLAA was identified as an amorphous copolymer. The “PLAA/CHCl₃/C₆H₁₄” ternary phase diagram was constituted by nonsolvent-induced phase separation (NIPS) by selecting chloroform (CHCl₃) as a good solvent and n-hexane (C₆H₁₄) as a nonsolvent. The phase diagram displays three distinguishable regions: the homogeneous zone, the metastable zone, and the phase separation zone. These regions are identified by the binodal and spinodal curves. The ternary phase diagram establishes a theoretical foundation for the preparation and processing of PLAA nanoparticles, composite materials, and porous fibers or membranes. Full article

Plastic waste and industrial residues like steel slag pose significant environmental challenges, with limited recycling solutions. This study investigates a sustainable approach by repurposing waste polystyrene and steel slag into composite membranes via electrospinning for membrane distillation applications. Steel slag incorporation enhanced membrane porosity, hydrophobicity, and thermal stability, with process optimization performed through response surface methodology by varying slag content (0–10 wt%), voltage (15–30 kV), and feed rate (0.18–10 mL·h⁻¹). Optimized membranes achieved a reduced fiber diameter (1.172 µm), high porosity (82.3%), and superior hydrophobicity (contact angle 102.2°). Mechanical performance improved with a 12% increase in tensile strength and a threefold rise in liquid entry pressure over pure polystyrene membranes, indicating greater durability and wetting resistance. In direct contact membrane distillation, water flux improved by 15% while maintaining salt rejection above 98%. Under photothermal membrane distillation, evaporation rates rose by 69% and solar-to-thermal conversion efficiency by 60% compared to standard PVDF membranes. These results demonstrate the feasibility of transforming waste materials into high-performance, durable membranes, offering a scalable and eco-friendly solution for sustainable desalination. Full article

Myelin is a membranous structure critically important for human health. Historically, it was believed that myelin remained largely unchanged in the adult brain. However, recent research has shown that myelin is remarkably dynamic, capable of adjusting axonal conduction velocity and playing a role in learning, memory, and recovery from injury, in response to both physiological and pathological signals. Axons are more efficiently insulated in myelinated fibers, where segments of the axonal membrane are wrapped by the myelin sheath. Although extensive data are available on the electrical properties of myelin, its structural and mechanical characteristics—as well as the role of its lipid composition—are also relevant, although much less explored. The objective of our review is derived from this point since alterations in lipid components can lead to axonal dysfunction, giving rise to neurological disorders such as multiple sclerosis and other demyelinating conditions. In this review, concerning the lipid composition of myelin, we focus on two distinct classes of lipids: sphingolipids and long-chain fatty acids, emphasizing the differential contributions of saturated versus polyunsaturated species. We analyze studies that correlate the mechanical vulnerability of myelin with its lipid composition, particularly sphingomyelin, thereby underscoring its role in protecting neurons against physical stress and providing a robust microstructural network that reinforces the white matter as a whole. From a biochemical perspective, we examine the susceptibility of myelin to oxidative stress, metabolic disorders, and extreme nutritional deficiencies in relation to the role of long-chain fatty acids. Both perspectives highlight that the aforementioned lipids participate in a complex biomechanical balance that is essential for maintaining the stability of myelin and, consequently, the integrity of the central and peripheral nervous systems. Full article