Search Results (49)

Deposit return systems (DRS) can increase the capture of beverage packaging, but material circularity is not determined by return rate alone. A returned container contributes to high-value circularity only if it passes recognition, sorting, pre-processing, and material-specific quality gates. This article evaluates the material-quality performance of three returned beverage-packaging materials—polyethylene terephthalate (PET), aluminium and reusable glass—using a quality-gated high-value recovery framework. The model defines a high-quality recovery index, HQR = R × Q × Y, where R is the return rate, Q is the quality factor of the returned stream, and Y is the reprocessing or reuse yield. The HQR indicator describes the quality of the entire DRS process. The core purpose of the HQR model is to distinguish nominal packaging return from high-quality material recovery and to show whether returned PET, aluminium and reusable glass streams remain suitable for high-value circular pathways. A survey-supported early-stage return scenario (R = 0.50) is compared with the 77% and 90% separate-collection targets used in European policy. To strengthen the PET branch of the model, a pilot PET stream-quality and processing-yield dataset was incorporated, including PET purity, colour composition, non-PET impurities, residual moisture, organic residues, intrinsic viscosity, washed PET flake or pellet yield, and sorting/washing rejection. The pilot data indicate that Lithuania had higher PET quality (98.2% PET purity, 80% clear PET, 1.8% non-PET impurities, IV = 0.74 dL/g, and 84.5% washed PET yield) than the Polish regional average (94.3% PET purity, 72.7% clear PET, 5.7% non-PET impurities, IV = 0.721 dL/g, and 80.3% washed PET yield). At R = 0.50, the pilot-derived PET HQR is approximately 37.8% for Lithuania and 31.6% for the Polish regional average. The results indicate that the same nominal return rate can lead to substantially different high-quality recovery outcomes because PET is constrained by stream purity, colour, contamination, and processing yield; aluminium by alloy and remelting control; and reusable glass by inspection, breakage, and refill compatibility. The proposed framework can support structured DRS operator reporting by identifying the material-quality and yield variables that should be measured alongside mass collection; however, operator-level validation is required before the model can be used as a predictive performance tool. Full article

Hybrid composites combining natural and synthetic fibers offer a pathway to sustainable structural materials, yet their performance is often limited by weak interfacial bonding and mechanical mismatches between constituents. Here, we address these challenges in bamboo/glass fiber hybrid epoxy composites through a sequential alkali and silane surface modification strategy. Alkali treatment removes amorphous lignin and hemicellulose, creating a roughened, cellulose-rich surface; subsequent grafting with (3-aminopropyl) triethoxysilane introduces an amino-functionalized interphase that covalently bonds with the epoxy matrix. This combined treatment increases the tensile strength of bamboo fibers by 51.2% and the interfacial shear strength by 136.6%, reaching values comparable to those of commercial glass fibers. The resulting hybrid composite exhibits a tensile strength of 485 MPa and a flexural modulus of 30.2 GPa, corresponding to improvements of 39.4% and 98.3%, respectively, over the unmodified hybrid system. Dynamic mechanical analysis further confirms an enhanced storage modulus across a wide temperature range. This work demonstrates that rational interfacial design via sequential functionalization offers a viable route to high-performance, lightweight, and structurally stable bamboo/glass fiber hybrid composites for sustainable engineering applications, such as reusable concrete formwork. Full article

Background: Circular economy (CE) practices, such as glass bottle refilling, are critical to the beverage industry’s sustainability. However, coordinating manufacturer marketing efforts with collector reverse logistics investment remains a strategic challenge. Methods: This study develops a Stackelberg game-theoretic model featuring a manufacturer and a collector. The model incorporates communication effort as a demand driver and analyzes the role of bottle quality (damage rates) and the reusable bottle unit cost on the optimal decisions of the players and the collection rate. Results: Equilibrium analysis shows that the quality of the reusable bottle and the rate of bottle damage are crucial in reducing the operational costs of the refilling program. Additionally, these factors significantly influence the decisions made by manufacturers and collectors regarding their investments in communication and collection systems. Conclusions: The study demonstrates that successful refilling requires strategic coordination between manufacturers and collectors, particularly in terms of communication and investment in reverse logistics. Managerial insights indicate that investing in the quality of bottles is the key factor for achieving joint profitability. Full article

Droplet manipulation constitutes a fundamental operation in numerous bio-microfluidic applications, including but not limited to medical diagnostics and targeted drug delivery. Among the various technologies developed for this purpose, magnetic digital microfluidics (MDMF) has emerged as a compelling approach due to its inherent advantages of contamination-free actuation, low cost, and configurational flexibility. Nevertheless, conventional MDMF remains constrained by its reliance on bulky instrumentation and substantial power consumption for generating controllable magnetic fields, which limit its in-field applications. To address these limitations, this work presents a programmable and portable electromagnetic microfluidic droplet manipulation platform that synergistically integrates static and dynamic magnetic fields to enable non-contact, high-precision droplet control under ultra-low power conditions. The proposed system comprises an electromagnetic actuation module, a permanent magnet, and a glass substrate coated with Teflon film. The entire system is secured by a PMMA support structure, within which a glass substrate is mounted and spatially separated from the permanent magnet. The PMMA support is fabricated using a milling process, offering a simple manufacturing procedure and high structural reusability and reproducibility. The control logic is implemented on a field-programmable gate array (FPGA) development board, facilitating fully autonomous operation powered by a standard battery. The platform operates at a low voltage of 3.5 V and a driving current of 180 mA, corresponding to a total power consumption of merely 0.63 W, while achieving robust manipulation of droplets in the volume range of 0.5 to 5 μL. A maximum average droplet velocity of up to 0.6 cm/s was attained under optimal conditions. The proposed platform offers a scalable and energy-efficient solution for portable droplet-based assays and holds significant promise for integration into point-of-care diagnostic tools and field-ready biochemical analysis systems. The platform demonstrates excellent operational stability and reproducibility, as validated by repeated actuation experiments with a positioning deviation of approximately 0.1 mm under optimized conditions. The fabrication process also exhibits high reliability with consistent performance across multiple experimental runs. Full article

One of the many applications of metal–organic frameworks (MOFs) is their use as adsorbents for removing emerging contaminants, such as ciprofloxacin (CIP), a fluoroquinolone-class antibiotic, from aqueous environments. We selected the copper-based MOF HKUST-1 and coupled it with TiO₂, then immobilized the composite on glass beads (TiO₂/HKUST-1@GB) to produce a reusable photocatalyst. The immobilization of the composite on glass beads improved the structural strength as well as the reusability of the photocatalyst. Together, these properties pave the way for scale-up for commercial applications in continuous-flow water treatment systems. Herein, we used XRD, FTIR, and SEM to characterize the immobilized catalyst and assess its structural, morphological, and optical properties. Photocatalytic experiments showed 98% degradation in 45 min under UV irradiation at pH 6 and a CIP concentration of 200 μgL⁻¹. The TiO₂/HKUST-1@GB composite showed higher degradation compared to pristine TiO₂ and HKUST-1 due to enhanced charge–carrier separation and synergistic interfacial effects. The reusability of the composite over five cycles was observed, with high stability and negligible Cu and Ti leaching, indicating promising environmental performance. Thus, TiO₂/HKUST-1@GB provides an efficient and sustainable approach for removing ciprofloxacin from aqueous solutions. The degradation performance, reusability, and ability to work simultaneously in adsorption and photocatalytic processes make TiO₂/HKUST-1@GB a promising candidate for the advanced treatment of aqueous-phase antimicrobial compounds such as ciprofloxacin. Full article

This study investigates the sustainable reuse of industrial enamel frit production waste generated during enamel application processes and evaluates its potential from a process-oriented glass-forming and -shaping perspective. Enamel frit waste collected from an industrial production line in Türkiye was subjected to comprehensive characterization, including XRD, XRF, TG/DTA, dilatometry, and CIE Lab* color analysis, with the primary aim of assessing forming compatibility rather than final product performance. Following calcination and controlled fritting, the waste material was processed through mold-based glass-forming experiments using firing schedules derived from thermal analysis. The results reveal pronounced chemical and thermal heterogeneity among enamel frit production wastes, leading to variable melting behavior across samples. Nevertheless, selected waste compositions exhibited sufficient viscous flow for shaping at reduced firing temperatures of approximately 850 °C. This study demonstrates that selected enamel frit production wastes—obtained from industrial enameling processes in slurry, powder, or granular form—can be reshaped into glass forms under controlled low-temperature conditions. The novelty of this study lies in investigating industrial enamel production frit waste as a reusable material within a circular economy framework, specifically focusing on its application in mold-based glass forming for artistic and educational contexts, thereby fostering collaboration between industrial waste management and glass art practice. Full article

In the present study, glass/ceramic hybrid fibers were chosen as a paper matrix, which effectively balance toughness and high-temperature resistance for soot combustion applications. In order to address the issue of unevenness in the performance of paper-type catalysts caused by the differences in the dispersion behavior of glass fibers and ceramic fibers in water, a facile foam-forming technology was proposed. The obtained glass fiber/mullite composite paper with various mass ratios (1:1, 2:1, 3:1, 4:1, and 5:1) exhibit high evenness, and better high-temperature resistance than the pure glass fibers. After impregnating K-Mn active ingredients, 15K5Mn-GFF-3G1C (GF/CF = 3:1) demonstrates high tensile strength, excellent catalytic activity (T50 = 388 °C), reusability (five cycles), and high-temperature stability (800 °C, 12 h). Full article

Polymers such as PLA, PLA reinforced with carbon fiber (PLA + CF), and PETG are widely employed in utensils, structural components, and biomedical device housings where load-bearing capability and chemical resistance are desirable. This is particularly relevant for reusable applications in which sterilization with hydrogen peroxide (HP) or ethylene oxide (EO) is often required. In this study, the impact of HP and EO sterilization processes on the mechanical, thermal, and structural properties of PLA, PLA + CF, and PETG was evaluated. The mechanical properties assessed included elongation at break, elastic modulus, and tensile strength after sterilization. The thermal properties examined comprised thermal stability and the coefficient of thermal expansion (CTE). Additionally, Fourier Transform Infrared Spectroscopy (FTIR) was performed to detect potential alterations in functional groups. For PLA, sterilization with HP and EO resulted in a 22% increase in ultimate tensile strength (UTS) and a 21% increase in elastic modulus, accompanied by a noticeable reduction in ductility and the appearance of more brittle fracture surfaces. PLA + CF exhibited greater stability under both sterilization methods due to the reinforcing effect of carbon fibers. In the case of PETG, tensile strength and stiffness remained stable; however, HP sterilization led to a remarkable increase in elongation at break (294%), whereas EO sterilization reduced it. Regarding thermal properties, glass transition temperature (Tg) showed variations: PLA presented either an increase or decrease in Tg depending on the sterilization treatment, PLA + CF displayed a Tg reduction after EO sterilization, while PETG exhibited a moderate Tg increase under HP sterilization. CTE decreased at lower temperatures but increased after EO treatment. FTIR analysis revealed only minor chemical modifications induced by sterilization. Overall, HP and EO sterilization can be safely applied to additively manufactured medical components based on these polymers, provided that the structures are not subjected to high mechanical loads and do not require strict dimensional tolerances. Full article

The high environmental impact caused by the accumulation of single-use plastic calls for measures to curb this problem, from a ban on single-use plastic tableware to the production of a wide range of biodegradable and reusable products. The aim of this study was to investigate how tableware made of different materials affects consumers’ sensory perception and emotional and hedonic responses when eating the same meal. In this study, four types of meals of animal or plant origin were selected for the experiments, which were served warm or cold. Accordingly, four groups of university students were instructed to taste the corresponding meal while using three sets of tableware made of different materials: polypropylene, wood/cardboard, and a stainless steel/ceramic/glass control set (regular set). Overall, the results suggest that the use of regular tableware elicited a positive emotional profile, while the use of disposable, wooden, and plastic tableware elicited negative emotional responses, which is consistent with the acceptability of the meal samples—regular tableware received higher ratings, while both types of disposable tableware received lower ratings. Finally, the material of the tableware only led to changes in odor and flavor perception when warm-served meals were sampled—higher intensities were reported when students used the regular tableware sets. Wooden cutlery imparted an atypical woody flavor to the meals, regardless of the type of meal. Full article

Catalysis plays a pivotal role in green chemistry practices, particularly in reducing waste generated during chemical synthesis. Decatungstate (DT) emerges as a potent photocatalyst for Type I oxidations, exhibiting remarkable resilience to oxygen quenching, a characteristic that sets it apart from other excited triplet state photocatalysts. While homogeneous DT catalysis demonstrates effectiveness, its solubility poses challenges for its separation and recycling. To address these limitations, we focus on the development and comparison of heterogeneous DT photocatalysts, aiming to optimize their yield, recovery, and reusability. We synthesized tetrabutylammonium decatungstate (TBADT)-supported catalysts using silica, alumina, titanium dioxide, and glass wool and characterized them using diffuse reflectance measurements. Subsequently, we evaluated their photocatalytic performance by monitoring the oxidation of 1-phenylethanol and cyclohexanol under UVA irradiation. Our findings reveal that TBADT@silica emerges as the most effective catalyst, achieving approximately 20% conversion of cyclohexanol and 50% conversion of 1-phenylethanol with good reusability. Interestingly, we observed that 3-aminopropyl-triethoxysilane (APTES) treatment, intended to enhance DT anchoring, unexpectedly quenches the ³DT* triplet state, reducing catalytic activity. This unexpected finding underscores the importance of careful consideration in designing robust and recyclable heterogeneous decatungstate catalysts. Our research contributes significantly to the advancement of heterogeneous photocatalysis, paving the way for future applications in flow photochemistry. Further, we share a Python code (Google 3.12.11) to correct spectra obtained in Cary spectrometers. Full article

Addressing the urgent need for lightweight and reusable energy-absorbing materials in aviation impact resistance, this study introduces an innovative multi-directional braided metamaterial design enabled by 4D printing technology. This approach overcomes the dual challenges of intricate manufacturing processes and the limited functionality inherent to traditional textile preforms. Six distinct braided structural units (types 1–6) were devised based on periodic trigonometric functions (Y = A sin(12πX)), and integrated with shape memory polylactic acid (SMP-PLA), thereby achieving a synergistic combination of topological architecture and adaptive response characteristics. Compression tests reveal that reducing strip density to 50–25% (as in types 1–3) markedly enhances energy absorption performance, achieving a maximum specific energy absorption of 3.3 J/g. Three-point bending tests further demonstrate that the yarn amplitude parameter A is inversely correlated with load-bearing capacity; for instance, the type 1 structure (A = 3) withstands a maximum load stress of 8 MPa, representing a 100% increase compared to the type 2 structure (A = 4.5). A multi-branch viscoelastic constitutive model elucidates the temperature-dependent stress relaxation behavior during the glass–rubber phase transition and clarifies the relaxation time conversion mechanism governed by the Williams–Landel–Ferry (WLF) and Arrhenius equations. Experimental results further confirm the shape memory effect, with the type 3 structure fully recovering its original shape within 3 s under thermal stimulation at 80 °C, thus addressing the non-reusability issue of conventional energy-absorbing structures. This work establishes a new paradigm for the design of impact-resistant aviation components, particularly in the context of anti-collision structures and reusable energy absorption systems for eVTOL aircraft. Future research should further investigate the regulation of multi-stimulus response behaviors and microstructural optimization to advance the engineering application of smart textile metamaterials in aviation protection systems. Full article

This study investigated the remediation of organic acid pollutants, specifically butyric acid (C₄H₈O) and valeric acid (C₅H₁₀O₂), as well as their binary mixtures in the vapor phase at various ratios. The remediation process involved the use of a continuous pilot-scale reactor. A TiO₂ catalyst was deposited on glass fiber tissue (GFT) and ultraviolet (UV) irradiation with an intensity of 20 W/m². The main objective of this study was to assess the effectiveness of the photocatalytic process by oxidizing and mineralizing a mixture of carboxylic acids in a rectangular reactor at pilot scale. This was achieved by calculating the removal efficiency and the selectivity of CO₂ (S_CO2). Each individual compound was treated separately, followed by the treatment of binary mixtures with molar fractions of 0.25, 0.5, and 0.75. The concentration of pollutants at the inlet varied between 50, 100, 150, and 200 mg/m³, while the flowrate ranged from 2 to 6 m³/h. The obtained results for the removal efficiency of butyric acid, the binary acid mixture (25% butyric acid + 75% valeric acid), and valeric acid were satisfactory, with percentages of 58%, 32%, and 41%, respectively. It is evident that the selectivity toward CO₂ is better for butyric acid compared to valeric acid and the binary carboxylic acid mixture, with values of 43.70%, 33.49%, and 21.96%, respectively, across all concentrations. A simulation model based on mass transfer and catalytic oxidation mechanisms was developed and successfully validated against the experimental data for each pollutant. Reusability tests conducted on the TiO₂ on GFT, both in its initial (clean) state and after 50 h of the photocatalytic treatment of butyric acid, showed a 15% decrease in photocatalytic efficiency. Full article

Both tungsten trioxide (WO₃) nanosheet arrays and tungsten trioxide/zinc oxide (WO₃/ZnO) nanocomposites were grown on fluorine-doped tin oxide (FTO) coated glass slides using a hydrothermal method to develop a visible-light-driven photocatalyst with easy reusability. Field emission scanning electron microscopy (FE-SEM) observations confirmed the formation of irregular oxide nanosheet arrays on the FTO surfaces. X-ray diffraction (XRD) analysis revealed the presence of hexagonal WO₃ and wurtzite ZnO crystal phases. UV-Vis diffuse reflectance spectroscopy showed that integrating ZnO nanostructures with WO₃ nanosheets resulted in a blue shift of the absorption edge and a reduced absorption capacity in the visible-light region. Photoluminescence (PL) spectra indicated that the WO 0.5/ZnO 2.0 sample exhibited the lowest electron-hole recombination rate among the WO₃/ZnO nanocomposite sample. Photocatalytic degradation tests demonstrated that all WO₃/ZnO nanocomposite samples had higher photodegradation rates for a 10 ppm methylene blue (MB) aqueous solution under visible-light irradiation compared to pristine WO₃ nanosheet arrays. Among them, the WO 0.5/ZnO 2.0 sample showed the highest photocatalytic efficiency. Furthermore, it exhibited excellent recyclability and high photodegradation stability over three cycles. Full article

Membrane technology is widely used in various aspects of wastewater treatment; however, single membrane technology has a series of disadvantages, such as high selectivity, poor recycling performance, and susceptibility to contamination. In this study, a treatment method combining an advanced oxidation process and membrane separation technology was proposed, and a geopolymer-based Fenton-like catalytic tubular membrane (GFM) was prepared by using H₂O₂ as a blowing agent by the direct foaming method. It was shown that the optimum conditions for the preparation of the membrane were a water glass modulus of 1.8 M, the addition of foaming agent of 1 mL, and a thickness of the membrane of 6.5 mm, with a flux of 6942 L·m⁻²·h⁻¹. Due to the characteristics of the tubular membrane, the possibility of adding hydrogen peroxide directly inside the membrane allows an optimal Fenton-like removal, which is better than outside the membrane, thus reducing the consumption of hydrogen peroxide. The tubular membrane has a multi-stage porous structure, high flux, and a high specific surface area (68.74 m²/g). The GFM/H₂O₂ Fenton-like system formed is capable of almost completely degrading all kinds of synthetic dyes under various stringent conditions, and the XRD, FTIR, and TG analyses and cycling tests showed that the GFM has excellent stability and a significant advantage in terms of reusability. Full article

Fe-based metallic glass (MG) exhibits excellent performance as a heterogeneous catalyst in degradation but is rarely used as a working electrode in electro-Fenton (EF) systems. We used Fe₇₈Si₉B₁₃ MG as the working electrode to investigate the effect of the EF process on the degradation efficiency of p-nitrophenol (p-NP). The EF system had the highest catalytic efficiency (the reaction rate was 3.4 times that of chemical degradation) at a voltage of −1 V (vs. SCE) and showed 95.6% degradation of p-NP within 30 min. The electrode voltage accelerated the generation of hydroxyl radicals (·OH) in the system, thus promoting pollutant degradation. In addition, the Fe₇₈Si₉B₁₃ MG cathode demonstrated good structural stability and reusability after 10 cycles. Fe₇₈Si₉B₁₃ MG ribbons can serve as a suitable cathode material and provide potential optimization solutions for the degradation of organic pollutants. Full article