Hydrogels have been promising for high-humidity applications, including underwater restoration and underwater medicine. However, conventional hydrogels exhibited poor mechanical properties and loss of adhesion due to the hydration layer in a humid environment. Herein, an underwater adhesive hydrogel based on waste chrome leather scraps with high strength was devised through multi-network structure design and surface-anchored adhesive. Firstly, a multi-network hydrogel was constructed by using waste chrome leather scraps hydrolysate as the first network, polyacrylamide as the second network, and polysulfonate as the third network. Subsequently, the adhesive poly(dopamine methacrylamide-co-methoxyethyl acrylate) was anchored onto the surface of the multi-network hydrogel, which effectively enhanced the adhesion property of the hydrogel. The hydrogel demonstrated remarkable adhesion in aqueous environments (adhesive strength greater than 200 kPa), which was attributed to the adhesion and hydrophobic groups in the adhesive. Furthermore, the synergistic effect of the three networks resulted in an excellent compressive strength of the hydrogel (40 MPa compressive strength, 95% compression deformation). The findings of this work open a promising direction on how to convert waste chrome leather scraps into high value-added products and develop effective high-performance underwater adhesives, which offer a promising material for applications requiring mechanical strength and underwater adhesion.
The exploitation into new materials of even the smallest scraps of textiles would contribute to their possible success in sectors such as the automotive industry. In this work, alkaline treatment with low sodium hydroxide (NaOH) concentrations was applied to flax and hemp textile residues, aiming to determine the most suitable process conditions as a function of the quality of the treated fibres. Several parameters were considered: the temperature and the concentration of the alkaline solution and the immersion time in the alkaline solution and, eventually, in distilled water during the neutralization phase. Drying tests were carried out under controlled temperature conditions to assess the effects of the various treatment parameters. The effects of the various procedures were elucidated by thermogravimetric analysis (TGA), scanning electron microscopy (SEM), X-ray diffraction (XRD) to assess crystallinity, atomic force microscopy (AFM) to characterize surface roughness, and nitrogen absorption/desorption cycles to determine how microporosity develops with treatment. It is suggested that only the 1.5 wt./vol.% treatment produced some worthwhile modifications of the fibres to prepare them for their use in composites, more evidently in flax than in hemp, though care needs to be taken about fibre embrittlement and potential water permeability.
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Recovering critical strategic metals from superalloy scraps is indispensable to sustaining the materials supply chain. However, the excellent physicochemical properties of superalloy make them difficult to dissolve and separate, thereby hindering their recycling and reutilization. Here, we design a molten salt metal-air electrolyzer (MMAE) that synergistically oxidizes and pulverizes scraps, which generates oxide powders that can be easily dissolved and separated for all element recovery. The corrosivity of molten chloride and electrochemical polarization can convert scraps at the anode into soluble metal chlorides, while oxygen is reduced to O2- in the form of soluble CaO. Subsequently, the soluble metal cations encounter O2- in molten CaCl2-NaCl to precipitate as insoluble oxides. The MMAE constructs two dynamic metal/metal chloride and oxygen/CaO interfaces, achieving a high dissolution rate of 0.290 g/(cm2∙h). Subsequent roasting process preferentially extracts rhenium (Re) with a recovery efficiency of 90.46%, followed by selective separation and recovery of other metals with a recovery efficiency of >93% under low acid consumption. Life cycle assessment analysis shows its low energy consumption and environmental impact. Overall, the MMAE is a general method to recover a range of superalloy scraps, opening up an effective pathway for advancing sustainable metal recycling.
The European catfish (Silurus glanis) is an invasive predatory species threatening biodiversity in the Tagus River (Portugal), while remaining underexploited as a food resource. Despite its potential contribution to invasive species management, limited knowledge exists on its suitability for developing value-added food products, particularly using processing scraps. This study aimed to valorise this species through the development and characterisation of six value-added food products produced from fillets and processing scraps. Nutritional, microbiological, textural, and sensory properties were evaluated. Microbiological analyses confirmed the absence of Salmonella spp., Listeria monocytogenes, and E. coli in all products; however, the high microbial counts observed in Powerbites indicate the need for improved hygiene and process control. Protein content ranged from 10.05 to 16.89 g/100 g, with complete essential amino acid profiles and relevant contributions to adult daily indispensable amino acid requirements. The products also showed low to moderate fat content, favourable fatty acid profiles, and meaningful contributions of vitamins B12 and E. Sensory evaluation indicated overall positive acceptance, although some formulations require further optimisation. These findings highlight the nutritional, technological, and sustainable potential of European catfish-based products, supporting their use as value-added food alternatives while contributing to the valorisation of an underused invasive species.
To estimate the prevalence of Campylobacter jejuni infection among apparently healthy dogs versus dogs with acute diarrhea in central New York, identify risk factors for infection among dogs, and characterize the isolates to evaluate potential risk to public health. In this prospective study, fecal samples were collected from dogs from January 2022 through September 2023. Exposure data on each dog were obtained via client questionnaire. Real-time PCR was used to detect C jejuni, and positive samples were subjected to bacteriologic culture. Isolate characterization via antimicrobial susceptibility testing and whole-genome sequencing was performed. A total of 212 dogs were included. The prevalence of fecal C jejuni shedding as detected by PCR did not differ significantly between healthy dogs and dogs with acute diarrhea. Campylobacter jejuni PCR-positive status was more common among puppies (14.3%) than adults (2.8%), and it was more common among dogs that had recently consumed table scraps or trash (9.6%) versus dogs without that history (2.0%). A history of acute diarrhea was not significantly associated with C jejuni PCR-positive status, although the relatively small number of dogs with diarrhea precluded a robust comparison to healthy dogs. Campylobacter jejuni was identified in healthy dogs and dogs with acute diarrhea, underscoring the potential for zoonotic transmission. Puppies and cases with a history of consuming table scraps or food waste may be at increased risk.
The recycling of carbon fiber reinforced thermoplastics (CFRTP) is intrinsically complex, as it encompasses multiple interdependent variables, including the quality and heterogeneity of the incoming waste stream, as well as limitations on end-use applications, often restricted to nonstructural components, governed by the resulting mechanical and physicochemical properties of the recycled composite. Therefore, this work aimed to propose a sustainable route for the mechanical recycling of primary carbon fiber (CF)/polyamide 6 (PA6) composite blanket scrap preconsumer waste originating from the processing of components in the automotive sector. The waste was cut into specific geometric shapes, such as squares and triangles of two sizes (small: ∼5 cm; large: ∼10 cm), and placed in an aluminum mold, followed by hot compression molding to produce four reprocessed laminates. The laminates were inspected by ultrasound, and the volume fractions of reinforcement, matrix, and porosity were determined using the acid digestion method. The reprocessed laminates were evaluated for their thermal properties (differential scanning calorimetry, DSC, and thermogravimetric analysis, TGA), mechanical properties (interlaminar shear strength, ILSS, flexural strength, and Izod impact strength), and the morphological characteristics of the fracture surface. The results indicated superior values in the ILSS test, and the fracture surface morphology revealed satisfactory positioning, good adhesion, and interaction between the matrix and reinforcement in the reprocessed laminates. However, the patch arrangement and, mainly, the random orientation of the CF resulted in a drastic reduction in flexural performance. Laminate C, with smaller, triangular patches, resulted in greater impact resistance because it acted as a barrier to crack propagation and energy absorption. Reprocessing thermoplastic composite scraps proved feasible and satisfactory. Highlights: The reuse of carbon fiber reinforced thermoplastic composite scraps can be a viable solution for obtaining a secondary product.
The growing demand for sustainable materials in electrical and electronic applications has led to the reuse of industrial and electronic waste in high-performance polymer composites. In this study, rigid polyurethane foam waste (WRPU), recycled tire waste (RTW), and printed circuit board (PCB) scraps were incorporated as fillers into a polyurethane matrix using methylene diphenyl diisocyanate (MDI) as a binder. The composites were fabricated via mechanical stirring followed by hydraulic compression. Response Surface Methodology (RSM) using a Central Composite Design (CCD) was employed to optimize the filler composition for dielectric performance. The optimal formulation—15.94 wt% WRPU, 3.0 wt% RTW, and 10.0 wt% PCB—achieved a dielectric constant of 4.45. Confirmation experiments and simulations using COMSOL Multiphysics yielded values of 4.33 and 4.50, respectively, with minimal error margins. FTIR confirmed functional group integration, HR-SEM revealed uniform filler dispersion and strong interfacial bonding, and TGA indicated improved thermal stability. The results highlight the dielectric potential of recycled polymer composites as environmentally friendly dielectric materials, although further studies are needed on breakdown strength, dielectric loss and resistivity for assessing high-voltage insulation applications, such as battery cell separators and power systems.
In this study, the valorization of poly(lactic acid) (PLA) waste as well as rice husk into sustainable materials was explored. To simulate the industrial valorization of defective PLA parts, scraps and burrs, PLA was reprocessed (rPLA) by melt extrusion and further plasticized with 15 wt.% of acetyl tributyl citrate (ATBC) and reinforced with rice husk (RH) or rice husk biochar (RHB) in 1 or 3 wt.%. The melt flow index was determined to assess the effect of reprocessing and the addition of RH or RHB on the material degradation. The obtained films were characterized in terms of their structural, mechanical, and thermal behavior. The water-related behavior of the materials was evaluated by measuring the static water contact angle and the water vapor transmission rate (WVTR). Compostability was proposed as an end-of-life option, therefore disintegration under composting conditions was assessed. Reprocessing increased the MFI and slightly reduced the strength and the modulus, consistent with chain scission. ATBC facilitated the processability, improved the particles' dispersion and provided ductility to the final materials. RH and RHB acted mainly as nucleating agents and strongly modified the surface wettability. A low RHB loading improved the WVTR, whereas a higher filler content and ATBC generally increased the WVTR. All the films were completely disintegrated within 18 to 21 days. These results show practical valorization routes to obtain rPLA films with tunable properties and to preserve the inherent composting disintegration of PLA.
Global sustainability efforts have long focused on the heavy industries, overlooking the light and stone processing industries-despite their substantial solid waste generation and low value-added waste disposal methods. This study aims to develop a light-stone industrial symbiosis plan to unlock the circular potential of these under-prioritized industries. While industrial clustering offers potential for synergistic waste reutilization in the light and stone processing industries, practical implementation remains hindered by a long-standing data deficit. This study compiles a refined database covering 304 enterprises and eight key waste types (polyester waste, blended fabrics, bovine hair, trimming scraps, leather waste, footwear waste, crushed stone, and stone processing waste), and designs a plant-by-plant light-stone industrial symbiosis plan. By integrating high-resolution data with Material Flow Analysis, Life Cycle Assessment, and transport modeling, the proposed plan is validated, yielding three key findings: (1) The ten recycled products exhibit varying environmental contributions (0.7%-27.9%). This enables policymakers to prioritize key recycled products to formulate targeted symbiosis pathways based on local industrial structures, waste profiles, and key environmental concerns; (2) Inter-industry symbiosis drives 81.9% of waste reutilization gains, while intra-industry symbiosis delivers 92.3% of economic benefits. The greater environmental benefits of inter-industry symbiosis remain under-realized as firms favor high-profit intra-industry symbiosis, necessitating targeted policy interventions; (3) Light-stone symbiosis increases Fujian Province's solid waste reutilization rate by 16.9% with significant spatial disparities, requiring careful consideration of uneven potential gains and inter-city waste transport risks. This study provides a scalable template for advancing circular economy in similar under-prioritized industrial clusters worldwide.
In recent years upstream Li extraction from battery scraps and black mass has gained significantly in importance due to its potential for higher achievable overall Li yields and increased flexibility in downstream processing. Various process routes have been developed and partially industrially implemented. Three major process types were identified through a comprehensive assessment of scientific literature, patent literature, and structured interviews with industry experts. These process types are based on smelting with enrichment of Li in the slag or flue dust phase, roasting with subsequent selective Li leaching, and pure hydrometallurgical processes using either an oxidative or reductive leaching mechanism. Based on the available scientific, patent and expert knowledge, this review critically discusses the current state of development with respect to reaction mechanisms and process design, industrial implementation and engineering aspects, decarbonization potential, integration in the battery recycling chain and economics. Process routes based on roasting with subsequent selective Li leaching currently appear to represent the predominant industrial approach in Asia and are under development in Europe. The available evidence suggests that this preference is primarily associated with a favorable combination of sufficient achievable lithium yields, process robustness, suitability for the current market size, and economic considerations. Current industrial developments indicate that smelting routes involving lithium enrichment in the flue dust phase are likely to reach broader industrial implementation within the next decade, although their economic viability is expected to depend on substantially larger processing capacities. Currently, pure hydrometallurgical processes only play a minor role, with the exception of LFP black mass.
This technical study presents calendering as an innovative and continuous industrial solution for the reuse of uncured carbon fiber prepreg scraps, which are typically discarded in large quantities in the aerospace sector. By applying heat and pressure through rollers, the authors successfully transform residual fragments into functional sheets, promoting a circular economy that reduces environmental impact and raw material costs. Although the process induces a slight fiber misalignment, which decreases longitudinal strength, the results reveal significant improvements in transverse properties and increased material isotropy. Finally, the research validates the feasibility of this technique by fabricating a curved structural demonstrator, proving that these recycled composites maintain high stiffness and suitable thermal stability for secondary aeronautical applications.
With the large-scale production and utilization of silicon solar panels, substantial quantities of photovoltaic tungsten wire scraps are generated during their manufacturing process. To alleviate environmental burdens and enhance economic benefits, the development of highly efficient photovoltaic tungsten wire recycling technology has become an urgent priority. Herein, we report a novel method for recycling photovoltaic tungsten busbars based on molten salt electrolysis. This approach achieves efficient tungsten extraction without employing toxic reagents or generating secondary pollution. The rare earth oxide (La2O3) added to the photovoltaic tungsten busbars is concentrated in the electrolyte and cathode, enabling effective separation from the tungsten product (sodium tungsten bronze). And lanthanum is recovered during the electrolyte purification process. The purity of recycled tungsten powder reaches 99.93%, with lanthanum oxide residues at the ppm level, meeting industrial application standards. Overall, this study effectively avoids ammonia emissions and wastewater generation inherent in conventional recycling processes, streamlines operational workflow, and delivers significant economic and environmental benefits.
To address the inefficiency and unfairness of traditional manual scrap sorting, we propose the application of 3D vision technology for grading in this work. The multi-view 3D reconstruction algorithm achieves an accuracy within 1 mm in both synthetic and real scrap scenes. This level of accuracy meets the requirements for scrap grading. Subsequently, an automated processing workflow in a non-overlapping scrap scenario is investigated, in which a pipeline based on the multi-view reconstruction integrating point cloud segmentation technique is proposed. Four-point cloud clustering segmentation methods, including Euclidean clustering, Kmeans, DBSCAN and Region Grow, are compared, and it is found that the Euclidean-clustering-based point cloud segmentation algorithm provides the best overall trade-off, achieving an mIoU score of 99.35%, while the thickness measurement error is less than 0.5 mm. The workflow suggests improved robustness and reliability compared to using a single 2D image for thickness inference. These results indicate that 3D vision may provide a valuable basis for the future development of scrap grading systems.
The study investigates the technology of direct Cr alloying of steel in an induction furnace using Cr-containing oxide raw materials and an FeAlSiCa metallothermic reducing agent under atmospheric conditions. The experimental design included four charge variants: scrap-based, DRI-based, A-series (50% scrap/50% DRI), and B-series (75% scrap/25% DRI). For A-series and B-series, the FeAlSiCa content was varied from the baseline value to reduced levels of -10% and -20%. The results demonstrate that Cr recovery strongly depends on the metallic component of the charge. The highest Cr recovery (up to 83%) was consistently achieved for the DRI-based charge, while mixed charges showed intermediate values depending on the DRI fraction and reducer amount. Reduction in FeAlSiCa content led to a decrease in Si transfer to steel, but was accompanied by lower Cr recovery. The produced steels were characterized by a uniform distribution of alloying elements, low impurity levels (S, P < 0.03%), and the formation of a dense, non-disintegrating slag. The results confirm that direct Cr alloying in an induction furnace can be effectively implemented under atmospheric conditions without vacuum or protective gas atmosphere, while the presence of DRI plays a key role in enhancing Cr assimilation.
Coordination-chemistry-driven reconstruction offers a powerful yet largely unexplored route for transforming bulk metals into functional nanomaterials with programmed surface states. Herein, we report a green, recyclable wet-chemical protocol that integrates top-down oxidative dissolution of copper with bottom-up crystallization to produce octahedral Cu2O submicron crystals. In a strongly alkaline medium, transient Cu-NH3 coordination promotes coordination-driven oxidative dissolution of scrap copper to generate a metastable [Cu(OH)4]2- aqueous precursor, while aldehyde-functionalized dextran (ODex) serves as a mild reductant and a surface-coordinating ligand. A self-catalytic acceleration pathway enables rapid room-temperature crystallization within minutes, ODex-regulated octahedral Cu2O (ODex-Octa-Cu2O) exposing {111} facets, decorated with ODex-Cu2+ complexes and stabilized Cu-vacancy-rich relaxed atomic layers. This coordination-induced surface reconstruction tailors the surface electronic and defect structure; density functional theory further reveals the Frontier orbital theory evolution upon ODex-Cu2+ modification of Cu2O(111) and the concomitant work function regulation, which together stabilize the lattice and optimize interfacial adsorption-desorption kinetics. Meanwhile, ODex-Octa-Cu2O exhibits ultrahigh mass-normalized activity for 4-nitrophenol hydrogenation (knor = 32.36 s-1 mg-1 mL), benefiting from the in situ generated surface-active hydrogen, and efficient glucose electrooxidation enabling a bifunctional glucose fuel cell. The fully recyclable alkaline medium further realizes a sustainable "metal-to-nanomaterial" conversion route.
This study aims to systematically evaluate the balancing mechanism between road performance, carbon emissions, and economic cost when selecting asphalt materials for severe cold regions, filling the gap in multi-criteria decision-making for composite chemical modifications. To address alternating temperatures, heavy traffic, and modified asphalt transport difficulties, this study presents a novel evaluation framework focusing on the performance-environmental-cost nexus of a desulfurized rubber powder composite SBS-modified asphalt mixture, which provides a clear technological breakthrough for high-ratio scrap tire recycling in seasonal frost zones. Two reference mixtures serve as comparisons: a conventional rubber powder composite SBS (styrene-butadiene-styrene triblock)-modified asphalt mixture (CR-SBS) and an SBS-modified asphalt mixture (SBS). A comparative experiment was conducted between the two materials and the SBS-modified asphalt mixture (ACR-SBS) compounded with desulfurized rubber powder. High-temperature stability was tested by the rutting test, low-temperature crack resistance by the beam bending test, and water stability by the immersion Marshall and freeze-thaw splitting tests. Life cycle carbon emissions and economic costs were quantified from raw material acquisition to construction. The results show that desulfurized rubber powder composite with ACR-SBS delivers the most superior overall road performance. However, it also generates the highest life cycle carbon footprint. Its total carbon emission reaches 162,800 kgCO2eq, which is 13.7% (19,600 kgCO2eq) higher than SBS (143,200 kgCO2eq) and 7.7% (11,600 kgCO2eq) higher than CR-SBS (151,200 kgCO2eq). The total cost of ACR-SBS is 391,000 CNY, which is 1.5% (6000 CNY) higher than SBS (385,000 CNY) and 1.3% (5000 CNY) lower than CR-SBS (396,000 CNY). These findings provide a basis for the selection of high-performance, low-carbon, and economical composite-modified asphalt in severe cold regions.
The escalating demand for miniaturization in electronics necessitates advanced laser micromachining for precise micro-via fabrication in PTFE-based PCBs. This study addresses challenges in controlling CO2 laser kerf depth in PTFE, a material known for properties that complicate material removal. Employing a two-level full factorial Design of Experiments, the effects of number of loops, aperture, and pulse duration were systematically investigated. This analysis revealed that while pulse duration statistically impacted ablation depth, the number of loops was operationally most critical due to its direct proportionality with kerf depth in PTFE, leveraging its low thermal conductivity. Aperture, defining the laser spot size, was often constrained by PCB geometric specifications. The predictive models developed demonstrated robust generalizability across different PTFE-based laminates. Validation of the production of PCBs achieved a 100% success rate in meeting geometric tolerances and surface integrity. This DoE-based framework establishes a process window, significantly reducing parameter identification time and scrap, thereby enhancing manufacturing yield.