Search Results (21,159)

Healthcare waste management is a growing environmental and economic challenge due to increasing waste volumes, hazardous materials, and continued reliance on linear disposal methods such as incineration and landfilling. This review aims to examine how circular economy and zero-waste approaches can be applied to healthcare waste management to improve sustainability, resource efficiency, and system performance. A structured narrative review was conducted using peer-reviewed literature obtained from prominent scientific databases, concentrating on circular strategies, zero-waste initiatives, digital technologies, and policy frameworks relevant to healthcare waste systems. The reviewed studies indicate that practices such as improved waste segregation, recycling and material recovery, reusable product design, digital waste tracking, and Extended Producer Responsibility can significantly reduce waste generation, lower environmental impacts, and achieve cost savings, while maintaining infection control and patient safety. However, the review also identifies key barriers to implementation, including regulatory complexity, limited infrastructure, financial constraints, and weak coordination among stakeholders. The novelty of this review lies in its integrated analysis of circular economy and zero-waste strategies through the lens of digital enablement, offering a systems-based framework for transforming healthcare waste management beyond incremental improvements. The findings highlight that successful circular healthcare waste management requires strong institutional leadership, supportive policies, and the integration of digital technologies to enable monitoring, traceability, and decision-making. This review enhances the comprehension of how circular economy principles can facilitate the transition from linear to sustainable healthcare waste systems and provides guidance for policymakers, healthcare managers, and researchers. Future research should focus on evaluating real-world implementation, advancing recyclable and reusable medical materials, and developing standardised indicators to measure circular performance in healthcare settings. Full article

This study investigates the 55%Al-Zn-Si coating system. Using microstructural characterization and thermodynamic simulation, we systematically analyzed its microstructure formation, solidification behavior, and the regulatory effects of Cr, Nb, and V micro-alloying elements. The results show that the typical coating consists of a primary α-Al dendritic skeleton and an interdendritic Zn-rich eutectic phase, exhibiting a characteristic spangle morphology. The addition of Si is crucial. By participating in the formation of a Fe-Al-Si ternary compound layer, it effectively suppresses the intense reaction at the Fe/Al interface, providing essential conditions for the sufficient growth of the outer Al-rich dendrites and the formation of a continuous transition layer. Thermodynamic analysis further clarifies that the coating solidification follows three distinct stages: precipitation of the primary α-Al phase, an Al-Si binary eutectic reaction, and a final Al-Zn-Si ternary eutectic transformation. Regarding micro-alloying, this study reveals the specific roles of different elements: Cr significantly refines the transition layer structure, promoting its transformation from coarse lamellae into a fine and uniform morphology; V tends to combine with Al to form high-melting-point enriched regions, inhibiting the growth of Fe-Al intermetallics and reducing the thickness of the brittle transition layer by approximately 50%; conversely, the addition of Nb disrupts the normal solidification sequence, inducing abnormal segregation of Al-rich and Si-rich phases, which compromises the homogeneity and integrity of the coating structure. Through an in-depth analysis of the fundamental solidification mechanism and micro-alloying effects, this research provides an important theoretical basis for optimizing the microstructure of hot-dip Al-Zn sheets via precise composition design and micro-alloying strategies. Full article

Interest in improved disposal pathways and proliferation-resistant systems for used nuclear fuel recycling has driven research on monoamide extractants. Existing comparisons against the industry standard, tributyl phosphate (TBP), emphasize a fundamental approach and span a wide range of test conditions. This work narrows that range and addresses process-scale considerations by presenting hydrodynamic performance results alongside extraction capacity at optimized conditions. The monoamide solvents, 1.0 M DEHiBA (N,N-di(2-ethylhexyl)isobutanamide), 1.5 M DEHBA (N,N-di(2-ethylhexyl)butanamide), and 1.5 M DEHDMPA (N,N-di(2-ethylhexyl)-2,2-dimethylpropanamide), are compared to 1.1 M TBP in bench-scale extraction tests with nitric acid (2–6 M) and uranium (∼0.8 M). Performance is assessed with distribution ratios and dispersion number ratings and supported by specific gravity and viscosity measurements. DEHBA and DEHDMPA exhibited inadequate coalescence behavior with failed or poor dispersion ratings despite uranium distribution ratios of 2.06 ± 0.03 and 0.86 ± 0.01 at O/A = 1.9, limiting suitability for process application. TBP and DEHiBA maintained adequate dispersion ratings across all conditions tested, with maximum distribution ratios of 4.37 ± 0.08 at O/A = 2.6 and 0.67 ± 0.01 at O/A = 2.9, respectively. Higher viscosity values for DEHBA (5.21 cP ± 0.3%) and DEHDMPA (6.53 cP ± 0.4%) relative to TBP (2.04 cP ± 0.4%) and DEHiBA (3.18 cP ± 0.4%) correlate with observed coalescence deficiencies. The methods presented in this work demonstrate the significance of evaluation beyond extraction capacity. Full article

Waste tire disposal and high-ground-stress soft rock roadway instability are pressing global challenges. This study develops sustainable rubber granule concrete (RGC) using waste tire rubber as a key component, aiming to realize waste valorization and floor heave control. RGC’s mechanical properties (uniaxial/triaxial compression, compressibility, ductility) were systematically tested, and its pressure relief mechanism was validated via finite element analysis (ABAQUS/FLAC) and 60-day field monitoring. Results show that RGC with optimal parameters (12% rubber content, 3–4 GPa elastic modulus, 250–350 mm thickness) achieves 64% bottom stress reduction and >40% displacement control. The material’s excellent energy absorption and flexibility address the brittleness of conventional concrete, ensuring stable support in high-stress environments. This work provides a sustainable, cost-effective concrete modification strategy, bridging waste recycling and geotechnical engineering, with broad implications for low-intensity, high-toughness material applications. Full article

The global transition toward renewable energy and decarbonization is intrinsically linked to the management of critical materials. Rare Earth Elements (REEs) are no exception, as they play a strategic role at the center of climate goals. Therefore, this review provides a comprehensive assessment of the REE landscape, explicitly addressing the proposed Demand-Sustainability-Risk Nexus (DSR-Nexus), which integrates technological demand, environmental sustainability, and geopolitical supply risks. A systematic review based on PRISMA methodology was conducted to analyze scientific contributions published between 2015 and 2026, revealing a significant research imbalance. By 2025, while 87% of works focus on resource availability, production, and recycling, only 1.4% address the global supply chain and its geopolitical implications. Key findings highlight that China’s dominance in mining, processing, and refining capacities, accounting for 69.5%, 92%, and 94%, respectively, creates structural vulnerabilities for future environmental goals. In contrast, emerging producers such as Malaysia and the United States are expected to contribute 9% and 8% of refining capacity, respectively. Furthermore, this review discusses environmental trade-offs, including high energy intensity, water consumption, and radioactive byproducts. It also examines mitigation strategies, such as recycling, urban mining, and material substitution. Ultimately, achieving a resilient energy transition requires expanding supply, strengthening circular strategies, and international cooperation. Full article

This study investigates the feasibility of incorporating high-volume municipal solid waste incineration (MSWI) fly ash into geopolymers, with a focus on its effects on mechanical performance and fragmentation behavior. A systematic experimental program was conducted in three stages. Geopolymer mixtures were first prepared with MSWI fly ash substitution rates ranging from 50% to 100% at seven distinct levels. Uniaxial compression tests were then performed to evaluate mechanical properties, followed by sieve analysis to examine fragment size distribution. The fractal dimension (D) was adopted to quantitatively characterize the degree of fragmentation. The results indicate that dry density, compressive strength, and elastic modulus all decrease progressively with increasing MSWI fly ash content. Specifically, as the fly ash content increased from 50% to 100% the compressive strength decreased from 9.57 MPa to 3.18 MPa. Notably, even at a 100% substitution rate, the compressive strength reached 3.18 MPa, which is 59% higher than the 2.0 MPa minimum requirement specified in the JTG/T F20-2015 standard. These findings demonstrate that MSWI fly ash can be effectively utilized at high replacement levels to produce sustainable geopolymers with satisfactory mechanical properties. This approach presents a viable strategy for recycling industrial solid waste into value-added construction materials. Full article

Electric two-wheelers (E2Ws) are promoted as lower-emission options in emerging economies. Their long-term cost competitiveness depends mainly on battery durability and how batteries are managed at the end of their life. This research examines Li-ion and nickel-cobalt-manganese (NCM)-type batteries versus the previously common lead-acid batteries in these markets. The study uses a 12-year total cost of ownership (TCO) framework that includes battery degradation, estimated first-life duration, and alternative lifecycle pathways. It covers three sensitivity analysis cases: conservative, base case, and optimistic. Three scenarios are evaluated: (1) no lifecycle management, (2) refurbishment for first-life extension, and (3) integrated lifecycle management with refurbishment, second-life utilisation, and recycling. Results show that managing the battery lifecycle can reduce TCO. The amount of reduction depends on first-life duration, ownership horizon, refurbishment cost, downstream residual value, and use intensity. The greatest TCO gains are found in battery categories with short first-life duration, allowing substantial residual value recovery during ownership. Batteries with first-life durations of 12 years or more provide smaller benefits. These findings support optimising lifecycle pathways for maximum residual value. Improved TCO performance, along with supportive infrastructure, policies, and market development, is critical for broader E2W adoption. Full article

Variability in life cycle assessment (LCA) results for metal recycling technologies arises from multiple sources, including allocation methods, recycling route, regionality of impacts, and type of waste treated. Among these factors, waste composition is particularly critical, as it directly influences process performance by affecting auxiliary material consumption and emissions. This work investigates four waste categories: metals from incineration bottom ash (MBA), waste-printed circuit boards (WPCBs), industrial waste from gold refining (GRA), and spent automotive and industrial catalysts (SCs). The Climate Change (CC) for 1000 kg of waste was estimated at 3251 × 10³ kg CO₂eq for WPCBs, 3923 × 10³ kg CO₂eq for MBA, 1569 × 10³ kg CO₂eq for GRA, and 2101 × 10³ kg CO₂eq for SCs. A sensitivity analysis was performed to assess the influence of allocation methods on results for 1kg of recycled metal. The highest variability in CC across waste categories was observed for gold (up to 8477%) with the black-box economic allocation method, while different allocation methods reached 21,700% for WPCBs. These results highlight the strong influence of methodological choices and waste characteristics, emphasizing the need for transparent and consistent LCA reporting. Full article

Life cycle assessment (LCA) is an important analytical method used to evaluate the environmental impacts of products, services, or processes throughout their entire life cycles—from the extraction of raw materials and production to use and end-of-life treatment. LCA enables the identification of stages with the highest environmental impact burden (hotspots) and supports strategic environmental initiatives, the circular economy, standards, and policies aimed at improving sustainability. This paper analyses the application of LCA in metallurgy, with a focus on primary aluminium production. It outlines the principles of life cycle thinking and explores decarbonisation opportunities within the aluminium industry. This study includes a life cycle impact assessment case study comparing the most significant environmental impacts of primary aluminium production in different regions of the world, including Europe and Asia. The analysis was performed using openLCA software 2.5 with the OzLCI2019 database. Environmental impacts were calculated using the ReCiPe 2016 Midpoint (H) method. The results indicate that primary aluminium production mainly affects impact categories related to high energy consumption, the use of carbon anodes, and associated emissions. The highest impacts were identified in ecotoxicity, followed by global warming, land use, ozone formation, and fossil resource scarcity. No significant regional differences were observed. Full article

This study investigates the leaching behavior of the LiNi_0.65Co_0.25Mn_0.10O₂ cathode material in a phosphoric acid medium, with metallic copper recycled from spent battery components serving as a reducing agent. The aim was to develop an efficient approach for the recovery of Li, Ni, Co, and Mn while providing a mechanistic understanding. Leaching experiments were performed by varying key parameters, including copper addition, acid concentration (0.2–0.8 mol·L⁻¹), cathode mass (0.2–1.0 g), stirring rate (0–600 rpm), and temperature (35–80 °C). Thermodynamic analysis, supported by Pourbaix and species distribution diagrams, was used to interpret metal behavior. The results show that lithium is readily dissolved, whereas the extraction of Ni, Co, and Mn depends on the presence of copper, which enables their reduction and dissolution. Optimal conditions (0.4 mol·L^‒1 H₃PO₄, 0.2 g Cu, 600 rpm, 80 °C) enabled rapid extraction, exceeding 90% within 30 min, while near-complete extraction (~100%, 99%, 99%, and 97% for Li, Ni, Co, and Mn) was achieved after 60 min. Structural analysis revealed a transformation from the layered structure to spinel-like intermediates, followed by their dissolution and formation of copper phosphate phases. The proposed system represents an efficient approach for the sustainable recycling of NMC cathodes. Full article

The synthesis of heterocyclic compounds such as pyridines, quinazolinones and coumarins is a fundamental area of organic chemistry due to their wide application in the pharmaceutical and chemical industries, agro-industry, and other fields of modern technology. As these compounds are produced in large quantities and have significant industrial importance, the development of sustainable and environmentally friendly synthetic approaches has become a key objective of green chemistry. In this context, this review examines the principles, methods and applications of the sustainable synthesis of pyridines, quinazolinones and coumarins in deep eutectic solvents (DESs), a new class of solvents characterized by low volatility, non-toxicity, ease of preparation and recyclability, often from renewable sources. Special emphasis is placed on synthetic strategies that achieve reaction efficiency while reducing environmental impact, including processes without additional catalysts or with reusable catalysts. The paper provides a comprehensive overview of recent advances and highlights the potential of DESs as a viable alternative to conventional organic solvents in the synthesis of bioactive pyridine, quinazolinone and coumarin compounds. Full article

This bibliometric study examined 179 Scopus-indexed publications on the physical and mechanical properties of medium-density fiberboard (MDF) published between 2016 and 2025. BiblioMagika^® was used for performance analysis, and Biblioshiny was used for keyword co-occurrence, thematic mapping, and thematic evolution. The papers identified as the cohort for analysis had received 2830 citations in total, with an average of 15.81 citations per paper, and an average h-index of 30. The European Journal of Wood and Wood Products and BioResources were the most productive sources. Three distinct categories were identified through keyword mapping among the studies reviewed: (1) advanced composites and reinforcement, (2) adhesive and emission-related studies, and (3) circular-material strategies. Thematic evolution showed a trend away from traditional resin-performance topics toward broader sustainability-related themes, particularly bio-based adhesives and recycling-related topics. Overall, this review provides a quantitative overview of publication patterns, influential sources, and thematic development in MDF research. It also provides direction for future MDF research, focusing on durability, large-scale feasibility, life-cycle assessments, and practical implementation. Full article

Human serum albumin (HSA), as a natural protein carrier, possesses excellent biocompatibility and drug binding capacity. Due to the synergistic effects of the enhanced permeability and retention (EPR) effect and Gp60/SPARC-mediated active targeting, this drug carrier demonstrates favorable tumor selectivity and can be enriched in tumor tissues to achieve long-term therapeutic effects. Particularly, HSA undergoes pH-dependent recycling through the neonatal Fc receptor (FcRn), which significantly prolongs its half-life and enhances its feasibility as a drug delivery platform. In practical clinical applications, the regulation of HSA release rates requires multiple strategies to work synergistically. Additionally, the targeting efficiency of delivery systems due to tumor heterogeneity remains a major bottleneck limiting its universality. This article systematically reviews the unique advantages, clinical applications, challenges, and future perspectives of HSA as a prodrug carrier in tumor therapy. Full article

Water pollution, caused by selenium contamination, is a significant global issue due to its toxic effects on humans and animals. Selenium occurs in several oxidation states, among which selenite and selenate are the most mobile and bioavailable forms. Traditional water treatment methods are often limited in efficiency, whereas adsorption offers a simple, cost-effective, and efficient solution. Various adsorbents, including metal and mineral oxides, carbon-based materials (activated carbon, graphene oxide), biosorbents, and nanocomposites, have shown high potential for Se removal. Adsorbent modifications—physical, chemical, or composite—significantly enhance adsorption capacity, selectivity, and material stability. Studies have demonstrated that nanomaterials and nanocomposites, such as MnFe₂O₄, PAA-MGO, magnetic MOFs, and magnetite-based biochars, enable rapid removal of Se(IV) and Se(VI) with high adsorption capacities. Se(IV) is primarily adsorbed through innersphere complexation, while Se(VI) forms weaker outer-sphere interactions, explaining differences in removal efficiency. Factors such as pH, the presence of surface hydroxyl and amino groups, surface charge, and competing ions strongly influence the adsorption process. Multivalent ions reduce Se adsorption efficiency, whereas monovalent ions (NO₃⁻ and Cl⁻) have minimal impact. Modified adsorbents, nanomaterials, and nanocomposites provide sustainable and practical solutions for selenium removal from water, combining high efficiency, selectivity, and reusability, making them suitable for real-world water treatment applications. Full article

To address the difficulty of efficiently removing calcium impurities from the manganese sulfate stripping solution obtained during the recycling of spent lithium batteries, this work proposed a binary synergistic extraction system. Quantum chemical calculations were used to screen the optimal combination (2A + 2B). The binding energy indicated the molecules combined with calcium are relatively more stable. Experimental optimization determined the optimal conditions as follows: 50 vol% of A, 25 vol% of B, saponification rate 60%, phase ratio (O/A) 2.5:1, and pH 6.0. In continuous extraction tank experiments, the calcium concentration decreased from 681 mg/L to 5 mg/L after a seven-stage counter-current extraction, with an extraction efficiency of about 99.3%. Infrared spectroscopy confirmed that the P=O double bond was the key functional group. This study provides an efficient and feasible technological pathway for the preparation of battery-grade manganese sulfate. Full article