Search Results (4,893)

Municipal solid waste landfills may remain sources of environmental concern long after closure because heavy metals can persist in soils and affect ecosystem recovery. This study presents an integrated assessment of a closed municipal solid waste landfill in Kokshetau, Northern Kazakhstan, by combining field-based soil geochemical analysis with remote sensing monitoring of vegetation dynamics. A radial-gradient sampling design was used to characterize spatial patterns of contamination and to distinguish zones with different levels of anthropogenic impact. The results showed a clear concentration of heavy metals, particularly Zn and Pb, in the central part of the landfill, where integrated pollution and ecological risk indices indicated the highest levels of technogenic pressure. Time-series analysis of Landsat-derived vegetation indices for 2017–2025 revealed poorer vegetation condition in the most contaminated areas, with NDVI and EVI values increasing toward the landfill periphery. The observed negative association between vegetation indices and ecological risk suggests that remote sensing indicators can provide useful information on the ecological condition of closed landfill sites, although they should be interpreted together with field measurements. The novelty of this study lies in the combined use of geochemical contamination indices and long-term vegetation-index monitoring to assess post-closure landfill conditions in an arid continental region of Central Asia, where such integrated studies remain limited. The findings highlight the persistence of environmental risks after landfill closure and support the use of vegetation indices as non-invasive tools for monitoring rehabilitation and prioritizing further field investigations. Full article

Achieving a circular and climate-neutral bioeconomy by 2050 requires not only high-quality recycling but also the large-scale integration of renewable carbon from biomass and atmospheric CO₂ into material systems. Plastics represent the world’s largest and most rapidly growing carbon sink, positioning them as a critical intervention point for replacing fossil-based feedstocks with renewable alternatives. Because plastic packaging is one of the most visible material streams encountered by consumers in daily life, a transition toward sustainable, recyclable bioplastics has the potential to deliver both meaningful environmental benefits and strong societal impact, accelerating public awareness and acceptance of renewable carbon solutions. Poly(ethylene furanoate) (PEF)—a fully bio-based polyester synthesized from plant-derived 2,5-furandicarboxylic acid (FDCA) and monoethylene glycol (MEG)—offers a promising pathway toward more sustainable packaging due to its superior mechanical strength and gas-barrier performance relative to polyethylene terephthalate (PET). This study presents a cradle to grave life cycle assessment (LCA) of PEF resin production and PEF bottle applications, using industrially relevant, at-scale process data covering biomass feedstock conversion, polymer synthesis, packaging manufacture, use phase, and end of life. Bottle applications were selected as a focal point due to their technical maturity, commercial relevance, and suitability for direct comparison with incumbent PET systems. The results indicate that PEF can reduce greenhouse gas emissions by up to 71% and fossil resource depletion by 26% compared to PET at the resin level when biogenic carbon uptake is included. Moreover, the material’s enhanced functional properties enable lightweight, recyclable bottle designs with carbon footprint reductions of up to 88% for 500 mL formats under a baseline recycling rate scenario of 72%, with the remaining share directed to municipal solid-waste incineration with energy recovery. Sensitivity analyses reveal that virgin PEF maintains environmental advantages over PET even when PET incorporates high levels of recycled content, highlighting the complementary roles of renewable carbon and circular material strategies. Prospective scenario modeling underscores the importance of sustainable feedstock selection and process electrification, with sucrose-based routes offering the largest potential for further decarbonization. Overall, the findings demonstrate that PEF is a scalable biopolymer capable of delivering substantial climate benefits while supporting circularity objectives. By targeting a highly visible consumer application—plastic packaging—this transition amplifies the societal impact of adopting renewable carbon materials. The study provides actionable insights for policymakers, industry stakeholders, and sustainability practitioners working to advance a more resilient, renewable, and consumer-recognizable plastics economy. Full article

The overuse of mineral fertilizers has brought about numerous matters such as deteriorating soil health, crop safety concerns, and environmental pollution. The global requirements for effective waste handling and sustainable agricultural production have been growing continuously. Therefore, integrated nutrient management method might be a key way to achieve circular agriculture, such as replacing chemical fertilizers with organic fertilizers. In modern agriculture, digestate that is a byproduct of anaerobic digestion as a fertilizer is becoming increasingly favored as a viable method for improving crop yield and quality. However, the application of digestate in agriculture have not yet been fully explored. This review addresses a knowledge gap by synthesizing current research on digestate as a fertilizer. Firstly, the physical–chemical and biological properties of digestate are discussed. Following that, this review focuses on its specific impact on crop growth and quality. Lastly, it outlines the challenges faced in the application of digestate and looks ahead to future trends. With appropriate policy support and technological innovation, digestate holds promise for advancing environmental sustainability. This review aims to provide direction and reference for future research on the application of digestate. Full article

The railway sector is crucial for transportation, but infrastructure maintenance generates significant waste and requires large amounts of materials, increasing environmental impact. Circular economy integration mitigates this impact through material recovery. This study focused on the recycling of bushes embedded in railways sleepers, currently disposed of in landfills, obtaining high-density polyethylene (HDPE). The developed scalable process converted contaminated bushes into pellets, whose environmental sustainability was assessed through life cycle analysis. Challenges of the recycled material, such as high viscosity and heterogeneity, were partially addressed with a slipping agent and a compatibilizer, increasing the material melt index from 0.71 to 1.62 g/10 min. Carbon fiber waste addition improved thermal stability, mechanical stiffness, and electrical conductivity. Compatibilized blends offered the best balance of mechanical properties but lower electrical conductivity. The Young modulus was increased from 1.20 GPa for the neat matrix to 4.40 GPa for the system containing 30% carbon fibers in weight, with no significant decreases in the yield stress, while showing the lowest electrical conductivity. To reduce environmental impact and produce a tougher material without compromising conductivity, the compatibilizer was replaced with HDPE from PET bottle caps, resulting in comparable mechanical properties and higher electrical conductivity but reduced fiber/matrix interface. Full article

As a major global sugar crop and lignocellulosic feedstock, sugarcane processing traditionally suffers from single-product dependency and low byproduct utilization, causing resource waste and environmental factors. To address this, the ‘sugarcane processing tree’ framework offers a pathway for full-component valorization. This review systematically summarizes the high-value utilization pathways for sugarcane juice, bagasse, and filter mud. Key quantitative insights reveal that the functional sugars offer high profitability due to premium market prices; bagasse pretreatment constitutes 40–50% of overall biorefinery costs; and crude wax recovery from filter mud stagnates at only 5–8%, limiting commercial scale-up. Current bottlenecks are characterized by low pretreatment efficiency, subpar strain performance, and high isolation costs. Future advancements must integrate coupled biorefining, synthetic biology, and standardized frameworks to spearhead the low-carbon, circular transition of the sugarcane industry for sustainable development. Full article

Cheese production generates large volumes of whey, and high-strength wastewater with elevated organic load, salinity, and nutrient content. Although whey contains valuable components including lactose, proteins, and minerals, approximately half of global production remains underutilized, contributing to eutrophication and oxygen depletion in aquatic ecosystems. Conventional physicochemical and biological treatment methods are limited by high operational costs, energy demands, and secondary waste generation. Microalgae-based bioremediation has emerged as a promising sustainable strategy for whey valorization, enabling simultaneous nutrient removal and biomass production. Through a focused review of the current literature, this study analyzes microalgal strains commonly applied in whey remediation, their cultivation modes (photoautotrophic, heterotrophic, and mixotrophic), nutrient uptake mechanisms, and operational conditions. The review highlights cultivation systems, biomass recovery techniques, and potential conversion of microalgal biomass into high value bioproducts, including biofuels, pigments, proteins, and biofertilizers. Critically, a major research gap exists: no studies systematically examine whey-grown microalgal biomass for bioplastic or film production, despite its elevated polysaccharide and protein content. Future development requires integrated biorefinery approaches, optimized cultivation strategies, and supportive policy frameworks to enable large-scale circular economy implementation within the dairy industry. Full article

Hydrothermal carbonization (HTC) of wet biomass faces a fundamental tradeoff between higher heating value (HHV) and energy recovery (ER), where conditions that enhance carbon densification often reduce solid-phase energy retention. This study investigates whether co-biomass selection combined with citric acid (CA) catalysis can overcome this tradeoff in HTC of water hyacinth (WH), an invasive aquatic feedstock. WH was co-processed with wheat straw (WS), rice husk (RH), and chicken manure (CM) at 240–270 °C, with CA-assisted experiments performed at 240 °C. Individual feedstock HTC confirmed the HHV–ER tradeoff, and co-HTC without catalysis failed to resolve it. CA addition improved carbon densification but reduced ER when applied to WH alone. The WH–CM–CA system uniquely achieved a concurrent HHV of 21.3 MJ kg⁻¹ and ER of 95.8%, with synergistic effects of 50.0% and 29.7%, respectively. FTIR and elemental analysis indicated that Maillard-type condensation between WH-derived sugars and CM-derived amino acids drove preferential solid-phase carbon retention. These findings demonstrate that resolving the HHV–ER tradeoff requires coupling CA catalysis with biochemical complementarity between carbohydrate-rich and protein-rich feedstocks. This approach provides a practical route for hydrochar production with high energy density and recovery for waste-to-energy applications, supporting circular and low-carbon valorization of invasive aquatic biomass and livestock waste streams. Full article

Sarcopenia, characterized by progressive loss of muscle mass and function, is highly prevalent among patients with heart failure (HF) and contributes to frailty, disability, and poor prognosis. Shared mechanisms—chronic inflammation, neurohormonal dysregulation, mitochondrial dysfunction, inactivity, and inadequate nutrition—promote anabolic resistance and accelerate muscle wasting. This narrative review summarizes current evidence on the interplay between HF and sarcopenia, focusing on practical strategies for integrated management. Exercise training, particularly combined aerobic and resistance programs, improves physical performance and quality of life, while targeted nutritional interventions ensure adequate energy and protein intake and mitigate malnutrition. Emerging evidence supports the synergistic benefit of coupling tailored dietary support with structured rehabilitation. Despite robust data, implementation of person-centered, multidisciplinary care remains limited. Routine screening for sarcopenia and nutritional risk should be embedded in HF pathways to enable early intervention, functional recovery, and improved long-term outcomes. Full article

Gold, as a critical material with both financial and industrial value, is widely used across numerous fields such as finance, aerospace and medical care. Under the global background of increasing geopolitical risks and the advancement of high-tech industries, the demand for gold continues to grow steadily. The main raw materials for extracting gold are mainly divided into ore and electronic waste. Currently, conventional cyanidation remains the dominant industrial method for gold recovery. However, issues such as pollution and high toxicity of cyanide tailings are driving global efforts to explore environmentally friendly alternatives. Therefore, the development of green and efficient gold extraction technology has become a global research hotspot. This article focuses on cyanide-free leaching technologies, providing a detailed review of their current developments, advantages, and limitations, and proposing future trends in gold extraction. The future development directions of gold extraction include the development of thiosulfate–glycine leaching systems, the combination of multi-technology collaborative processes such as ultrasonic assistance and biological treatment to enhance efficiency, the strengthening of microbial metallurgy technology, and the construction of a resource recycling system for electronic waste. This review provides new insights and development directions for extracting gold for sustainable development. Full article

The transition to climate neutrality necessitates a profound transformation of mining systems. In this context, this study focuses on reviewing the role of circular economy models in transforming mining systems. Circular models propose reconfiguring systems into climate-neutral and more resource-efficient configurations. A synthesis of recent literature highlights several circular strategies frequently addressed throughout the mining life cycle. These include waste recovery, secondary resource recovery, water reuse, and the integration of renewable energy. The outcomes of circular approaches have the potential to reduce greenhouse gas emissions and resource consumption. They can also help improve the system’s efficiency through the creation of new economic value streams. Large scale implementation remains constrained because of economic, technological, and governance factors. In light of these findings, the paper recommends an integrated conceptual framework. It ties circular strategies to decarbonization pathways and sustainability outcomes. It does so because the circular economy is not merely a supporting approach but a necessary mechanism to enable the transition to climate-neutral and regenerative mining systems. Full article

The industrial extraction of chitin from shrimp shell waste conventionally employs corrosive chemical treatments, which pose significant environmental hazards and compromise polymer integrity. This study introduces a sustainable and highly efficient microbial biorefining strategy for the recovery of α-chitin from Litopenaeus vannamei shells, utilizing a sequential fermentation framework. Two potent strains—Bacillus haynesii MGPUMGRI, known for its proteolytic capabilities, and Lactobacillus delbrueckii MGPUMGRI, which produces lactic acid—were isolated and optimized. A notable technical achievement was the purification of an approximately 40 kDa extracellular alkaline protease from B. haynesii, which demonstrated optimal activity at pH 9.0 and 37 °C. Under optimized conditions, the sequential process—emphasizing enzymatic deproteinization (72.30 ± 1.56%) followed by lactic acid-mediated demineralization (84.98 ± 1.96%)—achieved a high-purity chitin recovery of 61.33 ± 1.06%. Comprehensive characterization using SEM-EDX, FTIR, and XRD confirmed the successful preservation of the α-chitin polymorphic structure, which exhibited a fragmented fibrillar morphology and a crystallinity index (CrI) of 60.51%. These findings indicate that this dual-strain bioprocess offers a scalable and environmentally friendly alternative for the valorization of seafood waste into high-quality biogenic polymers, while minimizing the ecological impact of chitin production. Full article

Recyclers worldwide face a common bottleneck: incoming mixed plastic bales are chemically opaque, yet the choice between mechanical recycling, chemical recycling, and energy recovery hinges on contaminant levels that cannot be judged by visual inspection alone. This study develops and validates a tiered analytical decision-support framework that translates standard laboratory measurements into explicit, actionable go/no-go routing criteria for any mixed polyolefin waste stream. The framework is organized into three successive analytical tiers of increasing specificity: Tier 1 uses FTIR and DSC for rapid polymer identification and thermal subclass confirmation; Tier 2 applies TGA/DTG for thermal stability assessment and filler quantification; and Tier 3 deploys ICP-OES, WD-XRF, CIC, and TG–MS for targeted heavy metal, halogen, and evolved gas profiling, triggered only when Tier 1/2 flags are raised. This staged logic minimizes unnecessary testing while ensuring that contaminant-relevant information is captured where it matters. The framework is demonstrated on nine blind mixed plastic waste streams (P1–P9) supplied by an industrial recycling facility without prior disclosure of polymer identity, filler content, or additive history—conditions that replicate the uncertainty encountered at any sorting plant globally. Application of the tiered protocol identified dominant polymers (HDPE, LDPE, PP), quantified inorganic fillers (CaCO₃ up to ~38 wt%), and detected hazardous contaminants, including chlorine (up to ~1900 ppm), lead, chromium, and titanium, enabling each stream to be assigned to a specific recycling route with defined contaminant thresholds. Because the method relies exclusively on commercially available, vendor-independent instrumentation and follows a reproducible, rule-based decision logic, it is directly transferable to recycling facilities in any geographic context without site-specific calibration. The proposed framework thus provides a practical, scalable decision-support tool for feedstock-level quality control under emerging regulations such as the UNEP Global Plastics Treaty. Full article

This work presents, for the first time, a novel cross injection analysis (CIA) system for the simultaneous multi-determination of key biomarkers associated with diabetic nephropathy—namely, albumin, creatinine, and glucose—within a single analytical run. Unlike conventional flow-based techniques that rely on sequential measurements, the proposed CIA platform integrates multiple analytical pathways into a unified design, enabling one-shot multi-analyte analysis without the need for complex separation units or injection valves. The system employs peristaltic pumps and a rectangular platform with orthogonal flow channels, allowing concurrent aspiration and efficient transport of reaction products to compact detectors. Albumin determination was based on ion-association with tetrabromophenolphthalein ethyl ester. Creatinine was measured using the Jaffé reaction. Glucose was colorimetrically detected via its reaction with 3,5-dinitrosalicylic acid. The developed CIA provides enhanced sensitivity through its pre-mixing effect, enabling reliable quantification of trace analytes. Excellent analytical performance was achieved, including wide linear ranges (r² > 0.99), good precision (RSD < 7%), and rapid analysis (5 min). The method was validated against established reference methods, showing no significant differences, and successfully applied to urine with satisfactory recoveries (84.8–107.3%). Importantly, the proposed system adheres to green chemistry by minimizing reagent consumption and waste generation, offering a sustainable approach for multi-parameter clinical analysis. Full article

Waste heat recovery from automotive exhaust gases represents an important strategy for improving vehicle energy efficiency. This study experimentally investigates the performance of a thermoelectric generator (TEG) system based on TEC1-12706 modules running under different cold-side cooling conditions and incorporating a Hot Rolled Steel (HRS) protective layer on the hot side. The HRS plate was used to ensure uniform heat distribution and protect the thermoelectric module against thermal shocks generated by a 250 °C heat source. Four cooling regimes were experimentally analyzed: natural convection and forced airflows equivalent to 40, 60, and 90 km/h. The results proved that increasing airflow intensity significantly improved the temperature difference across the module, from approximately 16 ± 2 °C under natural convection to nearly 40 ± 2 °C at the highest airflow velocity. Correspondingly, the steady-state voltage generated increased from approximately 0.25 ± 0.01 V to over 0.60 ± 0.01 V under an 82 Ω resistive load. The measured hot-side temperature remained below 75 °C in all experimental conditions, confirming the thermal protection capability of the HRS layer. The experimental data also revealed a near-linear relationship between voltage and temperature difference, consistent with the Seebeck effect. The proposed configuration shows the feasibility of combining thermal protection and forced convection cooling to improve the stability and electrical performance of thermoelectric waste heat recovery systems intended for low-power automotive auxiliary applications. Full article

The geographic and economic contexts play a major role in decision-making when it comes to municipal solid waste management. In the present study, simulations are carried out using the Waste and Resource Assessment Tool for the Environment (WRATE) software academic version 3.0.1, based on the Ecoinvent database (version 2) to assess the greenhouse gas emissions released by 1 ton of municipal solid waste with a typical composition characterizing upper middle-income countries, with an organic fraction of approximately 50% by weight. The variation over time (2000 to 2022) with no intended transformation in the management strategy is first analyzed, then several transformations are applied by varying the waste management routes (open dumping, landfilling, recycling and composting) as well as the energy recovery integration. The results are then discussed based on the waste categories and the performed operations (landfilling, recycling, transportation, treatment and recovery). The results revealed that the most promising scenario includes limited open dumping that does not exceed 10%, landfilling with at least 20% energy recovery, and major fractions addressed to composting and recycling. Overall, this scenario returns a negative carbon footprint with a value of approximately−0.35 tons of CO₂-Eq/ton of MSW. Results are mostly applicable to countries with similar waste composition and infrastructure levels; preconditions include source segregation, compost markets, and landfill gas infrastructure. Full article