Search Results (55,416)

The transition toward low-carbon energy systems has intensified interest in sustainable hydrogen production technologies. One of the most promising methods for producing green hydrogen is water electrolysis powered by renewable energy. This work reviews recent advances in electrode materials used in four major electrolysis technologies: alkaline (ALK), proton exchange membrane (PEM), solid oxide electrolysis cells (SOEC), and anion exchange membrane (AEM). A bibliometric analysis of scientific publications from 2021 to 2025 highlights the rapid growth of research and the increasing importance of electrode materials in improving electrolysis performance. Operating environments, material requirements, and catalytic properties are compared across these systems. Recent developments in electrocatalysts—including transition-metal alloys, heterostructured catalysts, defect-engineered materials, and nanostructured systems—are evaluated in terms of catalytic activity, durability, and scalability. Particular attention is given to reducing noble metal usage while maintaining high electrochemical performance. Results indicate that transition-metal-based catalysts and engineered interfaces can achieve activity comparable to noble-metal systems while offering better cost efficiency. However, challenges related to long-term durability, large-scale synthesis, and standardized testing persist. Continued interdisciplinary research in materials design and electrochemical engineering is essential to enable efficient, durable, and cost-effective green hydrogen production. Full article

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

Gravity energy storage systems (GESS) have emerged as a promising long-duration energy storage technology capable of supporting large-scale renewable integration and enhancing grid resilience. However, the modeling framework for the hoisting electromechanical subsystem in wire-rope-based GESS remains underdeveloped, thereby limiting the accurate characterization of its transient grid-connected behavior, dynamic operating response, and cross-domain coupling effects. Existing studies commonly simplify wire ropes and related transmission components as rigid bodies or low-dimensional mechanical elements, failing to adequately account for their flexibility and the resulting high-dimensional nonlinear dynamics. Although related studies in mine hoisting and elevator systems have addressed mechanical vibration phenomena, they primarily focus on mechanical-side effects, such as shock loading and guide-structure response, whereas the mechanism by which flexible mechanical vibrations propagate through electromechanical coupling and influence electrical dynamic performance remains inadequately understood. To address this gap, this study establishes a distributed-parameter model for the wire-rope hoisting mechanism based on Hamilton’s principle and solves the corresponding vibration governing equations using the Galerkin method to capture nonlinear multi-modal dynamics. An electromechanical coupling model is then developed to elucidate how rope-vibration-induced tension fluctuations propagate through the drive chain, resulting in torque ripple, electrical interharmonics, and low-frequency grid-side oscillations. A Bessel-function-based analytical representation is further introduced to explain the formation of interharmonic clusters and beat-frequency phenomena under converter modulation. An experimental prototype is constructed to validate the proposed modeling framework. The measured vibration spectra, beat-frequency characteristics, and torque ripple align closely with analytical predictions, confirming the model’s capability to capture key propagation paths from rope vibration to electromechanical oscillation and grid-side dynamic response. The results provide a solid theoretical foundation for vibration mitigation, dynamic analysis, and control design of hoisting electromechanical subsystems in gravity energy storage applications. Full article

This study presents an integrated process for the recovery and purification of lithium hydroxide (LiOH) from lithium sulfate (Li₂SO₄) solution obtained by sulfuric acid leaching of spent crucibles used for producing the cathodes of LIBs. The recovered leachate contains considerable concentrations of metallic impurities, including Na, K, Mg, Ca, Al, and Ni, which hinder the direct production of high-purity LiOH. To overcome this limitation, a pretreatment step combining cation- and anion-exchange resins was introduced to control impurity levels and condition the solution prior to conversion. Under the optimized ion-exchange condition of 10 g cation-exchange resin and 50 g anion-exchange resin, the solution pH was adjusted to 6–7, resulting in effective impurity removal through combined ion-exchange and solution-conditioning effects. More than 90% of Al was removed, while Mg, Ca, Na, K, and Ni were removed by approximately 70–75%. After purification, LiOH was produced through a double-displacement conversion reaction using Ba(OH)₂. The results showed that the reaction temperature and the [OH]:[Li] molar ratio were the key parameters governing the sulfate-removal-based apparent conversion efficiency and filtrate-based LiOH purity. Excess OH⁻ promoted the formation of dissolved and complexed species, thereby lowering the purity of the LiOH-containing filtrate. In contrast, the optimum condition was identified at 70 °C and an [OH]:[Li] molar ratio of 1:1, under which SO₄²⁻ was effectively removed as solid BaSO₄. Under these conditions, the sulfate-removal-based apparent conversion efficiency reached 91.91%, and the filtrate-based LiOH purity was 98.84%. X-ray diffraction analysis confirmed the coexistence of LiOH·H₂O and LiOH phases in the final recovered product, whereas the precipitate was identified as single-phase BaSO₄, indicating effective sulfate removal. Overall, this study demonstrates the feasibility of producing high-purity LiOH from sulfation-derived Li₂SO₄ leachate through a sequential process consisting of impurity removal, conversion, and drying. The findings provide fundamental process data for the design of lithium recovery and purification routes using spent cathode crucibles as secondary lithium resources. Full article

Despite Mozambique’s substantial natural gas reserves, most households rely on solid biomass for cooking, with serious consequences for public health, livelihoods, and the environment. The domestic use of these resources could improve energy efficiency, security, and sustainable development. This mixed-methods study uses household interviews, descriptive statistics, multinomial, and conditional logit models, analyzing data from a random survey of 434 households in energy-rich peripheries of northern Inhambane and Maputo City to ascertain the determinants of household cooking energy choice. Results reveal that rising income increases the odds of choosing electricity, LPG, and biomass over natural gas. In energy-rich peripheries, the odds of selecting biomass over natural gas are reduced by 96.2% compared to non-energy-rich regions. Educational and urban habitation are positively correlated with the adoption of electricity and liquefied petroleum gas (LPG). Price serves as a significant negative predictor of fuel selection (OR ≈ 0.000001), whereby each unit increase in price per GJ substantially diminishes the likelihood of opting for alternatives over domestic gas. Monthly fuel expenditure positively predicts electricity, LPG, and biomass adoption (OR = 1.0042), with effects accumulating meaningfully across realistic spending ranges. Households that experienced energy system incidents were more than twice as likely to switch away from natural gas (OR = 2.072), reflecting the critical role of infrastructure reliability in fuel choice. Given natural gas’s potential as a clean cooking transition fuel, the government should prioritize investment in gas infrastructure, expand domestic supply, and promote public awareness of the health and environmental benefits of clean cooking energy. Full article

Macrofungi are renowned for their rich nutritional and bioactive compounds. This study aimed to assess bioactive compounds, amino acids, and functional properties of flours produced through solid-state fermentation of bean and rice co-products with macrofungi. Three species (Pycnoporus sanguineus, Fistulina hepatica, and Laetiporus cincinnatus) were cultivated in humidified and sterilized broken ‘carioca’ beans or in a mixture of broken beans (70%), rice bran (20%) and broken rice (10%). Following fermentation, the colonized biomass was dried and milled into flour. The sample derived from broken beans cultivated with F. hepatica (102F) exhibited significantly higher β-glucans content (50.75 mg/g) of flour. All fermented flour samples showed elevated essential amino acid levels surpassing those reported in the literature for carioca beans. Phenolic compounds exhibited a notable increase, exceeding threefold in total phenolic content in the fermented samples. Sample 102F particularly excelled in antioxidant and cytotoxic activities. Principal component analysis revealed that these properties were linked to the highest content of β-glucans and specific phenolic compounds, such as sinapic and ellagic acids. These findings indicate that solid-state fermentation effectively enhances the nutritional and bioactive profile of bean and rice co-products, with F. hepatica emerging as the most promising treatment for bean and the bean–rice mixture. Full article

To promote the synergistic utilization of phosphogypsum (PG), steel slag (SS), and fly ash (FA), a ternary all-solid-waste binder, namely PG-SS-FA cementitious material (PSA), was prepared. The effects of SS content on workability, setting behavior, mechanical properties, hydration products, pore structure, and microstructure were systematically investigated. The results showed that increasing SS content continuously reduced the fluidity of PSA, while the setting time first shortened and then increased. The fastest setting was observed at 40% SS, with initial and final setting times of 126 and 321 min, respectively. Increasing SS from 20% to 40% enhanced the hydration reaction, promoted the formation of AFt and C-(A)-S-H gel, reduced residual unreacted phases, and refined the pore structure, resulting in the highest compressive and flexural strengths for M40. However, further increasing SS to 60% and 80% reduced the fly ash proportion and limited the sustained supply of reactive Si/Al species, despite increasing Ca²⁺ availability and alkalinity, thereby restricting later-age gel accumulation and pore refinement and ultimately weakening mechanical performance. Overall, the performance evolution of PSA is governed by the coupled effects of alkali/Ca supply from SS, sulfate supply from PG, and reactive Si/Al supply from FA. The optimal performance at 40% SS is attributed to the synergistic construction of an AFt framework and continuous pore filling by C-(A)-S-H gel. Full article

Oil sands tailings from tailings solvent recovery units (TSRU) contain elevated sulfide minerals and can generate acid mine drainage (AMD) upon atmospheric exposure. This study investigated how prior weathering influences acidity and solute release under controlled laboratory conditions. A six-month column leaching experiment was conducted using TSRU tailings with distinct exposure histories: weathered and semi-weathered tailings from a previous greenhouse-scale reclamation capping experiment, along with weakly weathered tailings stored in sealed barrels. Columns were subjected to repeated wet–dry cycles, analyzing the geochemistry of the leachate and solid-phase changes using X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). All treatments produced highly acidic leachates (pH < 2), indicating that TSRU tailings retain the capacity to generate acidity regardless of prior exposure. However, the dominant geochemical mechanisms differed by weathering history. Weakly weathered tailings generated progressive increases in acidity and solute release, consistent with active sulfide oxidation. Semi-weathered tailings had more stable responses, suggesting partial sulfide depletion and secondary phase formation. Weathered tailings produced leachates showing evidence of rapid flushing with limited new solute generation. After leaching, residual pyrite remained in all materials, with shifts in surface sulfur speciation providing evidence of progressive surface sulfur oxidation, transformation, and the redistribution of sulfate phases. These results demonstrate the mechanisms involved in AMD generation in TSRU tailings, highlighting the importance of the weathering history and the need for field-scale validation. Full article

Agriculture currently faces multiple challenges associated with climate change, the reduction in arable land, and the need to produce food more efficiently in terms of water and nutrient use. This study evaluated an Internet of Things (IoT)-based hydroponic monitoring system with threshold-controlled recirculation for lettuce (Lactuca sativa) under open-field thermal stress conditions, comparing it with a conventional closed recirculating PVC pipe-based hydroponic system operated using fixed pump timing. The architecture integrated an ESP32 microcontroller, sensors for nutrient solution temperature, pH, total dissolved solids (TDS), turbidity voltage, dissolved oxygen (DO), and electrical conductivity (EC), Wi-Fi/HTTPS connectivity, a PHP–MySQL server, and a web interface for near-real-time monitoring. During the growing period, 241,797 readings were recorded between 21 January and 13 February 2026. The threshold-based logic activated the pump mainly according to nutrient solution temperature and DO, while pH, EC, TDS, and relative turbidity voltage were monitored as operational indicators. The sensor-instrumented system operated with pump activation during approximately 28.5% of the monitoring period, while temperature exhibited high variability and peaks of 40.19 °C. Visual crop monitoring showed greater canopy uniformity in the sensor-instrumented system, supporting the technical feasibility of low-cost IoT-based monitoring and threshold-controlled recirculation for open-field hydroponic production of lettuce. Full article

Solid amine adsorbents can capture CO₂ at indoor-relevant concentrations (~1000 ppm), but many high-capacity adsorbents rely on granular or powdery supports that are difficult to integrate directly into air purification systems. Here, we applied three amination strategies to commercial fibrous substrates: bridge-grafting on viscose (TEPA-AMVF), direct grafting on polyacrylonitrile (TEPA-PAN), and physical impregnation on pore-engineered activated carbon fibre felt (PEI-ACF). These adsorbents were systematically screened under simulated indoor conditions (1000 ppm CO₂, 27 °C, 50% RH). A significant capacity difference was observed: TEPA-AMVF (24.8 mg g⁻¹) < TEPA-PAN (35.8 mg g⁻¹) ≪ PEI-ACF (97.0 mg g⁻¹). The superior performance of PEI-ACF was attributed to KOH activation, which produced a mesopore-rich structure (average pore diameter 26.1 nm at an optimal KOH/carbon ratio of 1.25) and enabled high nominal amine utilisation (0.19 mmol CO₂ mmol N⁻¹). PEI-ACF maintained high breakthrough-derived CO₂ uptake across realistic indoor conditions (64.2–118.6 mg g⁻¹ over 0%–100% RH; 71.6–124.5 mg g⁻¹ over 400–5000 ppm CO₂), exhibited rapid kinetics (pseudo-first-order rate constant k = 1.77 h⁻¹; 81.7% of equilibrium uptake within 1 h), and showed stable but partial regeneration over four adsorption–desorption cycles at 60–70 °C under N₂. Compared with granular or resin-based amine sorbents, the self-supporting PEI-ACF felt is expected to offer practical advantages for filter-integrated CO₂ removal, including mechanical integrity under airflow, reduced risk of particle leakage, and compatibility with HVAC filter slots. Remaining challenges include direct pressure-drop validation, operation in O₂-containing indoor air, long-term cycling, and management of CO₂ released during regeneration. Full article

Patterned lead-halide perovskite microstructures are promising for integrated optoelectronics, photonics, and polarization-sensitive devices, but the practical growth behavior of compositionally tunable microcrystals under simple static confinement remains insufficiently understood. Here, we investigate template-assisted confined crystallization of MAPbBr₃ and MAPbBr_3−xCl_x microstructures using patterned polydimethylsiloxane (PDMS) stamps. MAPbBr₃ was first examined as a reference system to evaluate pattern transfer, morphology, substrate compatibility, and characteristic growth imperfections. Periodic microstructures with template spacings from 0.8 to 10 μm were obtained on Si/SiO₂, ITO, PDMS, and MAPbBr₃ macrocrystal substrates. Static stamping creates strong edge–center morphological divergence: thick patterned microcrystals and coalesced domains formed preferentially near the sample edges, whereas thinner isolated microcrystal arrays were more common in central regions. XRD, AFM, SEM, SAED, EDX, HRTEM, PL microscopy, and TRPL analyses show that the method can generate well-crystallized and optically active perovskite domains while also producing multidomain aggregates, incomplete pattern transfer, pressure-induced wrinkling, and nanoscale secondary crystallites. Extension to MAPbBr_3−xCl_x demonstrates that patterned mixed-halide microstructures can be obtained with composition-dependent structural and optical properties. Nevertheless, XRD, EDX, PL, and TRPL results indicate that Cl-rich samples are not fully described by a simple homogeneous solid-solution model, likely involving compositionally heterogeneous crystallization and a Br-rich emissive component. Preliminary MAPbCl₃-on-MAPbBr₃ experiments further show that PDMS-confined patterning can be coupled with substrate-mediated halide exchange or interfacial recrystallization. Overall, static PDMS-confined crystallization is established as a simple exploratory platform for producing diverse patterned perovskite microstructures. This approach is well-suited for the manual selection of suitable crystals and the fabrication of individual microdevices; however, improved control over pressure, mass transport, nucleation localization, and composition will be required when the uniformity of produced patterned microcrystals is desired. Full article

Propyl gallate (PG) is an effective food antioxidant, but its performance in food systems may be limited by poor water compatibility and processing instability. In this study, rice starch was used as a carrier matrix to prepare starch–PG complexes by extrusion cooking, and the effects of PG incorporation on starch structure, antioxidant activity, and in vitro digestibility were evaluated. Starch was blended with PG at 0, 25, 50, and 100 mg/g and processed by extrusion, and the resulting samples were characterized by complex index analysis, small-angle X-ray scattering, Fourier-transform infrared spectroscopy, solid-state carbon-13 nuclear magnetic resonance, X-ray diffraction, pasting and rheological measurements, 1-diphenyl-2-picrylhydrazyl (DPPH) radical-scavenging assay, in vitro digestibility, and density functional theory calculation. Extrusion disrupted the native semi-crystalline structure of starch, while PG incorporation promoted complex formation, with the highest complex index (88.28%) observed at 50 mg/g PG. Structural analyses indicated increased short-range order, higher single-helical content, and the development of V-type crystalline features in the PG-containing extruded starches. These starches also retained DPPH radical-scavenging activity and showed slower in vitro starch hydrolysis, with resistant starch increasing to 25.78%. Overall, extrusion cooking appears to be a feasible approach for preparing starch–PG complexes that preserve antioxidant functionality and reduce in vitro digestibility. Full article

To promote the high-value utilization of industrial solid wastes and address the disposal of excavated soils, a novel low-carbon composite cementitious material, solid waste-based geopolymer cement (SGPC), was developed, consisting of soda residue (SR), granulated blast furnace slag (GGBS), phosphogypsum (PG), and ordinary Portland cement (PC) in a mass ratio of 10:81:9:25, with industrial solid wastes accounting for 80% of the binder. The effects of water-to-solid ratio (W/S = 0.41–0.49) on the workability, mechanical performance, and microstructural evolution of SGPC-stabilized soil were systematically investigated to provide a sustainable alternative to conventional cement-based stabilizers. The results indicate that the optimum water-to-solid ratio is 0.43 (SGPC43), with a 28-day unconfined compressive strength of 1450 kPa, exceeding the engineering requirement of 0.8 MPa and reaching over 85% of that of a pure cement system (C43). The flowability remained 163 mm after 60 min, with initial and final setting times of 43 h and 58 h, respectively. Microstructural analysis revealed that the alkalinity provided by soda residue promotes the hydration of slag and phosphogypsum, forming interwoven calcium (alumino) silicate hydrate (C–(A)–S–H) and ettringite (AFt), which fill pores and form a dense structure, thereby enhancing mechanical performance. Environmental and economic assessments show that the CO₂ emission of SGPC43 per ton of binder decreases from 930 kg CO₂-e/t to 235 kg CO₂-e/t (approximately 74.7% reduction), while the material cost decreases from 110 USD/t to 53 USD/t (approximately 51.8% reduction). A simplified uncertainty analysis indicates that the carbon reduction remains at 70% ± 5% and the cost reduction at 50% ± 5%, confirming the robustness of the results. Overall, SGPC43 demonstrates excellent engineering performance, environmental benefits, and economic feasibility, highlighting its potential as a low-carbon and sustainable stabilizing material. Full article

Coal has been Malaysia’s primary energy source for electricity generation for the past few decades, resulting in increased greenhouse gas emissions and irreversible environmental damage. Solid Oxide Fuel Cells (SOFCs) have emerged as a viable clean-energy alternative to mitigate these environmental effects. There has been significant emphasis on developing pollution-free technology, with limited attention given to the environmental impact of SOFC. Research and development efforts have primarily focused on the design and technical aspects of SOFC. Prior to the introduction of SOFC to market, quantifying the environmental footprint of SOFC manufacturing is necessary to support a sustainable energy transition. This study conducts a comprehensive Life Cycle Assessment (LCA) of SOFC manufacturing in accordance with ISO 14040 and 14044 standards. The analysis focuses on a planar electrolyte-supported SOFC with a lifespan of 4.57 years, using a functional unit of 1 kWh electrical output. The Environmental Footprint (EF) 3.1 method implemented in GaBi Software was used for the impact assessment. Key environmental impact categories considered in the LCA include Climate Change (CC), Acidification Potential (AP), Eutrophication Potential (EP), Ozone Depletion Potential (ODP), Photochemical Ozone Formation (POF), and Human Toxicity Potential (HTP). The total climate change impact is approximately 19.674 kg CO₂ eq./kWh, with the Balance of Plant (BoP) phase contributing 91% of this impact, while the fuel cell stack phase contributes 1.25%. The study identifies key areas for improvement, primarily related to BoP and other high-impact processes, and emphasizes the importance of targeted measures to effectively reduce the environmental impacts associated with SOFC manufacturing. Full article