Search Results (1,851)

The oily wastewater produced by transformer oil leakage contains pollutants such as mineral oil, metal particles, aged oil and additives, which can disrupt the dissolved oxygen balance in water bodies, pollute soil and endanger human health through the food chain, causing serious environmental pollution. Effective oil–water separation technology is the key to ecological protection and resource recovery. This paper reviews the principles, influencing factors and research progress of traditional (gravity sedimentation, air flotation, adsorption, demulsification) and new (nanocomposite adsorption, metal–organic skeleton materials, superhydrophobic/superlipophilic modified films) transformer oil–water separation technologies. Traditional technologies are mostly applicable to large-particle-free oil and are difficult to adapt to complex matrix wastewater. However, the new technology has significant advantages in separation efficiency (up to over 99.5%), selectivity and cycling stability (with a performance retention rate of over 85% after 20–60 cycles), breaking through the bottlenecks of traditional methods. In the future, it is necessary to develop low-cost and efficient separation technologies, promote the research and development of intelligent responsive materials, upgrade low-carbon preparation processes and their engineering applications, support environmental protection treatment in the power industry and encourage the coupling of material innovation and processes. Full article

The fiberboard industry remains heavily reliant on synthetic, formaldehyde-based adhesives, which, despite their cost-effectiveness and strong bonding performance, present significant environmental and human health concerns due to volatile organic compound (VOC) emissions. In response to growing sustainability imperatives and regulatory pressures, the development of non-toxic, renewable, and high-performance bio-based adhesives has emerged as a critical research frontier. This review, conducted through both narrative and systematic approaches, synthesizes current advances in green adhesive technologies with emphasis on lignin, tannin, starch, protein, and hybrid formulations, alongside innovative synthetic alternatives designed to eliminate formaldehyde. The Evidence for Policy and Practice Information and Coordinating Centre (EPPI) framework was applied to ensure a rigorous, transparent, and reproducible methodology, encompassing the identification of research questions, systematic searching, keywording, mapping, data extraction, and in-depth analysis. Results reveal that while bio-based adhesives are increasingly capable of approaching or matching the mechanical strength and durability of urea–formaldehyde adhesives, challenges persist in terms of water resistance, scalability, cost, and process compatibility. Hybrid systems and novel crosslinking strategies demonstrate particular promise in overcoming these limitations, paving the way toward industrial viability. The review also identifies critical research gaps, including the need for standardized testing protocols, techno-economic analysis, and life cycle assessment to ensure the sustainable implementation of these solutions. By integrating environmental, economic, and technological perspectives, this work highlights the transformative potential of green adhesives in transitioning the fiberboard sector toward a low-toxicity, carbon-conscious future. It provides a roadmap for research, policy, and industrial innovation. Full article

Dissolved organic matter (DOM) is central to biogeochemical cycles in estuarine-coastal zones, with its source-sink dynamics linking regional ecological functions to global carbon budgets. As a typical semi-enclosed bay in southern China, Zhanjiang Bay (ZJB) features intense tidal mixing and significant seasonal runoff variations, making it a representative system for understanding DOM dynamics in complex land–sea interaction zones. The migration of dissolved organic carbon (DOC) is crucial for bay carbon budgets, yet its estimation is constrained by land–water interface dynamics and in situ observation limitations. To clarify the regulation of DOM’s fate and exchange flux in ZJB, this study integrated in situ observations, ultraviolet spectroscopy, and three-dimensional fluorescence techniques to analyze DOM tidal dynamics and net DOC exchange flux. Results indicated terrestrial runoff dominated rainy-season DOC sources, resulting in slightly higher concentrations (1.86 ± 0.46 mg·L⁻¹) compared to the dry season (1.82 ± 0.20 mg·L⁻¹). Terrestrial inputs endowed rainy-season DOM with high molecular weight and aromaticity, with microbial humic substances (C2) accounting for 36%. Tidal fluctuations affected DOC via water exchange: ebb tides diluted concentrations with low-DOC open-ocean seawater, while flood tides increased them through high-DOC bay water discharge. Dry-season DOM relied on in situ biotransformation, characterized by low molecular weight and aromaticity, with the protein-like fraction (C4) accounting for 24.3%. Fluorescence index (FI = 1.77–1.79) confirmed DOM as a mixture of allochthonous and autochthonous sources, with significant in situ contributions and weak humification. Net DOC exchange flux, regulated by terrestrial runoff, was 3.6–4.6 times higher in the rainy season, decreasing from the estuary to the coast. In conclusion, the joint regulation of terrestrial runoff-driven seasonal dynamics and tidal water exchange governs ZJB’s DOM dynamics, providing valuable insights for biogeochemical research in semi-enclosed bays. Full article

Wildfires alter multiple soil functions in forest ecosystems, but how they reconfigure the linkages between these functions is not fully understood. We evaluated the 1-year-postfire and 11-year-postfire effects of wildfire on carbon sequestration, nutrient cycling, fertility maintenance, and erosion regulation, as well as their relationships, in a Chinese boreal larch forest. We further identified the environmental drivers regulating these associations. One year postfire, the soil fertility index transiently increased by 85%, whereas the carbon sequestration and nutrient cycling declined by 58% and 54%, respectively. Principal component analysis showed that wildfire decoupled the multivariate relationships between four soil functions. While these functions were closely clustered in unburned controls, they became dispersed one year postfire, indicating functional dissociation. After eleven years of recovery, a partial reassembly occurred, but with a reconfigured functional structure distinct from the pre-fire state. For the functional pairs, the impact of wildfire was limited to shifting the relationship between the soil fertility and nutrient cycling from a non-significant negative correlation to a significant positive correlation. Redundancy analysis showed that the soil water content remained the primary environmental driver of soil functional relationships before and after the fire, but its role reversed from negative in unburned stands to positive during the postfire recovery, suggesting a shift toward water-mediated functional coupling. Wildfires in boreal forests have far-reaching effects on soil ecosystems, including impacts on the relationships between various soil functions. Our results indicate that wildfire reconfigures the network of soil function linkages in boreal forests, with implications for the recovery of boreal soil ecosystems. Full article

This study presents an integrated Life Cycle Sustainability Assessment (LCSA) of the Natural gas-to-methanol (NGTM) and methanol-to-gasoline (MTG) pathways using Aspen HYSYS process modeling, Environmental Life Cycle Assessment (LCA), Social Life Cycle Assessment (SLCA), and Life Cycle Costing (LCC). The results reveal significant variability in sustainability performance across process units. The DME and MTG Reactors Section generates the highest direct greenhouse gas (GHG) emissions at 0.86 million tons CO₂-eq, representing 54.9% of total global warming potential, while the Compression Section consumes 2717.5 TJ/year of energy, making it the dominant source of electricity-related indirect emissions. Distillation and Purification withdraws 31,100 Mm³/year of water—approximately 99% of total demand—yet delivers 86.6% of the overall economic surplus despite high operating costs. Social impacts concentrate in the Methanol Reactor Looping and DME and MTG Reactors Sections, with human health burdens of 305.79 and 804.22 DALYs, respectively, due to catalyst handling and high-pressure operations. Sensitivity results show that methanol purity rises from 0.9993 to 0.9994 with increasing methane content, while gasoline output decreases from 3780 to 3520 kg/h as natural gas flow increases. The findings provide process-level evidence to support sustainable development of natural gas-based fuel conversion industries, aligning with Qatar National Vision 2030 objectives for industrial diversification and lower-carbon energy systems. Full article

In the context of carbon neutrality, the large-scale integration of renewable energy sources has led to frequent load changes in coal-fired boilers. These fluctuations cause key operational parameters to deviate significantly from their design values, undermining combustion stability and reducing operational efficiency. To address this issue, we introduce a novel predictive control method to enhance the control precision of key parameters under complex variable-load conditions, which integrates a coupled predictive model and real-time optimization. The predictive model is based on a coupled Transformer-gated recurrent unit (GRU) architecture, which demonstrates strong adaptability to load fluctuations and achieves high prediction accuracy, with a mean absolute error of 0.095% and a coefficient of determination of 0.966 for oxygen content (OC); 0.0163 kPa and 0.987 for bed pressure (BP); and 0.300 °C and 0.927 for main steam temperature (MST). These results represent substantial improvements over lone implementations of GRU, LSTM, and Transformer models. Based on these multi-step predictions, a WOA-based real-time optimization strategy determines coordinated adjustments of secondary fan frequency, slag discharger frequency, and desuperheating water valves before deviations occur. Field validation on a 300 t/h boiler over a representative 24 h load cycle shows that the method reduces fluctuations in OC, BP, and MST by 62.07%, 50.95%, and 40.43%, respectively, relative to the original control method. By suppressing parameter variability and maintaining key parameters near operational targets, the method enhances boiler thermal efficiency and steam quality. Based on the performance gain measured during the typical operating day, the corresponding annual gain is estimated at ~1.77%, with an associated CO₂ reduction exceeding 6846 t. Full article

Decarbonizing industry, improving urban sustainability, and expanding clean energy use are key global priorities. This study presents a techno-economic analysis (TEA) and life-cycle assessment (LCA) of green hydrogen (GH₂) production via water electrolysis for low-carbon applications in the Central Asian region, with Uzbekistan considered as a representative case study. Solar PV and wind power are used as renewable electricity sources for a 44 MW electrolyzer. The assessment also incorporates recent advances in alkaline water electrolyzers (AWE) enhanced with metal–organic framework (MOF) materials, reflecting improvements in efficiency and hydrogen output. The LCA, performed using SimaPro, evaluates the global warming potential (GWP) across the full hydrogen production chain. Results show that the MOF-enhanced AWE system achieves a lower levelized cost of hydrogen (LCOH) at 5.18 $/kg H₂, compared with 5.90 $/kg H₂ for conventional AWE, with electricity procurement remaining the dominant cost driver. Environmentally, green hydrogen pathways reduce GWP by 80–83% relative to steam methane reforming (SMR), with AWE–MOF delivering the lowest footprint at 1.97 kg CO₂/kg H₂. In transport applications, fuel cell vehicles powered by hydrogen derived from AWE–MOF emit 89% less CO₂ per 100 km than diesel vehicles and 83% less than using SMR-based hydrogen, demonstrating the substantial climate benefits of advanced electrolysis. Overall, the findings confirm that MOF-integrated AWE offers a strong balance of economic viability and environmental performance. The study highlights green hydrogen’s strategic role in the Central Asian region, represented by Uzbekistan’s energy transition, and provides evidence-based insights for guiding low-carbon hydrogen deployment. Full article

The behavior of the carbon cycle within the Land-Ocean Aquatic Continuum (LOAC) is shaped not only by aquatic processes but also by chemical interactions occurring at the atmosphere–water interface. In particular, the transport of acid rain precursors such as SO₂ and NO_x to surface waters via deposition can alter the water’s pH balance, thereby affecting Dissolved Inorganic Carbon (DIC) fractions and CO₂ emission potential. In this study, air quality measurements from three monitoring stations (Bosna, Karatay, and Meram) in Konya province of Türkiye, along with precipitation and temperature data from a representative meteorological station for the period 2021–2023, were analyzed using the Mann–Kendall Trend Test. Additionally, seasonal pH values of groundwater were examined, and their trends were compared with those of the other variables. The findings reveal striking differences on a station basis. At the Bosna station, while NO (Z = 10.80), NO₂ (Z = 9.47), and NO_x (Z = 10.04) showed strong increasing trends, O₃ decreased significantly (Z = −15.14). At the Karatay station, significant increasing trends were detected for CO (Z = 10.01), PM₁₀ (Z = 8.59), SO₂ (Z = 5.55), and NO_x (Z = 2.44), whereas O₃ exhibited a negative trend (Z = −6.54). At the Meram station, a significant decrease was observed in CO (Z = −11.63), while NO₂ showed an increasing trend (Z = 3.03). Analysis of meteorological series indicated no significant trend in precipitation (Z = −0.04), but a distinct increase in temperature (Z = 2.90, p < 0.01). These findings suggest that the increasing NO_x load in the Konya atmosphere accelerates O₃ consumption and, combined with rising temperatures, creates a potential for change in the carbon chemistry of aquatic systems. The results demonstrate that atmospheric pollutant trends constitute an indirect but significant pressure factor on the aquatic carbon cycle in semi-arid regions and highlight the necessity of integrating atmospheric processes into carbon budget analyses within the scope of LOAC. Full article

Lake sediments on the Tibetan Plateau serve as crucial carbon sinks in the regional carbon cycles. In recent decades, climate change has triggered significant hydrological changes in many lakes across this region, potentially impacting their carbon-sink functions. Previous studies have predominantly focused on the dynamics of organic carbon burial, largely overlooking the contribution of inorganic carbon sinks, and particularly lacking systematic investigation into the carbon burial processes in lakes experiencing water level decline. Therefore, this study examines a sediment core from Lake Yamzhog Yumco, a lake in the southern Tibetan Plateau with a gradually declining water level. The mineralogical and geochemical analyses of both lake and catchment sediments show that the inorganic carbon (carbonates are dominated by aragonite) and organic carbon are primarily authigenic origin. Over the past four decades, the inorganic carbon burial rate (ICBR) in Lake Yamzhog Yumco has been primarily controlled by water level fluctuations and is closely related to hydrochemical processes regulated by regional climate change. In contrast, the increase in the organic carbon burial rate (OCBR) has been co-influenced by both water level changes and regional temperature. During this period, the ICBR reached as high as 186 g m⁻² yr⁻¹, approximately five times the OCBR. This demonstrates that in lakes in semi-arid regions, the sink potential of inorganic carbon significantly exceeds that of organic carbon, highlighting the necessity of incorporating inorganic carbon burial into carbon-sink assessments. This study provides novel perspectives for a deeper understanding of the driving mechanisms behind carbon burial in Tibetan Plateau lakes and offers a scientific basis for accurately assessing and predicting regional carbon-sink potential. Full article

The use of activated carbon (AC) in environmental applications, particularly for water and air purification, is highly valued due to its excellent microstructural and adsorption properties. However, its powdered form presents significant challenges in industrial applications, such as difficulty in handling and potential environmental risks due to its tendency to disperse easily. To overcome these issues, converting activated carbon into a more industrially viable form, such as pellets, is crucial. In this study, pelletizing AC within a crosslinked polyvinyl alcohol–diglycidyl ether of bisphenol A (PVA–DGEBA) matrix enabled the production of structurally stable cylindrical pellets through the formation of a robust three-dimensional polymeric network. This approach required minimal binder usage and facilitated processing at relatively low temperatures, effectively overcoming common disintegration issues associated with traditional pelletization methods reliant on linear polymer binders and compression-based techniques. The resulting pellets exhibited methylene blue (MB) adsorption (q max ~14.8 mg/g of pellet), which is about 50% of the initial AC’s adsorption capability, and retained structural integrity across multiple aqueous cycles. They also remained stable in methanol, ethanol and acetone by showing no observable disintegration, which highlights their excellent stability. Comprehensive characterizations, including hardness tests, swelling behavior, and various structural evaluations, revealed a mechanical strength of 3.37 ± 0.46 MPa and an adsorption volume of ~250 cm³/g through Brunauer–Emmett–Teller analysis, confirming effective crosslinking and the adsorption capabilities of the pellets. This eco-friendly and stable pelletization strategy demonstrated great potential for low-temperature pelletizing of AC, ensuring advanced applications in wastewater treatment even under pressurized conditions, presenting a significant improvement over the traditional method. Full article

This study examines the use of electronic waste (e-waste) as an alternative material in concrete for sustainability and natural resource conservation. Various e-wastes, such as Polyvinyl Chloride (PVC), Glass-Reinforced Plastic (GRP), Glass Fiber-Reinforced Polymer (GFRP), cross-linked polyethylene (XLPE), polyethylene (PE), electronic cable waste (ECW), Waste Electrical Cable Rubber (WECR), copper fiber (Cu Fib.), aluminum Fibers (Al fib.), steel fibers, basalt fibers, glass fibers, aramid−carbon fibers, Kevlar fibers, jute fibers, and optical fibers, were tested for influence on compressive, flexural, tensile strength, modulus of elasticity, and water absorption. Outcomes show that fine particle waste at low levels (0.2–1.5%) can improve mechanical performance, while higher levels of replacement or coarse particles generally reduce performance. Mechanical and physical properties are highly sensitive to material type, particle size, and dose. Life cycle assessment (LCA) and predictive modeling are recommended as validation for sustainability benefits. Full article

Winter processes are increasingly recognised as important components of ecosystem carbon cycling, yet ¹³C-CO₂ fluxes from temperate forests and peatlands remain poorly quantified. This study quantified cold-season ¹³C-CO₂ fluxes in a Scots pine forest and a temperate fen in western Poland using manual closed chambers coupled with a Picarro G2201-i isotope analyser. Measurements were conducted during the cold half of the year and related to soil temperature, air temperature and, at the forest site, soil moisture. Median ¹³C-CO₂ fluxes were about twice as high in the forest (607 µg·m⁻²·h⁻¹) as in the fen (290 µg·m⁻²·h⁻¹), indicating stronger winter respiratory activity in the mineral soil than in the water-saturated peat. In the forest, ¹³C-CO₂ fluxes showed a weak, non-significant tendency to increase with temperature, whereas in the fen they were significantly negatively correlated with soil temperature and tended to peak near 0 °C, pointing to an important role of zero-curtain and freeze–thaw conditions. These plot-scale measurements provide rare constraints on winter ¹³C-CO₂ losses from temperate forest–peatland mosaics and highlight the need to represent cold-season isotopic fluxes in carbon–climate assessments. From a biogeochemical perspective, the findings emphasize that ¹³C losses during the cold season can occur as transient, high-intensity ‘hot moments’. Such episodic fluxes should therefore be explicitly incorporated into winter carbon accounting and isotopically enabled carbon–climate feedback assessments to improve the fidelity of annual net ecosystem exchange projections. Full article

Atmospheric water harvesting (AWH) offers a decentralized and renewable solution to global freshwater scarcity. Bio-derived and hybrid aerogels, characterized by ultra-high porosity and hierarchical pore structures, show significant potential for high water uptake and energy-efficient, low-temperature regeneration. This PRISMA-guided systematic review synthesizes evidence on silica, carbon, MOF-integrated, and bio-polymer aerogels, emphasizing green synthesis and circular design. Our analysis shows that reported water uptake reaches up to 0.32 g·g⁻¹ at 25% relative humidity (RH) and 3.5 g·g⁻¹ at 90% RH under static laboratory conditions. Testing protocols vary significantly across studies, and dynamic testing typically reduces these values by 20–30%. Ambient-pressure drying and solar-photothermal integration enhance sustainability, but performance remains highly dependent on device architecture and thermal management. Techno-economic models estimate water costs from USD 0.05 to 0.40 per liter based on heterogeneous assumptions and system boundaries. However, long-term durability and real-world environmental stressor data are severely underreported. Bridging these gaps is essential to move from lab-scale promise to scalable, commercially viable deployment. We propose a strategic roadmap toward 2035, highlighting the need for improved material stability, standardized testing protocols, and comprehensive life cycle assessments to ensure the global viability of green aerogel technologies. Full article

Headwater streams comprise almost 90% of global river networks, and their microorganisms play critical roles in organic matter decomposition and nutrient cycling. These functions, however, are affected by recurrent drying and rewetting. This study examined spatial variation in microbial enzyme activity tied to organic carbon degradation (β-glucosidase, phenol oxidase, and peroxidase) and nitrogen (N-acetylglucosaminidase) and phosphorus (phosphatase) mineralization in water, epilithic biofilm, leaf litter, and sediment in two intermittent streams: Gibson Jack Creek (Idaho, USA) and Pendergrass Creek (Alabama, USA), representing different climactic and physiographic settings. Microbial activity was greater in Gibson Jack Creek, where the activity of leaf litter enzymes varied along the stream network, and there were strong correlations in microbial activity between different stream habitats. Microbial activity in Pendergrass Creek showed primarily within-habitat associations. Activity in water, sediment, and biofilm showed broader spatial heterogeneity in both stream networks. Ratios of microbial activity (enzyme stoichiometry) suggested that microbial communities in both systems were primarily limited by carbon and phosphorus, although there was more spatial variation in nitrogen limitation, particularly in water and sediment at Pendergrass Creek and in biofilm at Gibson Jack Creek. These findings underscore the spatial heterogeneity and environmental sensitivity of microbial processes in intermittent streams. Full article

Reclamation measures are essential tools for enhancing ecosystem functions and promoting ecological sustainability. This study focused on the Jiangnan mining area within the Muli coalfield in Qinghai Province, China. Four organic fertilizer reclamation treatments were established, namely, unfertilized control (CK, 0), low fertilizer (LF, consisting of sheep manure at 165 m³/ha and commercial organic fertilizer at 7.5 t/ha), medium fertilizer (MF, using 330 m³/ha of sheep manure and 15.0 t/ha of commercial organic fertilizer), and high fertilizer (HF, using 495 m³/ha of sheep manure and 22.5 t/ha of commercial organic fertilizer), with a natural meadow near the experimental site selected as a reference for evaluation. Through a field vegetation survey and indoor analysis, the primary productivity, water conservation, carbon cycle, nitrogen cycle, and phosphorus cycle of five ecosystem functions and ecosystem multifunctionality (EMF) were quantified, and the trade-off relationships among ecosystem functions were analyzed. The findings indicate the following: (1) Compared to the unfertilized control, organic fertilizer reclamation significantly enhanced all individual ecosystem functions and EMF, with the EMF value under the high-fertilizer treatment (EMF = 0.69) even exceeding that of the natural grassland (EMF = 0.60). (2) This intervention altered the original trade-off patterns (E_RMSD = 0.03), intensifying trade-offs among multiple ecological functions (E_RMSD = 0.09), whereas natural grassland exhibited the strongest trade-off intensity (E_RMSD = 0.26). In summary, while organic fertilizer reclamation effectively enhances the multifunctionality of alpine mining ecosystems, it also amplifies trade-off effects among ecological functions to varying degrees. Therefore, future long-term positioning observations are required to evaluate the ecological stability and sustainability of this restoration technology under extreme climatic conditions and to further explore reasonable grazing and mowing management plans in order to coordinate multiple ecological functions, thereby promoting the development of the reclamation ecosystem in alpine mining areas toward coordination and health. Full article