Search Results (92,419)

To comprehensively assess the emissions of flue gas pollutants from municipal solid waste incineration (MSWI) in China and their socioeconomic driving factors, this study employs a bottom-up approach to develop an integrated carbon and air pollutant emission inventory for 1016 MSWI plants in 2024. We apply a Random Forest (RF) model to analyze the underlying drivers. Results indicate that for air pollutants, NO_x has the highest emissions, whereas mercury (Hg) and dioxins (polychlorinated dibenzo-p-dioxins and dibenzofurans, PCDD/Fs) are identified as priority control pollutants due to their high toxicity. Spatially, emissions display a distinct “high in the east, low in the west” pattern, concentrated in eastern coastal provinces, with characteristic pollutants being prominent in specific regions. Meanwhile, among greenhouse gases (GHGs), CO₂ dominates mass emissions, while N₂O exhibits significant global warming potential. Driver analysis reveals that Gross Domestic Product (GDP) and MSWI treatment capacity are key common drivers, showing stable positive and negative contributions, respectively. The number of invention patent applications is specifically and strongly associated with NO_x and heavy metal emissions. This study provides a national-scale integrated quantification of MSWI emissions and a quantitative analysis of their driving mechanisms using RF, offering a critical data foundation and scientific basis for supporting synergistic pollution and carbon reduction. Full article

Green infrastructure (GI) provides essential ecosystem services for urban sustainability in the face of urbanization and climate change, including stormwater management, heat mitigation, and reduction in carbon dioxide (CO₂) concentration levels. Existing studies often focus on single-dimensional ecological effects, lacking a systematic investigation of their synergies and trade-offs. This study developed a coupled framework integrating scenario design, model simulation, and multi-indicator evaluation. Fifty-six scenarios, varying by GI combinations, weather conditions, and total annual runoff control rate (RCR), were applied to a high-density industrial district in Nanjing. The results showed that: (1) GI combinations enhanced comprehensive benefits, with the combination including bioretention (BR), permeable pavement (PP), and green roof (GR) performing most effectively. This was followed by the combination of BR and PP, then by BR and GR, while the use of BR alone provided the lowest effectiveness. (2) PP was a key synergistic component, improving heat mitigation and reducing CO₂ concentration levels through the beneficial effects of rainfall events. (3) Exceeding the optimal RCR threshold for some GI combinations diminished tree space and three-dimensional green volume, shifting synergies into trade-offs. (4) Three-dimensional green volume was positively correlated with reductions in Physiological Equivalent Temperature (PET) and CO₂ concentration, confirming its core role. (5) Rainfall boosted carbon sinks, while a significant cooling enhancement required PP. This study elucidates the water–heat–carbon synergy in small-scale GI, supporting multi-objective optimization in high-density urban renewal. Full article

Plastic waste poses a major environmental issue because it persists in nature for long durations and recycling facilities are not readily available. The conversion of waste materials into hydrogen creates two beneficial effects that help decrease pollution levels and establish hydrogen as a clean energy source for sustainable low-carbon systems. In this study, an integrated process for plastic-to-hydrogen conversion was developed using Aspen HYSYS v14. The system uses pyrolysis, steam reforming, and the water–gas shift (WGS) reaction, through pseudo-components of polyethylene, polypropylene and polystyrene to model decomposition processes. Following optimization, the hydrogen fraction in the syngas rose from 0.664 to 0.733. At this stage, the process produced roughly 651 kg of hydrogen per hour in steady operation. In addition, char and pyrolysis oil were produced as co-products that can be valorized in circular economy applications The implementation of heat integration achieved an 8% reduction in utility demand that proves that internal energy recovery stands as a vital element for sustainable design. The techno-economic analysis showed that the project would achieve a 39% internal rate of return and payback period of 5.95 years, thus proving its financial stability. The research demonstrates how modern process modeling techniques enable the creation of clean technology systems that address plastic pollution problems while producing low-carbon hydrogen. Full article

Rapid urbanization and climate change are intensifying heat exposure in cities, making effective adaptation strategies essential. This study presents a streamlined digital twin modeling framework for simulating the impact of nature-based solutions (NBSs) on outdoor thermal comfort, developed within the Intelligent Communities Lifecycle (ICL) software suite. The approach automates the import of urban geometry from OpenStreetMap and integrates geolocated weather data, enabling users to efficiently test scenarios involving NBSs and surface material modifications. Outdoor thermal comfort is quantified using the Universal Thermal Climate Index (UTCI), with results visualized through an interactive cloud-based 3D platform to support participatory urban planning. The methodology is demonstrated in Meunierstraat, Leuven (Belgium), where three planning alternatives are compared across seasonal extremes. Simulations show that targeted NBS interventions, particularly temporary participatory measures, can improve thermal comfort under extreme heat. However, the benefits are seasonally dependent and spatially heterogeneous, emphasizing the value of high-resolution, scenario-based analysis. This integrated workflow enhances both technical evidence and stakeholder engagement. While the tool is capable of linking outdoor comfort improvements with building energy performance and carbon emissions, the present paper focuses solely on the outdoor thermal comfort results, leaving indoor–outdoor coupling analysis as a direction for future work. Full article

Small communities in the Kingdom of Saudi Arabia (KSA) without a sewerage system commonly rely on septic tanks and long-distance transport of wastewater to the nearest centralized treatment facilities, resulting in high operational costs, social nuisance, and limited opportunities for treated effluent reuse. For a small community of 1300 persons in Al Qaraa (Qassim, KSA), this study performs life cycle analysis (LCA) to evaluate the environmental sustainability of a low-cost membrane bioreactor (LC-MBR)-type for decentralized on-site treatment as an alternative to wastewater transportation to a conventional extended aeration activated sludge process (EA-ASP)-type centralized system operating in the nearest larger city of Al-Bukayriyah. SimaPro^® 8.3.0.0 with the ecoinvent 3.0 database and ReCiPe 16 midpoint methodology shows that the decentralized LC-MBR scenario outperformed the centralized option with a 49 km-long wastewater transportation route in 13 out of 15 selected midpoint categories when considering relative and normalized impacts. In the EA-ASP, primary treatment dominated environmental impacts across most categories, driven by high energy demand for wastewater pumping, whereas freshwater and marine eutrophication were primarily influenced by treatment efficiency. With smaller normalized values, secondary treatment had a greater relative impact on urban and agricultural land occupation categories, attributed to the use of clay and rice bran in low-cost membrane fabrication in an LC-MBR. Tertiary treatment in the LC-MBR scenario, incorporating coagulation and granular activated carbon, significantly reduced freshwater eutrophication. Although normalized endpoint impacts indicated comparable ecosystem impacts for both systems, the LC-MBR resulted in 8% lower impacts on human health and 60% lower on resource depletion. Overall, the findings support decentralized wastewater treatment as a sustainable solution for small communities in arid regions and provide valuable insights for policy and decision-making. Full article

This study investigates the thermodynamic and technological aspects of smelting medium-carbon ferromanganese from Zhezdinsky manganese ore using ferrosilicomanganese and lime. The equilibrium distribution of components in the oxide-metal system was calculated using HSC Chemistry 10.0 within the temperature range of 573–2073 K. The modeling results revealed the effect of lime and ore consumption on slag phase composition as well as on manganese and silicon contents in the metallic phase. Experimental validation was performed in a laboratory Tamman resistance furnace and in a 100 kVA large-scale laboratory electric arc furnace. The chemical compositions of metal and slag were determined by bulk chemical analysis, while microstructure and local elemental distribution were examined using SEM-EDS. An increase in slag basicity was found to promote the transfer of silicon into the silicate phase while simultaneously reducing manganese losses to the slag. The large-scale laboratory smelting experiments, with a duration of 100–120 min per heat, enabled the establishment of a stable processing regime and the production of a metal with an average composition of 88.1 wt.% Mn, 1.6 wt.% C, and 0.03 wt.% Si. The corresponding slag contained approximately 15 wt.% MnO and 21 wt.% SiO₂. SEM-EDS analysis showed that the alloy possesses a heterogeneous microstructure consisting of an Fe-Mn metallic matrix with finely dispersed silicide microphases. Local silicon concentrations in these phases reach 15–24 wt.%, which explains the discrepancy between local and bulk chemical compositions. The experimental data are in good quantitative agreement with the thermodynamic modeling results, confirming that slag basicity and composition control are key factors for improving manganese recovery and stabilizing metal composition. The identified relationships can be applied in the development of industrially oriented smelting regimes for producing medium-carbon ferromanganese from Kazakhstan manganese raw materials. Full article

Digitalization and decarbonization are unfolding in parallel, yet firm-level evidence on whether digital economy development delivers substantive low-carbon performance remains mixed. Using a 2008–2022 panel of Chinese listed firms matched to a city-level digital economy index, we estimate lagged fixed-effects models and examine capability and governance channels through firm digital transformation and ESG disclosure. The local digital economy is positively associated with the green transition level (GT ) and transition speed (GTS ), and it significantly increases digital transformation (DT ) and ESG disclosure (ESG ), consistent with partial mediation. By contrast, effects on carbon intensity are small and become insignificant once year effects are included, indicating that short-run emissions outcomes are dominated by macro energy conditions and potential rebound forces. Overall, digital development appears to accelerate strategic transition and disclosure capacity more quickly than operational emissions efficiency. Policy implications are twofold: align digital infrastructure with ESG data governance and verification, and coordinate digitalization with energy-system reforms to enable sustained emissions reductions. Full article

The transition towards climate neutrality requires the development of spatially explicit planning approaches that account for territorial differences and land-use dynamics. Within this conceptual framework, this study has the objective of identifying and discussing spatially explicit planning approaches that can support the transition to climate neutrality in different regional spatial contexts. With reference to this research question, a methodological framework is introduced and applied that is designed to support climate neutrality through spatial planning strategies. Carbon sequestration (CS) serves as a key metric to evaluate both the current state and the temporal evolution of this process, examined in connection with the provision of specific ecosystem services (ESs) within the relevant spatial setting. The work is structured as follows. An approach is developed to define the provision of ESs. Drawing on previous research and detailed assessments of environmental, landscape, and socio-cultural features, the study considers the following ESs: maintaining or improving habitat quality to sustain the life cycles of wild species valuable to humans; regulating climate by mitigating land surface temperature; agricultural and forestry production; and nature-based recreational opportunities. Moreover, spatial relationships between CS capacity and ES provision are examined through geographically weighted regressions, allowing comparisons across Basilicata, Campania, and Sardinia, three Regions in southern Italy forming the Italian Mezzogiorno. The multifunctional characteristics of ES supply contributes to optimizing CS capacity and advancing climate neutrality goals. In particular, in all three regional contexts, high values of CS capacity elasticity are recognized in relation to habitat quality and ground temperature mitigation, and very low elasticity conditions as regards the supply of recreational ESs and agricultural and forestry production. Full article

The transition to low-carbon urban environments is a cornerstone of global sustainability efforts. However, evaluating the diverse management efforts driving this transition is frequently hindered by fragmented and heterogeneous data. This study introduces a novel Retrieval-Augmented Generation (RAG) framework to systematically evaluate urban low-carbon governance. RAG represents a significant methodological innovation, integrating advanced information retrieval with generative artificial intelligence to provide a transparent and evidence-based assessment of policy implementation. The proposed framework is applied to evaluate the low-carbon energy practices of 296 Chinese cities. A critical finding is the systemic neglect of the “Check” phase across all urban tiers, posing a significant challenge to the long-term sustainability of carbon reduction initiatives. Conversely, high-performing cities are characterized by robust “Feedback” mechanisms. Policy priorities also vary significantly with city scale: larger cities emphasize strategic development and low-carbon transitions, while smaller cities focus on foundational planning and ecological preservation. This framework serves as a transparent, process-oriented tool for evidence-based low-carbon governance, thereby facilitating more resilient and sustainable urban pathways. Full article

This study investigates alkali-activated recycled pumice as a sustainable cement replacement for hydraulic concrete used in rigid pavements. Cement was replaced at 15%, 25%, and 50% by mass and activated using NaOH solutions at 1 N, 0.5 N, and 0.25 N, resulting in nine mixture variants. Mechanical performance was assessed through compressive strength at 7, 14, and 28 days, and flexural strength at 28 days. Durability was evaluated via natural carbonation depth at 210 and 1090 days. X-ray diffraction (XRD) identified aluminosilicate phases in the pumice, supporting its alkali-reactive potential. Mixtures with 15% pumice replacement achieved compressive strengths up to 20.99 MPa, comparable to the control mix (20.45 MPa), whereas 25% and 50% replacements produced moderate strength reductions. Flexural strength in 15% mixtures (7.38–7.44 MPa) was also comparable to the control (7.30 MPa), while higher replacement levels reduced flexural performance. Carbonation resistance improved for mixtures with an optimized alkaline-to-pumice ratio (APR, defined as NaOH concentration relative to pumice content) between 0.0167 and 0.02, indicating more balanced activation and reduced CO₂ ingress. Overall, alkali-activated recycled pumice enables partial cement replacement while maintaining mechanical performance and carbonation resistance at 15% substitution, supporting circular economy strategies and lowering the carbon footprint of rigid pavement concrete. Full article

This study assessed whether electrochemical activation of mixing water can enhance autoclaved aerated concrete (AAC), in which fly ash replaces sand as the siliceous component. Mixing water was electrolyzed in a diaphragm-type “Melesta” unit to obtain the catholyte and anolyte, and fly ash was pre-exposed to the catholyte for up to 15 min. The material’s behavior was evaluated using slurry flow tests, scanning electron microscopy, Fourier-transform infrared spectroscopy, macropore-uniformity analysis, mercury intrusion porosimetry, and shrinkage and short-term durability indicators. At an approximately constant density class near 600 kg/m³, the catholyte-pretreated fly-ash AAC mixes showed a near-monotonic increase in compressive strength with increasing fly-ash replacement (relative to the sand-based reference), while fresh-mixture fluidity decreased. The pore structure became more uniform, as indicated by a decrease in the standard deviation of pore diameters from 0.175 to 0.133 mm, and porosimetry indicated a higher micro-porosity fraction in fly-ash AAC than in sand-based AAC. Capillary shrinkage remained essentially unchanged, and short-term durability indicators (durability coefficients after 25 cycles) showed a small improvement. Overall, electrochemically activated water promoted a more regular pore system and stronger interpore walls under autoclave curing, supporting higher fly-ash utilization without loss of dimensional stability. The results are limited to one fly-ash source (Ekibastuz TPP); transferability should be verified using ashes with different glass content, fineness, and carbon/LOI. Full article

Against the backdrop of China’s “Dual Carbon” strategy, transitioning to high-quality energy development (HQED) is imperative for balancing decarbonization with economic resilience. This study explores the transformative role of the digital economy as a primary driver of this transition. Using provincial panel data from 2013 to 2023, we employ a two-way fixed effects model to quantify the impact of digital economy on high-quality energy development. Our empirical results demonstrate that the digital economy significantly bolsters high-quality energy development, a finding that holds across rigorous robustness and endogeneity checks. Mechanism analysis reveals three critical transmission pathways: fostering technological innovation, accelerating industrial structure upgrading, and promoting industrial sophistication. Furthermore, heterogeneity analysis indicates a pronounced positive effect in the Eastern and Central regions, whereas the impact in the Western region remains limited, highlighting a “digital divide” in energy transition. These findings suggest that policymakers should prioritize digital infrastructure in lagging regions and leverage digital tools to bridge the gap between industrial upgrading and energy efficiency. Full article

Against the backdrop of China’s vigorous promotion of green and low-carbon development, this study empirically examines the impact of ESG greenwashing on corporate financial sustainable development performance, using a sample of Chinese A-share-listed companies from 2018 to 2023. Empirical results indicate that ESG greenwashing significantly undermines corporate financial sustainable development performance. Furthermore, accounting conservatism mediates the relationship between ESG greenwashing and corporate financial sustainable development performance, whereas negative external media coverage moderates it. This research provides robust theoretical and empirical support for standardizing corporate ESG practices and advancing the achievement of green sustainable development objectives. Full article

Nitrogen oxides (NO_x), carbon monoxide (CO), sulfur dioxide (SO₂), and volatile organic compounds (VOCs) in industrial waste gases pose significant threats to environmental quality and human health. Catalytic purification is recognized as a leading abatement technology, crucial for meeting increasingly stringent emission regulations. Rare-earth (RE) catalytic materials, particularly those based on cerium (Ce), lanthanum (La), praseodymium (Pr), and neodymium (Nd) oxides, have attracted intense research due to their unique electronic configurations, high oxygen storage capacity (OSC), facile reversible redox reactions Ce⁴⁺, Ce³⁺, and exceptional thermal stability. This paper provides a comprehensive and methodical overview of RE catalysts used in industrial waste-gas purification. Initially, the physicochemical characteristics of RE elements and their multifaceted roles as active phases, supports, and promoters are explained. Subsequently, the latest developments in RE-based catalysts for NO_x abatement, CO oxidation, VOC degradation, and the removal of sulfur-bearing gas are critically reviewed. The discussion emphasizes structure–activity relationships, reaction mechanisms, and the synergistic interactions between RE elements and transition metals. Comparative analyses are presented through tables focusing on catalyst composition, reaction conditions, performance parameters, and stability. Special attention is given to the enhanced resistance to water vapor and sulfur poisoning afforded by RE materials. Finally, current challenges and future research prospects, including cost reduction, scalability, and long-term durability, are suggested. This review aims to provide practical guidance for the rational design and industrial translation of next-generation RE catalytic materials for air pollution control. Full article

Cement is one of the primary construction materials in ground improvement applications that employ the binder stabilization method. Due to the high carbon dioxide emissions in its production, evaluating environmentally friendly alternative binder materials is a popular research topic. Industrial by-products such as fly ash (FA) and ground granulated blast-furnace slag (GGBS) are alternatives to traditional cement, especially in deep soil mixing (DSM) applications, and can enhance sustainability in construction projects. Since these materials are not active when used alone, alkali activation is proposed to modify them as binding agents in ground improvement projects. This study presents the outcomes of a primary laboratory test phase for on-site applications. FA and GGBS precursors supplied by local plants, mixed with soil and activator solutions in applicable ratios, and samples were prepared for laboratory tests. Unconfined compression tests were applied with strain measurements after several curing durations, between 1 and 54 weeks. Average compression strength and modulus of elasticity values were recorded at approximately 12.3 MPa and 11.7 GPa, respectively, in samples with an average dosage. An empirical correlation between the strength and stiffness modulus was found. Strength and stiffness values were comparable to traditional materials, indicating the potential of these industrial by-products when activated under alkali conditions. The carbon footprints of cement and alkali-activated by-products were compared based on calculated CO₂-eq emissions. Full article