Search Results (1,238)

As an energy-intensive sector, China’s iron and steel industry is crucial for achieving “Dual Carbon” goals. This study fills the research gap in systematically comparing the synergistic effects of multiple policies by evaluating five key measures (2020–2023) in ultra-low-emission retrofits and clean energy alternatives. Using public macro-data at the national level, this study quantified cumulative reductions in air pollutants (SO₂, NOx, PM, VOCs) and CO₂. A synergistic control effect coordinate system and a normalized synergistic emission reduction equivalent (AP_eq) model were employed. The results reveal significant differences: Sintering machine desulfurization and denitrification (SDD) showed the highest AP_eq but increased CO₂ emissions in 2023. Dust removal equipment upgrades (DRE) and unorganized emission control (UEC) demonstrated stable co-reduction effects. While electric furnace short-process steelmaking (ES) and hydrogen metallurgy (HM) showed limited current benefits, they represent crucial deep decarbonization pathways. The framework provides multi-dimensional policy insights beyond simple ranking, suggesting balancing short-term pollution control with long-term transition by prioritizing clean alternatives. Full article

Hydrogen-assisted fatigue cracking presents a critical challenge to the structural integrity of legacy carbon steel natural gas pipelines being repurposed for hydrogen transport, posing a major barrier to the deployment of hydrogen infrastructure. This study systematically evaluates the fatigue crack growth (FCG) behavior of API 5L X60 pipeline steel under varying hydrogen–natural gas (H₂–NG) blending conditions to assess its suitability for long-term hydrogen service. Experiments are conducted using a custom-designed autoclave to replicate field-relevant environmental conditions. Gas mixtures range from 0% to 100% hydrogen by volume, with tests performed at a constant pressure of 6.9 MPa and a temperature of 25 °C. A fixed loading frequency of 8.8 Hz and load ratio (R) of 0.60 ± 0.1 are applied to simulate operational fatigue loading. The test matrix is designed to capture FCG behavior across a broad range of stress intensity factor values (ΔK), spanning from near-threshold to moderate levels consistent with real-world pipeline pressure fluctuations. The results demonstrate a clear correlation between increasing hydrogen concentration and elevated FCG rates. Notably, at 100% hydrogen, API X60 specimens exhibit crack propagation rates up to two orders of magnitude higher than those in 0% hydrogen (natural gas) conditions, particularly within the Paris regime. In the lower threshold region (ΔK ≈ 10 MPa·√m), the FCG rate (da/dN) increased nonlinearly with hydrogen concentration, indicating early crack activation and reduced crack initiation resistance. In the upper Paris regime (ΔK ≈ 20 MPa·√m), da/dNs remained significantly elevated but exhibited signs of saturation, suggesting a potential limiting effect of hydrogen concentration on crack propagation kinetics. Fatigue life declined substantially with hydrogen addition, decreasing by ~33% at 50% H₂ and more than 55% in pure hydrogen. To complement the experimental investigation and enable predictive capability, a modular machine learning (ML) framework was developed and validated. The framework integrates sequential models for predicting hydrogen-induced reduction of area (RA), fracture toughness (FT), and FCG rate (da/dN), using CatBoost regression algorithms. This approach allows upstream degradation effects to be propagated through nested model layers, enhancing predictive accuracy. The ML models accurately captured nonlinear trends in fatigue behavior across varying hydrogen concentrations and environmental conditions, offering a transferable tool for integrity assessment of hydrogen-compatible pipeline steels. These findings confirm that even low-to-moderate hydrogen blends significantly reduce fatigue resistance, underscoring the importance of data-driven approaches in guiding material selection and infrastructure retrofitting for future hydrogen energy systems. Full article

The cement industry accounts for approximately 7–8% of global CO₂ emissions, primarily due to energy-intensive clinker production and limestone calcination. With cement demand continuing to rise, particularly in emerging economies, decarbonization has become an urgent global challenge. The objective of this study is to systematically map and synthesize existing evidence on technological pathways, policy measures, and economic barriers to four core decarbonization strategies: clinker substitution, energy efficiency, alternative fuels, as well as carbon capture, utilization, and storage (CCUS) in the cement sector, with the goal of identifying practical strategies that can align industry practice with long-term climate goals. A scoping review methodology was adopted, drawing on peer-reviewed journal articles, technical reports, and policy documents to ensure a comprehensive perspective. The results demonstrate that each mitigation pathway is technically feasible but faces substantial real-world constraints. Clinker substitution delivers immediate reduction but is limited by SCM availability/quality, durability qualification, and conservative codes; LC₃ is promising where clay logistics allow. Energy-efficiency measures like waste-heat recovery and advanced controls reduce fuel use but face high capital expenditure, downtime, and diminishing returns in modern plants. Alternative fuels can reduce combustion-related emissions but face challenges of supply chains, technical integration challenges, quality, weak waste-management systems, and regulatory acceptance. CCUS, the most considerable long-term potential, addresses process CO₂ and enables deep reductions, but remains commercially unviable due to current economics, high costs, limited policy support, lack of large-scale deployment, and access to transport and storage. Cross-cutting economic challenges, regulatory gaps, skill shortages, and social resistance including NIMBYism further slow adoption, particularly in low-income regions. This study concludes that a single pathway is insufficient. An integrated portfolio supported by modernized standards, targeted policy incentives, expanded access to SCMs and waste fuels, scaled CCUS investment, and international collaboration is essential to bridge the gap between climate ambition and industrial implementation. Key recommendations include modernizing cement standards to support higher clinker replacement, providing incentives for energy-efficient upgrades, scaling CCUS through joint investment and carbon pricing and expanding access to biomass and waste-derived fuels. Full article

Achieving carbon emission reduction synergy is vital for green economic transformation. This study examines whether environmental governance pressure promotes such synergy, simultaneously driving carbon reduction and pollution control. Leveraging the 2012 Ambient Air Quality Standard as a quasi-natural experiment, we employ a continuous difference-in-differences (DID) method on 250 prefecture-level cities from 2009 to 2022. Our findings reveal that increased environmental governance pressure significantly reduces both the total amount and intensity of carbon emissions, demonstrating a clear synergistic effect. This synergy is positively correlated with reductions in major air pollutants (e.g., SO₂ and NO_x), indicating that pressure curbs both the total amount and intensity of carbon emissions. Mechanistic analysis shows that this pressure primarily curtails carbon emissions by fostering green innovation and accelerating cleaner energy transitions, with no ‘green paradox’. It also promotes low-carbon industrial restructuring while reducing reliance on end-of-pipe pollution management. Heterogeneity analysis indicates stronger synergistic effects in regions with lower emission reduction costs (e.g., western China, less developed industrial bases). We recommend robust central government environmental regulation policies to amplify local governance pressure, strengthen carbon reduction synergy, and facilitate continuous green development. Full article

Electrochemical CO₂ reduction reaction (CO₂RR) is a key technology for achieving carbon neutrality and efficient utilization of renewable energy, capable of converting CO₂ into high-value-added carbon-based fuels and chemicals. Copper (Cu)-based catalysts have attracted significant attention due to their unique performance in generating multi-carbon (C₂₊) products such as ethylene and ethanol; however, there are still many controversies regarding their complex reaction mechanisms, active sites, and the dynamic evolution of intermediates. In situ Raman spectroscopy, with its high surface sensitivity, applicability in aqueous environments, and precise detection of molecular vibration modes, has become a powerful tool for studying the structural evolution of Cu catalysts and key reaction intermediates during CO₂RR. This article reviews the principles of electrochemical in situ Raman spectroscopy and its latest developments in the study of CO₂RR on Cu-based catalysts, focusing on its applications in monitoring the dynamic structural changes of the catalyst surface (such as Cu⁺, Cu⁰, and Cu²⁺ oxide species) and identifying key reaction intermediates (such as *CO, *OCCO(*O=C-C=O), *COOH, etc.). Numerous studies have shown that Cu-based oxide precursors undergo rapid reduction and surface reconstruction under CO₂RR conditions, resulting in metallic Cu nanoclusters with unique crystal facets and particle size distributions. These oxide-derived active sites are considered crucial for achieving high selectivity toward C₂₊ products. Time-resolved Raman spectroscopy and surface-enhanced Raman scattering (SERS) techniques have further revealed the dynamic characteristics of local pH changes at the electrode/electrolyte interface and the adsorption behavior of intermediates, providing molecular-level insights into the mechanisms of selectivity control in CO₂RR. However, technical challenges such as weak signal intensity, laser-induced damage, and background fluorescence interference, and opportunities such as coupling high-precision confocal Raman technology with in situ X-ray absorption spectroscopy or synchrotron radiation Fourier transform infrared spectroscopy in researching the mechanisms of CO₂RR are also put forward. Full article

County-level administrative areas serve as fundamental components in China’s territorial spatial governance, and the precision and consistency of their carbon emission reduction policies are directly linked to the efficacy of the “dual-carbon” strategy’s execution. However, the spatiotemporal evolution characteristics, future trends, and driving factors of carbon emissions from territorial spatial function (TSF) utilisation at the county level remain unclear, posing a fundamental theoretical issue that local governments urgently need to address when formulating carbon reduction policies. This study developed a framework to simulate the spatial distribution of carbon emissions resulting from land use at the county level. It simulated the carbon emissions in Qionglai City from 2009 to 2023, analysed the spatial-temporal evolution characteristics and future trends using global Moran’s I, the Getis-Ord $G_i^{*}$ index, and the Hurst index, and employed the Geographically and Temporally Weighted Regression (GTWR) model for analysis. The findings indicated the following: (1) From 2009 to 2023, the city’s total carbon emissions increased from 852,300 tonnes to 1,422,500 tonnes, showing a significant phased trend. Among these, rural production spaces (RPSs) were the primary carbon sources, accounting for over 70% of annual carbon emissions each year. (2) County carbon emissions exhibit a pronounced positive geographical correlation and aggregation distribution, characterised by notable regional heterogeneity. (3) From 2009 to 2023, the city’s regional carbon emissions rose dramatically by 65.69%, while 29.66% of the areas experienced negligible increases; 99% of the regions are projected to maintain the historical growth trend, but this continuity exhibits spatial and temporal variations. (4) Economic growth, industrial structure, and development intensity are the core driving factors of carbon emissions at the county level, with spatial variations in their impact. The research findings not only provide a basis for Qionglai City, China, to formulate precise and sustainable carbon reduction policies (such as developing differentiated carbon emission control measures based on the spatiotemporal heterogeneity of carbon emissions and their driving factors), but also offer insights for similar regions worldwide in controlling carbon emissions and addressing global climate change (for example, by optimizing land spatial function utilisation, reducing carbon sources, and maximizing carbon sink capacity). Full article

Swine manure poses significant challenges for anaerobic digestion due to its low carbon-to-nitrogen (C/N) ratio and elevated ammonia concentrations, both of which restrict methane generation. This study investigated the impact of integrating low-intensity ultrasound with co-digestion of piggery wastewater and food waste leachate. Laboratory-scale upflow anaerobic sludge blanket (UASB) reactors were employed under four operational conditions to evaluate anaerobic digestion performance, track shifts in microbial community structure, and assess the abundance of antibiotic resistance genes (ARGs). Co-digestion significantly enhanced methane production, yielding 1.3–3.2 times more than manure alone, while low-intensity ultrasound further increased methane yields by approximately 36–44% at high loading rates. Moreover, coupling low-intensity ultrasound with co-digestion led to the most rapid recovery following an overloading shock. Unexpectedly, ultrasound treatment alone increased the expression of certain ARGs (tetG, sul1, ermB) and the Integrase gene (intI1), while co-digestion led to a reduction in these genetic markers. These findings clearly indicate that the concurrent application of co-digestion and low-intensity ultrasound achieved the highest methane yield, the fastest recovery after organic overloading, and greater suppression of specific ARGs. Full article

The escalating problem of nitrate pollution, coupled with the environmental burden of the Haber-Bosch process, has spurred intense interest in the electrocatalytic nitrate reduction reaction (eNO₃RR) as a sustainable route for simultaneous wastewater treatment and ammonia production. However, the efficiency and selectivity of eNO₃RR are hampered by the multi-step proton-coupled electron transfer process and the competing hydrogen evolution reaction. This review provides a comprehensive and critical overview of recent advances in understanding and designing catalysts for eNO₃RR. We begin by elucidating the fundamental mechanisms and key reaction pathways, followed by a discussion on how critical parameters (e.g., electrolyte microenvironment, applied potential, reactor design) dictate performance. Further discussion of recent advances in catalysts, including single-metal catalysts, alloy catalysts, transition metal compounds, single-atom catalysts, carbon-based non-metal catalysts, and composite catalysts, highlights their significant roles in enhancing both the efficiency and selectivity. A distinctive feature of this review is its consistent critical assessment of catalysts through the dual lenses of practicality and sustainable development. Finally, we outline prevailing challenges and propose future research directions aimed at developing scalable and commercially viable electrocatalytic systems for green nitrogen management. Full article

As the world races toward carbon neutrality, the true test lies not in ambition but in implementation, particularly in regions such as the Middle East, North Africa, and Türkiye (MENAT), where energy demand is accelerating and emissions trajectories remain uncertain. Despite increasing global focus on decarbonization, the MENAT region remains empirically underexplored, with limited and often inconclusive evidence on the environmental impacts of structural factors such as energy intensity, human capital, social globalization, and financial globalization. This study addresses these gaps by integrating the Environmental Kuznets Curve (EKC) hypothesis with the Stochastic Impacts by Regression on Population, Affluence, and Technology (STIRPAT) framework, employing an empirical strategy using panel data from MENAT countries covering the period from 2000 to 2021. Utilizing a suite of robust panel estimators, our results suggest that there is a U-shaped connection between income and CO₂ emissions, which invalidates the EKC hypothesis. Additionally, energy intensity, human capital, and urbanization are found to increase emissions, whereas technological innovation, social globalization, and financial globalization contribute to CO₂ emissions reduction. The panel heterogeneous causality tests give insights on the inference causality between CO₂ emissions and its drivers. These results highlight the urgent need for MENAT economies to embed renewable energy, low-carbon technologies, and sustainability-focused policies into the core of their development agendas to prevent the intensification of emissions alongside rising income levels. Full article

The Belt and Road Initiative (BRI) promotes significant cross-border investment, raising critical questions about its environmental consequences, particularly regarding carbon emissions. This paper uses panel data from 47 countries that participated in the “Belt and Road Initiative” earlier from 2000 to 2020 to conduct theoretical analysis and empirical research on the relationship between the coordinated development of two-way FDI and carbon emission intensity, dividing it into scale effect, technology effect and structure effect. The coordinated development of two-way FDI can have an increasing or decreasing impact on carbon emission intensity through these three effects. The main findings of this paper are as follows: (1) The improvement of the degree of coordinated development of two-way FDI significantly reduces carbon emission intensity. (2) The improvement of the degree of coordinated development of two-way FDI can enhance the level of technological innovation, while the improvement of the level of technological innovation will increase carbon emission intensity, thereby reducing the carbon emission reduction effect of the coordinated development of two-way FDI. (3) The improvement of the degree of coordinated development of two-way FDI can reduce carbon emission intensity by promoting the upgrading of industrial structure. Based on the above conclusions, this paper puts forward the following suggestions for the subsequent development of countries along the “Belt and Road”: (1) Further increase two-way FDI and promote the coordinated development of two-way FDI. (2) Promote the upgrading of industrial structure and the green transformation of technology. (3) Increase economic freedom to provide a good environment for economic development. Full article

This study investigates the impact of working capital management (WCM) on profitability in the Indian cement industry, an energy-intensive sector central to the country’s infrastructure growth. Using a balanced panel of listed firms over 2010–2024, we employ pooled OLS, two-way fixed effects, quantile regressions, and dynamic system GMM to address heterogeneity and endogeneity concerns. The results demonstrate that reductions in the cash conversion cycle (CCC), accelerated receivables collection, leaner inventories, and prudent use of payables significantly improve profitability. Quantile regressions reveal that highly profitable firms capture larger absolute gains from CCC reductions, while size-split analysis indicates that smaller and liquidity-constrained firms achieve proportionally greater marginal relief. These findings represent complementary perspectives rather than unified statistical relationship, a limitation we acknowledge. Dynamic estimates confirm the robustness of results after accounting for persistence and reverse causality. Beyond firm-level outcomes, the study contributes conceptually by linking WCM efficiency to sustainability financing: liquidity released from shorter operating cycles can be redeployed into green and energy-efficient investments, offering a potential channel for ESG alignment in carbon-intensive industries. Policy implications highlight the role of digital reforms such as TReDS and e-invoicing in strengthening liquidity efficiency, particularly for mid-sized firms. The findings extend the international WCM profitability literature, provide sector-specific evidence for India, and suggest new avenues for integrating financial and sustainability strategies. Full article

As climate change intensifies, reducing agricultural carbon emissions has become crucial for achieving sustainable development goals. Digital finance, with its potential to transform traditional farming practices, may play a key role in this transition. This study examines the impact of digital finance on agricultural carbon emission intensity (ACE) based on comprehensive provincial data from China (2011–2022). Through rigorous econometric analysis, we find that digital finance significantly reduces ACE, with particularly strong effects in western regions compared to eastern and central areas. The results demonstrate that agricultural total factor productivity serves as an important channel through which digital finance lowers emissions. Furthermore, environmental regulation enhances digital finance’s emission reduction potential, while spatial analysis reveals positive spillover effects to neighboring regions. These findings remain robust across various model specifications and testing methods. The study provides valuable insights into how digital financial tools can contribute to low-carbon agricultural development, highlighting the importance of region-specific policies and inter-regional coordination for maximizing environmental benefits. Full article

Carbon emissions in the building materialization stage are highly significant and concentrated. Quantification at this stage is essential for assessing carbon reduction potential, guiding energy-saving strategies, and supporting China’s “dual carbon” goals in the construction sector. Distinct from conventional environmental and energy economics analytical approaches, the building carbon emissions in the materialization stage (BCEMS) in 30 provinces of China from 2010 to 2021 were calculated using multi-source data, and the characteristics of their spatio-temporal evolution were analyzed. The key influencing factors were identified using a geographic detector, and their spatial heterogeneity was analyzed with the Geographically and Temporally Weighted Regression (GTWR) model from a geographical analysis perspective. The results indicated the following: (1) From 2010 to 2021, BCEMS exhibited a trend of an “initial increase followed by a decrease and subsequent fluctuation”, with an average annual growth rate of 4.28%. Building materials were the largest contributor to BCEMS, particularly cement and steel. Spatially, the emissions displayed a pattern of “higher in the east, lower in the west”. High–high-agglomeration areas remained stable over time, primarily in Zhejiang and Fujian provinces, while low–low-agglomeration areas were concentrated in Xinjiang. (2) Single-factor detection revealed that fixed assets, population density, and the liabilities of construction enterprises were the dominant factors driving the emissions’ spatial evolution. Two-factor interaction detection identified the economic society and the construction industry as the key influencing domains. (3) The economic development level and the total population showed a positive correlation with BCEMS, with the effect intensity increasing from west to east. The urbanization level and fixed assets also generally showed a positive correlation with BCEMS; however, their effect intensity initially increased positively from west to east and then turned into a negative enhancement. The findings provide references for implementing regionally differentiated carbon reduction measures and promoting green and low-carbon urban transformation in China’s construction industry. Full article

Synechocystis sp. PCC 6803 is a photosynthetic microbe with high potential for capturing excessive atmospheric carbon while generating valuable bioproducts, like glucose. Current cultivation technologies remain expensive, closed-source, and poorly suited for downstream processing. This study presents a low-cost, open-source bioreactor platform with integrated modules for Synechocystis cultivation and glucose extraction. The system incorporates a photobioreactor, a lysis module, and a pressure-driven filtration setup. Optical density was continuously monitored using a custom-built module, and glucose was quantified using high-performance liquid chromatography (HPLC). Under an incident light intensity of approximately 400 $\mathsf{\mu }\mathrm{m}\mathrm{o}\mathrm{l}$${\mathrm{m}}^{-2}$${\mathrm{s}}^{-1}$, cultures reached a biomass productivity of 90 mg ${\mathrm{L}}^{-1}{\mathrm{day}}^{-1}$, with a specific growth rate of $0.166{\mathrm{day}}^{-1}$ and glucose concentrations up to $5.08$$\mathrm{m}\mathrm{g}{\mathrm{L}}^{-1}$. A model was developed to predict the growth based on measured environmental parameters, achieving a strong predictive accuracy with a mean absolute error and variance of $0.0009\pm 0.0003$. The system demonstrates up to 65% reduction in cost compared to commercial alternatives. This modular platform provides an accessible solution for biomanufacturing research and serves as a template for sustainable cyanobacteria-derived glucose production. Full article

This study compares the environmental impacts of building reconstruction and renovation in aging building improvement projects and quantitatively assesses their carbon reduction potential from a life cycle perspective. A life cycle assessment (LCA) methodology was used to estimate greenhouse gas emissions across all stages—production, transportation, construction, operation, and disposal. A reinforced concrete (RC) structure in Seoul served as the case study, with three scenarios modeled: maintaining the existing structure, reconstruction, and renovation. Results show that renovation produced a carbon emission intensity of approximately 1.37 × 10³ kg–CO₂eq/m²—46.21% lower than the existing building and 22.34% lower than reconstruction. Renovation offered significant embodied carbon savings during the production and demolition phases. In the operational phase, emissions were reduced by 47.50% through upgrades such as high-performance insulation, better windows, and renewable energy systems. While reconstruction showed some emission reductions, its environmental burden remained higher due to the need for new materials and additional demolition waste. Overall, renovation demonstrates greater carbon reduction potential across the building’s life cycle. These findings underscore its value as a key strategy for achieving carbon neutrality in the building sector by 2050 and provide scientific evidence to inform design and policy decisions. Full article