Search Results (13,299)

This study investigated the impact of cobalt/nickel-silicate loadings on graphitic carbon nitride at 10% and 20% doses, designated (CoNiSi-10) and (CoNiSi-20), for the removal of ciprofloxacin (CPF), a hazardous, bioaccumulative antibiotic. The synthesized composites were characterized in detail using SEM, EDX, TEM, N₂ adsorption–desorption, XRD, and FTIR techniques. The CoNiSi-10 and CoNiSi-20 exhibited CPF q_t values of 64 and 107 mg g⁻¹, respectively, which were consistent with the surface area results. Adsorption kinetics indicated that CPF uptake on CoNiSi-10 and CoNiSi-20 fitted the Lagergren model, with the liquid-film and intraparticle-diffusion mechanisms co-governing CPF sorption. The isotherm investigations indicated CPF adsorption on CoNiSi-10 and CoNiSi-20 aligned with the Langmuir model, suggesting a homogeneous surface, while the Dubinin-Radushkevich results primarily indicated physisorption-based CPF removal. The thermodynamic analyses supported the physisorption outcome and indicated that CPF sorption onto CoNiSi-10 and CoNiSi-20 was endothermic. A five-cycle reusability test yielded average efficiencies of 94% and 96% for CoNiSi-10 and CoNiSi-20, respectively, and an after-sorption analysis indicated their stability and robustness. The ease of synthesis and excellent sorption performance may nominate CoNiSi-10 and CoNiSi-20 as promising adsorbents for treating pharmaceutically contaminated wastewater. Full article

Azo dyes are a major cause of environmental pollution, but under lab-based conditions can be removed using a coupled adsorption and electrochemical oxidation process; the Nyex Rosalox™ (NR) process. However, wastewater effluents are more complex than tap water, indicating that there is a need to assess how altered effluent conditions affect the adsorption of azo dyes onto the adsorbent used (Nyex™ 2000) and overall removal efficiency of the NR process. Analysis indicates that higher temperatures, the addition of minor amounts of sodium chloride, or acidification increased adsorption, while the presence of dissolved organic carbon (DOC) only showed a minor impact if compared to baseline tap water conditions and appears to be dye-specific. Analyses further indicated that effluent conditions could have a major impact on the overall dye removal efficiency using the NR process, with up to 48% more being removed during acidic or saline conditions and, to a lesser extent, when DOC was present. Increased temperature or alkalinity had minimal impact, with inconsistent results across the dyes assessed. Combined, this highlights that effluent-specific conditions can have a major impact on the removal efficiency and should be considered during the planning stage of the azo dye treatment process. Full article

Tri-reforming of methane (TRM) has emerged as a promising pathway for low-carbon syngas production by integrating steam reforming, dry reforming, and partial oxidation within a single process. This coupling enables simultaneous CH₄ utilization and CO₂ valorization while enabling internal heat generation and flexible adjustment of the H₂/CO ratio for downstream synthesis. However, TRM performance cannot be adequately evaluated using conversion or energy efficiency alone, because the process involves complex interactions among competing reaction pathways, transport phenomena, catalyst stability, and thermodynamic irreversibility. This review provides a multiscale critical assessment of TRM from both first-law energy and second-law exergy perspectives, linking reaction-network fundamentals to reactor-level behavior and system-level performance. The literature evidence shows that although high temperatures and near-autothermal operation can enhance CH₄ conversion and reduce external heat demand, these conditions may simultaneously intensify deep oxidation, hotspot formation, carbon-forming tendencies, and exergy destruction. While equilibrium analyses help define feasible operating windows, they are insufficient without kinetic modeling and reactor-scale studies that capture spatial non-uniformities and pathway competition. Across reported TRM systems, exergy destruction is consistently concentrated within the reformer, identifying the reacting core as the dominant thermodynamic bottleneck. Accordingly, the key challenge in TRM is not simply to maximize conversion but to preserve chemical work potential while maintaining syngas quality and operational stability. Viewed from this perspective, TRM is better understood as an irreversibility-aware multiscale design problem in which optimal performance depends on the integrated optimization of catalyst functionality, reactor architecture, heat management, and system-level operation. Full article

A pilot-scale moving-bed biofilm reactor (MBBR), operated under alternating intermittent aeration (IA) and non-aeration phases, was used for single-stage carbon (C) and nitrogen (N) removal from high-fluctuating municipal wastewater via simultaneous nitrification–denitrification. The reactor was operated under highly variable chemical oxygen demand to total nitrogen (COD/TN) ratios, low dissolved oxygen (DO) conditions, and progressively extended non-aerated periods to evaluate process robustness under real operational conditions. An active denitrifying biofilm developed on the carriers after 23 days of the anoxic start-up, as confirmed by batch activity tests. Under the most carbon-limited condition tested (COD/TN = 5.5), the application of 16 h·d⁻¹ of non-aerated phases at DO levels of 0–1.0 mg·L⁻¹ enabled simultaneous COD, N–NH₄⁺ and TN removal efficiencies of 70, 95 and 84%, respectively. These results confirm that transient IA is an effective strategy for simultaneous C and N removal at very low COD/TN ratios and real fluctuating influent concentrations. Energy assessment showed that extended non-aeration phases reduced blower energy demand by 67% and total plant energy consumption by 34%, improving the environmental sustainability of the single-stage process. The main novelty of this study lies in the pilot-scale validation of an IA-MBBR for SND using real municipal wastewater under naturally fluctuating C and N loadings, thereby bridging previous laboratory-scale evidence with realistic operating conditions. Full article

Carbon reduction is an urgent challenge for developing nations that balance socioeconomic development and climate mitigation in global low-carbon control. As a key digital economy means, e-commerce development enables urban low-carbon transition. In this context, drawing on a Chinese panel dataset covering 283 cities during 2006–2022, and taking the National E-commerce Demonstration City Pilot Policy (NEDCP) as a quasi-natural experiment, we use a multi-stage difference-in-differences (DID) strategy to detect how NEDCP affects urban carbon emissions. The results reveal that the NEDCP greatly reduces carbon emissions at an urban scale, which remains robust through a series of robustness tests. Mechanism analysis focuses on three channels, which includes boosting energy efficiency, advancing the digital economy, and promoting green innovation. Heterogeneity tests show that these benefits are more strongly evident in cities with a higher openness, a larger population, better economic conditions, and a stronger innovation capacity. The spatial spillover effect test shows that the NEDCP not only promotes local carbon reduction, but also promotes carbon reduction in neighboring areas. These findings offer theoretical insights for enhancing the NEDCP’s environmental benefits, and a practical guide for differentiated low-carbon development strategies, especially for prioritizing logistics and innovation support and refining green e-commerce standards. Full article

This study presents a gate-to-gate life cycle assessment (LCA) of an industrial sweet cherry sorting and packing facility in Greece, directly addressing environmental sustainability in agri-food supply chains through data-driven impact quantification and improvement pathways in post-harvest operations. The assessment focuses on a gate-to-gate system boundary encompassing all processes inside the cherry sorting and packing facility, while upstream cherry production and downstream waste management are modeled and reported separately to provide system-level context. Core-stage hotspots are then analyzed in detail in the Results section, highlighting the dominant role of electricity use compared with packaging materials. The functional unit is defined as 1 kg of packed, market-ready cherries at the factory gate. Primary data are obtained from high-resolution, batch-level measurements of mass flows, energy use, water consumption, packaging materials and waste streams over a full processing season, structured as virtual sensor outputs. These sensor-informed operational data are combined with secondary life cycle inventory information from established databases to quantify climate change impacts and identify environmental hotspots across materials, energy, water, and waste, thereby delivering a quantified picture of environmental performance in the post-harvest stage. The results show that corrugated cardboard and associated packaging components are among the main contributors within the facility-level, gate-to-gate system, while the Core stage accounts for 28.43% of total GWP100. Upstream cherry production dominates the overall Upstream–Core–Downstream climate footprint with 70.61% of total impacts. Moreover, practical mitigation scenarios are modeled, including packaging optimization, partial substitution of grid electricity with photovoltaic generation, and increased water recirculation. Ιn the combined mitigation scenario, where packaging optimization, low-carbon electricity and improved water management are implemented simultaneously, total GWP100 decreases from 114,207.32 to 92,500.27 kg CO₂-eq (−19.0%) relative to the baseline, providing actionable sustainability improvements for industry stakeholders and supporting Sustainable Development Goals (SDGs) related to climate action and resource efficiency. In addition, the proposed virtual sensor architecture and data workflow support continuous monitoring, eco-efficiency management and near-real-time LCA implementation in post-harvest agri-food systems, enabling operational sustainability. Full article

Liver fibrosis is a severe but common disease without an easy-to-access option for efficient treatment. Mesenchymal stem cells (MSCs) of different origins have been tested for antifibrotic effects in vitro, in vivo, and in clinical studies over the two last decades, although the comparative efficiency of different subtypes remains not fully understood, especially for long-term survival. In this study, we aimed to compare the long-time persistence of favorable effects in male Wistar rats with liver fibrosis treated using MSCs derived from white adipose tissue (AdMSCs) and bone marrow (BMSCs). Liver fibrosis was induced by carbon tetrachloride. We studied the survival rate; oxidative index, assessed via laser Doppler flowmetry; hepatic markers in blood plasma—albumin, alanine aminotransferase, aspartate aminotransferase, and alkaline phosphatase; the ratio of liver to body mass; histological parameters—the number of adipocytes, lymphocytes, siderophages, and Ki67⁺ cells; and the relative areas of connective tissue proper and reticular fibers. Extra mortality was only typical for fibrotic animals subjected to the sham treatment in the first two weeks. Up to Day 270 of this study, both MSC-treated groups showed barely any differences from animals undergoing the sham treatment in terms of the oxidative index and blood markers, although AdMSC-treated rats presented a more favorable histological pattern than BMSC-treated ones, considering the relative area of reticular fibers and the Ki67 cell count. This study suggests that AdMSC treatments may be more appropriate than BMSC treatments in animal liver fibrosis models, with the results showing better potential for liver tissue regeneration 9 months after treatment. Full article

Urban sustainable development increasingly depends on interactions among multiple urban subsystems, yet existing studies often overlook cross-regional linkages and nonlinear development processes. This study investigates the coordinated development of urbanization, smart development, resilience, and low-carbon transition (USRL) from an efficiency perspective. Using panel data from 278 Chinese cities during 2010–2023, this work integrates the Super-SBM model, the Local–Tele Coupling Coordination Degree (LTCCD) framework, Dagum Gini decomposition, and machine learning techniques to examine the spatiotemporal evolution, spatial disparities, and driving mechanisms of coordinated development. The results show that coordinated development improved steadily over time, although subsystem evolution remained uneven, with resilience lagging behind other dimensions. Regional disparities gradually narrowed, but inter-regional differences remained the dominant source of spatial inequality. Innovation intensity, industrial upgrading, and high-quality foreign investment positively contributed to coordinated development, whereas fiscal and financial factors exhibited nonlinear effects. Interaction analysis further revealed that coordinated development is shaped by the combined influence of multiple drivers rather than by individual factors alone. Our findings suggest that urban sustainable development is jointly influenced by subsystem coordination, cross-regional interactions, and nonlinear development dynamics, highlighting the importance of integrating local and tele-coupling processes in urban sustainability research. Full article

La-MOFs exhibit strong affinity toward anions such as F⁻ and phosphate. However, conventional La-MOFs show limited regeneration performance when used as CDI electrodes, posing a major challenge for practical applications. In this study, a high-performance sulfur and nitrogen co-doped La-BDC-140-derived carbon electrode (La-CNS₃) was fabricated via a coupled carbonization and doping strategy. The optimized La-CNS₃ electrode possessed abundant defects, a mesoporous structure, favorable hydrophilicity, and rapid charge-transfer capability, which collectively enhanced fluoride electrosorption. At 1.4 V, La-CNS₃ achieved a fluoride removal capacity of 31.86 mg·g⁻¹ for 10 mg·L⁻¹ F⁻ solution and up to 195 mg·g⁻¹ at an initial F⁻ concentration of 100 mg·L⁻¹. More importantly, partial fluoride desorption was realized solely under reverse voltage, and the electrode maintained favorable defluoridation performance over 50 adsorption–desorption cycles. In actual groundwater treatment, the effluent fluoride concentration decreased to below 1.0 mg·L⁻¹ after 120 min. XPS analysis and DFT calculations revealed that fluoride removal was mainly governed by La-F coordination, surface hydroxyl/water ligand exchange, and interfacial charge redistribution. The La₂O₂S/g-C₃N₄ structure provided a favorable balance between fluoride adsorption strength and desorption reversibility. This work offers a promising strategy for designing efficient, selective, and electrically regenerable rare-earth-based CDI electrodes for fluoride-contaminated water treatment. Full article

There is increasing interest in structured layered double hydroxide (LDH)-based catalysts because they combine tunable acid–base/redox chemistry with reactor architectures that can reduce diffusion lengths, improve heat management, and lower pressure-drop penalties. This review evaluates LDH, LDH-derived oxide (LDO/MMO), reduced metal/LDO, reconstructed hydroxide-rich, and mixed dynamic states integrated into honeycomb monoliths, open-cell foams, meshes/felts, thin films, washcoats, coated plates, microchannels, capillaries, and additively manufactured lattices. To move beyond descriptive comparison, the literature is assessed using unified evaluation dimensions: operative active state, support architecture, coating/integration route, active-phase loading, coating thickness and uniformity, reactor-volume-normalized productivity or STY, ΔP/L, axial/radial thermal gradients, time-on-stream, coating loss, regeneration recovery, and pilot-readiness. Representative benchmarks illustrate both the promise and reporting gaps of the field: NiFe-LDH-derived monoliths for CO₂ methanation have reached ~70% CO₂ conversion at 300 °C with >90% CH₄ selectivity and only 0.7% post-test mass loss; NiFe-LDH/iron-foam monoliths retained 85% ozone conversion after 168 h; high-entropy LDH-derived oxides showed T50/T90 values of 246/254 °C for toluene oxidation; and Au/LDH capillary films achieved 31.9% glycerol carbonate yield and 3.78 g h⁻¹ g⁻¹ productivity. The strongest current cases are pollution abatement and CO₂ methanation, whereas biomass upgrading, fine-chemical flow, high-entropy coatings, and photo/electrocatalytic films require deeper module-level validation. Overall, structured LDH catalysts should be treated as coupled chemistry–coating–reactor systems whose performance must be judged simultaneously by activity, accessible catalyst inventory, transport efficiency, pressure drop, thermal profile, durability, regeneration, and manufacturability. Full article

The removal of heavy oil under low-temperature conditions is a significant global challenge. This study aimed to assess the long-term whole-cell biocatalytic degradation of heavy oil in water and soil by bacteria isolated from contaminated soil in Muroran, Japan, under cold conditions. Enrichment cultures using heavy oil as the sole carbon source yielded 15 potent heavy oil-degrading isolates. However, only the C1 strain retained its activity under low-temperature conditions and was identified as Pseudomonas aeruginosa C1 using 16S rDNA sequencing. Gas chromatography analysis revealed that at 30 °C (water medium), strain C1 degraded 57% of heavy oil within 7 days. At 15 °C, the degradation efficiency of C1 declined due to a temperature-dependent metabolic lag phase (1 day); however, at 15 °C, 70% degradation was observed in seven days. In long-term experiments at 5 °C and 10 °C, 35% and 40% degradation were recorded for C1 after 98 days. In artificially contaminated soil at 5 °C, C1 achieved 60% biodegradation. These results demonstrate cold-adapted whole-cell activity against heavy oil and motivate the design of controlled, contained ex situ reactors (e.g., enzyme-based or cell-free systems) for safe remediation in cold climates. Full article

This paper investigates a discrete diffusion carbon emission-absorption model with periodic boundary conditions derived via the piecewise constant argument scheme. The existence of equilibrium points is established, and sufficient conditions for the local asymptotic stability of the positive equilibrium are derived through eigenvalue analysis. Then, uniform boundedness of positive solutions is proved, and the global asymptotic stability of the interior equilibrium is established by an iterative method and the comparison principle for difference equations. Furthermore, the model is shown to undergo a flip bifurcation when a critical parameter threshold is reached, leading to period-doubling dynamics and chaotic behavior. The influence of spatial diffusion is examined through a Turing instability analysis, yielding conditions for diffusion-driven instability and spatial pattern formation. Finally, Decision Tree and Random Forest classifiers are used as proof-of-concept tools to efficiently approximate the analytically derived stability regions using Monte Carlo-generated data. Both classifiers successfully reproduce the analytical stability structure, while the Random Forest classifier provides higher accuracy and smoother stability boundaries. Numerical simulations support the theoretical results and illustrate the stability and bifurcation phenomena exhibited by the model. These findings indicate that the proposed framework is useful for analyzing carbon emission-absorption dynamics and that machine learning can serve as an efficient computational surrogate for identifying stability regions in nonlinear dynamical systems. Full article

Volatile organic compounds (VOCs) are major contributors to air pollution and pose significant risks to both environmental quality and human health. Biochar-based adsorption technology is an efficient and sustainable approach to VOCs removal. Herein, hybrid biochar was prepared from corn stover and municipal sewage sludge using the water vapor activation method, and its physicochemical characteristics and adsorption mechanisms for typical volatile organic compounds commonly produced during biomass-derived energy generation—such as methylbenzene, isopentane, and ethylene—were systematically investigated. The results show that hybrid biochar significantly outperformed single-source biochar, with its ability to adsorb methylbenzene, isopentane, and ethylene exceeding that of pure sludge biochar by 112.21%, 74.53%, and 66.72%, respectively, and surpassing pure corn stover biochar by 74.25%, 62.98%, and 55.25%, respectively. Competitive adsorption analysis indicated that the interaction strength between VOC molecules and the steam-treated hybrid carbon material was associated with their boiling points; compounds with higher boiling points tended to exhibit stronger affinity. This work provides an integrated waste utilization and pollution control strategy for VOCs removal. Full article

Direct ammonia fuel cells (DAFCs) offer a promising pathway for carbon-free energy conversion but their practical performance is limited by sluggish cathode kinetics. In this work, non-precious FeCoN catalysts offer a cost-effective solution, yet carbon support optimization is crucial for activity and stability. FeCoN/XC-72R, FeCoN/CNT, and FeCoN/CNH cathode catalysts were synthesized by annealing at 550–750 °C. Their structure and morphology were analyzed by X-ray diffraction (XRD) and scanning electron microscopy (SEM). Electrochemical behavior was evaluated by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) in alkaline medium containing KOH and NH₄OH. FeCoN/XC-72R exhibited the lowest resistance of 27 Ω and superior activity. In single cell tests using a 40 wt% PtIr/C anode catalyst at 2 mg cm⁻², the FeCoN/XC-72R catalyst achieved the highest power density of 71 mW/cm² under optimized conditions of 0.1M NH₄OH + 3M KOH, 100 °C, and O₂ feed. Among the carbon supports, carbon black (XC-72R) proved the most effective support for FeCoN catalysts in low concentration DAFCs, outperforming carbon nanotubes (CNTs) and carbon nanohorns (CNHs). These findings highlight the importance of carbon support selection in the design of efficient cathodes for next generation low concentration direct ammonia fuel cells. Full article

In this study, carbon quantum dots (CQDs) were synthesized from various lignocellulosic and hemicellulosic biomass precursors via a semi-hydrothermal torrefaction process, and their structural, optical, colloidal, and photocatalytic properties were systematically investigated. Biomass sources including Oriental thuja cone (Thuja orientalis), sawdust, tea waste, apricot kernel shell, walnut shell, sugar beet pulp, hazelnut residue, soybean residue, and chitosan were used to evaluate the effect of precursor composition on CQDs characteristics. UV–Vis spectroscopy confirmed the formation of CQDs in all samples, exhibiting characteristic π–π* and n–π* transitions, while significant variations in absorption intensity and spectral behavior were observed depending on biomass type. Dynamic light scattering and zeta potential analyses revealed that most CQDs exhibited aggregation tendencies, with limited systems showing improved colloidal stability due to electrostatic and/or steric stabilization. The synthesized CQDs were combined with TiO₂ and their influence on the photocatalytic degradation of Reactive Black 5 under UV irradiation was investigated. Although high decolorization efficiencies (85–98%) were achieved, total organic carbon removal remained lower (2.6–41.4%), indicating incomplete mineralization. The highest mineralization efficiencies were observed for TiO₂ systems modified with sawdust- and thuja-derived CQDs. Overall, the results demonstrate that the photocatalytic performance of CQDs-modified TiO₂ systems is governed not only by optical properties but also by surface functionalization, colloidal stability, and charge carrier dynamics. The findings highlight the critical role of biomass composition in determining CQD properties and provide a comparative framework for designing sustainable nanomaterials for environmental applications. Full article