Search Results (764)

External corrosion of buried ferrous water mains remains the dominant driver of structural failure in aging water distribution networks, yet the mechanisms linking soil physical and chemical heterogeneity to corrosion kinetics and product phase evolution have not previously been synthesized into a unified critical framework. This review evaluates three partially competing accounts of electrochemical degradation—anodic dissolution coupled to oxygen reduction within porous rust layers, redox cycling of iron oxide phases driven by seasonal soil moisture fluctuations, and microbially influenced corrosion (MIC) mediated by direct extracellular electron transfer (EMIC) and chemical metabolite pathways (M-MIC)—and assesses the weight of evidence for each. We demonstrate that corrosion products retain electrochemical activity long after formation, functioning as dynamic redox mediators that continue the reactions responsible for their own growth: the reduction of lepidocrocite under anoxic conditions regenerates Fe²⁺ ions that sustain anodic dissolution and catalyze oxygen reduction, while repeated soil moisture cycles drive the irreversible transformation of γ-FeOOH to Fe₃O₄, which fundamentally alters the conductivity and cathodic capacity of the rust layer. The widely cited universal critical-moisture threshold of 65% water-holding capacity (WHC) is evaluated and found to be a single-point approximation contradicted by texture-resolved experimental data that show the critical degree of saturation ranges from S_r ≈ 0.5 in sand to S_r ≈ 0.8 in clay. Modern machine learning analyses of field corrosion databases confirm that chloride content, pH, pipe-to-soil potential, and water content are the four highest-ranked predictors of maximum pit depth, consistent with the mechanistic framework developed here. The classical cathodic depolarization model of SRB-driven corrosion is evaluated against EMIC evidence and found insufficient: measured pure-culture SRB corrosion current densities range from 14 to 135 µA cm⁻², not the milliampere-level values reported in some earlier reviews. An explicit research agenda is proposed to address the five most consequential unresolved mechanistic questions. Full article

This study used silicate cement as the base material and nano-silica, fly ash, and bentonite as the composite modification components. Through laboratory tests, the engineering characteristics and impermeability and drying shrinkage properties of the modified slurry were systematically investigated. The results showed that the verification test mix proportion of the slurry was a water–binder ratio of 0.7, a nano-silica content of 2%, a fly ash content of 40%, and a bentonite content of 6%. This ratio of the slurry had the best comprehensive performance. Compared with pure cement slurry, the water loss rate decreased by 61.90%; the 3d, 7d, and 28d compressive strengths increased by 30.60%, 36.08%, and 20.08% respectively; the fluidity decreased by 6.38%; and the initial setting time decreased by 9.77%. The anti-seepage pressure of the verification test mix proportion slurry group reached 1.05 MPa, which was 43.84% higher than the pure cement reference group and was superior to each single addition group. Combined incorporation of nano-silica, fly ash, and bentonite remarkably improved the impermeability. The 56d drying shrinkage rate was 1257 × 10⁻⁶, which was 19.16% lower than that of the reference group. Based on X-ray diffraction (XRD) and scanning electron microscopy (SEM) tests, the microstructure was analyzed, and the hydration mechanism was discussed. The composite modification did not change the type of hydration products but significantly improved the microstructure. Nano-silica reacted with the hydration product Ca(OH)₂ in the early stage of hydration, accelerating the hydration process and promoting the interwoven coating of the hydration product on the calcium aluminosilicate crystals, thereby improving the compactness of the matrix. Fly ash participated in the pozzolanic reaction in the later stage of hydration, adhering to the secondary hydration products on the surface and gradually consuming them, further filling the pores and optimizing the interface structure. Combined with bentonite, nano-silica and fly ash jointly densified the matrix, refining the microstructure of modified samples and forming a continuous integrated hydration product network inside the grout. Full article

Plasmonic nanostructures offer a practical solution for solar-to-thermal conversion, yet simultaneously achieving ultra-broadband absorption, scalable fabrication, and long-term stability using earth-abundant aluminum remains difficult. In this work, we present a three-dimensional (3D) crown-like aluminum nanostructure absorber that achieves an experimental average absorption of 92% across the solar spectrum (200–2500 nm), with only 1.9% degradation in average absorption over 24 months. The structure is fabricated via a scalable anodic aluminum oxide (AAO) template-assisted method, enabling large-area production without costly lithography and exhibiting broad fabrication tolerance to deposition-thickness variations. Electromagnetic simulations and structure analysis reveal that the ultra-broadband absorption arises from three synergistic mechanisms: multi-mode electric resonances, magnetic resonance behavior within the metal–dielectric–metal architecture, and a graded-refractive-index profile. Proof-of-concept photothermal experiments under simulated sunlight offer experimental confirmation of the absorber’s solar-to-thermal conversion capability, showing substantially enhanced solar-to-thermal energy utilization compared to pure-water references. This work provides a scalable, durable, and cost-effective platform for ultra-broadband solar absorption and solar-to-thermal conversion, and offers a viable design strategy for plasmonic absorbers based on earth-abundant materials. Full article

The use of solar energy and semiconductor photocatalysts to reduce carbon dioxide (CO₂) into high-value fuels and chemicals is a promising approach to alleviate the current energy crisis and climate change. Layered double hydroxides (LDHs) are a special two-dimensional anionic clay material with a brucite-like structure. They have excellent properties such as adjustable layer cation types, interlayer anion types, and layer ratio. LDHs have been widely used in catalytic fields such as carbon dioxide reduction, water splitting, and ammonia synthesis, and are considered safe and green new photocatalysts. In recent years, researchers have conducted in-depth studies on the photocatalytic CO₂ reduction performance of hydrotalcite-like materials and have made certain progress. However, the low carrier mobility and low light utilization efficiency of pure LDHs greatly limit their catalytic reaction ability and further applications. More and more scientists are exploring methods based on regulating the structure of LDHs to improve the conversion efficiency and light utilization of products, such as changing the layer composition of LDHs, introducing vacancies in LDH structures, or coupling different types of semiconductors to construct heterojunctions. This article first summarizes the development history and structural properties of LDHs; Secondly, the mechanism of photocatalytic reduction of carbon dioxide was summarized; Thirdly, the application of LDH-based materials in photocatalytic reduction of CO₂ was classified and summarized. Although LDH-based photocatalysts have made significant progress in the field of photocatalytic reduction of CO₂, further exploration is still needed to investigate their photocatalytic active sites, mechanisms of action, synergistic mechanisms between components, and interfacial reaction mechanisms. Full article

Ellagic acid (EA) is a food-derived polyphenol with multiple biological activities, but its poor water solubility and aggregation in aqueous systems limit its accessibility to gut microorganisms. In this study, Fucus vesiculosus polysaccharide (FVP) was used as a natural carrier to prepare EA/FVP solid dispersions (SDs) with different mass ratios by solvent-assisted evaporation. Compared with pure EA, the SDs markedly improved the apparent solubility and aqueous dispersion stability of EA. The highest apparent solubility was observed for the EA/FVP 3/1 formulation (0.75 ± 0.03 mg/mL), which was approximately 6.25-fold higher than that of pure EA (0.12 ± 0.01 mg/mL). The improved dispersion behavior was associated with increased apparent viscosity, reduced aggregation, decreased crystallinity and possible non-covalent interactions between EA and the polysaccharide matrix. In vitro fecal fermentation showed that SDs enhanced the production of urolithins, including urolithin M5, urolithin M6, urolithin C, iso-urolithin A and urolithin B, without generating new metabolite types. The EA/FVP 1/3 formulation showed the strongest promotion of urolithin production, with iso-urolithin A reaching 2.36 ± 0.28 μM. 16S rRNA sequencing showed that the enhanced urolithin production was accompanied by shifts in the fecal microbial community. Several bacterial genera positively correlated with urolithin biosynthesis, including Bacteroides_H, Negativicoccus, Parabacteroides_B, Unclassified_Eggerthellaceae and Lactococcus_A, were significantly enriched in the SDs groups. These findings suggest that FVP-based SDs may serve as a potential strategy for improving the apparent solubility, aqueous dispersion and microbial biotransformation of EA. Full article

Aquaculture has rapidly expanded, surpassing capture fisheries and playing a vital role in global food security. However, this growth raises environmental concerns, especially regarding nitrogen waste accumulation in recirculating aquaculture systems (RASs). Nitrogen compounds from uneaten feed and fish excreta, mainly ammonia (NH₃) and nitrite (NO₂⁻), lead to water pollution, eutrophication, and greenhouse gas emissions. This study describes the setup and the efficiency of a new photo-electrocatalytic (PEC) system in reducing nitrogen waste in a high-density RAS for rainbow trout (30 kg/m³). The PEC system, an evolution of a pure photocatalytic system, was integrated in the units of the RAS and tested for the first time in field conditions, combining photocatalysis and electrochemical oxidation to convert toxic nitrogen species (NH₃) into less harmful nitrogen forms (NO₃⁻ and N₂), aiming to mitigate both water and atmospheric pollution. Over a 4-week period, water nitrogen compounds, ammonia and greenhouse gases (carbon dioxide, nitrous oxide and methane) emitted by water were continuously monitored in two groups of three tanks (PEC vs. control). Each tank was equipped as an independent RAS unit. PEC treatment led to significantly lower NH₃ concentrations (0.96 ± 0.2 mg/L vs. 1.78 ± 0.2 mg/L, p < 0.01), lower NO₂⁻ levels and higher NO₃⁻ levels (61.77 ± 2.14 mg/L vs. 53.10 ± 2.14 mg/L, p < 0.01) in water, indicating efficient nitrogen oxidation. Gaseous emissions were also reduced: NH₃ (1.49 vs. 2.64 mg/m²/day, p < 0.05) and N₂O (1.44 vs. 2.88 mg/m²/day, p < 0.05). These results support PEC technology as a promising solution for improving nitrogen management in intensive aquaculture. Although challenges remain in optimizing energy use and scalability, PEC offers a valuable strategy for reducing environmental impact while sustaining productivity in the aquaculture industry. Full article

Wastewater treatment plants (WWTPs) can serve as hubs for converting waste into energy, thereby supporting a city’s energy needs. Thermal processes, especially gasification, enable the transformation of sewage sludge into valuable products by producing energy-rich syngas for electricity generation. However, conventional air-based gasification introduces nitrogen as a diluent, reducing the syngas energy density. Integrating electrolyzers for hydrogen production into WWTP operations offers a strategic advantage: the oxygen co-produced during water electrolysis can be utilized as a gasification agent, thereby minimizing nitrogen dilution and enhancing syngas quality. The present work assesses the simulation of a conventional WWTP integrated with gasification and electrolysis systems using Superpro Designer V13. The results demonstrate that using pure oxygen in the gasification unit reduces the process’s thermal energy requirements and increases the syngas energy content by 5.5% when operating in a CO₂ atmosphere at an equivalence ratio (ER) of 0.15. The integration of anaerobic digestion and sludge gasification improves the overall energy balance by increasing electrical output (67%) and enabling thermal energy recovery, allowing sludge drying without auxiliary fuel. Water electrolysis is integrated as an energy storage system, allowing flexible operation during periods of excess renewable electricity. However, a simplified balance of this strategy reveals negative economic results unless electricity prices are below 7.5 c€/kwh. This approach underscores the need for further research into the use of reclaimed water for hydrogen production, as well as improving process integration to reduce the energy and water footprints of technologies supporting the green transition. Full article

This study investigated the rheological, structural, barrier, mechanical, optical, and thermal properties of composite edible films based on citrus pectin and vegetable purées derived from broccoli, cauliflower, pumpkin, carrot, and their blends. Film-forming formulations were characterized in terms of rheological behavior, thickness, microstructure, gas and water vapor permeability, optical and mechanical properties, water contact angle, and thermal stability. The incorporation of vegetable purées significantly modified the properties of the pectin-based matrices. All film-forming solutions exhibited non-Newtonian shear-thinning behavior, with flow behavior index values below unity. The addition of vegetable purées markedly increased viscosity and flow resistance, indicating the formation of more structured systems with stronger intermolecular interactions. Apparent viscosity increased from 0.19 Pa·s in the control sample to 1.41 Pa·s and 1.19 Pa·s in the broccoli (B) and broccoli–cauliflower (B-CF) formulations, respectively, while the consistency coefficient increased from 0.29 to 51.38 Pa·sⁿ. Composite films exhibited lower water contents (0.090–0.114 gH₂O·g_d.m.⁻¹) than the control film (0.179 gH₂O·g_d.m.⁻¹) and were thicker (170–282 μm) than the pure pectin film (125 μm). Barrier analysis revealed a reduction in water vapor permeability from 18.99·10⁻¹⁰ to 10.74–14.69·10⁻¹⁰ g·m⁻¹·s⁻¹·Pa⁻¹ and a decrease in carbon dioxide permeability from 21.95 to 10.47–17.91 GRT. The carrot-containing film exhibited the highest tensile strength (62.17 MPa), whereas the pumpkin–carrot film demonstrated the most favorable combination of barrier and mechanical properties, including the lowest oxygen permeability (6.95 GRT), low water vapor permeability (10.74·10⁻¹⁰ g·m⁻¹·s⁻¹·Pa⁻¹), and high tensile strength (51.02 MPa). Thermogravimetric analysis revealed similar three-stage degradation profiles for all samples, while vegetable incorporation modified moisture release and increased residual mass. The obtained results confirmed the research hypothesis that vegetable-processing by-products can serve as valuable structure-forming components of pectin-based composite films and that interactions between vegetable-derived biopolymers and citrus pectin improve the mechanical, barrier, and functional properties of the resulting materials. Among the tested formulations, the pumpkin–carrot film demonstrated the greatest potential for further development as a biodegradable packaging material. The utilization of vegetable by-products in pectin-based films represents a sustainable approach supporting circular economy principles and the development of environmentally friendly packaging systems. Full article

Refractory metals are being studied as alternatives to Pd and its alloys for the separation of hydrogen in high-temperature processes. The development of a membrane reactor for the production of hydrogen via water splitting has required studying hydrogen permeability through Ta at temperatures above 1273 K, for which no data is available in the literature. A dedicated experimental setup has been realized for testing Ta tubes in the temperature range 673–1573 K. Despite the use of controlled atmospheres and ultra-pure gases (with oxygen content below a few ppm), the tests over 1473 K have involved the formation of oxide layers over the metal surfaces, as verified by SEM-EDS analyses. The presence of oxide layers significantly increases the energy barrier to permeation: in agreement with a modest surface oxidation, at lower temperatures (673–1273 K) the activation energy of 2679.8 K has been measured against the value of 30,691 K measured in the high-temperature tests (1473–1573 K). Full article

This study investigated the effects of drying method and ingredient form on the quality characteristics of tarhana enriched with purple sweet potato (Ipomoea batatas L.). Tarhana samples were formulated with purple sweet potato in two forms (puree and freeze-dried powder) at incorporation levels of 5% and 10%, and subjected to either traditional sun-drying or freeze-drying. The drying method emerged as the dominant factor influencing product quality. Freeze-dried samples exhibited significantly lower moisture content and water activity along with a highly porous microstructure, indicating favorable physicochemical characteristics associated with product stability. Purple sweet potato incorporation enriched the phenolic profile and improved antioxidant capacity, with greater retention observed under freeze-drying conditions, particularly in powder-based formulations. Microbiological analysis revealed that freeze-drying preserved higher populations of lactic acid bacteria while suppressing yeast and mold growth. Instrumental aroma analysis demonstrated a clear shift in volatile composition depending on processing conditions, with freeze-drying yielding a more favorable aroma profile compared to sun-drying. Freeze-drying was identified as a superior method for preserving bioactive compounds, microbial viability, and aroma quality in purple sweet potato-enriched tarhana. These findings highlight the functional potential of purple sweet potato as an ingredient in traditional fermented foods and provide a basis for the development of high-quality tarhana formulations. Full article

In this study, the rapidly setting and hardening high-belite sulfoaluminate cement (HBSAC) is used as the cementitious material, with natural river sand as the fine aggregate, and a high-performance repair mortar is prepared through the synergistic use of different polymers and admixtures. The influences of two polymers (VAE and HPMC) on the working performance, mechanical properties, and hydration characteristics of HBSAC mortars are systematically studied. The results showed that the two polymers had a significant improvement effect on the setting time, mortar flowability, and water retention rate of HBSAC mortar. Among them, VAE had a significant effect on the mortar flowability, and a 5% content could increase the flowability of HBSAC mortar by 29.8%. HPMC has a significant improvement effect on setting time and water retention rate; at 0.1% content, it can delay the initial setting time by 6.5 min and achieve a water retention rate of over 90%. As the polymer to binder ratio increases, both polymers, except for 2.5% VAE, which can slightly improve the flexural strength of mortar, will reduce the flexural and compressive strength of mortar, with VAE causing greater damage to strength. On the contrary, the polymer significantly enhanced the bond strength of the mortar. Compared with the cement control group, the 28 d bond strength of 5% VAE and 0.1% HPMC groups increased by 56.7% and 15.1%, respectively. Moreover, the addition of polymers delayed the occurrence of the exothermic peaks of HBSAC dissolution and ettringite formation, but the total amount of hydration heat released within 48 h was higher than that of pure cement. The diffraction peaks of AFt in the hydration products of VAE-HBSAC paste at 3d and 28d showed significant enhancement, and the peak intensity increased with higher doping levels, while the diffraction peak intensity of C₂S showed a certain decrease. The polymer significantly increased the weight loss peak intensity and mass loss after heating of AFt, AH₃, AFm, and C-S-H gel. The SEM images indicate that VAE can form a mesh on the surface of hydration products and refine the crystal size of AFt; HPMC wraps more flocculent substances around the hydration products, thereby improving the compactness of paste. This study can provide scientific reference for improving the performance and promoting the practical application of high-performance rapid repair mortar for concrete structure damage. Full article

Dissolved oxygen (DO) is a critical indicator for assessing marine ecological health and hypoxia risk. Most existing DO prediction studies rely on time-series forecasting models, which require continuous temporal observations and are often unreliable in practical marine monitoring scenarios due to sparse sampling, missing records, and heterogeneous measurement conditions. To address this limitation, this paper investigates the problem of non-temporal DO prediction, aiming to learn a direct nonlinear mapping between environmental drivers and DO concentration. To explicitly model nonlinear pairwise interaction effects between environmental variables, we propose a Factor-Interaction Neural Network (FINN), which decomposes DO estimation into main effects and structured pairwise interaction effects. This interaction-driven design enhances both representation capacity and interpretability compared with conventional multilayer perceptrons. Furthermore, we develop a physics-informed extension, termed PI-FINN, by incorporating oceanographic-consistent regularization priors that reflect key DO formation mechanisms, including temperature-related solubility behavior, depth-wise smoothness associated with stratification, and chlorophyll-driven biological oxygen production tendencies. To evaluate the physical plausibility of model predictions beyond standard accuracy metrics, we introduce a physics-consistency assessment protocol based on Physics Consistency Violation Rate (PCVR) and its robust variant, and further analyze their convergence stability under different driver-weight configurations. Extensive experiments on a real-world marine dataset demonstrate that FINN achieves competitive predictive accuracy compared with strong machine learning baselines (e.g., SVR, Random Forest, and XGBoost), while the proposed physics-informed design mainly improves the physical consistency, robustness, and interpretability of DO estimation under heterogeneous environmental regimes, although it does not necessarily guarantee superior RMSE or MAE performance compared with purely data-driven models. Specifically, FINN achieves an RMSE of 0.3130, an $R^2$ of 0.9831, and a PCVR of 0.4826 on a dataset composed of key environmental variables, including depth, temperature, salinity, and chlorophyll-a, collected under sparse and irregular sampling conditions. Ablation studies confirm the effectiveness of both factor-interaction modeling and physics-guided regularization components. Overall, the proposed framework further provides a reliable tool for sustainable environmental monitoring by enabling physically consistent dissolved oxygen prediction under sparse observational conditions. Such capability is critical for supporting sustainable water resource management, hypoxia risk assessment, and long-term ecological protection. Full article

Nowadays, bioplastics are increasingly being used as an alternative to single-use fossil-based plastics. However, a major challenge associated with bioplastics is the need for higher amounts of plastic additives to achieve material properties comparable to those of conventional plastics, which raises concerns regarding their potential ecological impact. In this study, we evaluated the capacity of mixed liquor sludge from a wastewater treatment plant (WWTP) to eliminate bioplastics and their associated plastic additives compared to fossil-based materials. To this end, we exposed three items under controlled laboratory conditions: pure polylactic acid (PLA) pellets, a PLA garbage bag and a conventional fossil-based polyethylene (PE) bag. The study of plastic degradation was carried out by pyrolysis coupled with gas chromatography high-resolution mass spectrometry (Pyr-GC-HRMS). The results show a higher degree of degradation of biobased bags (96.8 ± 4.0%) and PLA pellets (91.3 ± 9.0%), whereas fossil-based bags of PE exhibited negligible degradation (18.3 ± 25.8%). Furthermore, leaching compounds generated during the treatment process were monitored using a suspect screening strategy by means of liquid chromatography coupled with high-resolution mass spectrometry (LC-HRMS). The main results showed that the concentration of several tentatively identified compounds increased after treatment because of the leaching process or because they were degradation products of other previously leached additives. The evaluation of the associated toxicity of these compounds using predicted no-effect concentrations (PNECs) disclosed that these compounds may pose a risk to organisms in receiving waters. Full article

Photocatalytic water splitting for hydrogen (H₂) evolution is a critical sustainable energy strategy, and cadmium sulfide (CdS) is a promising visible-light photocatalyst due to its suitable band gap. However, the practical application of pure CdS is severely hindered by rapid charge-carrier recombination and significant photocorrosion. In this work, we constructed a CdS/vanadium carbide (VC) photocatalyst via a simple ultrasonic method. The structural, morphological, optical, and photoelectrochemical properties of the composites were systematically investigated. Under visible light (λ ≥ 420 nm) and with 0.35 M Na₂S-0.25 M Na₂SO₃ as the sacrificial agent, the optimized composite featuring a CdS:VC mass ratio of 10:1 (denoted CV-10) achieved a remarkable hydrogen evolution rate of 3485.6 μmol g⁻¹ h⁻¹. This rate represents a 60-fold enhancement over pure-phase CdS and significantly surpasses that of a conventional Pt/CdS catalyst. Furthermore, the CV-10 composite demonstrated excellent stability, showing no activity decay after 16 h of cycling. Spectroscopic and electrochemical analyses revealed that the metallic VC can function as an efficient cocatalyst, accelerating charge separation and transfer while suppressing electron–hole recombination. This work demonstrates that noble-metal-free VC is a highly effective and low-cost cocatalyst, providing a new pathway for designing efficient and stable CdS-based photocatalysts in solar hydrogen production. Full article

The reasonable structural design and interfacial modification of heterojunction photocatalysts for accelerated charge separation and boosting photocatalytic activity remains a crucial challenge in solar-driven water splitting for H₂ production. Herein, a hierarchical structured In₂S₃/Ti₃C₂/TiO₂ ternary heterojunction was effectively constructed through a facile hydrothermal method integrated with a self-assembly strategy, in which Ti₃C₂ and TiO₂ were loaded on the surface of hierarchical In₂S₃ microspheres assembled from nanosheets. In the photocatalytic system, the in situ electron paramagnetic resonance verifies that the photogenerated charge transfer between In₂S₃ and TiO₂ obeys a typical S-scheme mechanism. Meanwhile, the introduction of Ti₃C₂ MXene as a conductive cocatalyst further promotes the separation and transfer of photogenerated charge through the formation of a Schottky junction, thus remarkably boosting the photocatalytic performance. Under simulated sunlight irradiation, the In₂S₃/Ti₃C₂/TiO₂ ternary heterojunction exhibits a superior H₂ production rate compared to pure TiO₂ and In₂S₃. Moreover, the ternary heterojunction also displays outstanding stability after five consecutive cycling tests. This work highlights the synergistic integration of an S-scheme and Schottky junction in a ternary heterostructure for efficient charge separation, providing a feasible strategy for designing high-performance photocatalysts toward solar-driven H₂ production. Full article