Search Results (673)

Luminescent organic–inorganic Cu(I) halide hybrid molecular crystals exhibit remarkable structural diversity and photophysical properties, but their application in aqueous environments is often limited by insufficient stability. Herein, we report portable and reusable photoluminescent sensors based on Cu(I)–I triethylenediamine derivatives [Cu₄I₆(pr-ted)₂] and [Cu₃I₅(bz-ted)₂] (pr-ted = 1-propyl-1,4-diazabicyclo[2.2.2]octan-1-ium; bz-ted = 1-benzyl-1,4-diazabicyclo[2.2.2]octan-1-ium). Their submicrometric particles exhibit intense UV-excited emissions and high photoluminescence quantum yields but limited water stability. To address this limitation, ultrasound sonication was employed to control particle size and produce stable suspensions that can be incorporated into polymeric matrices via 3D printing with photocurable resins or polylactic acid (PLA) films by drop-casting, yielding mechanically robust composites that retain their structural and optical properties. The devices used act as selective turn-off luminescent sensors for Fe³⁺ in aqueous media, with nanomolar detection limits (1.33–1.58 nM) below regulatory thresholds for drinking water. Moreover, [Cu₃I₅(bz-ted)₂] enables tetracycline detection in river water with a limit of detection of 0.038 nM. Mechanistic studies indicate that reversible photoinduced electron transfer is the primary quenching pathway, while composites maintain sensing performance over multiple reuse cycles. Full article

The growing volume of construction and demolition waste has made discarded concrete a major source of urban solid waste, placing increasing pressure on land resources and the environment. Recycling waste concrete into recycled aggregate concrete (RAC) offers an effective solution for resource conservation and carbon reduction, aligning with the goals of sustainable development. However, due to the residual mortar, high porosity, and microcracks of recycled aggregates, RAC generally exhibits lower compactness, strength, and durability than conventional concrete, particularly under freeze–thaw conditions where degradation accelerates and service life decreases. To address these challenges, this study investigates the optimization of RAC mix design and its frost resistance performance for pavement base applications. An orthogonal experimental design was employed, with the water-to-binder ratio, recycled aggregate replacement ratio, and air-entraining agent dosage as key variables, while 7-day compressive strength, permeability coefficient, and rebound modulus served as evaluation indices. The influence and interaction of these factors were analyzed to determine an optimal mix meeting both mechanical and durability requirements. Rapid freeze–thaw cycling tests were then conducted to examine the variations in mass loss, relative dynamic modulus, and compressive strength retention, followed by exponential and damage variable modeling to characterize the degradation process. Results show that the water-to-binder ratio primarily governs strength, the replacement ratio affects stiffness and permeability, and the air-entraining agent significantly enhances frost resistance by improving pore structure. The optimized mix retained over 70% of its relative dynamic modulus after 300 freeze–thaw cycles, exhibiting superior durability. This work establishes a systematic framework for multi-factor optimization and durability evaluation of RAC, providing theoretical and practical guidance for its application in cold-region pavement bases. Full article

Phenolic-rich extracts from Satureja montana were evaluated before and after diazomethane treatment to determine how chemical derivatization influences their antioxidant capacity. Native and modified extracts were compared experimentally by measuring total phenolic content, ferric reducing antioxidant power (FRAP), and Fe²⁺-chelating ability. EN1 exhibited the highest concentration of phenolic compounds, reaching 1278.54 mmol/g, whereas EM2 retained only 1.99 mmol/g. In the FRAP assay, reducing power followed the order EN1 (9.36) > EN2 (3.72) > EM2 (2.08), with EM2 still exceeding caffeic, chlorogenic, and ferulic acids. In contrast, the modified extracts showed superior metal chelating capacity, with EM1 and EM2 displaying IC₅₀ values of 0.70 and 0.82 mg/mL, respectively, both markedly lower than those of the native extracts and the pure standards. To rationalize these differences, a DFT study was performed at the B3LYP/6-311++G(d,p) level, examining 18 proposed phenolic acids and their methylated derivatives associated with the extracts. All methylation reactions were thermodynamically favorable, particularly for compounds 18 (−57.10 kcal/mol), 16 (−53.96), 6 (−53.34), and 3, 9, and 11 (−52.71). Solvent effects were found to be structure-dependent: caffeic acid showed BDE values of 72.29, 73.59, and 74.43 kcal/mol in the gas phase, water, and benzene, respectively, whereas syringic acid displayed values of 80.44, 77.09, and 80.65 kcal/mol under the same conditions. Likewise, the ionization potential of caffeic acid decreased from 180.09 kcal/mol in the gas phase to 133.26 kcal/mol in water and 154.22 kcal/mol in benzene. Among all analyzed species, methyl 3,4-dihydroxycinnamate exhibited the lowest BDE (71.60 kcal/mol) as well as the most favorable ΔG°r toward HOO• (−11.06 kcal/mol). Full article

The coexistence of emulsified oil, dissolved organics, and heavy metal ions in industrial oily wastewater makes one-step treatment highly challenging. Herein, an organic-inorganic co-modified PVDF composite membrane (MTSP) was fabricated via nonsolvent-induced phase separation, with tea polyphenols, SiO₂, and fibrous MXene synergistically incorporated. The resulting membrane exhibited a superhydrophilic/underwater oleophobic surface, with a water contact angle of 1° and an underwater oil contact angle of ~136°, owing to the optimized surface chemistry and hierarchical pore structure. As a result, the MTSP membrane effectively suppressed oil fouling while enabling rapid water transport. At 0.1 bar, the optimized membrane delivered an oil/water separation efficiency of ~99.5% and a high flux of 2420–2670 L·m⁻²·h⁻¹, while maintaining >99% separation efficiency for various emulsified oils, including kerosene, edible oil, n-hexane, and 1,2-dichloroethane. It also showed excellent recyclability and chemical stability, retaining >98–99% efficiency after five cycles and after 24 h exposure to pH 1 and pH 12 conditions. Notably, for complex simulated wastewater containing emulsified kerosene, phenol, and Fe³⁺, Cu²⁺, Zn²⁺, and Cd²⁺, the membrane maintained ~99% oil/water separation efficiency and simultaneously removed ~79% of phenol and 70–86% of heavy metal ions in a single filtration process. The superior performance is attributed to the synergistic effects of the superhydrophilic/underwater-oleophobic membrane surface, hierarchical transport channels enabling rapid water permeation, and multifunctional sites that adsorb/coordinate dissolved pollutants. This work provides a simple, scalable design strategy for PVDF-based membranes that integrate high-flux separation, antifouling performance, and multi-pollutant remediation for the treatment of complex oily wastewater. Full article

Understanding dry-out-induced weakening of reservoir and caprock rocks driven by gas displacement is critical for ensuring the operational safety and efficiency of underground gas storage (UGS). Using core samples from the Xiangguosi UGS collected from different regions and stratigraphic intervals, we quantify the evolution of dynamic elastic parameters during simulated downhole dry-out with a joint ultrasonic and nuclear magnetic resonance (NMR) monitoring system. The results show that as water saturation (S_w) decreases, the dynamic bulk modulus (K_d) and P-wave velocity (V_p) decline by varying degrees across specimens, with reductions ranging from 3.0% to 50.48% and from 1.34% to 17.56%, respectively, whereas the dynamic shear modulus (G_d) and S-wave velocity (V_s) show only minor variations throughout the process. These findings demonstrate that the sensitivity of dynamic parameters to dry-out is strongly specimen-dependent. Further analysis indicates that the dry-out response is highly variable and depends on a combination of petrophysical properties. Among these, the heterogeneity of the initial pore structure acts as an important factor, with its influence shaped by mineralogy and bulk frame rigidity. Cores with multimodal pore size distributions and well-developed macropores (long T₂ components) respond more strongly to dry-out, whereas higher clay mineral contents tend to mitigate modulus degradation by retaining water under stronger capillary confinement. Based on these observations, we propose a conceptual model of pore support and skeleton constraint. The model suggests that dry-out weakening arises from a progressive loss of pore fluid volumetric support to the rock skeleton as free water is preferentially displaced from meso- and macropores. These findings provide key experimental evidence and mechanistic insights for using geophysical methods to monitor dry-out zone expansion and to assess long-term formation stability in UGS. Full article

Artificial dams are key retaining structures in underground coal mine reservoirs, and their mechanical performance directly affects the safety and stability of underground water storage systems. This study investigates the effects of dam type, hydraulic pressure, and top boundary condition on dam behavior using three-dimensional finite element models developed in ABAQUS. Three representative dam types, namely flat slab, gravity, and arch dams, were analyzed under three upstream water pressures (0.5, 1.0, and 1.5 MPa) and three top boundary conditions (free, simply supported, and fixed), resulting in 27 numerical cases under an overburden pressure of 4 MPa. The results show that increasing water pressure consistently increases displacement and stress in all dam types, while the deformation mode and stress redistribution strongly depend on structural form and top restraint. The flat slab dam is more prone to edge cracking and local stress concentration, the gravity dam exhibits better overall stiffness and deformation stability, and the arch dam provides more efficient stress redistribution but shows stronger edge effects under restrained conditions. Overall, the gravity and arch dams demonstrate better mechanical adaptability than the flat slab dam. These findings provide a numerical basis for dam-type selection, structural optimization, and local reinforcement design in underground coal mine reservoirs. Full article

Agri-food waste valorization is critical for advancing sustainable packaging solutions. Citrus processing generates large amounts of peel residues that are often discarded, despite being rich in valuable biopolymers. This study presents a fully integrated, zero by-product valorization strategy for the fabrication and characterization of pectocellulosic nanocomposite films derived from orange peel (OP) biomass. Orange peel extract (OPE) was prepared and used for the biosynthesis of ZnO nanoparticles (NPs), while cellulose was obtained after the depectinization reinforced the pectin-rich supernatant used as the film-forming matrix (0–15% w/w). The optimized formulation containing 5% cellulose enhanced tensile strength by approximately 103% and reduced water vapor permeability by about 12.5% compared to the control, while maintaining structural homogeneity. Higher cellulose loading (≥10%) induced pore formation and compromised barrier and biological performance. Incorporation of ZnO NPs (1–5% w/w) into the optimized matrix further improved stiffness (YM = 163.9 MPa), improved UV-shielding capacity, antimicrobial activity (inhibition zones up to 16.0 mm), and antioxidant performance (98.2% ABTS inhibition). Biodegradation remained statistically unaffected by ZnO incorporation, with films retaining 29–35% degradation within 33 days. Overall, this work demonstrates the transformation of OP waste into multifunctional biodegradable active packaging materials, reinforcing circular bioeconomy principles. Full article

Heat-induced softening of apple fruit varies markedly among cultivars; however, the biochemical factors underlying these differences remain incompletely understood. This study investigated the relationship between cell wall modifications and thermal flesh breakdown in three apple cultivars (‘Bramley’s Seedling’, ‘Fuji’, and ‘Toki’). Fruit flesh samples were heated under controlled conditions and analyzed for changes in texture properties, cell structure, cell wall composition, and molar mass distribution. Heating increased water-soluble pectin in all cultivars, with a markedly greater increase in ‘Bramley’s Seedling’, indicating pronounced pectin solubilization during thermal treatment. A pronounced shift from high- to low-molar-weight polymers in the Na₂CO₃-soluble fraction was also observed only in ‘Bramley’s Seedling’, suggesting extensive depolymerization of the Na₂CO₃-soluble pectic polymers. A decrease in hemicellulose and cellulose content following heating was observed exclusively in ‘Bramley’s Seedling’. Consistently, this cultivar exhibited significantly lower gumminess and chewiness compared with the other cultivars. Beyond compositional changes, ‘Bramley’s Seedling’ exhibited severe tissue disintegration and distinctive rheological behavior indicative of extensive cell rupture. In contrast, ‘Fuji’ and ‘Toki’ retained relatively stable cell wall structures and maintained tissue integrity after heating. These findings suggest that cultivar-dependent disassembly of cell wall polysaccharides, particularly pectin depolymerization and solubilization, is strongly associated with heat-induced tissue breakdown. Full article

As demand for sustainable plant protein rises, pumpkin seeds emerge as a promising but underutilized source. Conventional alkaline extraction (ALK) often impairs protein functionality, prompting interest in non-thermal alternatives. This study systematically compared the functional, colloidal, and structural properties of pumpkin seed protein isolates obtained via ALK (conducted at 50 °C), ultrasound-assisted (UAE), and microwave-assisted extraction (MAE). UAE produced the highest extraction yield (50.07%), superior overall solubility, greatest water and fat absorption capacities, and lowest least gelation concentration (12%). Furthermore, UAE best preserved native protein secondary structure (retaining 43.45% alpha-helix), as quantified by FTIR peak deconvolution, and maintained an intact, flake-like morphology under scanning electron microscopy (SEM), yielding the most uniform particle size distribution. Conversely, MAE achieved the highest protein content (73.53%) and the most negative zeta potential, leading to the highest emulsifying and foaming capacities despite inducing a bimodal particle size and irregular, porous surface morphology. ALK performed the poorest across structural and functional metrics, severely denaturing the proteins due to combined alkaline and thermal stress. UAE is recommended for applications requiring optimal solubility and gelation, whereas MAE is highly effective for emulsion- and foam-based food systems, reinforcing pumpkin seeds as a viable sustainable protein ingredient. Full article

This study investigates the effect of metakaolin (MK) as a partial replacement of cement (CEM I) in high-workability mortars, with emphasis on fresh-state behaviour, mechanical properties, microstructural development, and carbon footprint implications. Mortars were produced with MK replacement levels ranging from 0 to 50% by mass of binder, under a constant water-to-binder ratio and fixed superplasticiser amount. Fresh-state results showed that increasing MK content reduced flowability due to its high fineness; however, high workability was maintained for replacement levels up to 20%. At 28 days, MK replacement up to 10% retains approximately 90–95% of the control compressive and flexural strength, whereas higher replacement levels lead to gradual strength reductions (to ~55–60% at 50% MK), despite comparable early-age strength gains across all mixes. Durability-related indicators demonstrated reduced water absorption and capillary uptake at moderate MK contents (approximately 20–30%), indicating refined pore structure and reduced pore connectivity. Microstructural analyses using SEM, TGA, and XRD confirmed effective portlandite consumption and the formation of dense C–A–S–H-type hydration products at moderate MK replacement levels, whereas excessive MK contents resulted in unreacted MK. A comparative carbon footprint assessment showed that MK incorporation leads to proportional reductions in embodied CO₂ emissions, with replacement levels of 10–20% providing the most favourable balance between mechanical performance, durability, and environmental benefit. Therefore, the results demonstrate that MK can be used as a supplementary cementitious material for producing low-carbon, high-workability mortars. Full article

The aim of this work was to evaluate the compositional, functional, antioxidant, thermal, and structural properties of faba bean flour (FBF) and a faba bean protein concentrate (FBC) elaborated by a sustainable dry fractionation method. Proximate composition was determined by analyzing the content of moisture, protein, lipids, ash, total dietary fiber, starch, and available carbohydrates. A methanolic extract was used to analyze total polyphenols and antioxidant capacity using complementary methods. The fatty acid profile was determined by gas chromatography. Techno-functional properties were assayed, determining water-holding capacity (WHC), oil absorption capacity (OAC), and retention capacity of different solvents (SRC), water activity, pH, and titratable acidity. Structural and thermal properties were studied by FTIR and DSC. The dry method produces a concentrate with a low quantity of starch (2.5 vs. 25.6%) and carbohydrates and higher amounts of proteins (61.14 vs. 23.61%). Lipids, mainly mono and polyunsaturated ones, and polyphenols with high antioxidant activity. FBC absorbed a greater proportion of lactic acid, likely due to its higher acidity, and showed higher oil absorption, but retained less water compared to FBF. FTIR and DSC results suggested that the heat-treated proteins (in FBC) exhibited some degree of protein denaturation, unlike the FBF proteins. These findings highlight the potential of dry-fractionated faba bean concentrate as a sustainable and functional food ingredient, particularly for products aimed at improving nutritional quality. Its enhanced antioxidant profile, favorable lipid composition and unique techno-functional properties make it a promising alternative for developing plant-based foods. Full article

Urban districts are increasingly exposed to overlapping heat stress and stormwater loads driven by warming trends, more intense rainfall, and continued growth of impervious surfaces. Pavements occupy a large share of the public right-of-way, so their material and structural design offers a scalable pathway for urban climate adaptation. Yet the literature on porous asphalt remains fragmented, with hydrological performance often assessed using infiltration or permeability metrics in isolation, while thermal studies frequently report surface cooling without consistently tracking the governing water budget or its persistence. To reconcile these disconnected strands, this review synthesizes a conceptual hydro-thermal balance framework in which runoff mitigation and heat moderation are treated as a coupled problem controlled by storage, drainage pathways, and evaporative demand. Within this framing, cooling is primarily water-limited: permeability enables wetting and redistribution, but the magnitude and duration of temperature reduction depend on how much water is retained near the surface and how long it remains available for evaporation, rather than on permeability alone. The review integrates the current understanding of mixture structure and pore connectivity, permeability–storage behavior, moisture availability and evaporation, and the operational factors that govern performance persistence. Laboratory and field evaluation approaches are summarized alongside modeling methods used to interpret coupled hydro-thermal responses under different climates. Practical constraints—including clogging, maintenance requirements, and durability risks under repeated moisture–temperature cycling—are discussed as mechanisms that can progressively suppress both infiltration and water availability, undermining long-term function without performance-based specifications and life-cycle planning. Finally, design and policy implications are outlined for integrating porous asphalt into coordinated heat-and-stormwater strategies, and research priorities are identified to advance standardization, long-term monitoring, and coupled hydro-thermal–mechanical assessment. Full article

Electrochemical chlorine production is of considerable industrial importance in areas such as water treatment, chemical manufacturing, and disinfection. However, conventional precious metal-based dimensionally stable anodes (DSAs), such as RuO₂- and IrO₂-based systems, are limited by high cost and resource constraints, motivating the development of low-cost alternative catalysts. In this study, Mn₃O₄ electrodes with controllable defect characteristics were fabricated by electrochemical deposition under various processing conditions. The effects of defect modulation and surface modification on the structural, electronic, and electrochemical properties of the electrodes were systematically evaluated. X-ray diffraction analysis confirmed that all deposited films retained a stable tetragonal Mn₃O₄ crystal structure, indicating that the deposition parameters primarily influenced defect states rather than the bulk phase. Mott–Schottky measurements revealed that the Mn₃O₄ electrodes exhibited p-type semiconducting behavior, with charge carrier densities on the order of 10¹⁴ cm⁻³, suggesting that oxygen vacancy-related defect states may contribute to the observed electronic properties of the electrodes. To further enhance anodic performance, Pt was introduced onto the Mn₃O₄ surface via sputtering, resulting in significantly improved charge transfer characteristics. Electrochemical measurements demonstrated that the best performing Pt/Mn₃O₄ electrodes delivered a current density exceeding 100 mA cm⁻² at an applied potential of 1.5 V versus Ag/AgCl. More importantly, defect-enriched Pt/Mn₃O₄ electrodes exhibited markedly enhanced chlorine evolution activity, with the chlorine production rate increasing from approximately 14 µmol cm⁻² to 29 µmol cm⁻², corresponding to an enhancement of about 2.07-fold. Faradaic efficiency analysis further showed that sample (g) and sample (n) achieved chlorine evolution efficiencies of 59.2% and 74.6%, respectively, indicating a higher tendency toward chlorine evolution for the Pt-modified electrodes under the tested conditions. These findings suggest that the synergistic combination of defect engineering and surface modification effectively modulates the electronic structure of Mn₃O₄, providing a viable strategy for improving chlorine evolution performance. Full article

Soil salinity poses a major challenge to agricultural productivity, especially threatening food security in arid and semi-arid areas. Traditional soil reclamation methods, such as leaching, chemical amendments, and drainage engineering, usually need large amounts of water, involve high costs, and can lead to environmental problems. This review compiles existing knowledge on innovative strategies for managing saline soils, focusing on buried interlayer systems that use materials like straw, sand, gravel–sand mixtures, and biochar. These interlayers improve soil hydraulic properties by preventing capillary rise, encouraging salt leaching, and reducing surface salt buildup. Biochar stands out as a particularly useful material because of its stability, large surface area, porosity, and high cation exchange capacity. These features help improve soil structure, increase water retention, and effectively retain sodium. Evidence from lab and field tests shows that buried biochar layers can stop salt from moving upward, aid in desalinating the root zone, and boost crop yields. While straw and sand interlayers show potential in reducing salinity, biochar is noted for its multifunctionality and long-term effectiveness in addressing salinity problems. The success of buried biochar systems depends on several factors, including the properties of the biochar, how much is used, how deep it is buried, and the specific soil and climate conditions. This review highlights how these systems work, compares their performance, and points out research gaps, advocating for their potential as a sustainable, resource-efficient way to manage salinity and improve soil health over the long term. A substantial proportion of the existing evidence is derived from controlled laboratory studies, and the buried biochar layer approach remains an emerging technique that requires further validation under field conditions. Still, significant knowledge gaps persist regarding long-term performance and water-salt dynamics, while site-specific soil variability and scalability challenges may limit the effective implementation of biochar interlayer systems under field conditions. Full article

Agroindustrial residues represent an abundant and underutilized source of carbon-rich materials for environmental remediation. In this study, annatto processing waste (Bixa orellana), a largely unexplored lignocellulosic by-product generated during pigment extraction, was converted into hydrochar via hydrothermal carbonization at 200 °C for 3 h. The resulting hydrochar (HC-AW) exhibited a predominantly amorphous carbon structure with retained oxygen-containing surface functionalities, and a solid yield of 44%, indicating efficient biomass conversion under subcritical conditions. Adsorption performance toward tetracycline was evaluated through pH-dependent experiments, kinetic modeling, equilibrium isotherms, and thermodynamic analysis. Maximum adsorption occurred under near-neutral conditions (pH ≈ 7), consistent with the interplay between tetracycline speciation and the hydrochar surface charge (pH_PZC ≈ 6.3), highlighting its potential applicability under realistic water treatment conditions without pH adjustment. Kinetic data were well described by the pseudo-second-order model, while equilibrium results were best fitted by the Langmuir model, with a maximum adsorption capacity of 14.94 mg g⁻¹ at 30 °C. Thermodynamic analysis indicated a spontaneous and slightly endothermic adsorption process. Overall, the results highlight the potential of annatto-derived hydrochar as a low-cost adsorbent and provide insight into the relationship between surface properties and adsorption behavior governing antibiotic removal from aqueous systems. Full article