Search Results (2,002)

Rapid urbanisation and climate-induced extreme weather events have intensified urban stormwater runoff challenges. Biofiltration systems have emerged as effective, sustainable urban drainage solutions for mitigating these impacts. A total of 78 peer-reviewed studies were assessed to synthesise findings on how design parameters influence pollutant removal performance in biofiltration systems treating urban stormwater runoff. Peer-reviewed articles published from 1 January 1995 to 3 June 2025 were retrieved from Scopus and Web of Science (WoS). Non-peer-reviewed, non-empirical, incomplete, or non-relevant studies were excluded. Rigorous application of a standardised review protocol and predefined criteria was employed to mitigate bias. The findings reveal high removal efficiencies for certain trace metals, ammonium, Escherichia coli (E. coli), hydrocarbons, and microplastics, with inconsistent removal for total nitrogen, nitrates, and phosphorus. The primary pollutant removal mechanisms were adsorption, ion exchange with select media, and denitrification in saturated zones. Only 22% of the reviewed studies incorporated a saturated zone, while 18% included a protective surface layer, despite both design elements being associated with improved pollutant removal performance. Variations in media composition and stormwater quality limit comparability across studies. This review highlights the need for context-specific design guidance and further exploration of multi-functional media to enhance multi-pollutant removal. Full article

The sluggish kinetics of the hydrogen oxidation reaction (HOR) in alkaline media remain a primary bottleneck for anion exchange membrane fuel cells (AEMFCs), necessitating catalysts that synergistically optimize the adsorption of hydrogen (*H) and hydroxide (*OH) intermediates. Herein, we construct a well-defined heterointerface between Pd clusters and CeO₂ on nitrogen-doped carbon (Pd-CeO₂/NC) to electronically engineer the active sites. Spectroscopic studies and theoretical calculations collectively reveal that CeO₂ acts as an electron acceptor, drawing electrons from Pd via interfacial Pd-O-Ce bridges. This charge transfer induces a downshift of the Pd d-band center, which optimally tunes the adsorption strength of both *H and *OH at the interface, thereby breaking the scaling relationship that limits HOR activity. The resulting Pd-CeO₂/NC catalyst achieves an exceptional exchange current density of 3.66 mA cm⁻², surpassing that of commercial Pt/C by a factor of two and ranking among the best reported noble metal catalysts. Furthermore, it exhibits outstanding long-term stability and remarkable CO tolerance, retaining high activity in an atmosphere containing 1000 ppm CO. This work underscores the profound efficacy of metal–oxide heterointerface engineering in regulating electronic structures for multi-intermediate optimization, offering a viable design principle for advanced alkaline HOR electrocatalysts. Full article

This study reports the development and characterization of hierarchical electrospun scaffolds based on poly (L-lactic acid) (PLA) and polyacrylonitrile (PAN) reinforced with calcium oxide (CaO) nanoparticles (18.5 ± 4.7 nm) for skin regeneration. Six configurations, including two five-layer multilayer systems (PLA/PAN/CaO and PAN/PLA/CaO), were evaluated to determine how composition and deposition sequence influence physicochemical, mechanical, and biological performance. FT-IR, XRD and DSC confirmed the successful integration of CaO, while thermal analysis evidenced an effect of chain mobility and interfacial interactions within multilayer systems. Cross-sectional SEM revealed the presence of both fibers with continuous interfaces. Nitrogen adsorption showed that CaO significantly increased the specific surface area (e.g., from 4.6 m²/g in neat PLA to 21.65 m²/g in PLA/CaO), with type IV isotherms indicating mesoporosity. Wettability assays demonstrated reduced contact angle in PLA (from 126.3° to 91.8°) and sequence-dependent surface properties in multilayers. Tensile testing confirmed that the multilayer architecture bridged the mechanical gap between compliant PLA and high-strength PAN, yielding intermediate moduli (~10–11 MPa) and balanced toughness. Antibacterial assays against S. aureus and E. coli showed that CaO significantly reduced bacterial viability, with PLA/PAN/CaO achieving the highest inhibition (up to 37.1%). In vitro HaCaT assays and in vivo implantation in BALB/c mice confirmed high cytocompatibility and biocompatibility. These findings demonstrate that multilayer electrospinning of PLA/PAN/CaO enables the design of structurally integrated, bioactive, and mechanically balanced scaffolds for advanced wound healing and dermal repair. Full article

In this study, we prepare N–doped biochar loaded with β-CD, using cotton stalks as a carbon source, and evaluate its removal efficiency for tetracycline (TC) and methylene blue (MB) from aqueous solutions. This composite uniquely integrates molten salt activation, nitrogen doping, and β-CD grafting, resulting in an exceptionally high specific surface area of 1943 m²/g and abundant active sites. The findings reveal that β-CD-NKBC-1.5 (5 g of N–doped biochar loaded with 1.5 g of β-CD) demonstrates remarkable capabilities for both TC and MB removal across an extensive pH spectrum, reaching peak adsorption levels of 1269.8 and 969.4 mg/g at 308.15 K, respectively—outperforming most previously reported biochar-based adsorbents. The adsorption process is well described by the pseudo-second-order and Langmuir models, indicating that monolayer chemisorption is the dominant mechanism. β-CD-NKBC-1.5 exhibits preferential adsorption for TC and MB and maintains high adsorption efficiency even with coexisting ions (Na⁺, K⁺, Ca²⁺, Mg²⁺, and SO₄²⁻) at concentrations up to 500 mg/L. The adsorption mechanism involves Lewis acid–base interactions, hydrogen bonding, π–π stacking, and pore filling. Full article

Activated carbons are usually prepared from natural precursors (e.g., fruit stones or nutshells) by carbonization and activation processes carried out at 400–1000 °C. They exhibit well-developed porosity, and chemical activation introduces hydrophilic functional groups on their surface, providing excellent sorption properties. However, the high temperatures required during thermal treatment increase production costs. In this work, cost-reducing methods for preparing carbon sorbents are proposed. Carbonization of H₃PO₄ activated waste pistachio nutshells was performed using classical pyrolysis (500 or 550 °C, 30 min, N₂ atmosphere) and microwave treatment (power 1000 W, 20 min). The properties of the synthesized carbons were characterized using thermogravimetry and spectroscopic techniques including infrared (ATR), Raman, photoelectron (XPS) spectroscopies, and scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM-EDS). Porous structure parameters were determined using nitrogen adsorption experiments. The efficiency of Pb²⁺ removal from spiked ultrapure, tap and river water was evaluated by batch sorption experiments and inductively coupled plasma–mass spectrometry. The most porous carbons were those prepared at 500 and 550 °C, with specific surface areas of 910 and 256 m²/g, respectively. Surface phosphates increased the Pb²⁺ sorption efficiency to 99% from ultrapure water, at an initial concentration of 300 µg Pb²⁺/L. The material obtained with the microwave method was not fully carbonized and remained nonporous, but it also exhibited 99% Pb²⁺ uptake from ultrapure water due to the presence of oxygen-containing surface groups. The Pb²⁺ removal from spiked tap and river water reached up to 84% and 94%, respectively, at the spiking level of 300 µg Pb²⁺/L. Full article

The dense passivation film (DPF) formed on the surface of martensitic stainless steel effectively improves corrosion resistance, but it also hinders the adsorption and diffusion of active nitrogen atoms during gas nitriding. In this work, the influence of the DPF of 1Cr11Ni2W2MoV stainless steel on gas nitriding was overcome by controlling the cooling rate during stainless steel solution treatment, thereby enabling the successful formation of a nitrided layer. The effects of nitrogen potential on the microstructure, phase constitution, and tribological performance of the nitrided layer were systematically investigated. A dense passivation film formed at a solid-solution cooling rate of 110 ± 5 °C/s effectively inhibited nitrogen diffusion, resulting in the absence of a nitrided layer. However, when the cooling rate during solid solution was reduced to 80 ± 5 °C/s, the precipitation of chromium carbide along the grain boundaries damaged the density and integrity of the DPF, thereby enabling the formation of a nitrided layer during gas nitriding. A high nitrogen potential enhanced nitrogen diffusion and increased the nitrided layer thickness. However, an excessively high nitrogen potential led to nitrogen enrichment along grain boundaries, resulting in microcracking and reduced mechanical integrity of the compound layer. When the nitrogen potential was 1.0, a uniform and crack-free nitrided layer with a surface hardness exceeding 1000 HV_0.1 was obtained. Tribological tests combined with SEM observations of the worn surfaces showed that gas nitriding significantly reduced the friction coefficient and wear rate compared with the matrix sample. Among the nitrided samples, H-10 exhibited the lowest friction coefficient and wear rate, whereas H-23 showed relatively inferior wear resistance due to microcrack-related brittleness. The dominant wear mechanism changed from severe abrasive–adhesive wear in the matrix sample to mild abrasive wear in the nitrided samples. These results indicate that regulating passivation film integrity through heat treatment, together with optimizing nitrogen potential, is an effective strategy for achieving high-quality gas nitriding and improved tribological performance in martensitic stainless steel. Full article

Biochars derived from post-consumer coffee residues were synthesized using NaCl and NaHCO₃ as impregnation agents, which were pyrolyzed at 500 and 1000 °C. Structural characterization revealed that NaHCO₃ treatment at 1000 °C generated a highly interconnected porous network, with a surface area of 1353.22 m² g⁻¹, pore volume of 0.83 cm³ g⁻¹, and average pore size of 2.6 nm. These features, confirmed by nitrogen physisorption and SEM, favor Na⁺ accessibility and insertion. XRD and Raman analyses indicated a predominantly amorphous carbon, with graphitic domains and an interplanar distance of ≈0.34 nm, providing both adsorption capacity and electrical conductivity. Electrochemical evaluation showed that BC_{NaHCO3-1000°C} achieved an initial capacity of 34 mAh g⁻¹, stable for more than 15 cycles, outperforming NaCl-treated biochars. However, despite the favorable morphology, the high surface area may also promote side reactions and irreversible capacity loss, limiting overall efficiency. These findings demonstrate the feasibility of valorizing coffee waste into carbonaceous materials for sodium-ion battery anodes, while highlighting the need for further optimization of porosity, graphitization, and compositional modifications to enhance energy storage performance. Full article

This study examines the utilisation of fly ash from the energy sector as a secondary raw material in cement composites, with the aim of improving sustainability while maintaining high mechanical performance. By partially replacing Portland cement with industrial by-products, the proposed approach supports resource efficiency and aligns cement composite production with circular economy principles. Three formulations were tested: a reference mix and mixes with 25% and 50% cement reduction. Compressive strength reached 41 MPa, confirming suitability for construction use. Chemical and textural properties were analysed using XRD, FTIR, TGA, and nitrogen adsorption (BET, BJH). The results showed structural modifications, including new crystalline phases and changes in porosity. XRD confirmed newly formed phases, while FTIR identified Si-O-Si and Al-O-Si bonds, indicating effective activation of fly ash. Reducing cement content increased surface area and mesoporosity, enhancing performance. The findings demonstrate that fly ash can serve as a sustainable substitute for Portland cement within a circular economy framework, supporting CO₂ emission reduction and resource conservation while enabling the production of durable and environmentally responsible cement composites. Full article

The efficient recovery of coalbed methane (CBM) is critically constrained by the inherent low permeability of coal reservoirs, a challenge predominantly attributed to mineral blockages within the pore-fracture structure. In this study, the deashing efficacy of several acid solutions (HCl, HNO₃, HF, and CH₃COOH) on bituminous coals from the Yushuwan (YSW) and Jiangna (JN) mines was initially assessed to determine the optimal acidizing system. Subsequently, the multi-scale evolution of pore-fracture structures and the fractal characteristics of coal samples treated with the optimized acids were systematically investigated. A multi-analytical approach, integrating scanning electron microscopy (SEM), X-ray diffraction (XRD) with microcrystalline peak-fitting, and low-temperature nitrogen gas adsorption (LT-N₂GA), was employed to quantitatively elucidate the underlying transformation mechanisms. The experimental results indicate that HCl and HNO₃ emerged as the most effective agents for the YSW and JN coals, respectively. Optimized acidification achieved significant reductions in ash content (specifically, an ash removal efficiency of 83.99% for HCl-treated YSW coal) through the selective dissolution of carbonate and clay minerals, thereby facilitating the exposure of the organic matrix and the induction of extensive dissolution pits and secondary fractures. Although the dissolution-induced collapse of mineral-supported fine pores led to a reduction in both total pore volume and BET specific surface area, the average pore diameter undergoes a substantial increase (e.g., nearly doubling from 9.0068 nm to 16.5126 nm for the JN coal). Furthermore, the reduction in Frenkel–Halsey–Hill (FHH) fractal dimensions (D₁ and D₂) indicates a decrease in pore-surface complexity and structural heterogeneity. These findings reveal that optimized acidification induces significant alterations in pore structure and mineral composition. The treatment facilitates the conversion of isolated pores into interconnected networks, accompanied by an increase in pore volume and a shift in pore size distribution toward larger dimensions. This research elucidates the mechanisms of mineral dissolution and pore expansion, providing a fundamental characterization of the microstructural evolution of coal in response to acid treatment. Full article

Uranium is a critical raw material for the nuclear industry. Given the vast uranium reserves in seawater, the development of efficient adsorbents is central to extraction technologies. Polyamidoxime (PAO)-based adsorbents are widely utilized due to their high affinity for uranium; however, traditional PAO materials often suffer from low mechanical strength and poor recyclability. To address these limitations, this study utilized natural balsa wood as a substrate. A three-dimensional porous cellulose skeleton (DES-W) featuring high porosity, hydrophilicity, and retained mechanical strength was constructed by partially removing lignin using a deep eutectic solvent (DES). Subsequently, polyamidoxime was loaded onto the inner walls of the DES-W via vacuum impregnation, resulting in a polyamidoxime-functionalized wood-based adsorbent (PAO-WA). The results indicated that PAO-WA achieved an equilibrium adsorption capacity of 45.31 mg/g at pH 6.0 with an initial uranium concentration of 50 mg/L, representing a twofold increase compared to the unmodified DES-W. The adsorption kinetics and isotherms followed the pseudo-second-order and Langmuir models, respectively, suggesting a mechanism dominated by monolayer chemisorption. Mechanism analysis confirmed that uranyl ions were primarily captured via coordination with nitrogen and oxygen atoms in the amidoxime groups, with residual carboxyl groups in the wood contributing to the adsorption process. This work offers a novel strategy for developing efficient, environmentally friendly, and mechanically robust adsorbents for uranium extraction from seawater. Full article

Both the Lower Silurian Longmaxi Formation and the Upper Permian Dalong Formation shales in southern China are organic-rich with well-developed nanoscale reservoir pores, demonstrating significant shale gas exploration potential. However, the current lack of in-depth research on the differential depositional and reservoir evolution characteristics of these two shale sequences has left the main controlling factors of the reservoirs unclear, thereby constraining breakthroughs in shale gas development. Focusing on the Longmaxi and Dalong formation shales in the Sichuan Basin, this study employed various analytical methods, including major and trace element analyses, X-ray diffraction (XRD), high-pressure mercury intrusion (HPMI), nitrogen adsorption, CO₂ adsorption, and scanning electron microscopy (SEM). Investigations into the depositional paleoenvironment, paleoproductivity, organic matter enrichment, and microscopic difference mechanisms of nanoscale reservoirs reveal that the Longmaxi Formation shale represents a passive continental margin shelf facies. It is characterized by strong terrigenous input, a predominance of quartz and clay minerals, and consists mainly of siliceous and argillaceous shale facies with high organic matter abundance. In contrast, the Dalong Formation shale was deposited in an intra-platform basin under the influence of intra-platform rifting. It features weak terrigenous input, highly reducing conditions, and strong paleoproductivity. Dominated by quartz and carbonate minerals, its lithofacies are primarily siliceous and calcareous shales. Within the Dalong Formation, the diagenetic dissolution of carbonate minerals promotes the development of micrometer-scale pores larger than 100 μm, while the extensive thermal evolution of organic matter fosters the formation of honeycomb- and embayment-like nanoscale micropores and mesopores, rendering it a relatively superior shale reservoir. Ultimately, the high-TOC shales in the lower part of the Longmaxi Formation and the upper part of the Dalong Formation are identified as the primary sweet spot intervals for future shale gas development. Full article

Converting carbon dioxide (CO₂) into value-added chemicals and/or capturing it before emission are complementary strategies to mitigate rising atmospheric CO₂ levels. Copper-based materials are widely investigated for CO₂ conversion because Cu can bind and electronically activate CO₂ and related intermediates. In this computational research, an evaluation of CO₂ activation in Cu_xSc_γ nanoclusters (Cu₃Sc, Cu₂Sc₂, and CuSc₃) anchored on a graphene bilayer doped with three nitrogen atoms (graphene-3N) was performed using conformational screening and thermochemical adsorption analysis at 298.15, 300, and 400 K. Initially, the Cu₃Sc, Cu₂Sc₂, and CuSc₃ nanoclusters were optimized and characterized (relative energy, multiplicity, and electronic characteristics), and the support model (graphene-3N bilayer) was validated by comparing free geometry with partially restricted geometry, corroborating minima through vibrational analysis. Subsequently, CO₂ adsorption/activation on Cu_xSc_γ @graphene-3N was evaluated, and ΔH and ΔG values were calculated. Ultimately, based on the ΔG(T) values, the Sabatier regimes were established, where it was observed that Cu₃Sc exhibits moderate exergonic adsorption (ΔG = −76.07, −67.31, and −58.92 kJ·mol⁻¹ at 298.15, 350, and 400 K). In contrast, Cu₂Sc₂ exhibits intense adsorption (−165.02, −156.36, and −148.04 kJ·mol⁻¹), and CuSc₃ results in practically irreversible fixation (−293.98, −287.32, and −279.09 kJ·mol⁻¹), giving priority to Cu₃Sc as the most optimal cluster in terms of activation-regeneration. Full article

Accurate estimation of soil hydraulic parameters under drip irrigation is essential for improving water flow simulations and optimizing irrigation management; however, field measurements in aeolian sandy soils are often expensive and time-consuming. This study focused on typical aeolian sandy soils in the Kubuqi Desert. Field drip irrigation experiments were conducted to obtain temporal variations in soil water content and wetting front advancement, which were used to inversely estimate and calibrate hydraulic parameters for different soil layers. Soil pore space characteristics were quantified using nitrogen adsorption, and their relationships with hydraulic parameters were analyzed through correlation and redundancy analyses. On this basis, the combined effects of particle-size distribution and pore space structure on parameter prediction were evaluated, and soil water movement under drip irrigation was simulated and validated using HYDRUS-2D/3D. The results indicated pronounced spatial variability in soil hydraulic parameters. Residual water content, saturated hydraulic conductivity, and pore-size distribution index were significantly correlated with specific surface area, total pore volume, mean pore diameter, micropore volume fraction, and pore fractal dimension. Compared with approaches based solely on particle-size distribution, incorporating pore space structure effectively reduced the prediction errors of both hydraulic parameters and wetting front migration, thereby improving simulation accuracy. These findings demonstrate that integrating particle-size distribution and pore space characteristics provides a feasible approach for the rapid estimation of hydraulic parameters and the analysis of water movement in aeolian sandy soils under drip irrigation. Full article

Red Amaranth (RA) Azo dye is a persistent pollutant in wastewater and stands as a toxicological risk, which has led to the development of effective methods for its removal and photocatalytic degradation. Therefore, CeO₂ nanoparticles were synthesized by a controlled precipitation method, and Ultraviolet-Visible (UV–Vis) analysis and Tauc plots yielded a band gap of ~3.24 eV. The CeO₂ nanoparticles showed the fluorite cubic phase, and nearly spherical particles with an average size of ~10 nm. Nitrogen physisorption revealed a type IV isotherm with a Brunauer–Emmett–Teller (BET) surface area of 85.27 m²·g⁻¹ and a total pore volume of 0.27 cm³·g⁻¹, indicating a mesoporous structure and high surface accessibility. The chemical behavior showed Ce and O, consistent with phase purity. Photocatalytic performance was evaluated in 20 ppm aqueous solution of RA under 365 nm UV irradiation (LED 100 W), with a temperature of ~20 °C and a 15 min dark adsorption step. Concentration decay was followed at λ_max = 520 nm by Lambert–Beer. The degradation efficiency η and pseudo-first-order kinetic were obtained from ln(C₀/C_t) vs. time. In addition, chemical oxygen demand (COD) tests were performed on RA solution before and after photodegradation, showing a COD reduction of ~85% (from 19.8 to 3 mg O₂·L⁻¹), which corroborates mineralization beyond chromophore bleaching. Under [C₀ = 20 mg·L⁻¹] and [m_cat = 1.0 g·L⁻¹], CeO₂ achieved [RA = 90% at 180 min, k = 0.0125 min⁻¹]. These results demonstrate that CeO₂ is an effective photocatalyst for RA degradation under UV-A irradiation, integrating adsorption, kinetic behavior, and mineralization performance into a coherent structure–property relationship. Full article

Efficient charge transfer and effective separation of photo-generated charge carriers are pivotal to the photocatalytic process. In this study, a novel CoAl₂O₄@nitrogen-doped graphitic carbon (CoAl₂O₄@NGC) composite photocatalyst was fabricated via a stepwise hydrothermal method coupled with high-temperature calcination, and its photocatalytic performance for CO₂ reduction was systematically investigated. X-ray diffraction (XRD), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS) and photoelectrochemical measurements were employed to characterize the phase structure, microstructure, surface chemical state and photoelectrochemical properties of the catalyst. Spinel-structured CoAl₂O₄ nanoparticles were uniformly anchored on the NGC substrate, forming a well-integrated composite interface. XPS analysis confirmed the coexistence of Co²⁺/Co³⁺ mixed valence states in CoAl₂O₄ which provides abundant redox sites for CO₂ activation. Photocatalytic tests showed that CoAl₂O₄@NGC exhibits excellent catalytic activity and cycling stability, with CO and CH₄ yields of 27.88 μmol·g⁻¹·h⁻¹ and 23.90 μmol·g⁻¹·h⁻¹, respectively. The narrow bandgap (1.54 eV) enhances visible light absorption, while efficient electron-hole separation and reduced charge transfer resistance improve photocatalytic efficiency. Theoretical calculations further reveal that CoAl₂O₄@NGC lowers the adsorption free energy of CO₂ and the energy barrier for COOH formation, thus facilitating the photocatalytic CO₂ reduction. This work provides insights for the design of efficient and stable photocatalysts for CO₂ reduction and deepens the understanding of the synergistic catalytic mechanism in the spinel/nitrogen-doped carbon composite system. Full article