Search Results (1,950)

This study developed a new magnetic adsorbent from waste coconut shells using high-temperature carbonization, EDTA-2Na chelation, and Fe₃O₄ magnetic loading. Response surface methodology optimized the preparation conditions to a mass ratio of activated carbon: EDTA-2Na:Fe₃O₄ = 2:0.6:0.2. Characterization (SEM, XRD, FT-IR, and EDS) showed that EDTA-2Na increased the surface carboxyl and amino group density, while Fe₃O₄ loading (Fe concentration 6.83%) provided superior magnetic separation performance. The optimal adsorption conditions of Cu²⁺ by EDTA-2Na-Fe₃O₄-activated carbon composite material are as follows: when pH = 5.0 and the initial concentration is 180 mg/L, the equilibrium adsorption capacity reaches 174.96 mg/g, and the removal rate reaches 97.2%. The optimal adsorption conditions for Pb²⁺ are as follows: when pH = 6.0 and the initial concentration is 160 mg/L, the equilibrium adsorption capacity reaches 157.60 mg/g, and the removal rate reaches 98.5%. The optimal adsorption conditions for Cd²⁺ are pH = 8.0 and an initial concentration of 20 mg/L. The equilibrium adsorption capacity reaches 18.76 mg/g, and the removal rate reaches 93.8%. The adsorption followed the pseudo-second-order kinetics (R² > 0.95) and Langmuir/Freundlich isotherm models, indicating chemisorption dominance. Desorption experiments using 0.1 mol/L HCl and EDTA-2Na achieved efficient desorption (>85%), and the material retained over 80% of its adsorption capacity after five cycles. This cost-effective and sustainable adsorbent offers a promising solution for heavy metal wastewater treatment. Full article

The interface between high-performance thermoelectric materials and electrodes critically governs the conversion efficiency and long-term reliability of thermoelectric generators under high-temperature operation. Here, we propose Al_xCoCrFeNi high-entropy alloys (HEA) as barrier layers to bond Cu-W electrodes with p-type skutterudite (p-SKD) thermoelectric materials. The HEA/p-SKD interface exhibited excellent chemical bonding with a stable and controllable reaction layer, forming a dense, defect-free (Fe,Ni,Co,Cr)Sb phase (thickness of ~2.5 μm) at the skutterudites side. The interfacial resistivity achieved a low value of 0.26 μΩ·cm² and remained at 7.15 μΩ·cm² after aging at 773 K for 16 days. Moreover, the interface demonstrated remarkable mechanical stability, with an initial shear strength of 88 MPa. After long-term aging for 16 days at 773 K, the shear strength retained 74 MPa (only 16% degradation), ranking among the highest reported for thermoelectric materials/metal joints. Remarkably, the joint maintained a shear strength of 29 MPa even after 100 continuous thermal cycles (623–773 K), highlighting its outstanding thermo-mechanical stability. These results validate the Al_xCoCrFeNi high-entropy alloys as an ideal interfacial material for thermoelectric generators, enabling simultaneous optimization of electrical and mechanical performance in harsh environments. Full article

Novel solid strong base catalysts have attracted considerable attention in fine chemical synthesis owing to their unique advantages. In this work, a magnetic solid strong base catalyst with controlled morphology and porous carbon shell structure was successfully fabricated using low-cost carbon sources combined with Fe₃O₄ nanoparticles. KOH was used to introduce strong basic sites through ultrasonic-assisted impregnation. The carbon shell acted as a protective barrier to suppress detrimental interactions between basic species and the support while maintaining structural integrity after high-temperature activation without morphology degradation. The obtained K/C/Fe₃O₄ catalyst exhibits excellent catalytic performance and near-ideal superparamagnetic behavior. In the transesterification reaction for dimethyl carbonate (DMC) synthesis, the K/C/Fe₃O₄ catalyst provides superior performance than conventional solid base catalysts and maintains stable activity over six consecutive cycles. Notably, efficient solid–liquid separation was achieved successfully via magnetic separation, demonstrating practical applicability for the K/C/Fe₃O₄ catalyst. Full article

The O3-type layered oxide materials have the advantage of high specific capacity, which makes them more competitive in the practical application of cathode materials for sodium-ion batteries (SIBs). However, the existing reported O3-type layered oxide materials still have a complex irreversible phase transition phenomenon, and the cycle life of batteries needs, with these materials, to be further improved to meet the requirements. Herein, we performed structural characterization and electrochemical performance tests on O3-NaNi_0.6−xFe_0.25Mn_0.15Mg_xO₂ (x = 0, 0.025, 0.05, and 0.075, denoted as NFM, NFM-2.5Mg, NFM-5.0Mg, and NFM-7.5Mg). The optimized NFM-2.5Mg has the largest sodium layer spacing, which can effectively enhance the transmission rate of sodium ions. Therefore, the reversible specific capacity can reach approximately 148.1 mAh g⁻¹ at 0.2C, and it can even achieve a capacity retention of 85.4% after 100 cycles at 1C, demonstrating excellent cycle stability. Moreover, at a low temperature of 0 °C, it also can keep capacity retention of 86.6% after 150 cycles at 1C. This study provides a view on the cycling performance improvement of sodium-ion layered oxide cathodes with a high theoretical specific capacity. Full article

Abiotic processes have ramifications in wastewater treatment, in situ degradation of organic matter, and cycling of nutrients in wetland ecosystems. Experiments were conducted to investigate abiotic oxidation of organic compounds (lactate) as a function of electron acceptors (ferric citrate and hydrous ferric oxide (HFO), media composition, and pH under anaerobic conditions, using sodium bicarbonate as the buffering agent. Dissolved inorganic carbon (DIC) was used as a proxy for the oxidation of substrates. HFO media generated more DIC compared to ferric citrate containing media. Light and pH had major roles in the oxidation of lactate in the presence of ferric iron. Under dark conditions in the presence or absence of Fe(III), the DIC produced was low in all pH conditions. Inhibition of DIC production was also observed upon photo exposure when Fe (III) was absent. Isotopically, the system showed initial mixing between the bicarbonate and the carbon dioxide produced from oxidation later being dominated by carbon isotope value of lactate used. These redox conditions align with previous studies suggesting cleavage of organic compounds by hydroxyl radicals. The slower redox processes observed here, compared to previous studies, could be due to the scavenging effect of chloride ion on the hydroxyl radical. Full article

Steel pickling sludge serves as a valuable iron source for synthesizing Fe-based catalysts in heterogeneous advanced oxidation processes (AOPs). Here, MoS₂@CoFe₂O₄ catalyst derived from steel pickling sludge was prepared via a facile solvothermal approach and utilized to activate peroxymonosulfate (PMS) for tetracycline hydrochloride (TCH) degradation. Comprehensive characterization using scanning electron microscopy (SEM)-energy dispersive spectrometer (EDS), X-ray photoelectron spectroscopy (XPS), and X-ray diffraction (XRD) confirmed the supported microstructure, composition, and crystalline structure of the catalyst. Key operational parameters—including catalyst dosage, PMS concentration, and initial solution pH—were systematically optimized, achieving 81% degradation efficiency within 30 min. Quenching experiments and electron paramagnetic resonance (EPR) analysis revealed SO₄^∙− as the primary oxidative species, while the catalyst maintained high stability and reusability across cycles. TCH degradation primarily occurs through hydroxylation, decarbonylation, ring-opening, and oxidation reactions. This study presents a cost-effective strategy for transforming steel pickling sludge into a high-performance Fe-based catalyst, demonstrating its potential for practical AOP applications. Full article

This study investigates the effectiveness of geopolymer-based binders for the stabilization of silty sand, aiming to improve its strength and durability under cyclic environmental conditions. A composite binder consisting of Ground Granulated Blast-furnace Slag (GGBS) and Recycled Glass Powder (RGP), modified with nano poly aluminum silicate (PAS), was used to treat the soil. The long-term performance of the stabilized soil was evaluated under cyclic wetting–drying (W–D) conditions. The influence of PAS content on the mechanical strength, environmental safety, and durability of the stabilized soil was assessed through a series of laboratory tests. Key parameters, including unconfined compressive strength (UCS), mass retention, pH variation, ion leaching, and microstructural development, were analyzed using field emission scanning electron microscopy (FE-SEM) and energy-dispersive X-ray spectroscopy (EDS). Results revealed that GGBS-stabilized specimens maintained over 90% of their original strength and mass after eight W–D cycles, indicating excellent durability. In contrast, RGP-stabilized samples exhibited early strength degradation, with up to an 80% reduction in UCS and 10% mass loss. Environmental evaluations confirmed that leachate concentrations remained within acceptable toxicity limits. Microstructural analysis further highlighted the critical role of PAS in enhancing the chemical stability and long-term performance of the stabilized soil matrix. Full article

Metal–organic frameworks (MOFs), particularly ZIF-8, have emerged as promising materials due to their high porosity, tunability, and chemical stability. In this study, we report the synthesis of ZnFe₂O₃-doped ZIF-8 composites with 10 wt% loading via a solvothermal method to enhance their optical and photocatalytic performance. Structural analyses confirmed the successful incorporation of ZnFe₂O₃ without disrupting the ZIF-8 framework. Optical studies revealed enhanced absorption in the visible range, a narrowed bandgap (4.26 eV vs. 4.37 eV for pristine ZIF-8), and an increased extinction coefficient, indicating superior light-harvesting potential. The photocatalytic activity was evaluated by methylene blue (MB) degradation under visible light, where the 10 wt% ZnFe₂O₃-ZIF-8 composite achieved 90% degradation efficiency, outperforming pristine ZIF-8 (67.8%). The catalyst also demonstrated excellent recyclability over five cycles and a proposed degradation mechanism involving ·OH and ·O₂⁻ radical formation. These findings demonstrate the potential of highly doped ZnFe₂O₃@ZIF-8 composites for environmental remediation and photonic applications. Full article

Corrosion fatigue damage significantly affects the long-term service of marine platforms such as propellers. Fatigue testing of pre-corrosion specimens is essential for understanding damage mechanisms and accurately predicting fatigue life. However, traditional seawater-based tests are time-consuming and yield inconsistent results, making them unsuitable for rapid evaluation of newly developed equipment. This study proposes an accelerated corrosion testing method for ZCuAl₈Mn₁₃Fe₃Ni₂ nickel–aluminum bronze, simulating the marine full immersion zone by increasing temperature, adding H₂O₂, reducing the solution pH, and preparing the special solution. Coupled with the fatigue test of pre-corrosion specimens, the corrosion damage characteristics and their influence on fatigue performance were analyzed. A numerical simulation method was developed to predict the fatigue life of pre-corrosion specimens, showing an average error of 13.82%. The S–N curves under different pre-corrosion cycles were also established. The research results show that using the test solution of 0.6 mol/L NaCl + 0.1 mol/L H₃PO₄-NaH₂PO₄ buffer solution + 1.0 mol/L H₂O₂ + 0.1 mL/500 mL concentrated hydrochloric acid for corrosion acceleration testing shows good corrosion acceleration. Moreover, the test methods ensure accuracy and reliability of the fatigue behavior evaluation of pre-corrosion specimens of the structure under actual service environments, offering a robust foundation for the material selection, corrosion resistance evaluation, and fatigue life prediction of marine structural components. Full article

Artificial intelligence (AI) has become ubiquitous in modern computing systems, from high-performance data centers to resource-constrained edge devices. As AI applications continue to expand into mobile and IoT domains, the need for energy-efficient neural network implementations has become increasingly critical. To meet this requirement of energy-efficient computing, this work presents a BWNN (binary-weighted neural network) architecture implemented using FeRAM (Ferroelectric RAM)-based synaptic arrays. By leveraging the non-volatile nature and low-power computing of FeRAM-based CIM (computing in memory), the proposed CIM architecture indicates significant reductions in both dynamic and standby power consumption. Simulation results in this paper demonstrate that scaling the ferroelectric capacitor size can reduce dynamic power by up to 6.5%, while eliminating DRAM-like refresh cycles allows standby power to drop by over 258× under typical conditions. Furthermore, the combination of binary weight quantization and in-memory computing enables energy-efficient inference without significant loss in recognition accuracy, as validated using MNIST datasets. Compared to prior CIM architectures of SRAM-CIM, DRAM-CIM, and STT-MRAM-CIM, the proposed FeRAM-CIM exhibits superior energy efficiency, achieving 230–580 TOPS/W in a 45 nm process. These results highlight the potential of FeRAM-based BWNNs as a compelling solution for edge-AI and IoT applications where energy constraints are critical. Full article

The influence of the copper (Cu) content on the corrosion resistance of 3.5%Ni low-carbon weathering steel was investigated using periodic dry–wet cycle accelerated corrosion tests. The mechanical properties of the steels were assessed via tensile and low-temperature impact tests, while corrosion resistance was evaluated based on weight loss measurements. Surface oxide layers were characterized using three-dimensional laser confocal microscopy, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and electrochemical methods. Electron probe microanalysis (EPMA) was employed to examine the cross-sectional morphology of the oxide layer after 72 h of accelerated corrosion tests. The results indicate that the solution state of Cu increased the strength of 3.5%Ni steels but significantly damaged the low-temperature toughness. As the Cu content increased from 0.75% to 1.25%, the corrosion rate decreased from 4.65 to 3.74 g/m² h. However, when there was a further increase in the Cu content to 2.15%, there was little decrease in the corrosion rate. With the increase in the Cu content from 0.75% to 2.15%, the surface roughness of 3.5%Ni weathering steel after corrosion decreased from 5.543 to 5.019 μm, and the corrosion behavior was more uniform. Additionally, the α/γ protective factor of the oxide layer of the surface layer increased from 2.58 to 2.84 with an increase in the Cu content from 0.75% to 1.25%, resulting in the oxide layer of the surface layer being more protective. For 1.25%Cu steel, the corrosion current density of rusted samples is lower (ranging from 1.2609 × 10⁻⁴ A/cm² to 3.7376 × 10⁻⁴ A/cm²), and the corrosion potential is higher (ranging from −0.85544 V to −0.40243 V). Therefore, the rusted samples are more corrosion resistant. The Cu in the oxide layer of the surface layer forms CuO and CuFeO₂, which are helpful for increasing corrosion resistance, which inhibits the penetration of Cl⁻. Full article

In order to improve the hydrogen storage properties of Laves phase AB₂-type alloys, a series of Ti_1−xZr_xMn_1.0Cr_0.85Fe_0.1 (x = 0.1–0.5) alloys were prepared by arc melting. The effects of Zr content on microstructure and hydrogen storage properties was investigated in detail. Crystal structure characterizations confirmed that all the alloys exhibit a single-phase C14 Laves structure, and the lattice parameters increase with increasing Zr content. The hydrogen storage measurements of the alloys indicate that with increasing Zr content, the hydrogen storage capacity initially increases and then decreases. The hydrogen absorption and desorption measurements of the alloys were performed by a Sieverts-type apparatus. Pressure–composition–temperature (P-C-T) tests at various temperatures showed that all the alloys display sloped plateaus. Increasing Zr content results in a gradual decrease in hydrogen absorption and desorption plateau pressures. Moreover, these alloys exhibit varying degrees of hysteresis, which also becomes more pronounced with a rise in Zr content. In summary, the Ti_0.7Zr_0.3Mn_1.0Cr_0.85Fe_0.1 alloy demonstrates the best comprehensive hydrogen storage capacity. Further investigation on the cyclic performance of the Ti_0.7Zr_0.3Mn_1.0Cr_0.85Fe_0.1 alloy was conducted. It was found that the alloy particles undergo significant pulverization after hydrogenation cycles, but the alloy maintained good phase structure stability and hydrogen storage performance. Full article

Prussian blue analogs (PBAs) are widely recognized as promising candidates for aqueous zinc-ion batteries (AZIBs) due to their stable three-dimensional framework structure. However, their further development is limited by their low specific capacity and unsatisfactory cycling performance, primarily caused by phase transformation during charge–discharge cycles. Herein, we employed a high-entropy strategy to introduce five different metal elements (Fe, Co, Ni, Mn, and Cu) into the nitrogen–coordinated M_a sites of PBAs, forming a high-entropy Prussian blue analog (HEPBA). By leveraging the cocktail effect of the high-entropy strategy, the phase transformation in the HEPBA was significantly suppressed. Consequently, the HEPBA as an AZIB cathode delivered a high reversible specific capacity of 132.1 mAh g⁻¹ at 0.1 A g⁻¹, and showed exceptional cycling stability with 84.7% capacity retention after 600 cycles at 0.5 A g⁻¹. This work provides innovative insights into the rational design of advanced cathode materials for AZIBs. Full article

This paper presents the electrical characterization of a flexible supercapacitor with a unique architecture incorporating a piezoelectric PVDF-TrFE film sandwiched between PEDOT:PSS:Graphene and LiTaO₃ as a charge-generating and charge-transferring layer. Impedance spectroscopy measurements reveal frequency-dependent capacitance behavior, reflecting the contributions of both piezoelectric and supercapacitor capacitances. Charge–discharge cycling tests demonstrate the device’s energy storage capabilities and indicate a potential enhancement through the piezoelectric effect. Supercapacitor cycling tests demonstrate the device’s energy storage capabilities, with an estimated specific capacitance of 10.14 F/g, a power density of 16.3 W/g, an energy density of 5.63 Wh/kg, and a Coulombic efficiency of 96.1% from an active area of 1 cm². The proposed structure can serve as an independent harvester and storage for low-power, wearable sensors. Full article

The presence of recalcitrant organic compounds in oilfield-produced-water poses significant challenges for conventional biological treatment technologies. In this study, an Fe³⁺-augmented composite bioreactor was developed to enhance the multi-pollutant removal performance and to elucidate the associated microbial community dynamics. The Fe³⁺-augmented system achieved efficient removal of oil (99.18 ± 0.91%), suspended solids (65.81 ± 17.55%), chemical oxygen demand (48.63 ± 15.15%), and polymers (57.72 ± 14.87%). The anaerobic compartment served as the core biotreatment unit, playing a pivotal role in microbial pollutant degradation. High-throughput sequencing indicated that Fe³⁺ supplementation strengthened syntrophic interactions between iron-reducing bacteria (Trichococcus and Bacillus) and methanogenic archaea (Methanobacterium and Methanomethylovorans), thereby facilitating the biodegradation of long-chain hydrocarbons (e.g., eicosane and nonadecane). Further metabolic function analysis identified long-chain-fatty-acid CoA ligase (EC 6.2.1.3) as a key enzyme mediating the interplay between hydrocarbon degradation and nitrogen cycling. This study elucidated the ecological mechanisms governing Fe³⁺-mediated multi-pollutant removal in a composite bioreactor and highlighted the potential of this approach for efficient, sustainable, and adaptable management of produced water in the petroleum industry. Full article