Search Results (360)

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

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 southeastern Yunnan region in the southwestern Nanpanjiang Basin is one of the most important manganese enrichment zones in China. Manganese mineralization is mainly confined to marine mud–sand–carbonate interbeds of the Middle Triassic Ladinian Falang Formation (T₂f), which contains several medium to large deposits such as Dounan, Baixian, and Yanzijiao. However, the geological processes that control manganese mineralization in this region remain insufficiently understood. Understanding the tectonic evolution of the basin is therefore essential to unravel the mechanisms of Middle Triassic metallogenesis. This study investigates how rift-related tectonic activity influences manganese ore formation. This study integrates global gravity and magnetic field models (WGM2012, EMAG2v3), audio-frequency magnetotelluric (AMT) profiles, and regional geological data to investigate ore-controlling structures. A distinct gravity low–magnetic high belt is delineated along the basin axis, indicating lithospheric thinning and enhanced mantle-derived heat flow. Structural interpretation reveals a rift system with a checkerboard pattern formed by intersecting NE-trending major faults and NW-trending secondary faults. Four hydrothermal plume centers are identified at these fault intersections. AMT profiles show that manganese ore bodies correspond to stable low-resistivity zones, suggesting fluid-rich, hydrothermally altered horizons. These findings demonstrate a strong spatial coupling between hydrothermal activity and mineralization. This study provides the first identification of the internal rift architecture within the Nanpanjiang Basin. The basin-scale rift–graben system exerts first-order control on sedimentation and manganese metallogenesis, supporting a trinity model of tectonic control, hydrothermal fluid transport, and sedimentary enrichment. These insights not only improve our understanding of rift-related manganese formation in southeastern Yunnan but also offer a methodological framework applicable to similar rift basins worldwide. Full article

This study presents the synthesis, characterization, and application of magnetic magnetite–zirconium dioxide (Fe₃O₄–ZrO₂) nanoparticles as an efficient nanoadsorbent for fluoride removal from water. The nanoparticles were synthesized using a wet chemical co-precipitation method with Fe/Zr molar ratios of 1:1, 1:2, and 1:4, and characterized using Fourier-transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), X-ray diffraction (XRD), and energy-dispersive X-ray spectroscopy (EDS). FTIR analysis confirmed the presence of Fe₃O₄ and ZrO₂ functional groups, while XRD showed that increased Zr content led to a dominant amorphous phase. SEM and EDS analyses revealed quasi-spherical and elongated morphologies with uniform elemental distribution, maintaining the designed Fe/Zr ratios. Preliminary adsorption tests identified the Fe/Zr = 1:1 (M1) nanoadsorbent as the most effective due to its high surface homogeneity and optimal fluoride-binding characteristics. Adsorption experiments demonstrated that the material achieved a maximum fluoride adsorption capacity of 70.4 mg/g at pH 3, with the adsorption process best fitting the Temkin isotherm model (R² = 0.987), suggesting strong adsorbate–adsorbent interactions. pH-dependent studies confirmed that adsorption efficiency decreased at higher pH values due to electrostatic repulsion and competition with hydroxyl ions. Competitive ion experiments revealed that common anions such as nitrate, chloride, and sulfate had negligible effects on fluoride adsorption, whereas bicarbonate, carbonate, and phosphate reduced removal efficiency due to their strong interactions with active adsorption sites. The Fe₃O₄–ZrO₂ nanoadsorbent exhibited excellent magnetic properties, facilitating rapid and efficient separation using an external magnetic field, making it a promising candidate for practical water treatment applications. Full article

Three previously synthesized ketene dithioacetals were used as intermediates to obtain four nucleophiles to synthesize ten tetra-substituted pyrazoles (11–20). This was achieved through microwave irradiation in ethanol as the solvent, yielding superb results ranging from 68.4% to 90.1%, in agreement with some of the principles of green chemistry. The proposed structures were determined using various spectroscopic techniques, including infrared spectroscopy and hydrogen and carbon-13 nuclear magnetic resonance. Furthermore, the compounds underwent in-silico evaluations using CLC-Pred and AdmetSAR software to predict the absorption, distribution, metabolism, excretion, and toxicity (ADMET) properties. This was combined with molecular docking calculations for four main cancer-related targets for pyrazole core, to facilitate screening for subsequent biological assessments. Based on the data generated from these analyses, it was identified two pyrazoles (11 and 18) likely to exhibit anti-tumor activity, while also demonstrating low toxicity levels. Upon selection, these two pyrazoles were subjected to toxicity assessments using the Artemia salina method and evaluated for their effects on the viability of Jurkat cancer cells with a potency of 45.05 and 14.85 µM to 11 and 18, respectively, and with a potency of above 100 µM for the non-carcinogenic cells HEK 293. Overall, the findings from these studies indicate pyrazole derivatives as potential anti-tumor candidates. Full article

The increasing prevalence of antimicrobial resistance alongside the pharmacological limitations and adverse effects associated with conventional antibiotics necessitates the development of novel and efficacious antimicrobial agents. In this study, magnetic iron oxide nanoparticles (MIONPs) were synthesized via a chemical co-precipitation method. Activated carbon (AC) derived from Hibiscus esculentus (HE) fruit was coated onto the nanoparticle surfaces to fabricate MIONPs/HEAC nanocomposites. To augment their antimicrobial properties, silver ions were chemically reduced and deposited onto the MIONPs/HEAC surface, yielding MIONPs/HEAC@Ag nanocomposites. Comprehensive characterization of the synthesized nanocomposites was performed using scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), vibrating sample magnetometry (VSM), dynamic light scattering (DLS), and zeta potential analysis. DLS measurements indicated average particle sizes of approximately 122 nm and 164 nm for MIONPs/HEAC and MIONPs/HEAC@Ag, respectively. Saturation magnetization values were determined to be 73.6 emu/g for MIONPs and 65.5 emu/g for MIONPs/HEAC. Antibacterial assays demonstrated that MIONPs/HEAC@Ag exhibited significant inhibitory effects against Escherichia coli ATCC 25922 and Staphylococcus aureus ATCC 25923, with inhibition zone diameters of 11.50 mm and 13.00 mm, respectively. In contrast, uncoated MIONPs/HEAC showed negligible antibacterial activity against both bacterial strains. These findings indicate that MIONPs/HEAC@Ag nanocomposites possess considerable potential as antimicrobial agents for biomedical applications, particularly in addressing infections caused by antibiotic-resistant bacteria. Full article

Phosphogypsum, a byproduct of phosphate fertilizer production, represents a significant environmental concern due to its large-scale production and low utilization rates. Although preparing phosphogypsum-based cementitious materials offers a potential solution to these issues, high-content phosphogypsum cementitious systems encounter significant technical barriers, including long setting durations and insufficient early-age strength development, thereby restricting their practical implementation. Hence, this research developed innovative modifiers through an environmentally friendly low-temperature thermal activation process (100–160 °C) utilizing recycled phosphogypsum aggregates and circumventing the substantial carbon emissions associated with conventional modification approaches. Systematic characterization demonstrated that the dehydration phase modifier synthesized at 120 °C (DH120) exhibited optimal phase composition, resulting in a 35.7% enhancement in its 14-d compressive strength (9.8 MPa vs. 7.2 MPa for the control) and an 11.3% reduction in its initial setting time (27.5 vs. 31.0 h for the control). Microstructural characterization by low-field nuclear magnetic resonance and X-ray diffractometry revealed that DH120 effectively enhanced refinement of the pore structure (37.7% mesopore volume reduction) and promoted the ettringite crystallization kinetics. This work establishes a sustainable framework for utilizing industrial byproducts in cementitious material systems. Full article

Climate change has driven global awareness of environmental issues, leading to the adoption of clean technologies aimed at reducing Greenhouse Gas (GHG) emissions. An effective method to assess environmental mitigation is the quantification of the Product Carbon Footprint (PCF) in the Life Cycle Assessment (LCA) of production processes. In the oil extraction industry, artificial lift systems use electro submersible pumps (ESPs) that can now incorporate new operating principles based on permanent magnet motors (PMMs) and CanSystem (CS) as an alternative to traditional normal induction motors (NIMs) and can help lower the carbon footprint. This study compares the PCF of ESPs equipped with PMMs and CS versus NIMs, using LCA methodologies in accordance with ISO 14067:2018 for defining the Functional Unit (FU) and ISO 14064-1:2019 to calculate the GHG inventory and the amount of CO₂ equivalent per year. The analysis spans five key stages and 14 related activities. For ESPs with NIMs, this study calculated 999.9 kg of raw materials, 1491.66 kW/h for manufacturing and storage, and 5.77 × 10⁴ kW/h for use. In contrast, ESPs with PMMs and CS required 656 kg of raw materials and consumed 4.44 × 10⁴ kW/h during use, resulting in an 23% reduction in energy consumption. This contributed to an 21.9% decrease in the PCF. The findings suggest that PMMs and CS offer a sustainable solution for reducing GHG emissions in oil extraction processes globally. Full article

The Chaoshan Depression, situated in the northern South China Sea, is a Mesozoic residual depression beneath the Cenozoic Pearl River Mouth Basin. Borehole LF35-1-1 has confirmed the existence of marine Jurassic layers rich in organic carbon within this depression. However, the understanding of petroleum geology in this area is limited due to the complex interplay of Mesozoic and Cenozoic tectonic activities and the poor quality of seismic imaging from previous surveys, which have obstructed insights into the characteristics of Mesozoic reservoirs and the processes of oil and gas accumulation. Recent quasi-3D seismic data have allowed for the identification of Mesozoic bioherms and carbonate platforms in the Middle Low Uplift of the Chaoshan Depression. This research employs integrated geophysical data (MCS, gravity, magnetic) and well data to explore the factors that influenced Middle Jurassic reef development and their implications for reservoir formation. The seismic reflection patterns of reefs and carbonate platforms are primarily characterized by high-amplitude discontinuous to chaotic reflections, with occasional blank reflections or weak, sub-parallel reflections, as well as significant high-velocity, high Bouguer gravity and low reduced-to-pole (RTP) magnetic anomalies. Atolls, stratiform reefs, and patch reefs are located on the local topographic highs of the platform. Three vertical evolutionary stages have been identified based on the size of atolls and fluctuations in relative sea level: initiation, growth, and submergence. The location of bioherms and carbonate platforms was influenced by paleotectonic topography, while their horizontal distribution was affected by variations in relative sea level. Furthermore, the reef limestone reservoirs from the upper member of the Middle Jurassic, combined with the mudstone source rocks from the Lower Jurassic and the lower section of the Middle Jurassic, as well as the bathyal mudstone caprocks from the lower part of the Late Jurassic, create highly favorable conditions for hydrocarbon accumulation. Full article

Under the dual impetus of the “Dual Carbon” goals and the construction of smart grids, the development of new energy power infrastructure has been fully realized. The All-Fiber Optical Current Transformer (FOCT), leveraging its unique advantages, is in the process of supplanting traditional current transformers to become the core component of power system monitoring equipment. Currently, to achieve higher precision and stability in magnetic field or current detection, FOCT structures frequently incorporate active components such as Y-waveguides and phase modulators, and closed-loop feedback systems are often used in demodulation. This has led to issues of high cost, complex demodulation, and difficult maintenance, significantly hindering the further advancement of FOCTs. Addressing the problems of high cost and complex demodulation, this paper proposes a passive multiplexing structure that achieves time-domain multiplexing of pulsed sensing signals, designs a corresponding intensity demodulation algorithm, and applies this structure to FOCTs. This enables low-cost, simple-demodulation current sensing, which can also be utilized for magnetic field detection, showcasing vast application potential. Full article

To enhance the mechanical properties and low-carbon characteristics of industrial solid waste concrete, this paper proposes a synergistic modification strategy using nano-SiO₂ and sodium silicate. The nano-SiO₂ sol and sodium silicate activator were prepared using magnetic heating and stirring technology, and a quadratic regression model (R² = 0.9575, p < 0.0001) for compressive strength with three factors and three levels was established using the response surface method (RSM-CCD). The modification mechanism was verified through optimization of the mix ratio using a desirability function, along with microscopic characterization via SEM and XRD. The results indicate the following: (1) the content of nano-SiO₂ (2.4%) contributed the most to the compressive strength of the concrete, and its interaction with sodium silicate (2.1%) significantly promoted the formation of C-S-H gel; (2) the optimized fly ash substitution rate (21.7%) can achieve a 28-day compressive strength of 34.8 MPa, with the model prediction error controlled within 5%; (3) microscopic analysis showed that the synergistic effect of multiple components lowered the volume porosity of the cementitious phase, forming a densified network structure. The multi-factor synergistic optimization approach for nano-SiO₂-modified alkali-activated concrete (NS-AAC) proposed in this study offers a reference for multi-objective mix design optimization of industrial waste-based concrete. Full article

UV radiation can change the internal molecular composition, macroscopic rheological properties, and microscopic chemical composition of asphalt. To study the effect of ultraviolet aging on asphalt and its structure–activity relationship, its rheological properties were measured by dynamic shear rheology and multiple stress recovery creep tests, its chemical compositions were measured by component composition, elemental composition, and infrared spectrum tests, and its molecular weight, distribution, and molecular structure were determined by gel permeation chromatography and nuclear magnetic resonance tests. Then, the molecular weight and molecular structure, rheological properties, and microchemical aging behavior of asphalt after UV aging were characterized by correlation analysis, and the structure–activity relationship was analyzed. The results show that the deformation resistance and elastic recovery ability of asphalt after UV aging are enhanced, and the flow performance is decreased. The ultraviolet radiation caused the aromatic hydrocarbons containing naphthenes and long alkyl chains in the asphalt to break and connect with asphaltenes with a ring structure. The asphaltene content in each bitumen sample exceeded 46%, and that in KL reached 55%, indicating that the bitumen changed into a gel structure. UV aging causes the aggregation of asphalt molecules, and the aggregation of molecules narrows the molecular distribution boundary and moves in the direction of macromolecules, resulting in the reduction of the dispersion coefficient by 2–10%. Hydrogen atoms will undergo condensation and substitution reactions due to long-chain breaking, cyclization, or aromatization under UV action, and the breaking of C=C bonds in carbon atoms will increase the stable aromatic ring, strengthen the stiffness of the molecular backbone, and make it difficult for the backbone to spin. Through correlation analysis, it was found that the molecular composition index could characterize the aging behavior index of asphalt, and that the aromatic structure was the most critical molecular change. Further, it was found that the sulfoxide group and carbonyl group could be used as evaluation criteria for the UV aging of asphalt because the correlation between them was above 0.7. This study provides an essential index reference for evaluating the performance change of asphalt under ultraviolet aging to save testing time. Moreover, the molecular structure characterization revealed the changes in internal molecular composition that were behind the observed aging properties, providing a theoretical basis for research on asphalt anti-aging technology. Full article

The sugar industry produces significant quantities of waste biomass, while other industrial sectors generate iron scrap as waste. This study seeks to make use of these waste products using an in situ approach that integrates carbonization, activation, and magnetization to convert sugarcane waste and iron scrap into a magnetic carbon composite adsorbent. The porosity of the activated carbon was enhanced by the activating agent potassium hydroxide (KOH) and further improved by the addition of iron scrap, which also imparted magnetic properties to the composite. The developed porosity of the composite increased the overall adsorption capacity of the adsorbent. The synthesis conditions were varied to examine the effects on the properties of the adsorbent. The amount of KOH used in the synthesis influenced the performance of the material. The best-performing adsorbent demonstrated strong potential in the treatment of wastewater by exhibiting an adsorption capacity of 1736.93 mg/g for the antibiotic tetracycline. The magnetic properties of the composite adsorbent enable simple separation and recovery, making the adsorbent reusable and lowering operating costs. This study provides a clear framework for the synthesis of waste-derived magnetic carbon composite adsorbents that can offer financial and environmental advantages while remaining effective in industrial contexts. Full article

Microcystins (MCs) are produced by cyanobacteria blooms in eutrophic water and can cause acute and chronic toxicity and even mortality to animals and humans. Previous MC removal strategies concernedonly highly contaminated water, in which the concentration of the pollutant was considerably larger than that in the natural world. In this study, we developed a composite of TiO₂-coated magnetic carbon microtube (C-TiO₂-Fe₃O₄) and used it as a photocatalyst to efficiently remove microcystin-LR (MC-LR) from water under visible light from water. And the huge surface of the carbon microtube dramatically boosted the adsorbability and charge mobility, which lowered the recombination rate of electron–hole pairs, and hence systematically enhanced photocatalytic activity. The combination of adsorption and photodegradation endowed the composite with a better performance in the removal of trace amounts of MC-LR than the C-TiO₂. It was found that increasing the contact time and catalyst dosage, acidic environment, and lower initial MC-LR concentration had positive effects on MC-LR removal. The optimum reaction conditions of C-TiO₂-Fe₃O₄ was a reaction time of 12.68 min, a catalyst dosage of 0.39 g·L⁻¹, and a pH of 7.72. The C-TiO₂-Fe₃O₄ (surface area normalized apparent reaction rate constants K/S_BET = 1.2 × 10⁻⁴) presented a higher reaction rate than C-TiO₂ (K/S_BET = 8.4 × 10⁻⁵). Moreover, the stable removal capability of C-TiO₂-Fe₃O₄ was confirmed over multiple cycles. Finally, the ecological safety performance was also evaluated after visible light illumination. This work paves the way for the development of more efficient and easily separable purifiers for the removal of pollutants and toxins from contaminated water. Full article

Electrochemical reduction is a promising strategy for the dechlorination of halogenated organic compounds, offering advantages such as enhanced electron transfer efficiency and increased hydrogen atom concentration. It has garnered significant attention for application in mitigating halogenated disinfection by-products (DBPs) in drinking water, owing to its high efficiency and simple operation. In this study, trichloroacetic acid (TCAA), a representative DBP, was selected as the target contaminant. A novel composite cathode comprising a metal–organic framework MIL-53(Fe)@C supported on an Nd magnet (MIL-53(Fe)@C-MAG) and its dechlorination performance for TCAA were systematically investigated. The innovative aspect of this study is the magnetic attachment of the MOF catalyst to the carbonized cathode surface treated through carbonization, which fundamentally differs from conventional solvent-based adhesion methods. Compared to the bare electrode, the MIL-53(Fe)@C-MAG achieved a TCAA removal efficiency exceeding 96.03% within 8 h of contact time. The structural characterization revealed that the α-Fe⁰ crystalline phase serves as the primary active center within the MIL-53(Fe)@C catalyst, facilitating efficient electron transfer and TCAA degradation. The scavenger experiments revealed that TCAA reduction involves a dual pathway: direct electron transfer and atomic hydrogen generation. The modified MIL-53(Fe)@C-MAG electrode exhibited robust electrolytic performance over a broad pH range of 3–7, with TCAA removal efficiency showing a positive correlation with current density within the range of 10–50 mA/cm². Furthermore, the electrode maintained exceptional stability, retaining more than 90% removal efficiency after five consecutive operational cycles. The versatility of the system was further validated by the rapid and efficient dechlorination of various chlorinated DBPs, demonstrating the broad applicability of the electrode. The innovative magnetic composite electrode demonstrates a significant advancement in electrochemical dechlorination technology, offering a reliable and efficient solution for the purification of drinking water contaminated with diverse halogenated DBPs. These results provide valuable insights into the development of electrolysis for dechlorination in water treatment applications. Full article