Search Results (1,169)

The hematite phase decorated with iron-doped cerium oxide nanoparticles (F@FC) was precipitated from cerium and iron oxalate intermediate products. The photocatalytic composite of graphitic carbon nitride (gCN) and F@FC was prepared by a simple method involving mixing the two components, followed by thermal treatment at 400 °C. According to electron microscopy, F@FC is composed of a submicron iron oxide (hematite) phase decorated with iron-doped cerium oxide nanoparticles deposited on gCN substrate. A hierarchically structured composite was observed instead of a simple mechanical mixture of α-Fe₂O₃, Fe-CeO₂, and gCN. To observe two types of degradation activity, photocatalytic and Photo-Fenton degradation activity, Rhodamine B (RhB) was applied as the model water pollutant. The influence of the amount of photocatalyst, the RhB concentration, the presence of cations and anions, the pH, and the effect of e⁻, h⁺, •OH, and •O₂⁻ scavenging reactants were studied. The Photo-Fenton degradation exhibited high efficiency across the entire tested pH range, whereas photocatalytic degradation showed comparable activity only at acidic pH. The F@FC-gCN composite catalyst exhibited a high degree of recyclability. The degradation pathways of photocatalytic and Photo-Fenton reactions were suggested by HPLC-MS analysis of the reaction products. A notable finding of this study was the observation that the green-yellow, fluorescent intermediate Rhodamine 110 was formed during the photocatalytic degradation of RhB. However, the high reactivity of the generated •OH radicals during Photo-Fenton degradation has been demonstrated to inhibit the formation of intermediate Rhodamine 110. Full article

The development of lithium-ion batteries (LIBs) capable of extreme fast charging (XFC) while preserving safety, durability, and practical energy density remains a central challenge for next-generation electric transportation and grid-scale storage. Conventional graphite anodes are fundamentally limited at high current densities by sluggish intercalation kinetics, which cause lithium plating, motivating the exploration of alternative insertion materials. This review provides a comprehensive and internally consistent assessment of titanium-based oxide anodes, encompassing TiO₂ polymorphs, lithium titanate (Li₄Ti₅O₁₂), and Wadsley–Roth titanium niobium oxides, through the combined lenses of crystal topology, diffusion pathways, redox chemistry, interfacial behavior, and resource scalability. By systematically comparing structural frameworks and electrochemical mechanisms across these material classes, we demonstrate that fast-charging performance is governed not by nano-structuring alone, but by the intrinsic coupling between operating potential, framework rigidity, and multi-electron redox activity. While Li₄Ti₅O₁₂ establishes the benchmark for safety and cyclability, and TiO₂ polymorphs provide structural versatility, titanium niobium oxides uniquely reconcile high theoretical capacity with minimal lithiation strain and open diffusion channels, positioning them as highly promising candidates for sub-10 min charging without catastrophic degradation. This review highlights the persistent obstacles these materials suffer, such as limited round-trip energy efficiency (RTE), interfacial gas evolution, poor dopant stability, and unsustainable extraction, while simultaneously exploring targeted design strategies to overcome them. Finally, this review provides a materials design and comparison framework for the development of safe, high-power, and commercially viable ultrafast-charging LIBs. Full article

Hexagonally ordered mesoporous carbon was ozonized, and the oxidized carbonaceous material was modified with L-arginine. The ozonized and L-arginine-modified carbons were extensively characterized and tested as Pb(II) ion adsorbents, with optimization of Pb(II) solution pH, exposure time, Pb(II) ion concentration and the presence of concurrent ions. Pb(II) adsorption equilibrium was achieved within 5 min at optimal pH = 2.6 or 5.3 for the oxidized and L-arginine-modified carbonaceous materials, respectively. The adsorption kinetics of both investigated materials were best described by the pseudo-first-order model. The maximum adsorption capacity for Pb(II) ions was determined to be 16 mg g⁻¹ (ozonized material) or 45 mg g⁻¹ (L-arginine-modified material). The Langmuir model provided the best fit for the adsorption isotherm data. Fe(III) ions mostly hindered the Pb(II) adsorption (up to 60%) on the L-arginine-modified carbon material. L-arginine-modified carbon was used to enrich Pb(II) from simulated urban roof runoff and its determination using the slurry sampling high-resolution continuum-source graphite furnace atomic absorption spectrometry technique. The developed analytical procedure was characterized by a limit of quantification of 2.63 µg L⁻¹, an enrichment factor of 50, and a recovery rate of 94.8%. Full article

Perfluoroalkyl and polyfluoroalkyl substances (PFASs) have become a global environmental concern due to their extreme persistence and toxicity. In this study, perfluorooctanoic acid (PFOA) was removed from aqueous solutions using porous carbon adsorbents synthesized from peach stones. The novelty of this work lies in the development of a procedure for obtaining a suitable carbon adsorbent, whose properties are consistent with the properties of the adsorbate. An appropriate activation was used, allowing the preparation of an adsorbent with a highly developed porous texture and a large surface area, which is a prerequisite for a significant adsorption capacity of the obtained adsorbents towards PFOA. Both carbon adsorbents obtained from peach pits, with clearly different surface chemistry—KOH-activated carbon (AC_KOH) and its nitric acid-oxidized derivative (AC_HNO3)—for PFOA adsorption were compared, along with the clarification of the relationship between the graphitic structure, pore development, surface functionality and adsorption characteristics. The first adsorbent was produced by chemical activation with KOH at 800 °C, while the second was obtained by oxidative modification of the activated sample with 12% HNO₃. Characterization by Raman spectroscopy, SEM, and nitrogen physisorption revealed a highly graphitized structure (ID/IG = 0.86) and well-developed porosity. Adsorption experiments were carried out at PFOA concentrations from 8 to 40 µmol/L using a spectrophotometric method based on methylene blue ion-pair extraction into chloroform. The results showed that AC_KOH exhibited a high maximum adsorption capacity of 1660 µmol/g (687.36 mg/g) and followed the Langmuir isotherm model, indicating monolayer adsorption. In contrast, AC_HNO3 showed a significantly lower adsorption capacity of 398.36 µmol/g (164.95 mg/g), which was attributed to electrostatic repulsion caused by acidic oxygen-containing surface groups. These findings demonstrate that peach stone-derived activated carbon is a promising, sustainable, and efficient adsorbent for the removal of PFOA from water. Full article

Autonomous mobile robots are transforming industries from e-commerce logistics to field exploration, but their effectiveness depends on onboard energy storage. This study addresses the challenge of selecting optimal battery technologies for autonomous mobile robots, balancing performance, energy efficiency, thermal stability, and cost across diverse applications. We focus on lithium-ion, lithium-polymer, and nickel-metal hydride batteries, the most common power solutions, each with distinct advantages and disadvantages in energy density, form factor, thermal stability, and cost. A dynamic modeling and simulation framework in MapleSim evaluated these chemistries under defined and representative operating conditions, tracking state of charge and temperature during charging and discharging. A Particle Swarm Optimization algorithm evaluated 37 battery configurations by thermal stability, energy efficiency, and cost across five use cases. Key results indicate that for logistics and warehousing, lithium nickel manganese cobalt oxide with graphite is optimal; for healthcare, lithium nickel manganese cobalt oxide with lithium titanate oxide excels; for manufacturing, lithium nickel cobalt aluminum oxide with graphite leads; for agricultural robots, lithium manganese oxide with graphite is best; and for exploration and mining, lithium iron phosphate with graphite is most reliable. These results provide a structured basis for battery selection, showing how simulation-driven, multi-criteria decision-making enhances energy management and operational reliability. Full article

We report, for the first time, waimirite-(Y) in Egypt. This is only the third reported occurrence of this mineral in the world. This observation arose during our study of the rare earth element (REE) mineralization associated with the Neoproterozoic rare-metal granite intrusion in Wadi Abu Rusheid in the Eastern Desert of Egypt. The principal lanthanide and yttrium (Y) hosts in the area are waimirite-(Y) and bastnäsite-(Ce) in leucogranite and bastnäsite-(Y) in adjacent metasedimentary country rock. The leucogranite is a strongly fractionated, metaluminous to weakly peraluminous (A/CNK = 0.98–1.03), medium- to high-K calk-alkaline I-type granite. The metasediments are composed of upper greenschist to lower amphibolite-grade biotite schists with variable amounts of amphibole, graphite, and garnet. Leucogranite contains accessory Li-bearing mica, garnet, zircon, fluorite, and columbite in addition to the REE minerals. It is enriched by three orders of magnitude relative to primitive mantle in Li, Rb, Th, Ta, Nb, Pb, U, and Sn; relative to these highly enriched elements the concentrations of Sr, Ba, Ga, Zr, Hf, and Y are notably low. The REE patterns of most samples show strong enrichment in heavy relative to light REE but occasional samples have light REE-enriched patterns controlled by accessory REE minerals, and all display strong negative Eu anomalies (Eu/Eu* ≤ 0.05). The whole-rock chemistry of the metasedimentary units are different; relative to average upper continental crust they show enrichments of one to two orders of magnitude in Li, Rb, Pb, Sn, Cs, and sometimes Cr and Zn. The REE patterns of the metasedimentary units are nearly flat, with some samples showing negative Eu anomalies. Waimirite-(Y), nominally YF₃, also contains several weight percent each of Yb, Dy, and Er. The empirical formula (based on one cation) is (Y_0.55Ce_0.02Pr_0.01Nd_0.02Sm_0.02Gd_0.02Dy_0.05Er_0.04Yb_0.05Th_0.05Ca_0.16Pb_0.01)_∑1.00(F_2.48O_0.52)_∑3.00. Bastnäsite-(Ce) in leucogranite samples, nominally Ce(CO₃)F, also has several weight percent each of Nd₂O₃ and La₂O₃. The REE host in metasedimentary rocks is bastnäsite-(Y), nominally Y(CO₃)F, but also rich in Nd₂O₃ (11–19 wt.%) and La₂O₃ (4–14 wt.%). It is intimately associated with fluorophlogopite. The geochemical, mineralogical, and textural evidence indicates that waimirite-(Y) and bastnäsite-(Ce) in leucogranite crystallized from granite-derived F- and CO₂-bearing hydrothermal fluids, whereas the source of Y for growth of the bastnäsite-(Y) in the metasedimentary rocks is unclear; the large negative Ce anomaly in bastnäsite-(Y) suggests an oxidizing supergene setting. Despite their proximity, if there is a genetic connection between the mineralization in the granite and in its country rocks, the relationship is not evident from elemental patterns or host mineralogy. Full article

Linear alkylbenzene (LAB) is the main raw material used to make biodegradable detergents, and its production process is based on aromatic alkylation. HY zeolites that have undergone controlled dealumination and desilication have led industrial standards amongst solid acid catalysts because of their controllable acidity and hierarchical pore structure. Coke formation in such systems can assume a dual role, which is dependent on its condition. Though the over-deposition is known to cause deactivation by blocking the micropores, Bronsted acid-site masking, and diffusion collapse, the low-level deposition could also be done to increase the monoalkylate selectivity by the pore mouth catalysis, steric modulation, and selective suppression of secondary alkylation pathways. The critical review is done on the structural-kinetic interaction that determines the coke evolution in HY-based catalysts. In order to moderate the acid-site density and enhance hydrothermal stability, dealumination (Si/Al optimization of about 2.5 to 30–100) occurs, but to reduce deep-pore coke formation, desilication (interconnected mesopores) is created. The bimodal porosity and regulated acidity are found to be synergistic, as hierarchical HY zeolites produced through successive cycles of steam and alkaline treatments not only show LAB selectivity in excess of 90% but also exhibit much longer catalyst lifetimes. Quantitative research on the beneficial coke regime revealed that it was composed of about 36 wt% hydrogen-rich species, which were localized at the pore mouths, hence enhancing monoalkylation selectivity by 15–40%. Beyond a critical transition window (e.g., 8–12 wt.%), coke formation to condensed polyaromatic and graphitic products leads to fast deactivated coke formation, which is due to percolation limits and transport-controlled kinetics. More advanced techniques of characterization of the coke, e.g., temperature-programmed oxidation (TPO), ²⁷Al MAAS NMR, and UV-Raman spectroscopy, indicate how the coke is changed to highly structured graphitic deposits of high oxidation activation energy. Activity recovery of 85–98% is obtained in regeneration processes, including controlled oxidative calcination, microwave-based and plasma-based processes, and thermal management protocols, and it would be determined by the chemistry of the coke, its spatial distribution, and the regeneration protocols. This paper has developed a mechanistic coke control system by cross-tuning the acidity and development of an effective pore network, which led to a sustainable aromatic alkylation reaction with minimal activity loss, high selectivity, and long life. Full article

Azo dyes in textile industry effluents cause major environmental problems, highlighting the need to remove these compounds before discharge. The Nyex Rosalox™ (NR) process, a water treatment process that combines adsorption, electrochemical oxidation, and in situ regeneration using a patented novel graphite-based adsorbent (Nyex™ 2000 media), could potentially be used to remove azo dyes before being discharged. In this study the efficiency of the NR process for removing these compounds is assessed. Analyses indicate that (i) the Nyex™ media was able to adsorb all azo dyes quickly, with 50% of the total dye absorbed being absorbed in the first 30 min and >10% in the first minute alone and (ii) all azo dyes used were completely oxidised during the NR process without the formation of any detectable harmful byproducts that were previously observed during the electrochemical oxidation of azo dyes, with only a relatively small amount of energy needed to enable optimal electrochemical oxidation. The Nyex™ media can be consistently regenerated, maintaining its adsorptive capacity after extensive reuse, albeit the use of fresh adsorbent will always have a slightly greater adsorptive capacity. Combined, these findings suggest that the NR process can effectively destroy azo dyes with relatively low energy, proving an effective method of water treatment without producing harmful secondary pollutants. Full article

Quantum dots (QDs) have drawn a lot of attention as photocatalytic materials due to the growing need for environmentally friendly wastewater treatment technologies. Among these, carbon-based QDs, including graphene oxide quantum dots (GOQDs), graphitic carbon nitride (g-C₃N₄), and carbon quantum dots (CQDs), have exceptional optical, electronic, and surface characteristics that increase their suitability for degrading pollutants when exposed to sunlight or visible light. These composites are better at transferring charges, staying stable in light, and breaking down pollutants. Metal-based QDs like ZnO and CdS also have strong photocatalytic activity, but their sustainability remains a concern due to the potential release of toxic ions when they corrode in light. The green synthesis approach addresses these challenges. Using natural extracts, like polyphenols from tea leaves, to biofunctionalize surfaces has been shown to reduce toxicity and improve photocatalytic performance. Green synthesis using renewable precursors solves problems with toxicity, resource depletion, and environmental pollution, which supports a low-impact and circular technological approach. This study examines recent developments in the making, modifying, and use of QD-based photocatalysts in the environment, with a focus on CQD/g-C₃N₄ hybrid systems. Future research should focus on making green, non-toxic, regenerable, and highly active carbon-based QDs for safe large-scale water treatment. Full article

High concentrations of ionized ammonia (${\mathrm{NH}}_4^{+}$) have been increasingly reported in municipal drinking water systems, posing a severe public health risk as excessive ingestion can lead to life-threatening conditions. Despite its importance, there is a significant lack of sensing technologies designed for continuous-flow monitoring outside laboratory settings, particularly those providing a robust, low-cost methodology suitable for resource-limited environments. To address these challenges, in this work, we report the development of an impedance sensor featuring a 3D-printed housing (3D-IS) for monitoring aqueous ionized ammonia (${\mathrm{NH}}_4^{+}$). The sensing electrodes, composed of zinc oxide and graphite, allow for the detection of concentrations 10 times lower and 60 times higher than current environmental limits. Its innovative, optimized design, analogous to that of industrial pressure gauges, highlights its potential for use in continuous water flow conditions outside the laboratory, such as water treatment plants. The level of ${\mathrm{NH}}_4^{+}$ in water is monitored by changes in impedance magnitude, with optimal performance observed at a frequency of 100 kHz. At this frequency, the impedance magnitude decreased by nearly two orders of magnitude as the ${\mathrm{NH}}_4^{+}$ concentration increased from 0 to 1 μM. Under these optimized conditions, the sensor exhibited a sensitivity of 2 kΩ/log(μM) and a linearity exceeding 90%. Furthermore, we propose an equivalent circuit model that accurately describes the experimental data, explaining the transduction process. We also describe, from an electrical perspective, the phenomenon of adsorption on the sensor’s transducer surface, thereby ensuring the device’s selectivity. The sensor was evaluated using dilutions of a standard ammonium solution for IC in distilled water, as well as with real groundwater samples, obtaining ∼99.7% of correlation with ion chromatography and a limit of detection of 2 μM. Finally, our device can provide information relatively quickly, with the added advantage of stable response under continuous-flow and real conditions, making it an attractive option for integration into a field sensor node. Full article

ZnMgAl layered double hydroxides (LDHs) were synthesised via coprecipitation, and oleic acid and stearic acid were grafted onto their surfaces via dehydration condensation to obtain two nano-lubricant additives, OA-ZnMgAl LDH and SA-ZnMgAl LDH. These surface modifications significantly improved the dispersion stability of ZnMgAl LDH in lubricating oil. Tribological tests showed that, at their respective optimal concentrations for friction reduction or wear resistance, ZnMgAl LDH, OA-ZnMgAl LDH, and SA-ZnMgAl LDH reduced the coefficient of friction by 3%, 20%, and 16%, and decreased the wear scar diameter by 7%, 9%, and 14%, respectively, compared with the base oil (XMP-Mobil 320). To clarify the lubrication mechanism, the wear morphology and chemical composition were analysed using 3D optical profilometry, X-ray photoelectron spectroscopy, scanning electron microscopy, and FIB-SEM. The results indicate that LDHs react with the steel surface under load and shear to form a multilayer protective film consisting of an inner oxide layer and an outer graphite layer, preventing direct contact between friction pairs. In addition, the rolling and filling effects of partially unreacted LDHs further reduce friction and wear. Full article

Catalytic ozonation often suffers from a low ozone utilization rate and incomplete mineralization of organic pollutants. To address these challenges, we designed and prepared a novel catalyst via a one-step thermal polymerization method, anchoring single-atom manganese on a glucose-derived carbon network-modified C₃N₅ framework (Mn/C-C₃N₅). Aberration-corrected high-angle annular dark-field scanning transmission electron microscopy (AC-HAADF-STEM) on an FEI Titan Themis Z microscope confirmed the atomic dispersion of Mn sites, while Raman spectroscopy using a Renishaw inVia Reflex laser micro-Raman spectrometer verified the successful incorporation of a graphitic carbon network within the C₃N₅ matrix. Moreover, electrochemical analyses, including electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV) performed on a Bio-Logic SP-150 electrochemical workstation, demonstrated that the integration of the conductive carbon matrix substantially enhanced the interfacial charge transfer capability. The optimized Mn/C-C₃N₅ catalyst demonstrated exceptional performance in phenol mineralization, achieving a 97% total organic carbon (TOC) removal within 60 min, a remarkable improvement compared to pristine C₃N₅ (30%). Furthermore, the catalyst exhibited excellent operational stability, preserving more than 95% of its original activity over five repeated runs. Mechanistic investigations, including electron paramagnetic resonance (EPR) spectroscopy and radical quenching experiments, revealed that the Mn/C-C₃N₅ system accelerated the generation of multiple oxidizing radicals (•O₂⁻, ¹O₂, and •OH), with •OH identified as the predominant reactive species responsible for complete mineralization. This work establishes an integrated catalytic platform and provides fundamental insights into electronic structure modulation for designing advanced oxidation catalysts. Full article

Biogenic carbon dots (CDs) are emerging as promising plant biostimulants, yet their effects during early crop establishment remain underexplored. Here, we synthesized and characterized Spirulina-derived CDs and evaluated their efficacy as seed nanopriming agents in rice (Oryza sativa L.). CDs exhibited nanoscale size, abundant surface functionalities, and a highly negative ζ-potential, indicative of stable aqueous dispersions. Spectroscopic characterization (Raman and FTIR) confirmed a graphitic–amorphous carbon structure. Near-infrared spectroscopy coupled to principal component analysis revealed time-dependent metabolic changes during imbibition, identifying 8–12 h as the optimal priming window. Nanopriming with Spirulina CDs (0.2 mg mL⁻¹ for 12 h) increased the seed germination rate (25%), the germination speed index (17%), vigor index I (22%), and root length (37%) compared to hydropriming. Biochemically, the nanoprimed seedlings accumulated higher levels of starch (24%), total carbohydrates (8%), and total phenolics (20%), without evidence of oxidative imbalance, based on antioxidant capacity measurements and proteomic profiling. Proteomic analysis revealed coordinated metabolic reprogramming, characterized by increased abundance of proteins involved in translation, energy metabolism, and ion/nutrient homeostasis, alongside reduced abundance of proteins associated with defense and catabolic processes. This shift from stress-preparation to growth-oriented metabolism supports improved seedling establishment. Overall, Spirulina-derived CDs function as effective nanobiostimulants that promote early metabolic activation and resource mobilization, offering a sustainable strategy to enhance rice seedling establishment. Full article

Background: Traditional methods exhibit an extremely low removal efficiency for antibiotics in water, making an efficient and energy-saving approach urgently needed. Methods and Results: In this study, a novel catalytic approach based on the in situ generation of high-valent iron (Fe(IV)/Fe(V)) has been developed by adding biochar instead of modifying the electrode materials (in previous studies) for the efficient removal of sulfamethoxazole (SMX) from water. Fe(IV)/Fe(V) was produced by the anodic oxidation of low concentrations of Fe(III) and subsequently activated by nitrogen-doped corn stalk biochar (NBC). The results showed that the degradation efficiency increased from 50.83% to 90.67% within 60 min after the addition of nitrogen-modified biochar. The abundant defect structures, graphitic N and oxygen-containing functional groups in NBC endowed the catalyst with excellent activation capability. Quenching experiments and methyl phenyl sulfoxide (PMSO) probe experiments revealed that singlet oxygen (¹O₂) and Fe(IV)/Fe(V) were the main contributors to SMX degradation. Degradation pathways were inferred based on transformation products (TPs) and density functional theory (DFT) calculations. Ecotoxicity prediction using the ECOSAR program indicated that the TPs formed in the E/Fe(III)/NBC system exhibited markedly lower toxicity to aquatic organisms than the parent SMX. Furthermore, the E/Fe(III)/NBC system maintained a high degradation efficiency for SMX in real aquatic environments. Additionally, the E/Fe(III)/NBC system showed high removal rates for other sulfonamides such as sulfadiazine (SDZ), sulfamethoxypyridazine (SMP), sulfathiazole (STZ) and sulfadoxine (SDX). Conclusions: Overall, the E/Fe(III)/NBC system was demonstrated to be a highly efficient and sustainable technology for removing various antibiotics from water. Full article

Per- and polyfluoroalkyl substances (PFASs) have raised considerable concern due to their ubiquity, persistence, bioaccumulation, and toxicity. However, cost-effective, high-performance adsorbents for PFAS removal from aquatic environments remain limited. Here, we synthesized a porous graphitic biochar adsorbent (Zn-BBC) from banana peel waste via zinc chloride (ZnCl₂) activation and applied it to removing ten legacy and alternative PFASs from water. Zn-BBC achieved removal efficiencies > 95% for all target PFASs. The adsorption of PFASs onto Zn-BBC followed pseudo-second-order (PSO) kinetics, suggesting chemisorption. Additionally, the adsorption isotherms were well described by the Sips model, indicating surface heterogeneity. Zn-BBC exhibited robust performance over a broad pH range (3–9). Coexisting ions (CO₃²⁻, SO₄²⁻, Zn²⁺, Ca²⁺, and Mg²⁺), tested individually at 10 mM each, had negligible effects on the adsorption of the PFASs examined, except for perfluorobutanoic acid (PFBA). In contrast, humic acid (10 mM) significantly reduced the removal rates of PFBA, perfluorohexanoic acid (PFHxA), and hexafluoropropylene oxide dimer acid (GenX). Nevertheless, in river and lake waters, Zn-BBC achieved >85.0% removal of all PFASs except PFBA. In regeneration experiments, Zn-BBC exhibited excellent reusability. Experimental characterization and density functional theory (DFT) calculations jointly revealed that PFAS adsorption involves electrostatic interactions, hydrophobic interactions, π-CF interactions, surface complexation, and hydrogen bonding. These results suggest that Zn-BBC is a promising sorbent for PFAS removal in water. Full article