Anthraquinone-2-sulfonate enhances endogenous denitrification and phosphorus removal: Electron shuttle-mediated syntrophic partnerships.

Miniaturized chromate-free chloride assay in fish sauce based on linear height calibration of AgCl precipitate in inverted microtubes

Enhanced detection of bisphenol A with silver-anchored N-doped carbon electrocatalyst

Mechanistic elucidation of free nitrous acid–derived reactive nitrogen species along with synergistic pretreatment approaches for improved volatile fatty acid production from sludge

Transfer of multivariate calibrations for potentiometric multisensor systems to account for non-calibrated interferences.

Liquid–liquid extraction of neodymium from sulfate solutions has been studied. The effect of different parameters on the extraction recovery such as type of extraction, extractant concentration, diluent type, pH, time and aqueous/organic phase ratio has been investigated. A mixture of di(2-ethylhexyl) phosphoric acid (D2EHPA) and tri-n-butyl phosphate (TBP) in kerosene achieved a neodymium extraction recovery of over 80%. pH has a great influence on the extraction recovery of neodymium in sulfate solutions. At a pH below 1, the mixture of D2EHPA and TBP exhibited very low efficiency for the extraction of neodymium from sulfate solutions.The optimum extraction conditions as follow: extraction solvent type and concentration: D2EHPA (15%) + TBP (5%) + 80% kerosene; pH 3.5; extraction time 10 min and at an aqueous to organic phase ratio of 0.75.Furthermore, the stripping experiments indicated that a 3.0 M nitric acid (HNO₃) solution provided the optimum conditions for neodymium recovery, achieving complete stripping within 10 minutes.

Theory-guided design of hard carbon anode from graphitization-prone precursors remains challenging because oxidation and carbonization routes lack mechanisms to selectively disrupt ordered π-π stacking while preserving structural integrity during carbonation for performance. We propose an intrinsic heteroatom-assisted site-preferential oxidation mechanism that enables framework disruption and kinetically inhibits restacking during carbonization of petroleum asphaltenes rich in heteroatoms. Electronic inhomogeneity of nitric acid makes its acid-derived radicals preferentially anchor on heteroatom-modified sites, inducing steric hindrance and oxidation-guided pore evolution that yields turbostratic hard carbon with expanded interlayer spacing and closed pores. Operando characterization and density functional theory (DFT) calculations identified this heteroatom-mediated localized reactivity as the origin of suppressed graphitization and enhanced sodium-storage kinetics. The resulting material delivers a high initial Coulombic efficiency (ICE) of 89.7% and a reversible capacity of 404.1 mAh g-1, with a 93.2% capacity retention after 2200 cycles, outperforming most reported pitch-derived hard carbons. Practical applicability is demonstrated in a 1.2 Ah pouch-cell, while cradle-to-gate life cycle assessment (LCA) indicates substantially reduced environmental impacts as compared with representative commercial hard carbons. Beyond offering a generalizable strategy for converting low-quality thermoplastic carbon sources into durable sodium-ion battery anode materials, this study also offers mechanistic insights into selective carbonization pathways.

Under conditions of depletion of natural resources and increasing volumes of techno-genic waste from metallurgical and alumina production, the development of technologies for the integrated processing of sludges with the extraction of valuable components becomes highly relevant. This study proposes a method for the combined processing of red mud and dump sludge to obtain pig iron, a rare earth element concentrate, and titanium dioxide. The reduction smelting of a briquetted charge composed of sludge mixtures was carried out in a muffle furnace at 1350–1400 °C with the addition of a reducing agent. Magnetic separation of cast iron slag made it possible to reduce the iron content in the non-magnetic fraction and increase the concentration of REEs. As a result of nitric acid leaching of the non-magnetic slag fraction, followed by neutralization and calcination of the titanium-containing precipitate, a rare earth element concentrate and titanium dioxide containing 96.5% TiO2 were obtained. The developed method ensures the utilization of technogenic raw materials and contributes to the creation of an additional resource base for the production of strategically important materials.

The efficacy of expired dapagliflozin (DAP) as a sustainable and cost-effective corrosion inhibitor for copper (Cu) in 1.0M HNO₃ was investigated using a combination of experimental and theoretical approaches. Chemical and electrochemical methods were applied to assess the anticorrosion efficacy over a range of concentrations and temperatures. The results demonstrated that the anticorrosion efficiency of expired DAP is significant and increases with increasing inhibitor concentration but decreases as the temperature rises. This indicates that the inhibition process is primarily governed by the physical adsorption of expired DAP molecules onto the Cu surface. However, the observed change in βₐ suggests that the adsorption is not purely physical in nature but rather involves a mixed physical and chemical adsorption mechanism. Potentiodynamic polarization (PDP) results indicate that expired DAP functions as a mixed-type inhibitor, effectively suppressing both anodic metal dissolution and cathodic reduction reactions. Moreover, a pronounced positive shift in the pitting potential (Eₚiₜₜ) was observed, indicating a significant enhancement in resistance to pitting corrosion. The thermodynamic parameters associated with both activation and adsorption processes were evaluated and analyzed, offering deeper insight into the corrosion inhibition mechanism. The inhibition effect of expired DAP is attributed to the formation of a stable complex between DAP molecules and Cu²⁺ ions adsorbed on the metal surface. Conductometric titration indicates a 1:1 stoichiometric ratio for the Cu²⁺-DAP complex. The adsorption of this complex reduces the corrosion rate and enhances inhibition efficiency. Theoretical calculations further confirm that DAP exhibits a strong tendency to absorb onto the Cu surface, reflecting its remarkable inhibitory potential. Good agreement between the theoretical predictions and the experimental results highlights the consistency of the applied approaches and strengthens confidence in the reported results.

Advancement in spacecraft propulsion systems has driven the development of hypergolic materials with high volumetric energy density (Ev), short ignition delay (ID) time, and low sensitivity. Traditional unsymmetrical dimethylhydrazine (UDMH) suffers from unsatisfactory Ev, stringent storage requirements, and carcinogenicity. Energetic coordination compounds (ECCs) are promising hypergolic materials that combine high-energy organic components with active metal centers. However, achieving high-performance hypergolic ECCs and elucidating the structure-property relationship for ID time remains challenging. In this study, two isostructural hypergolic ECCs, [Cd(DMI)4(CBH)2] 1 and [Ni(DMI)4(CBH)2] 2, were constructed using 1,2-dimethylimidazole (DMI) as a ligand and cyanoborohydride (CBH-). Both compounds show high energy density, short ID time, and low sensitivity. Ni-based 2 has a higher Ev (31.97 kJ·cm-3) than UDMH (25.60 kJ·cm-3) and ZIF-based materials such as Zn(AIm)2 (19.30 kJ·cm-3) and Co(AIm)2 (19.50 kJ·cm-3). Upon contact with red fuming nitric acid (RFNA), compound 2 exhibits a shorter ID (14 ms) than 1 (19 ms). Theoretical calculations indicate that the shorter ID time of 2 arises from its higher HOMO energy level involving the Ni center, a more electron-rich metal center, and stronger interaction with HNO3, rendering 2 a promising hypergolic material with excellent properties.

Corrosive wear at metal interfaces under aggressive environments poses a major challenge to the durability of engineering components. In internal combustion engines, exhaust gas recirculation promotes the formation of nitric acid (HNO3), accelerating the surface degradation of steel. In this study, reactive molecular dynamics simulations were employed to elucidate atomic-scale wear mechanisms at the diamond-like carbon (DLC)/iron (Fe) friction interface under H2O and HNO3 aqueous environments. In the presence of H2O, adhesive wear predominates because the Fe substrate fails to develop a protective oxide layer within the simulation time scale. Consequently, Fe atoms form Fe-C bonds with the DLC surface and are removed during sliding. In contrast, when both H2O and HNO3 are present, corrosive wear dominates while adhesive wear is suppressed. HNO3 reacts with the Fe surface to produce a layered Fe oxide and Fe nitride, which limit direct Fe-C bonding. During sliding, H2O reacts with Fe-N bonds within the nitride layer, forming Fe-NH2 structures. These reactions result in the detachment of the nitride layer as tribochemical debris whereas the oxide layer remains stable. Overall, the dominant wear mechanism at the DLC/Fe interface is environment-dependent: adhesive wear prevails in H2O, while corrosive wear becomes significant in the HNO3-H2O environment.

Over the past decades, the considerable increase in greenhouse gas emissions has caused alarming issues such as global warming. Numerous investigations have been carried out to enhance CO2 capture. One of the promising methods is to functionalize the MWCNTs, but different conditions and factors for functionalizing have significant effects on the adsorption. In this study, raw multi-wall carbon nanotubes were functionalized in two stages. First, they were modified using a mixture of 5 molars of sulfuric acid and nitric acid. Then, the carboxylated MWCNTs were functionalized with 1,3 Diaminopropane solutions. To obtain the optimum adsorbent parameters, the ratio of amine to solvent concentration and the reflux time of amine solution were changed. FTIR, FESEM, TGA, and nitrogen adsorption/desorption analyses were used to determine the characterizations of optimum adsorbents. Based on the experimental results, the maximum capacity equal to 3.37 mmolg- 1, obtained under conditions of 303K, and an initial pressure of 18.5bar when the amine to ethanol concentration ratio was 60% w/w. Furthermore, the effect of the MWCNTs diameter on adsorption capacity was investigated as well. Results proved that by increasing the MWCNTs diameter in the raw and amine-functionalized samples, the adsorption capacity increased. Additionally, the adsorption isotherms were evaluated by Langmuir and Freundlich models, and the isosteric heat of adsorption, the adsorption mechanism and the adsorption capacity were measured. Ultimately, the regeneration cycles of optimal adsorbent was performed in five stages, indicating that the adsorbent was stable enough for the regeneration process.

Affinity of four different extraction chromatographic resin for Pd and Ag: Toward efficient separation of Pd from Ag.

Ficus natalensis (Natal fig), an evergreen tree of the family Moraceae, is widely distributed across tropical and temperate regions and cultivated in Egypt. Members of the Moraceae family are traditionally employed as expectorants, hypoglycemic agents, and mild laxatives, with reported neuroprotective, analgesic, anti-inflammatory, and antihypertensive effects. The present study aimed to profile the secondary metabolites of F. natalensis fruit using ultra-performance liquid chromatography coupled with tandem mass spectrometry (UPLC-MS/MS) and test its anti-inflammatory potential. A total of 160 metabolites were annotated in both positive and negative ionization modes, belonging to diverse phytochemical classes such as phenolics (41), flavonoids (21), acids (26), glycosides (11), terpenoids, coumarins (4), iridoids (3), fatty acids/ester (22), sterols (8), sugar derivatives (6), and terpenoids (18). The anti-inflammatory activity of F. natalensis fruit methanolic extract was investigated using nitric acid (NO) inhibition assay, revealing an IC50 of 28.54 ± 1.66µg/mL, compared to resveratrol as a standard anti-inflammatory with an IC50 value of 10.21 ± 0.68µg/mL. Major bioactive constituents, including ellagic acid, gallic acid, betulinic acid, and quercetin derivatives, were identified and may underline the observed anti-inflammatory effect. The current findings highlight F. natalensis fruit as a rich source of bioactive metabolites with potential anti-inflammatory effect.

The objective of this work is to create a hollow cylindrical Aluminium (Al) 6061 alloy reinforced with 10 wt% Alumina (Al2O3) Functionally Graded Composite (Al 6061-10 wt% Al2O3 FGC) using horizontal centrifugal casting. Vickers microhardness testing revealed a maximum hardness of 108 HV at the Al2O3-rich exterior periphery, which is 76% higher than the Al2O3-depleted interior region. Optical microstructural and XRD (X-ray Diffraction) analysis confirmed the gradient distribution of Al2O3 particles. Acidic immersion corrosion studies on the Al2O3-rich region were performed using Sulphuric acid (H2SO4), Hydrochloric acid (HCl), and Nitric acid (HNO3) solutions for immersion durations up to 216h. The highest Corrosion Rate (CR) (27.31mm/yr) was observed in HCl at 72h due to Chloride (Cl) ion attack and pitting, while the lowest CR (6.83mm/yr) occurred in HNO3 at 216h owing to stable oxide film formation. Taguchi's Signal-to-Noise Ratio (SNR) analysis indicated immersion duration as the most significant factor, with Analysis of Variance (ANOVA) confirming its 56.25% contribution to CR variation. High Resolution Scanning Electron Microscopy (HRSEM) analysis of corroded surfaces showed microcracks, interfacial regions, and surface damage. The findings highlight that controlling immersion duration and selecting appropriate acidic media can significantly enhance the corrosion resistance of Al2O3-reinforced Al 6061 FGCs, making them suitable for chemical industry applications.

Insight into the key role of dynamic Pb0 sites in the synergistic photocatalytic removal of BPA and Pb(II) over a Z-scheme CuCo2S4/BiOIO3 heterojunction.

Surface chemistry of porous carbon black was modified by oxidation either with hydrogen peroxide or nitric acid, and also by a thermal treatment with urea. The latter reduced the surface and introduced nitrogen groups to the carbon matrix. Sulfur was inserted into carbon pores using a steam-assisted sulfur insertion method. It resulted in a gradual and controllable pore filling, from ultramicropores to mesopores. Orthorhombic α-sulfur and monoclinic γ-sulfur were detected. In small pores, only Sx linear fragments could be formed. The fraction of γ-sulfur increased with an increased electrical conductivity and the amount of intrinsic defects of the initial carbon hosts. While an increase in the former could be directly linked to thermal conductivity, the defectous carbon likely binds to sulfur, helping to form and stabilize monoclinic crystals. Confinement effects further contributed to stabilizing metastable sulfur allotropes by physically limiting mobility and retarding phase transitions. Although amorphous sulfur was also formed during fast cooling, higher fractions of γ-sulfur were detected in the crystalline phase, especially in most conductive carbons. These findings highlight a complex interplay among carbon chemistry, microstructure, and electronic properties affecting the formation and stabilization of γ-sulfur and provide insights into sulfur-carbon interactions for designing advanced sulfur-based carbon materials.

Per- and polyfluoroalkyl substances (PFAS) are highly persistent pollutants with known adverse impacts on environmental and public health. Traditional gas-phase PFAS detection approaches often involve labor-intensive sample collection and preparation, while offering low temporal resolution. Alternatively, chemical ionization mass spectrometry (CIMS) allows for real-time airborne PFAS detection at sub-pptv sensitivity. While reagent ion generation often requires hazardous chemicals (e.g., nitric acid, methyl iodide (I-), and acetic anhydride), superoxide (O2-) CIMS provides a safer alternative and is better suited for mobile platforms where ventilation, space, and weight are constrained. O2- CIMS has five main reagent ions (i.e., O2-, (H2O)O2-, CO3-, (CO2)O2-, and CO2(H2O)O2-) and low-background mass spectra above m/z 200. Thus, it is well suited to the relatively high molecular weights of airborne PFAS. Mass calibration was performed with a 5 : 1 fluorotelomer alcohol (FTOH) permeation tube. Ionization was found to occur mainly through deprotonation or adduct formation. Calibrations for fourteen environmentally- and industrially-relevant PFAS compounds are presented, including FTOHs, fluorotelomer diols, fluorinated sulfonamides, epoxides, and glycol ethers. While perfluoroalkyl carboxylic acids (PFCAs) were not detected, O2- CIMS offered higher sensitivity and lower detection/quantification limits than I- CIMS for FTOHs; however, it remains a complementary PFAS measurement technique to I- CIMS. Moreover, it yielded distinct fingerprint signals for FTOHs, confirming compound identification. This study demonstrates the utility of O2- CIMS for real-time airborne PFAS analysis in commonly encountered environments by capturing 6 : 2 FTOH gaseous emissions from fast-food packaging at room temperature, underscoring its strong promise for future development and applications.

Effects of free nitrous acid stress on partial nitrification and partial denitrification and functional succession of bacteria under the influence of pH.

Abating industrial nitrous oxide emissions in the United States: legal, economic and scientific dimensions