Search Results (575)

Adsorption desulfurization of fuel oil is regarded as one of the most promising technologies for obtaining clean fuel because it can remove refractory sulfur compounds at ambient temperature and pressure. Studies indicate that HKUST-1, as an important type of metal–organic framework (MOF), is a potential candidate for adsorption desulfurization of fuel oil. In this work, we report that defective HKUST-1 can be rapidly synthesized at room temperature with the aid of NH₄F and exhibit superior adsorption desulfurization performance compared to conventional HKUST-1 by the solvothermal method. Moreover, the influence of adsorption parameters on the desulfurization performance of HKUST-1 prepared with the aid of NH₄F was investigated. We used 50 mg of HKUST-1-5 synthesized with 5 wt% added NH₄F to adsorb 5 g of model oil with a sulfur concentration of 1000 ppm at 25 °C for 1 h, and the adsorption capacity of the adsorbent reached 23.8 mgS/g, 46.8 mgS/g and 36.8 mgS/g for benzothiophene (BT), dibenzothiophene (DBT) and 4,6-dimethyldibenzothiophene (4,6-DMDBT), respectively, which are higher values than those of conventional HKUST-1. Such performance can be mainly attributed to its relatively small particle size and the presence of more unsaturated Cu sites. The results of regeneration experiments show that HKUST-1-5 still maintains excellent adsorption performance after four cycles. These findings highlight the great potential of this material as an efficient adsorbent for adsorption desulfurization of fuel oil. Full article

Introducing hierarchical structure into zeolites or synthesizing two-dimensional (2D) zeolite nanosheets have drawn much attention in catalysis and separation process due to the improvement in zeolites’ diffusion properties. In this study, Fe incorporated on the MFI zeolite framework (Fe-MFI) with the nanosheet morphology and unique hierarchical pore structure was successfully synthesized and applied for the adsorption and degradation of Rhodamine B (RhB) in a Fenton-like reaction in the presence of H₂O₂. The synthesis involved a seed-directed hydrothermal method in the presence of NH₄F and a subsequent NaOH treatment made the synthesized hierarchical Fe-MFI nanosheets (Fe-20-10) characterized by abundant highly dispersed framework Fe³⁺ species. As a result of these features, the Fe-20-10 showed excellent ability of adsorption and degradation efficiency of RhB, and enhanced durability due to negligible leaching of framework Fe³⁺ species. Moreover, the hydroxyl radicals were determined as the main the reactive oxygen species of RhB degradation, and a possible adsorption–degradation pathway was proposed. This work offers guidance for developing high-performance Fenton-like degradation catalysts. Full article

Chlorpyrifos CPF (O,O-diethyl O-(3,5,6-trichloro-2-pyridyl) phosphorothioate), known also as Chlorpyrifos-ethyl, is one of the most utilized organophosphorus pesticides worldwide. Additionally, CPF could be used as a chemical warfare agent surrogate. Although its acute toxicity is not high, it is responsible for both a large number of intoxications and chronic, delayed neurological effects. In this work, it is reported for the first time the qualitative and quantitative response produced by CPF vapors, using a pocket-held Time-of-Flight Ion Mobility Spectrometer (ToF IMS) with a non-radioactive ionization source and ammonia doping, model LCD-3.2E (Smiths Detection Ltd.), operated near ambient temperature (below 30 °C). Spectra of CPF in positive ion mode included two distinct product ion peaks; thus, identification of CPF vapors by IMS relies on these peaks—the monomer M·NH₄⁺ with reduced ion mobility K₀ = ca. 1.76 cm² V⁻¹ s⁻¹ and the dimer M₂·NH₄⁺ with K₀ = ca. 1.47 cm² V⁻¹ s⁻¹ (where M may be assignable to CPF molecule)—and positive reactant ions (Pos RIP) have K₀ = ca. 2.25 cm² V⁻¹ s⁻¹. Excellent sensitivity, with a limit of detection LOD of 0.72 ppb_v (10.5 μg m⁻³) and a limit of quantification LOQ of 2.41 ppb_v (35.1 μg m⁻³), has been noticed; linear response was up to 100 ppb_v, while saturation occurs over ca. 1000 ppb_v (14.6 mg m⁻³). Our results demonstrate that this method provides a robust tool for both off-site and on-site detecting and quantifying CPF vapors at trace levels, which has strong implications for either industrial hygiene or forensic investigations concerning the pesticide Chlorpyrifos, as well as for monitoring of environmental contamination by organophosphorus pesticides. Full article

In this study, benzophenone compounds substituted with electron-withdrawing groups (-NO₂, -F, and -Cl) and electron-donating groups (-OH, -CH₃, -NH₂, and -OCH₃) were employed as voltage stabilizers for crosslinked polyethylene (XLPE) insulation materials. At B3LYP/6-311+G(d,p) level, reaction Gibbs free potential energy data for eleven reaction channels and molecular characteristics, including electron affinity EA(s), ionization potential IP(s), and HOMO-LUMO gap (E_g) of benzophenone derivatives, were obtained. The effects of electron-donating and electron-withdrawing functional groups were systematically evaluated. The calculated results indicate that benzophenones exhibit the lowest Gibbs free energy barrier for grafting onto polyethylene among the investigated molecules. With the introduction of electron-donating groups, the reaction Gibbs free energy barrier increases. It is worth noting that 2-Nitrobenzophenone is considered to possess superior electrical resistivity, attributed to its highest electron affinity among the studied compounds. This investigation is expected to provide reliable insights for the development of modified polyethylene-based insulating materials for high-voltage cables. Full article

Surgical dead spaces are challenging to handle with current preventive methods. Tissue adhesives show promise in obliterating ‘dead spaces’, but the drawbacks of currently available adhesives prevent them from being used for dead space elimination. An adhesive powder based on N-Hydroxysuccinimide-poly(2-oxazoline), NHS-POx, combines robust adhesive strength in moist environments with favorable biocompatibility and biodegradability, which makes this an interesting candidate for eliminating spaces that remain between tissues after surgery. The current study evaluates the swelling, crosslinking speed, and degradation properties of this novel tissue adhesive. These results were then used to design multiple adhesive variants differing in pH, surfactant addition, and particle size, which were subsequently examined based on their wetting rates, adhesive strength, and durability. The powder displayed minimal swelling and rapid crosslinking properties, by which the latter could be increased by a basic buffer or surfactant addition and reduced by increasing particle size. The wetting rate of the powder increased when a surfactant (Pluronic F68) was added to the mix. The adhesive strength, as measured by tensile and shear strength measurements of different prototypes of the adhesive powder, was significantly better than that of a commercially available fibrin glue. The addition of both buffer and Pluronic F68 led to a breakdown of adhesive force after 14 days of incubation, while the prototype containing neither buffer nor Pluronic F68 still had measurable adhesive force after 14 days of incubation. The current study results display several characteristics of the NHS-POx-based tissue adhesive that are favorable for tissue approximation, preventing the occurrence of dead spaces. The most effective and usable adhesive prototype will be identified in further ex vivo and in vivo animal model studies. Full article

Hand hygiene (HH) is universally recognized as a pillar of infection prevention and control (IPC), both in hospitals and long-term care facilities such as nursing homes (NHs). An annual national survey based on the voluntary notification of purchased alcohol-based hand rubs (ABHRs) has been set up in France since 2019 to appraise the compliance to HH in NHs. The results pertaining to the Hauts-de-France (HdF) region were analyzed over the 2018–2023 period. The impact of factors such as the year, structure status, availability of an infection control link (ICL) nurse and/or an IPC team as well as constant participation in the survey was evaluated. A clear rise in the consumption of ABHRs was witnessed in 2020 followed by a progressive return to the 2018 baseline by 2023 for most NHs. This decrease was significantly less marked in NHs constantly participating in the survey. The ABHR indicator’s annual values were significantly higher in public NHs than in associative ones and in NHs with available ICL nurses/IPC teams. Finally, even though less than 50% of regional NHs reached the target of four daily ABHR uses per resident, they more frequently met it than French ones as a whole. This result underscores the need for ceaselessly reiterating the importance of HH and for pursuing training efforts in NHs with the help of ICL nurses and IPC teams. Full article

In the exploitation of ion-adsorption rare earth ores, the environmental effects of leaching agents are key constraints for green mining. Understanding the release behavior of typical heavy metals from soils under leaching conditions is of great significance. Laboratory column leaching experiments were conducted to systematically investigate the effects of three leaching agents—(NH₄)₂SO₄, Al₂(SO₄)₃, and MgSO₄—as well as varying concentrations of Al₂(SO₄)₃ on the release and speciation transformation of heavy metal Pb in mining-affected soils. The results revealed a three-stage pattern in Pb release—characterized by slow release, a sharp increase, and eventual stabilization—with environmental risks predominantly concentrated in the middle to late stages of leaching. Under 3% (NH₄)₂SO₄ and 3% Al₂(SO₄)₃ leaching conditions, Pb concentrations in soil increased significantly, with a higher proportion of labile fractions, indicating pronounced activation and risk accumulation. Due to its relatively weak ion-exchange capacity, MgSO₄ exhibited a lower and more gradual Pb release profile, posing substantially lower pollution risks compared to (NH₄)₂SO₄ and Al₂(SO₄)₃. Pb release under varying Al₂(SO₄)₃ concentrations showed a nonlinear response. At 3% Al₂(SO₄)₃, both the proportion of bioavailable Pb and the Risk Assessment Code (RAC) peaked, while the residual fraction declined sharply, suggesting a threshold effect in risk induction. All three leaching agents promoted the transformation of Pb in soil from stable to more labile forms, including acid-soluble, reducible, and oxidizable fractions, thereby increasing the overall proportion of active Pb (F1 + F2 + F3). A combined analysis of RAC values and the proportion of active Pb provides a comprehensive framework for assessing Pb mobility and ecological risk under different leaching conditions. These findings offer a theoretical basis for the prevention and control of heavy metal risks in the green mining of ion-adsorption rare earth ores. Full article

We developed dye-sensitized solar cells based on anatase–titanium dioxide (A-TiO₂) nanotubes (TiNTs) and nanocubes (TiNcs) with {001} crystal facets generated using simple and facile electrochemical anodization. We also demonstrated a simple way of developing one-dimensional, two-dimensional, and three-dimensional self-assembled TiO₂ nanostructures via electrochemical anodization, using them as an electron-transporting layer in DSSCs. TiNTs maintain tubular arrays for a limited time before becoming nanocrystals with {001} facets. Using FESEM and TEM, we observed that the TiO₂ nanobundles were transformed into nanocubes with {001} facets and lower fluorine concentrations. Optimizing the reaction approach resulted in better-ordered, crystalline anatase TiNTs/Ncs being formed on the Ti metal foil. The anatase phase of as-grown TiO₂ was confirmed by XRD, with (101) being the predominant intensity and preferred orientation. The nanostructured TiO₂ had lattice values of a = 3.77–3.82 and c = 9.42–9.58. The structure and morphology of these as-grown materials were studied to understand the growth process. The photoconversion efficiency and impedance spectra were explored to analyze the performance of the designed DSSCs, employing N719 dye as a sensitizer and the I⁻/I³⁻ redox pair as electrolytes, sandwiched with a Pt counter-electrode. As a result, we found that self-assembled TiNTs/Ncs presented a more effective photoanode in DSSCs than standard TiO₂ (P25). TiNcs (0.5 and 0.25 NH₄F) and P25 achieved the highest power conversion efficiencies of 3.47, 3.41, and 3.25%, respectively. TiNcs photoanodes have lower charge recombination capability and longer electron lifetimes, leading to higher voltage, photocurrent, and photovoltaic performance. These findings show that electrochemical anodization is an effective method for preparing TiNTs/Ncs and developing low-cost, highly efficient DSSCs by fine-tuning photoanode structures and components. Full article

The health impacts of atmospheric fine particulate matter (PM_2.5) in plateau regions have attracted concerns, along with local population growth and rapid urbanization. This study collected PM_2.5 samples at summer and winter in Xining, a city located in the northeastern Tibetan Plateau. The chemical composition of PM_2.5 and its cytotoxicity on human lung epithelial cells (A549) are characterized, and composition–cytotoxicity correlation is discussed. The toxic mechanisms of PM_2.5 in different seasons were further investigated through metabolomic analysis using high-resolution mass spectrometry. The average PM_2.5 mass concentration in Xining during winter was 2.10 times higher than that during summer. The carbonaceous components in PM_2.5 were dominated by OC, while the main water-soluble ions were SO₄²⁻, NO₃⁻, and NH₄⁺, with Mg, Al, Fe, and Ca also present in high concentrations in metal elements. LDH and ROS emerged as the most PM_2.5-affected toxicity indices in summer (34.59 ± 4.86 ng/L, 1.19× control) and winter (8.62 ± 1.25 ng/mL, 1.77× control), respectively. OC, Cl⁻, F⁻, Sn, Cr, SO₄²⁻, Pb, Zn, Mg, NO₃⁻, and NH₄⁺ may synergistically exacerbate oxidative stress and inflammatory responses on A549 cells in Xining. Furthermore, glutathione metabolism, amino acid metabolism, and sphingolipid metabolism were identified as key pathways influencing cellular oxidation and inflammation. Thimonacic, 9-(2,3-dihydroxypropoxy)-9-oxononanoic acid, and hypoxanthine were common metabolites in both seasons. Our findings greatly enhance the understanding of health risks associated with PM_2.5 in the plateau city. Full article

To address the critical challenges in pyrometallurgical recycling processes—such as poor feedstock adaptability, high energy consumption during roasting conversion, and the low added value of rare earth products—this study systematically investigated the mechanism and process optimization of ammonium bifluoride (NH₄HF₂) roasting for the recovery of neodymium–iron–boron (NdFeB) waste. Thermodynamic analysis confirmed the feasibility of the conversion reaction between NH₄HF₂ and the rare earth components in NdFeB waste. Single-factor experiments were conducted to examine the effects of roasting temperature, reaction time, and NH₄HF₂ dosage on rare earth recovery. The optimal conditions were a roasting temperature of 600 °C, a reaction time of 120 min, and a NH₄HF₂ dosage of 75 wt%, achieving a rare earth recovery rate of 98.81%. Furthermore, the response surface methodology (RSM) was employed to establish a quantitative model correlating process parameters with recovery efficiency. Variance analysis demonstrated that the model was highly significant (F = 136.94, p < 0.0001), with excellent agreement between actual and predicted values (R² = 0.9944). Factor contribution analysis revealed that NH₄HF₂ dosage had the most pronounced impact on rare earth fluorination, followed by roasting temperature and reaction time. Under optimized conditions, the purified rare earth fluoride obtained after acid leaching reached a purity of 99.43%, providing high-quality raw material for producing high-value-added rare earth products. Full article

To elucidate the spatial distribution characteristics of algal communities and their correlation with environmental factors in the Heilongjiang River, algal surveys and water quality monitoring were carried out from May to October 2023. The results were as follows: (1) In total, 234 species from 95 genera belonging to seven phyla were detected, mainly Bacillariophyta, Chlorophyta, and Cyanophyta. (2) The most dominant species in the Heilongjiang River in summer and autumn were Pseudanabaena minima (G. S. An) Anagnostidis and Phormidium gelatinosum Woronichin. The dominant species in the middle niche in summer and the dominant species in the broad niche in autumn were Bacillariophyta. (3) Canonical Correlation Analysis results revealed that the environmental factors that significantly affected the distribution of the epiphytic algae during the summer were COD, F-, and WT, while EC, TN, BOD₅, and pH significantly influenced the distribution of epiphytic algae in autumn. (4) Significant correlation heatmaps revealed that the dominant species were significantly correlated with WT and TP in the Greater Khingan Mountains in summer, whereas the dominant species were significantly correlated with COD, NH₃-N, and TP in the Heihe region, Lesser Khingan Mountains, and Sanjiang Plain. There was a significant correlation between the dominant species and TN in the Greater Khingan Mountains in autumn. The spatial distribution characteristics of the algal communities and the correlations between the dominant species and water environmental factors can provide a theoretical reference for the assessment of the water ecological health status. Full article

Crystal twinning, a common growth phenomenon, can substantially affect material performance in fields such as semiconductors, nonlinear optics, and drug development, yet its elimination during crystallization is challenging. This study presents a method for the controlled synthesis of ZSM-5 zeolite as either single crystals or twinned crystals using kaolin as the primary raw material. The method leverages the etching effect of ammonium fluoride (NH${⁠}_4$F) on the aluminosilicate structure derived from pre-treated kaolin. By adjusting the concentrations of NH${⁠}_4$F and the structure-directing agent tetrapropylammonium bromide (TPABr), pure ZSM-5 single crystals and twinned crystals were selectively synthesized. Conventionally, NH${⁠}_4$F is employed to introduce defects into zeolite structures. In contrast, this work demonstrates its utility in controlling crystal habit. The synthesis utilizes kaolin, an abundant and low-cost aluminosilicate mineral, to provide the entire aluminum source and a portion of the silicon source, offering an economical alternative to expensive precursors like aluminum isopropoxide. The resulting single and twinned crystals exhibited high crystallinity, demonstrating the viability of using natural minerals to produce high-quality zeolites. The physical and chemical properties of the kaolin-derived ZSM-5 were characterized and compared to those of ZSM-5 synthesized from conventional chemical reagents. A growth mechanism for the formation of single and twinned crystals is also proposed. Full article

Methane (CH₄), originating from ruminants, is a major source of greenhouse gas emissions in the agriculture industry. This study aimed to determine the potential of red seaweed Gracilaria lemaneiformis (G. lemaneiformis) as an anti-methanogenic feed additive for cattle. Three supplementation levels of seaweed (2%, 5%, and 10% of dry matter) were evaluated for their effects on gas production and rumen fermentation characteristics during 48 h in vitro fermentation. The results revealed a significant decrease in total gas production (TGP), CO₂, CH₄, ammonia nitrogen (NH₃-N), and volatile fatty acid (VFA) concentrations, with no differences in pH or dry matter disappearance (DMD). Notably, compared with the control group without seaweed, supplementation with 2% G. lemaneiformis effectively reduces CH₄ emissions by 27.5% (p < 0.05). Supplementation with 2% G. lemaneiformis decreased the abundance of methanogens g_norank_f_Methanomethylophilaceae, responsible for CH₄ generation, and increased the populations of bacteria (Kandleria and Succinivibrio) that compete with methanogens for substrates. Furthermore, upregulating the levels of 13(S)-HOTrE and 9(S)-HOTrE (polyunsaturated fatty acids) could inhibit methanogenic activity. Additionally, lower VFA concentrations will provide less raw materials for methane synthesis, thus further inhibiting methanogenesis. In summary, G. lemaneiformis, as a red seaweed with important economic value, can not only be applied to enhance marine carbon sinks but can also serve as a promising candidate for mitigating biomethane emissions in cattle. Full article

Pyridyl-thiourea complexes of formula [(Cym)MCl(κ²N_py,S-H₂NNS)][SbF₆] (Cym = η⁶-p-MeC₆H₄iPr; H₂NNS = N-(p-tolyl)-N′-(2-pyridylmethyl)thiourea); M = Ru (1), Os (2)) were synthesized by reacting the corresponding metal dimers [{(Cym)MCl}₂(μ-Cl)₂] with H₂NNS in the presence of NaSbF₆. Subsequent chloride abstraction with AgSbF₆, followed by NH deprotonation using NaHCO₃, afforded the cationic complexes [(Cym)M(κ³N_py,N_amide,S-HNNS)][SbF₆] (M = Ru (5a), (5c); M = Os (6a, 6c)) and [(Cym)M(κ²N_amide,S-HNNS)][SbF₆] (M = Ru (5b); M = Os (6b)). The proposed structures for the prepared compounds are based on NMR data. Complexes 5a, 5b, and 6a, 6b evolve to the thermodynamically more stable species 5c and 6c, respectively, in which the deprotonated ligand HNNS adopts a κ³N_py,N_amide,S coordination mode. Complexes 5c and 6c activate H₂, behaving as frustrated Lewis pair (FLP) species, and catalyze (5c and/or 6c) the hydrogenation of polar multiple bonds, including the C=N bonds of N-benzylideneaniline and quinoline, the C=C bond of methyl acrylate, and the C=O bond of 2,2,2-trifluoroacetophenone. Full article

This work presents a method for preparing an Fe₂O₃/MWCNT/Al composite electrode without the use of a binder. Synthesizing the composite material directly on conductive substrates allows one to obtain ready-made supercapacitor electrodes characterized by high values of specific capacity, as well as resistance to numerous charge/discharge cycles. Using an array of multi-walled carbon nanotubes (MWCNTs) as a conductive base for the synthesis of iron oxide allows for the production of a composite material that combines the positive properties of both materials. The Fe₂O₃/MWCNT/Al composite was formed using electrochemical oxidation of the MWCNT/Al material in a mixture of 0.1 M aqueous solution of Fe(NH₄)₂(SO₄)₂ (iron ammonium sulfate) and 0.08 M CH₃COONa (sodium acetate) in a 1:1 ratio. The proposed approaches to fabricating composite electrodes provide excellent performance characteristics, namely high cyclic stability and fast response time. For the first time, an Fe₂O₃/MWCNT/Al composite was obtained using electrochemical oxidation of Fe²⁺ on the surface of MWCNTs grown directly on aluminum foil. The specific capacitance of the obtained composite material reaches 175 F/g at a scanning rate of 100 mV/s. The capacity loss during cyclic measurements does not exceed 25% after 10,000 charge/discharge cycles. Full article