Search Results (853)

This review surveys recent advances and emerging prospects in phase-transfer catalysis (PTC) for fuel desulfurization. In response to increasingly stringent environmental regulations, the removal of sulfur from transportation fuels has become imperative for curbing SO_x emissions. Conventional hydrodesulfurization (HDS) operates under severe temperature–pressure conditions and displays limited efficacy toward sterically hindered thiophenic compounds, motivating the exploration of non-hydrogen routes such as oxidative desulfurization (ODS). Within ODS, PTC offers distinctive benefits by shuttling reactants across immiscible phases, thereby enhancing reaction rates and selectivity. In particular, PTC enables efficient migration of organosulfur substrates from the hydrocarbon matrix into an aqueous phase where they are oxidized and subsequently extracted. The review first summarizes the deployment of classic PTC systems—quaternary ammonium salts, crown ethers, and related agents—in ODS operations and then delineates the underlying phase-transfer mechanisms, encompassing reaction-controlled, thermally triggered, photo-responsive, and pH-sensitive cycles. Attention is next directed to a new generation of catalysts, including quaternary-ammonium polyoxometalates, imidazolium-substituted polyoxometalates, and ionic-liquid-based hybrids. Their tailored architectures, catalytic performance, and mechanistic attributes are analyzed comprehensively. By incorporating multifunctional supports or rational structural modifications, these systems deliver superior desulfurization efficiency, product selectivity, and recyclability. Despite such progress, commercial deployment is hindered by the following outstanding issues: long-term catalyst durability, continuous-flow reactor design, and full life-cycle cost optimization. Future research should, therefore, focus on elucidating structure–performance relationships, translating batch protocols into robust continuous processes, and performing rigorous environmental and techno-economic assessments to accelerate the industrial adoption of PTC-enabled desulfurization. Full article

In this work, the synthesis and structural characterization of the smallest possible member of the family of bis-functionalized {MnMo₆O₂₄} Anderson–Evans polyoxometalates (POMs) is reported. The synthesis of the title compound TBA₃{[HC(CH₂O)₃]₂MnMo₆O₁₈} (1) was accomplished by using trimethylolmethane as the capping unit (TBA: tetra(n-butyl)ammonium, n-B_u4N⁺). The molecular structure of the organic–inorganic POM gave rise to yet undisclosed ¹H-NMR features, which are discussed thoroughly. Single-crystal X-ray diffraction (XRD) analysis revealed a highly regular 3D packing of the polyoxoanions within a matrix of TBA cations. The hybrid POM is of particular interest regarding potential applications in photocatalysis (i.e., hydrogen evolution) and energy storage. Thus, the electrochemical and thermal properties of 1 are also analyzed. Full article

As the primary biological risk threatening safe dairy production, bovine mastitis control highly relies on environmental disinfection measures. However, the mechanisms by which chemical disinfectants influence host–environment microbial interactions remain unclear. This study systematically investigated the disinfection efficacy and regulatory effects on microbial community composition and diversity of glutaraldehyde-benzalkonium chloride (BAC) and glutaraldehyde-didecyl dimethyl ammonium bromide (DAB) at recommended concentrations (2–5%), using 80 environmental samples from intensive dairy farms in Xinjiang, China. Combining 16S rDNA sequencing with culturomics, the results showed that BAC achieved a disinfection rate of 99.33%, higher than DAB’s 97.87%, and reduced the environment–gut microbiota similarity index by 23.7% via a cationic bacteriostatic film effect. Microbiome analysis revealed that BAC selectively suppressed Fusobacteriota abundance (15.67% reduction) and promoted Bifidobacterium proliferation (7.42% increase), enhancing intestinal mucosal barrier function through butyrate metabolism. In contrast, DAB induced Actinobacteria enrichment in the environment (44.71%), inhibiting pathogen colonization via bioantagonism. BAC’s long-acting bacteriostatic properties significantly reduced disinfection costs and mastitis incidence. This study first elucidated the mechanism by which quaternary ammonium compound (QAC) disinfectants regulate host health through “environment-gut” microbial interactions, providing a critical theoretical basis for developing precision disinfection protocols integrating “cost reduction-efficiency enhancement-risk mitigation.” Full article

Secondary iron overload exacerbates osteoporosis by elevating reactive oxygen species (ROS), which suppress osteoblast function and enhance osteoclast activity, disrupting bone remodeling. Reducing iron overload and oxidative stress may improve bone health. Epigallocatechin-3-gallate (EGCG), the main bioactive compound in green tea extract (GTE), is recognized for its antioxidant and iron-chelating properties. This study examined the effect of GTE on bone formation and mineralization in iron-overloaded human osteoblast-like MG-63 cells. An iron-overloaded model was established using ferric ammonium citrate (FAC), followed by treatment with GTE, deferiprone (DFP), or their combination. GTE significantly reduced intracellular iron, ROS levels, and lipid peroxidation while upregulating the osteogenic marker BGLAP, the anti-resorptive marker OPG, and osteogenic mineralization, indicating restored bone health. These results suggest that EGCG-containing GTE mitigates iron-induced oxidative stress and promotes osteogenesis, highlighting its potential as a natural therapeutic supplement for managing iron-overload-associated osteoporosis. Full article

A previously pyrometallurgical process, developed to obtain a Pb-Ag alloy and a slag rich in sulfur from the recycling of a mixture of industrial wastes of jarosite and lead paste, was thermodynamically assessed at 1200 °C. The industrial jarosite sourced from a Mexican zinc hydrometallurgical plant corresponded to an ammonium jarosite with a measurable silver content. The specific heat capacity (Cp) of the ammonium jarosite was obtained from TGA and DSC measurements, as well as the thermodynamic functions of enthalpy, entropy, and Gibbs free energy. The Cp was successfully modeled using polynomial regression, with a second-degree polynomial employed to describe the low-temperature behavior. The thermodynamic data generated were input into the thermodynamic software FactSage 8.2 for modeling of the lead paste–ammonium jarosite-Na₂CO₃-SiC system and represented by stability phase diagrams. The thermodynamic assessment of the pyrometallurgical process predicted compounds formed at high temperatures, showing that a Pb-Ag alloy and a slag rich in Na, S, and Fe (NaFeS₂ and NaFeO₂) were obtained. The compounds formed evidence of the effective sulfur retention in the slag, which is crucial for mitigating SO₂ emissions during high-temperature treatments. The experimental compounds, after solidification, were determined by X-ray diffraction measurements to be Na₂Fe(SO₄)₂ and Na₂(SO₄), which reasonably match the thermodynamic assessment. The heat capacity of the ammonium jarosite provides essential thermodynamic insights into the compositional complexities of industrial waste, which are particularly relevant for thermodynamic modeling and process optimization in pyrometallurgical systems aimed at metal recovery and residue valorization. Full article

Pear black spot disease seriously threatens the pear industry. Currently, its control mainly relies on chemical fungicides while biological control using antagonistic microorganisms represents a promising alternative approach. This study identified and characterized Bacillus velezensis TRMB57782 as a biocontrol strain through whole-genome sequencing. AntiSMASH analysis predicted the strain’s potential to produce secondary metabolites such as surfactin, difficidin, and bacilysin. In vitro experiments demonstrated that TRMB57782 inhibited the growth of Alternaria gaisen. In vivo experiments using excised branches and pear fruits at two different stages also showed significant control effects. A preliminary exploration of the metabolic substances of TRMB57782 was carried out. The strain can produce siderophores and three biocontrol enzymes. Crude extracts obtained by the hydrochloric acid precipitation and ammonium sulfate saturation precipitation of the bacterial liquid exhibited significant activity and volatile organic compounds showed biocontrol activity. Meanwhile, the effects of strain TRMB57782 on the hyphae of pathogenic fungi were studied, leading to hyphal atrophy and spore shrinkage. This paper provides an effective biocontrol strategy for fragrant pear black spot disease, reveals the antibacterial mechanism of Bacillus velezensis TRMB57782, and offers a new option for the green control of pear black spot disease. Full article

The design of high-performance drilling fluid systems is of vital importance for the safe and efficient exploitation of natural gas hydrates. Incorporating appropriate nanoparticles into drilling fluids can significantly enhance drilling fluid loss control, wellbore stability, and hydrate inhibition. However, the combined effects of nanoparticles and conventional additives on hydrate inhibition in drilling fluid systems remain poorly understood. In this study, the influence of nanoparticles on hydrate formation was first evaluated in a base mud, followed by an investigation of their combined effects with common drilling fluid additives. The results demonstrate that hydrophilic nano-CaCO₃ particles exhibit hydrate inhibitory effects, with the strongest inhibition observed at 3.0%. Composite system tests (incorporating nanoparticles with sepiolite, filtrate reducers, and flow modifiers) revealed diverse effects on hydrate formation. Specifically, the combination of nanoparticles and sepiolite promoted hydrate formation; the combination of nanoparticles and filtrate reducers showed divergent effects. Mixtures of nanoparticles with 0.2% low-viscosity anionic cellulose (LV-PAC), carboxymethyl starch (CMS), and low-viscosity carboxymethyl cellulose (LV-CMC) inhibited hydrate formation, while mixtures with 0.2% sulfonated phenolic resin (SMP-2) and hydrolyzed ammonium polyacrylonitrile (NH₄-HPAN) accelerated hydrate formation. Notably, the incorporation of nanoparticles with 0.3% guar gum, sesbania gum, high-viscosity carboxymethyl cellulose (HV-CMC), or high-viscosity polyanionic cellulose (HV-PAC) resulted in the complete inhibition of hydrate formation. By contrast, the synergistic inhibition effect of the nanoparticle/xanthan gum (XC) composite system was relatively weak, with the optimal compounding concentration determined to be 0.3%. These findings provide critical insights for the development of drilling fluid systems in natural gas hydrate reservoirs, facilitating the optimization of drilling performance and enhancing operational safety in hydrate-bearing formations. Full article

Urine, which has a high concentration of urea, can be used as a sustainable resource for nutrient recovery and sustainable energy. However, urea undergoes hydrolysis, catalyzed by urease, generating ammonia and carbon dioxide. As ammonia is released during hydrolysis in stored urine, the pH rises progressively until the pK_a of ammonium is reached (i.e., 9.3). At elevated pH levels, struvite and other related precipitates are formed. These reactions lower the efficiency of ammonia and urea nitrogen recovery and often cause scaling, pipe blockage, and odors. Herein, we explore an approach to stabilize urea, using pharmaceuticals and their metabolites that are commonly present in human urine. Based on a survey of the urease inhibitory effects of twenty-three pharmaceuticals and metabolites, we determined that the polyphenolic and disulfide-containing compounds had the highest urease inhibition efficiency. Specifically, outstanding inhibitors include catechol (CAT), hydroquinone (HYD), and disulfiram (DSF). Furthermore, when added to urine, these compounds resulted in the retardation of urease-catalyzed hydrolysis, leading to longer-term urine stabilization upon storage. Reaction mechanisms for urease inhibition by polyphenolics and disulfiram are proposed. Evidence is provided that pharmaceutical metabolites can stabilize urea and thus could lead to a sustainable method for nitrogen nutrient recovery from stored urine. Full article

Energetic complexes with multi-component architectures represent a frontier in contemporary energetic materials research. In this work, we report a novel high-energy complex—bis(5-nitro-3-(dinitromethyl)-1,2,4-triazole)-hexaamminecobalt(III) [[Co(NH₃)₆](HNTD)(NTD)·H₂O]—that is synthesized using the oxygen-rich energetic compound 5-nitro-3-(trinitromethyl)-1,2,4-triazole (HNTF) as a precursor. Compared with metallic H₂NTD salts, [Co(NH₃)₆](HNTD)(NTD)·H₂O exhibits a higher density (ρ = 1.886 g cm⁻³) and unrivaled energy properties (V_d = 8030 m s⁻¹ and P = 29.2 GPa). The formation of a dense hydrogen-bonding network—mediated by ammonium groups in the [Co(NH₃)₆]³⁺ core and nitro groups of HNTD⁻ and NTD²⁻—significantly dampens the mechanical sensitivity (IS = 10 J and FS = 140 N). These combined attributes establish [Co(NH₃)₆](HNTD)(NTD)·H₂O as a promising high-energy-density material (HEDM), offering critical insights for the design of next-generation energetic complexes. Full article

Current tomato harvesters rely primarily on external color as the sole indicator of ripeness. However, this approach often results in premature harvesting, leading to insufficient lycopene accumulation and a suboptimal nutritional content for human consumption. Such limitations are especially critical in controlled-environment agriculture (CEA) systems, where maximizing fruit quality and nutrient density is essential for both the yield and consumer health. To address that challenge, this study introduces a novel, multimodal harvest readiness framework tailored to nutrient film technology (NFT)-based smart farms. The proposed approach integrates plant-level stress diagnostics and fruit-level phenotyping using wearable biosensors, AI-assisted computer vision, and non-invasive physiological sensing. Key physiological markers—including the volatile organic compound (VOC) methanol, phytohormones salicylic acid (SA) and indole-3-acetic acid (IAA), and nutrients nitrate and ammonium concentrations—are combined with phenomic traits such as fruit color (a*), size, chlorophyll index (rGb), and water status. The innovation lies in a four-stage decision-making pipeline that filters physiologically stressed plants before selecting ripened fruits based on internal and external quality indicators. Experimental validation across four plant conditions (control, water-stressed, light-stressed, and wounded) demonstrated the efficacy of VOC and hormone sensors in identifying optimal harvest candidates. Additionally, the integration of low-cost electrochemical ion sensors provides scalable nutrient monitoring within NFT systems. This research delivers a robust, sensor-driven framework for autonomous, data-informed harvesting decisions in smart indoor agriculture. By fusing real-time physiological feedback with AI-enhanced phenotyping, the system advances precision harvest timing, improves fruit nutritional quality, and sets the foundation for resilient, feedback-controlled farming platforms suited to meeting global food security and sustainability demands. Full article

Nitrogen deposition is a critical driver of plant-soil interactions in forest ecosystems. However, the species-specific coordination of nitrogen uptake and carbon assimilation—traced using ¹⁵N- and ¹³C-labeled compounds—under varying nitrogen forms, depths, and time points remains poorly understood. We conducted a dual-isotope (¹⁵NH₄Cl, K¹⁵NO₃, and Na₂¹³CO₃) labeling experiment in a temperate secondary forest to investigate nutrient uptake and carbon assimilation in three understory species—Carex siderosticta, Maianthemum bifolium, and Oxalis acetosella—across three nitrogen treatments (control, low N, and high N), two soil depths (0–5 cm and 5–15 cm), and two post-labeling time points (24 h and 72 h). We quantified ¹⁵N uptake and ¹³C assimilation in above- and belowground plant tissues, as well as ¹⁵N and ¹³C retention in soils. C. siderosticta exhibited the highest total ¹⁵N uptake (2.2–6.9 μg N m⁻² aboveground; 1.4–4.1 μg N m⁻² belowground) and ¹³C assimilation (58.4–111.2 mg C m⁻² aboveground; 17.6–39.2 mg C m⁻² belowground) under high ammonium at 72 h. High nitrogen input significantly enhanced the coupling between plant biomass and nutrient assimilation (R² > 0.9), and increased ¹⁵N-TN and ¹³C-SOC retention in the surface soil layer (13,200–17,400 μg N kg⁻¹; 30,000–44,000 μg C kg⁻¹). Multifactorial analysis revealed significant interactions among nitrogen treatment, form, depth, and time. These findings demonstrate that ammonium-based enrichment promotes nutrient acquisition and carbon assimilation in responsive species and enhances surface soil C—N retention, highlighting the integrative effects of nitrogen form, species traits, and spatial–temporal dynamics on forest biogeochemistry. Full article

In this study, a one-pot, ultrasonic-assisted solvothermal method was successfully employed to prepare three copper-containing compounds: copper benzene-1,3,5-tricarboxylate (Cu₃(BTC)₂), copper powder, and copper-metalized activated carbon (Cu@AC). This method is efficient and safe and has potential for use in scalable production. The characteristics of the resulting products were analyzed using various techniques, including X-ray diffraction (XRD), scanning electron microscopy (SEM), specific surface area measurement along with pore size distribution, and thermogravimetric analysis–differential scanning calorimetry (TG-DSC). Additionally, the catalytic effects of these products on the thermal decomposition of ammonium perchlorate (AP) were evaluated. All three substances were found to lower the thermal decomposition temperature of AP and enhance heat release. Cu₃(BTC)₂ demonstrated exceptional catalytic performance and compatibility with AP, as shown using the vacuum stability test (VST). The thermal analysis results indicated that the thermal decomposition temperature and apparent activation energy of AP decreased from ~442 °C to around 340 °C and from ~207 kJ mol⁻¹ to approximately 128 kJ mol⁻¹, respectively, when 3 wt% Cu₃(BTC)₂ was contained in AP. Moreover, the heat released via the exothermic decomposition of AP increased from 740 J g⁻¹ to1716 J g⁻¹. A possible reaction mechanism is proposed based on the evolved gas analysis (EGA) findings to explain the observed catalytic effects. Full article

Pangong Tso, a typical plateau lake exhibiting an east-to-west gradient from freshwater to saline conditions, was used to simulate the migration and transformation of nitrogen compounds under different salinity conditions. This study systematically investigates the effects of salinity on nitrogen cycling and transformation in Pangong Tso sediments from 12 sites through controlled laboratory experiments and field monitoring across 120 sites. The data analysis method includes correlation analysis, ANOVA, structural equation modeling (SEM), and mixed-effects modeling (MEM). The results demonstrate that salinity significantly affects nitrogen cycling in plateau lakes. Salinity inhibits nitrification, resulting in an accumulation of ammonium nitrogen (NH₄⁺-N), while simultaneously suppressing gaseous nitrogen emissions through the inhibition of denitrification. Salinity has a significant negative effect on nitrite nitrogen (NO₂⁻-N), which is attributable to enhanced redox-driven transformations under hypersaline conditions. A salinity threshold of approximately 9‰ was identified, above which nitrite oxidation was strongly inhibited, consistent with the known high salinity sensitivity of nitrite-oxidizing bacteria (NOB). Higher salinity levels correlated positively with increased NH₄⁺-N and total nitrogen (TN) concentrations in overlying water (p < 0.01), and were further supported by observed increases in dissolved organic nitrogen (DON) and dissolved total nitrogen (DTN) along with rising salinity, and vice versa. Full article

Investigations of the synthesis of multicomponent coatings and their subsequent application to metal substrates to increase the wear resistance of materials is relevant for industry. Nickel compounds obtained from oxidized magnesia-iron nickel ores with a desorption rate of more than 94% were used to create Ni-MoO₃-WO₃ electroplating. Such composite samples formed from an aqueous alcohol solution reduced the content of sodium and ammonium chlorides. The annealing and dehydration of samples at a temperature of 725 °C in an air atmosphere made it possible to achieve the highest level of crystallinity. In this case, an isomorphic substitution of W atoms by Mo occurs, which is confirmed by electron paramagnetic resonance (EPR) spectroscopy studies. The invariance of the shape of the EPR spectrum with a sequential increase in microwave radiation power revealed the stability of the bonds between the particles. The surface morphology of Ni-MoO₃-WO₃ films deposited on an Al substrate is smooth and has low roughness. In this case, an increased degree of wear resistance has been achieved. Thus, a recipe for the formation of an electroplating with stable bonds between the components and increased wear resistance was obtained. Full article

The transition to renewable energy makes energy storage crucial. Aqueous organic redox flow batteries (AORFBs) show great potential in large-scale energy storage due to their outstanding safety compared to conventional systems. Derivatives of 2,2,6,6-tetramethylpiperidin-1-oxyl (TEMPO) show significant promise as catholyte materials in AORFBs. In this work, a bipyridine-ester dual-modified TEMPO derivative, (2,2,6,6-tetramethyl-1-piperidinyloxy)carbonyl-ethyl-(4-(pyridin-4-yl)benzyl) ammonium bromide (TEMP-BPy) was successfully synthesized via a two-step functionalization. The synthesized compound was experimentally confirmed to possess excellent electrochemical stability. The electron-withdrawing effect of the 4,4′-bipyridine moiety elevates the redox potential by 60 mV. When implemented as a catholyte paired with methyl viologen (MV) as the anolyte in AORFB, the TEMP-BPy/MV system demonstrates excellent performance: achieving a cell voltage of 1.28 V and an energy density of 14.5 Wh L⁻¹ at a 0.6 M (16.08 Ah L⁻¹) concentration with 71.3% material utilization. Notably, it demonstrates exceptional cycling stability with an average capacity retention of 99.86% per cycle over 200 cycles, and it exhibits particularly impressive initial stability, with an average capacity retention of 99.997% per cycle during the first 100 cycles. Full article