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Vanadium is a strategic metal that has many important industrial applications and is generated by the use of burning fossil fuels, which inevitably leads to their release into the environment, mainly in the form of oxides. The wastes generated by their use represent a major health hazard. Furthermore, it has attracted attention because several genotoxicity studies have shown that some vanadium compounds can affect DNA; among the most studied compounds is vanadium pentoxide, but studies in vivo with oxidation states IV and III are scarce and controversial. In this study, the genotoxic and cytotoxic potential of vanadium oxides was investigated in mouse bone marrow cells using structural chromosomal aberration (SCA) and mitotic index (MI) test systems. Three groups were administered vanadium(IV) tetraoxide (V2O4) intraperitoneally at 4.7, 9.4 or 18.8 mg/kg, and three groups were administered vanadium(III) trioxide (V2O3) at 4.22, 8.46 or 16.93 mg/kg body weight. The control group was treated with sterile water, and the positive control group was treated with cadmium(II) chloride (CdCl2). After 24 h, all doses of vanadium compounds increased the percentage of cells with SCA and decreased the MI. Our results demonstrated that under the present experimental conditions and doses, treatment with V2O4 and V2O3 induces chromosomal aberrations and alters cell division in the bone marrow of mice. [ABSTRACT FROM AUTHOR]

A series of mesoporous ceria-supported vanadium oxide catalysts were prepared and explored for aerobic oxidation of ethylbenzene to acetophenone without the involvement of any solvent or additive. Catalysts with varying contents of V2O5 (3, 6, and 10 wt%) on a mesoporous CeO2 support were prepared by the wet-impregnation method. Catalysts were characterized using techniques namely, XRD, Raman spectroscopy, BET surface area analysis, ICP-OES, FE-SEM, HR-TEM, XPS, and H2-TPR to establish a correlation between the physicochemical properties and catalytic performance. Among the investigated catalysts, the catalyst with 6 wt% of V2O5 on mesoporous ceria showed better activity with 69% ethylbenzene conversion and 88% acetophenone selectivity. The superior activity of this catalyst was ascribed to a strong synergetic interaction between ceria and vanadia as well as the formation of a CeVO4 phase, and a high specific surface area. The reaction parameters like temperature, pressure, and the amount of catalyst were optimized for possible commercial utilization. The stability of the catalyst was also investigated by the reusability test and was found to be stable and active up to five cycles. [ABSTRACT FROM AUTHOR]

Selective oxidation of benzyl alcohol under atmospheric oxygen is a sustainable route for the synthesis of benzaldehyde. The development of low-cost metal catalysts is a challenging research topic. Herein, supported vanadia catalysts on carbon nitride were prepared using vanadyl acetylacetonate as a precursor through a wet-impregnation method. The synthesized VO/eg-C3N4 were characterized by N2 adsorption–desorption, TG, XRD, FT-IR, XPS, UV–Vis, SEM, and O2-TPD. The eg-C3N4 material could disperse the vanadia species, and the distributions of vanadium cations (V5+/V4+) were largely dependent on the preparation temperature. In the selective oxidation of benzyl alcohol under atmospheric oxygen, the catalysts showed moderate catalytic activity. Under identical reaction conditions, the activity of VO/eg-C3N4 was higher than vanadia catalysts supported on SBA-15 and CNTs materials. [ABSTRACT FROM AUTHOR]

This study delves into an in-depth examination of the biomechanical characteristics of various materials commonly utilized in the fabrication of artificial ankle joints. Specifically, this research focuses on the design of an ankle joint resembling the salto-talaris type, aiming to comprehensively understand its performance under different loading conditions. Employing advanced finite element analysis techniques, this investigation rigorously evaluates the stresses and displacements experienced by the designed ankle joint when subjected to varying loads. Furthermore, this study endeavors to identify the vibrating frequencies associated with these displacements, offering valuable insights into the dynamic behavior of the ankle joint. Notably, the analysis extends to studying random frequencies across three axes of motion, enabling a comprehensive assessment of directional deformities that may arise during joint function. To validate the effectiveness of the proposed design, a comparative analysis is conducted against the star ankle design, a widely recognized benchmark in ankle joint prosthetics. This comparative approach serves dual purposes: confirming the accuracy of the findings derived from the salto-talaris design and elucidating the relative efficacy of the proposed design in practical application scenarios. [ABSTRACT FROM AUTHOR]

In this study investigation of accumulations of critical raw materials (cobalt (Co), antimony (Sb), vanadium (V), lanthanum (La) and tungsten (W)) from wastewater by using C. fracta were aimed. Besides, assessment of the potential health risks in terms of the use of organic fertilizer obtained from the macroalga to be harvested from the treatment were also aimed. Highest Co, Sb, V, La and W accumulations by algae in reactor were 125±6.2%, 201.25±10%, 318.18±15%, 357.97±18%, and 500±25%, respectively. When compared with control, Co, Sb, V, La and W in algae increased 2.25, 3.01, 4.18, 4.58, and 6 times, respectively. The algae was very high bioaccumulative for Co and La. Highest MPI was calculated as 3.94. Non-carcinogenic risk of CRMs according to different exposure types (ingestion, inhalation, and dermal) were calculated for man, woman and child. There is not any non-carcinogenic risk from the investigated exposure ways of algae as organic fertilizer. [ABSTRACT FROM AUTHOR]

Oxidovanadium(V) complex [VVO{Hen(3,5-dcp)4}] (where H4en(3,5-dcp)4, is a Mannich base synthesized from ethylenediamine, paraformaldehyde and 2,4-dichlorophenol) has been anchored onto chloromethylated polystyrene (PS–Cl) cross-linked with divinylbenzene to obtain [VVO{en(3,5-dcp)4}]@PS (@ refers to anchoring of complex onto polymer), a heterogeneous compound. Both of the synthesized (homogeneous as well as heterogeneous) vanadium compounds, after characterization, have been explored as biomimicking model catalysts for the type II copper site in phenoxazinone synthase. These compounds catalyze the oxidative condensation of o-aminophenol (OAP) into 2-aminophenoxazine-3-one (APX) by utilizing aqueous hydrogen peroxide in acetonitrile. Various reaction conditions like amounts of catalyst and oxidant, and temperature have been optimized to obtain maximum yield of APX. The polymer-immobilized complex demonstrates excellent catalytic activity, giving 96% yield of 2-aminophenoxazine-3-one under the optimized reaction conditions selectively. Its homogeneous analogue i.e. [VVO{Hen(3,5-dcp)4}], is also active and exhibits 83% yield. The heterogeneous catalyst i.e. [VVO{en(3,5-dcp)4}]@PS is stable, recyclable and reusable. [ABSTRACT FROM AUTHOR]

• TiO 2 /V 2 O 5 and commercial V-based catalysts possess the V-O-Ti interface sites. • The energy of NH 3 activation on V-O-Ti interface sites is much lower than V=O sites. • V-O-Ti interface sites can promote the water resistance of V-based catalysts. • The V-O-Ti entities together with adjacent Ti sites are active for NH 4 + activation. • V-O-Ti entities on V-based catalysts play a crucial role under realistic NH 3 -SCR conditions. TiO 2 -supported V 2 O 5 catalysts are commonly used in NO x reduction with ammonia due to their robust catalytic performance. Over these catalysts, it is generally considered that the active species are mainly derived from the vanadia species rather than the intrinsic structure of V-O-Ti entities, namely the interface sites. To reveal the role of V-O-Ti entities in NH 3 -SCR, herein, we prepared TiO 2 /V 2 O 5 catalysts and demonstrated that V-O-Ti entities were more active for NO x reduction under wet conditions than the V sites (V=O) working alone. On the V-O-Ti entities, kinetic measurements and first principles calculations revealed that NH 3 activation exhibited a much lower energy barrier than that on V=O sites. Under wet conditions, the V-O-Ti interface significantly inhibited the transformation of V=O to V-OH sites thus benefiting NH 3 activation. Under wet conditions, meanwhile, the migration of NH 4 + from Ti site neighboring the V-O-Ti interface to Ti site of the V-O-Ti interface was exothermic; thus, V-O-Ti entities together with neighboring Ti sites could serve as channels linking NH 3 pool and active centers for activation of NH 4 +. This finding reveals that the V-O-Ti interface sites on V-based catalysts play a crucial role in NO x removal under realistic conditions, providing a new perspective on NH 3 -SCR mechanism. [Display omitted] [ABSTRACT FROM AUTHOR]

Repurposing drugs by uncovering new indications for approved drugs accelerates the process of establishing new treatments and reduces the high costs of drug discovery and development. Metal complexes with clinically approved drugs allow further opportunities in cancer therapy—many vanadium compounds have previously shown antitumor effects, which makes vanadium a suitable metal to complex with therapeutic drugs, potentially improving their efficacy in cancer treatment. In this review, covering the last 25 years of research in the field, we identified non-oncology-approved drugs suitable as ligands to obtain different vanadium complexes. Metformin-decavanadate, vanadium-bisphosphonates, vanadyl(IV) complexes with non-steroidal anti-inflammatory drugs, and cetirizine and imidazole-based oxidovanadium(IV) complexes, each has a parent drug known to have different medicinal properties and therapeutic indications, and all showed potential as novel anticancer treatments. Nevertheless, the precise mechanisms of action for these vanadium compounds against cancer are still not fully understood. [ABSTRACT FROM AUTHOR]

Vietnamese ginseng (Panax vietnamensis Ha & Grushv.) is one of the most precious herbs in Vietnam because it contains many valuable bioactive compounds, especially ginsenosides. The protopanaxadiol synthase (PPDS) and protopanaxatriol synthase (PPTS) are considered the key enzymes for the ginsenoside biosynthesis pathway in Panax species. This study is the first report on the PPDS and PPTS genes and their enzymes in Vietnamese ginseng (named PvH_PPDS and PvH_PPTS, respectively). Two PvH_PPDS and PvH_PPTS genes contain 345 aa and 736 aa, respectively, with a common structure of 3 exons and 2 introns. The domain CYP450, which is conserved and essential for catalytic activity in the cytochrome P450 family, was detected in both of these genes. Their 3D protein structures were homology-modeled and annotated by bioinformatics tools. The phylogenetic tree shows that the PvH_PPDS and PvH_PPTS genes differ in their level of similarity with the corresponding genes of other Panax species. The elicitation of vanadium compounds improved the expression level of PvH_PPDS and PvH_PPTS genes as well as the accumulation of dammarane-type major ginsenosides in adventitious roots of Vietnamese ginseng. The present work is the first attempt to further understand two key enzymes in the biosynthesis of ginsenosides in this medicinal herb [ABSTRACT FROM AUTHOR]

Monolayer transition metal dichalcogenides, specifically H-phase vanadium disulfide (VS2), hold great significance as fundamental components for next-generation low-dimensional spintronic, optoelectronic, and future electronic devices. They also offer an opportunity to explore the intrinsic magnetic properties associated with monolayer H-phase VS2 crystals at room temperature. However, there have been limited experimental studies on synthesizing pure monolayer H-phase VS2 crystals using sodium metavanadate (NaVO3) and sulfur (S) as precursors for vanadium (V) and S, respectively. In this study, we present a facile atmospheric pressure chemical vapor deposition (APCVD) approach for the synthesizing monolayer H-phase VS2 crystals with a thickness of ∼0.7 nm. The lateral dimensions of monolayer VS2 crystals extends up to ∼26 µm. Additionally, we have modulated the growth parameters, such as the temperature of NaVO3 and the Ar gas flow rate, to obtain VS2 flakes with different sizes and morphologies. This significant advancement paves the way for the synthesis of monolayer H-phase VS2 crystals on SiO2/Si substrates using the APCVD technique. [ABSTRACT FROM AUTHOR]

Vanadium dioxide (VO2) and many binary compounds of vanadium can transform from a semiconducting state to a metallic state under the influence of temperature or light. The transformation is triggered by modifications in the oxide's crystalline structure, often initiated by changes in its light-sensing and electrical attributes. This ability makes them suitable for smart coatings, electronic switches, self-cleaning surfaces, window glass, and many more. These potential applications have prompted tremendous interest in VO2thin films, focusing on their fabrication and application. This article reviews current fabrication methods for VO2thin films, the potential application of their thermochromic and photochromic properties in self-cleaning coatings, the challenges facing their application, and some remedies devised to address the challenges. The various challenges facing its different synthesis and fabrication methods are also highlighted. First, the different transitional phases of VO2and routes to transform from one stage to the other are presented. [ABSTRACT FROM AUTHOR]

Over the last four decades, vanadium compounds have been extensively studied as potential antidiabetic drugs. With the present review, we aim at presenting a general overview of the most promising compounds and the main results obtained with in vivo studies, reported from 1899–2023. The chemistry of vanadium is explored, discussing the importance of the structure and biochemistry of vanadate and the impact of its similarity with phosphate on the antidiabetic effect. The spectroscopic characterization of vanadium compounds is discussed, particularly magnetic resonance methodologies, emphasizing its relevance for understanding species activity, speciation, and interaction with biological membranes. Finally, the most relevant studies regarding the use of vanadium compounds to treat diabetes are summarized, considering both animal models and human clinical trials. An overview of the main hypotheses explaining the biological activity of these compounds is presented, particularly the most accepted pathway involving vanadium interaction with phosphatase and kinase enzymes involved in the insulin signaling cascade. From our point of view, the major discoveries regarding the pharmacological action of this family of compounds are not yet fully understood. Thus, we still believe that vanadium presents the potential to help in metabolic control and the clinical management of diabetes, either as an insulin-like drug or as an insulin adjuvant. We look forward to the next forty years of research in this field, aiming to discover a vanadium compound with the desired therapeutic properties. [ABSTRACT FROM AUTHOR]

Thin films of superconducting V 3 Si were prepared by means of RF sputtering from a compound V 3 Si target at room temperature onto sapphire and oxide-coated silicon wafers, followed by rapid thermal processing under secondary vacuum. The superconducting properties of the films thus produced are found to improve with annealing temperature, which is ascribed to a reduction in defects in the polycrystalline layer. Critical temperatures (T c ) up to 15.3 K were demonstrated after thermal processing, compared to less than 1 K after deposition. The T c was always found to be lower on the silicon wafers, by on average 1.9 ± 0.3 K for the annealed samples. This difference, as well as a broadening of the superconducting transitions, is nearly independent of the annealing conditions. In situ XRD measurements reveal that the silicide layer becomes strained upon heating due to a mismatch between the thermal expansion of the substrate and that of V 3 Si. Taking into account the volume reduction due to crystallization, this mismatch is initially larger on sapphire, though stress relaxation allows the silicide layer to be in a relatively unstrained state after cooling. On oxidized silicon, however, no clear evidence of relaxation upon cooling is observed, and V 3 Si ends up with an out-of-plane strain of 0.3% at room temperature. This strain increases as the sample is cooled down to cryogenic temperatures, though the deformation of the polycrystalline layer is expected to be highly inhomogeneous. Taking into account also the reported occurrence of a Martensitic transition just above the critical temperature, this extrapolated strain distribution is found to closely match an existing model of the strain dependence of A-15 superconducting compounds. [ABSTRACT FROM AUTHOR]

Background and Aim: Insulin resistance is a metabolic disorder marked by insufficient tissue response to insulin secretion and hyperinsulinemia. This metabolic abnormality plays a crucial role in the pathogenesis of many diseases. It appears that changes in lifestyle, such as participating in exercise activity and consumption of non-medicinal supplements, will ameliorate this condition; therefore, the present study aims to investigate the effects of aerobic exercise and vanadium-zinc supplementation on body composition, lipid profile, and insulin resistance index in fructose-fed rats. Methods: In this experimental study, 56 male wistar rats were randomly assigned to one of seven groups (eight rats per group); 1) Normal control (NC), 2) Fructose control (FC), 3) Fructose + Moderate-intensity continuous training (FIT), 4) Fructose + High-intensity interval training (FCT), 5) Vanadium-zinc supplement (FS), 6) Moderate-intensity continuous training + Vanadium-zinc supplement (FSIT), and 7) High-intensity interval training + Vanadium-zinc supplement (FSCT). The protocol of moderate intensity continuous training consisted of running for 12 to 54 min at a velocity of 12 to 20 m/min on a motorized treadmill with a 5% to 15% incline (weeks 1 to 8); also High-intensity interval training performed 3 min bouts at 40 m/min, interspersed by 3 min active recovery at a running velocity of 20 m/min on a motorized treadmill with a 5% to 15% incline. Supplement groups received 10 mg/kg/day of vanadium-zinc through oral gavage. Body composition and serum levels of lipid profile, glucose, insulin, and HOMA-IR index were measured before and 48 hours after the final session of the training program in a fast state. Results: Eight weeks of aerobic exercise and vanadium-zinc supplementation significantly improved body composition (P = 0.0001), insulin resistance (P = 0.0001), and lipid profile indices (P≤0.05). Aerobic exercise combined with vanadium-zinc supplementation has the most significant impact on the modulation of serum insulin resistance, lipid profile, and, inguinal and retroperitoneal fat tissue (P≤0.05). Conclusion: Findings suggest that vanadium-zinc supplementation combined with aerobic exercise can be effective in improving metabolic conditions and body composition. [ABSTRACT FROM AUTHOR]

Vanadium based compounds are promising cathode materials for aqueous zinc (Zn)‐ion batteries (AZIBs) due to their high specific capacity. However, the narrow interlayer spacing, low intrinsic conductivity and the vanadium dissolution still restrict their further application. Herein, we present an oxygen‐deficient vanadate pillared by carbon nitride (C3N4) as the cathode for AZIBs through a facile self‐engaged hydrothermal strategy. Of note, C3N4 nanosheets can act as both the nitrogen source and pre‐intercalation species to transform the orthorhombic V2O5 into layered NH4V4O10 with expanded interlayer spacing. Owing to the pillared structure and abundant oxygen vacancies, both the Zn2+ ion (de)intercalation kinetics and the ionic conductivity in the NH4V4O10 cathode are promoted. As a result, the NH4V4O10 cathode delivers exceptional Zn‐ion storage ability with a high specific capacity of about 370 mAh g−1 at 0.5 A g−1, a high‐rate capability of 194.7 mAh g−1 at 20 A g−1 and a stable cycling performance of 10 000 cycles. [ABSTRACT FROM AUTHOR]

The structural and configurational characteristics of the species comprising the (VOx)n phase dispersed on TiO2(P25) are studied under oxidative dehydration conditions by in situ molecular vibrational spectroscopy (Raman, FTIR) complemented by in situ Raman/18O isotope exchange and Raman spectroscopy under static equilibrium at temperatures of 175–430 °C and coverages in the 0.40–5.5 V nm−2 range. It is found that the dispersed (VOx)n phase consists of distinct species with different configurations. At low coverages of 0.40 and 0.74 V nm−2, isolated (monomeric) species prevail. Two distinct mono-oxo species are found: (i) a majority Species-I, presumably of distorted tetrahedral O＝V(–O–)3 configuration with V＝O mode at 1022–1024 cm−1 and (ii) a minority Species-II, presumably of distorted octahedral-like O＝V(–O–)4 configuration with V＝O mode at 1013–1014 cm−1. Cycling the catalysts in the 430 → 250 → 175 → 430 °C sequence results in temperature-dependent structural transformations. With decreasing temperature, a Species-II → Species-I transformation with concomitant surface hydroxylation takes place by means of a hydrolysis mechanism mediated by water molecules retained by the surface. A third species (Species-III, presumably of di-oxo configuration with νs/νas at ∼995/985 cm−1) occurs in minority and its presence is increased when further lowering the temperature according to a Species-I → Species-III hydrolysis step. Species-II (O＝V(–O–)4) shows the highest reactivity to water. For coverages above 1 V nm−2, an association of VOx units takes place leading to gradually larger polymeric domains when the coverage is increased in the 1.1–5.5 V nm−2 range. Polymeric (VOx)n domains comprise building units that maintain the structural characteristics (termination configuration and V coordination number) of Species-I, Species-II, and Species-III. The terminal V＝O stretching modes are blue-shifted with increasing (VOx)n domain size. A lower extent of hydroxylation is evidenced under static equilibrium forced dehydrated conditions, thereby limiting the temperature dependent structural transformations and excluding the possibility of incoming water vapors as the cause for the temperature dependent effects observed in the in situ Raman/FTIR spectra. The results address open issues and offer new insight in the structural studies of VOx/TiO2 catalysts. [ABSTRACT FROM AUTHOR]

Fully oxidation roasting of vanadium slag are industrial methods to recover V(V) from vanadium slag, and discharges residue and wastewater containing highly toxic V(V) and Cr(VI). To avoid this, an environmentally friendly strategy for the direct recovery of low valence vanadium (LVV) from vanadium slag produced by selective oxidation roasting and self-pressure leaching was proposed, and the leaching process of the selective oxidation roasted slag was investigated in this study. It was found LVV recovery to be 68.38% in atmospheric leaching, and the structure of the vanadium slag particles was not completely broken down during the roasting process. In addition, the solubility of the newly formed vanadium compounds was low. When enhanced the leaching process by employing high-temperature self-pressure leaching conditions, 98.34% of the vanadium was recovered as VO2+ ion in solution accounting for 100%. In addition, silicon and titanium were enriched in the leaching residue, realizing the effective separation of vanadium and titanium in the leaching stage. Finally, the VOSO 4 electrolyte will be obtained with sufficient purity for use in batteries via solvent extraction. This process provides a novel approach for the comprehensive utilization of vanadium slag that directly recovers VOSO 4 -containing leaching solution from slag rather than oxidizing V(III) to V(V) then reduces to LVV. [ABSTRACT FROM AUTHOR]

This work reports the effect of tin (Sn) doping on the infrared (IR) and terahertz (THz) properties of vanadium dioxide (VO 2 ) films. The films were grown by hydrothermal synthesis with a post-annealing process and then fully characterized by X-ray diffraction (XRD), Raman spectroscopy, scanning electron microscopy (SEM), and temperature-controlled electrical resistivity as well as IR and THz spectroscopy techniques. Utilizing (NH 4 ) 2 SnF 6 as a Sn precursor allows the preparation of homogeneous Sn-doped VO 2 films. Doping of VO 2 films with Sn led to an increase in the thermal hysteresis width while conserving the high modulation depth in the mid-IR regime, which would be beneficial for the applications of VO 2 films in IR memory devices. A further analysis shows that Sn doping of VO 2 films significantly affects the temperature-dependent THz optical properties, in particular leading to the suppression of the temperature-driven THz transmission modulation. These results indicate Sn-doped VO 2 films as a promising material for the development of switchable IR/THz dichroic components. [ABSTRACT FROM AUTHOR]

Due to the formation of abundant hydroxyl groups on the TiO2 support, water in the ball-milling process promoted the dispersion of vanadia species on V2O5/TiO2 catalysts. Therefore, a high ratio of polymeric vanadyl species and strong redox capability were obtained for the vanadia-based catalyst, which led to good NH3-SCR activity. [ABSTRACT FROM AUTHOR]

Fluorescence spectroscopic studies of a pair of new oxido‐vanadium(V) compounds with biological thiols, such as homocysteine (Hcy), cysteine (Cys), and glutathione (GSH), have been investigated in this article. Despite notable progress in vanadium‐thiol chemistry, no attention has been paid to exploring vanadium‐based optical probes to study their interaction with biothiols. For this purpose, two oxido‐vanadium(V) compounds, 1 and 2, have been prepared involving a tridentate ONO donor‐based luminescent coumarin‐derived ligand. Single crystal X‐ray diffraction analysis, NMR (1H, 13C, and 51V) spectroscopy, XPS, and DFT calculations have been used to establish their identities. The vanadium center in these compounds has a distorted octahedral environment. In compound 2, a methanol molecule is coordinated to the vanadium(V) center in the trans position of the terminal oxido moiety. The latter exerts a strong trans‐labilizing influence on the coordinating methanol. Both 1 and 2 are weakly fluorescent. Photophysical investigations of the vanadium complexes in aqueous media at physiological pH (7.4) in the presence of various biothiols and amino acids showed significant fluorescence enhancement (83‐fold) of the vanadium complexes, specifically with Hcy. The specific affinity of the complexes for Hcy remained unchanged even in the presence of other biothiols and amino acids. Kinetic investigation reveals pseudo‐first order behavior of the compound with Hcy. Mechanistic studies have manifested that Hcy‐induced reduction triggers the decomplexation of the vanadium compound, followed by hydrolysis and subsequent cyclization. Time‐correlated single photon counting suggested that the radiative rate constant (kr) of 1 and 2 in the presence of Hcy serves as the prime factor for the fluorescence enhancement of the medium. Compound 1 has been tested efficiently for Hcy measurement in blood plasma rendering it suitable for practical applications. [ABSTRACT FROM AUTHOR]

Novel alumina-based materials enriched with vanadia and lanthana were successfully synthesized via in situ modification using a mechanochemical method, and were applied in ammonia-induced selective catalytic reduction of nitrogen oxides (SCR process). The synthesis was optimized in terms of the ball milling time (3 or 5 h), vanadium content (0.5, 1 or 2 wt% in the final product), and lanthanum content (0.5 or 1 wt% in the final product). Vanadium (V) oxide was immobilized on an alumina support to provide catalytic activity, while lanthana was introduced to increase the affinity of nitrogen oxides and create more active adsorption sites. Mechanochemical synthesis successfully produced mesoporous materials with a large specific surface area of 279–337 m2/g and a wide electrokinetic potential range from 60 to (− 40) mV. Catalytic tests showed that the incorporation of vanadia resulted in a very large improvement in catalytic performance compared with pristine alumina, increasing its efficiency from 14 to 63% at 400 °C. The best SCR performance, a 75% nitrogen oxide conversion rate at a temperature of 450 °C, was obtained for alumina enriched with 2 and 0.5 wt% of vanadium and lanthanum, respectively, which may be considered as a promising result. [ABSTRACT FROM AUTHOR]

Vanadium is a hard, silver-grey transition metal found in at least 60 minerals and fossil fuel deposits. Its oxide and other vanadium salts are toxic to humans, but the toxic effects depend on the vanadium form, dose, exposure duration, and route of intoxication. Vanadium is used by some life forms as an active center in enzymes, such as the vanadium bromoperoxidase of ocean algae and nitrogenases of bacteria. The structure and biochemistry of vanadate resemble those of phosphate, hence vanadate can be regarded as a phosphate competitor in a variety of biochemical enzymes such as kinases and phosphatases. In this review, we describe the biochemical pathways regulated by vanadium compounds and their potential therapeutic benefits for a range of disorders including type 2 diabetes, cancer, cardiovascular disease, and microbial pathology. [ABSTRACT FROM AUTHOR]

The results of the processing of ash from the combustion of fuel oil after roasting with the addition of Na2CO3 followed by aluminothermic melting are presented. As a result, metallic nickel and vanadium slag were obtained. Studies of slag, metal, and deposits on the electrode were carried out. The resulting metal contains about 90 wt% Ni. The main phases of scurf on the electrode are a solid solution based on periclase (Mg1–x–y–zNixFeyVzO), sodium-magnesium vanadate (NaMg4(VO4)3), and substituted forsterite (Mg2–x–yFexNiySiO4). The processing of ash made it possible to significantly increase the concentration of vanadium and convert it into more soluble compounds. Vanadium amount increased from 16.2 in ash to 41.4–48.1 V2O5 wt% in slag. The solubility of vanadium was studied during aqueous leaching and in solutions of H2SO4 and Na2CO3. The highest solubility of vanadium was seen in H2SO4 solutions. The degree of extraction of vanadium into the solution during sulfuric acid leaching of ash was 18.9%. In slag, this figure increased to 72.3–96.2%. In the ash sample, vanadium was found in the form of V5+, V4+ compounds, vanadium oxides VO2 (V4+), V2O5 (V5+), and V6O13, and nickel orthovanadate Ni3(VO4)2 (V5+) was found in it. In the slag sample, vanadium was in the form of compounds V5+, V4+, V3+, and V(0÷3)+; V5+ was presented in the form of compounds vanadate NaMg4(VO4)3, NaVO3, and CaxMgyNaz(VO4)6; V3+ was present in spinel (FeV2O4) and substituted karelianite (V2–x–y–zFexAlyCrzO3). In the obtained slag samples, soluble forms of vanadium are due to the presence of sodium metavanadate (NaVO3), a phase with the structure of granate CaxMgyNaz(VO4)6 and (possibly) substituted karelianite (V2–x–y–zFexAlyCrzO3). In addition, spinel phases of the MgAl2O4 type beta-alumina (NaAl11O17), nepheline (Na4–xKxAl4Si4O16), and lepidocrocite (FeOOH) were found in the slag samples. [ABSTRACT FROM AUTHOR]

Two sodium vanadium phosphates, synthetic analogues of the minerals kosnarite, Na3V2(PO4)3, and yurmarinite, Na7V4(PO4)6, were obtained by hydrothermal synthesis simulating a natural hydrothermal solution. While the Na3V2(PO4)3 phase belongs to the NASICON family and is well-known for its high-ionic conductivity, the new Na7V4(PO4)6 compound is a rare case of V2+-containing oxosalts, which are hard to prepare due to their instability in air. Here we report the crystal structure of heterovalent vanadium phosphate studied by single crystal X-ray diffraction, XANES spectroscopy, and topological ion migration modelling. A discussion of divalent vanadium compounds of both natural and synthetic origin is also given, with a review of the methods for their synthesis and a comparative analysis of V–O bond lengths. [ABSTRACT FROM AUTHOR]

[Display omitted] • A multifunctional vanadium trap and passivator are studied in the FCC process. • 10 wt% of barium titanate is required to optimize vanadium passivation performance. • Key features for selecting an effective vanadium passivator are investigated. • Investigation of vanadium passivation through a meticulous mapping technique. • Integrated findings confirm the passivator's ability to withstand 6000 ppm of vanadium poisons. In the FCC process, vanadium is the main deleterious feedstock poison that destroys the catalyst structure by hydrolysis of the zeolite framework. Specifically, vanadium compounds, including vanadium pentoxide and sodium vanadate with low melting points, as well as vanadic acid formation, are responsible for the main destructive mechanisms. This study introduces a well-tolerant barium titanate with high efficiency for vanadium passivation of the FCC catalyst. Namely, the barium titanate properties and performance of the FCC catalyst as a metal passivator were investigated. The vanadium passivation ability was scrutinized by various techniques such as XRD, N 2 -adsorption, NH 3 -TPD, SEM, and EDS mapping. The crystalline structure and surface retention of the zeolite component in the catalyst over contamination with 6000 ppm vanadium showed 18.7 % and 12 % more preservation, respectively, following the barium titanate addition. According to the EDS mapping, vanadium was evenly distributed over the catalyst for the passivator-free sample. In contrast, the catalyst containing barium titanate exhibited a higher concentration of vanadium in the zones with a higher barium titanate content. This phenomenon was linked to the irreversible deactivation of vanadium, precisely the spots where barium titanate is present. Furthermore, the catalytic evaluation results revealed that, upon increasing the vanadium level from 3000 to 6000 ppm, the conversion value and gasoline yield decreased by 18.1 % and 7.6 %, respectively, for the passivator-free sample. In contrast, a negligible change was observed for the catalyst containing 10 % passivator, with only a 3.1 % decrease in conversion and a 0.4 % decrease in gasoline yield due to the efficient performance of barium titanate in vanadium passivation. [ABSTRACT FROM AUTHOR]

[Display omitted] • (NH 4) 2 SO 4 was used instead of liquid H 2 SO 4 to introduce SO 4 2− into V 2 O 5 /CeO 2 ; • NO x conversion is over 95 % at 225–400 °C on 2 %SO 4 2−- V 2 O 5 /CeO 2 ; • The introduction of SO 4 2− enhanced Brønsted acid sites and the formation of polymeric vanadyl species; • The NH 3 -SCR reaction over 2 %SO 4 2−-V 2 O 5 /CeO 2 followed the Langmuir-Hinshelwood and Eley-Rideal routes concurrently. Ceria-supported vanadia (VO x /CeO 2) catalyst has been extensively investigated in the field of NO x selective catalytic reduction with NH 3 (NH 3 -SCR) but is limited in practical application owing to its poor sulfur resistance and high-temperature activity. Herein, a series of SO 4 2− modified V 2 O 5 /CeO 2 catalysts were fabricated to improve the overall catalytic performance. The 2 %SO 4 2−-V 2 O 5 /CeO 2 catalyst exhibited above 95 % NO x conversion, 90 % N 2 selectivity in the temperature range of 225–400 °C and excellent SO 2 + H 2 O tolerance, which was much better than V 2 O 5 /CeO 2 catalyst. Characterization results showed that the introduction of SO 4 2− over V 2 O 5 /CeO 2 increased the Ce3+/(Ce3++ Ce4+) ratio to promote the formation of oxygen vacancies and promoted the generation of more conducive polymeric vanadyl species. The synergistic effect of the redox sites and acid centers provided moderate redox property and enhanced surface acidity, thus improving the adsorption of NH 3 and inhibiting the over-oxidation of NH 3 that occurs on V 2 O 5 /CeO 2. In-situ DRIFTS indicated that the NO x reduction over V 2 O 5 /CeO 2 and 2 %SO 4 2−-V 2 O 5 /CeO 2 followed the Langmuir-Hinshelwood and Eley-Rideal routes concurrently. This study can expound the reasonable design of vanadium-based catalysts for efficient NO x reduction in industry. [ABSTRACT FROM AUTHOR]

By combining multinuclear 1H, 29Si, 27Al and 51V solid-state NMR experimental measurements with reactivity and selectivity data, as well as first-principles calculations, for ternary bi-layered supported VO x /Al 2 O 3 /SiO 2 catalysts, the structure of the dehydrated surface vanadia species was determined for each combination of supported VO x and AlO x active components. The specific structure of the surface vanadia sites in the ternary bi-layered supported VO x /Al 2 O 3 /SiO 2 catalyst system have been investigated for the first time. The following vanadia sites are proposed based on the current findings: At low vanadia content, surface VO(OH)(OSi) 2 sites form on the alumina-free surface of the SiO 2 support in the bi-layered supported VO x /Al 2 O 3 /SiO 2 catalyst system. In addition, two types of VO(OSi) 3 surface species are likely present in this system. On small alumina clusters, weakly bonded surface VO(OH)(OAl) 2 sites also form, along with the sites containing mixed Si/Al pods VO(OH)(OAl)(OSi). As the size of alumina clusters increases, strongly bonded VO(OAl) 3 centers form, alongside the surface sites containing mixed pods VO(OAl) 2 (OSi) and VO(OAl)(OSi) 2. The content of these sites increases with the loading of vanadia. Comparing supported VO x /SiO 2 , VO x /Al 2 O 3 , and bi-layered VO x /Al 2 O 3 /SiO 2 catalyst systems revealed differences in catalytic activity due to the presence of new sites with different pods, with OH groups as well as the influence of Al-O-Si bonds on the electronic structure of surface vanadia sites on the alumina clusters. During the formation of dimethyl ether (DME), the turnover frequency (TOF DME) of the catalysts decreases with increasing domain size of the alumina clusters on SiO 2. Addition of surface VO x sites, however, slightly decreases the TOF DME with the higher vanadia content weakening the activity of the alumina clusters. When surface VO x exists predominantly as V/Al 1 and V/Al 2 , TOF redox depend on the vanadia content with lower vanadia content resulting in higher the TOF redox values. The 51V NMR spectra show that this decrease in redox TOF value correlates with the appearance of vanadia sites associated with silica pods. The activity of the catalysts was tested in methanol conversion reactions. [Display omitted] • Various VO x sites were studied in bi-layered supported VO x /AlO x /SiO 2 catalysts. • VO(OH)(OSi) 2 and VO(OSi) 3 sites are formed at low and high VO x loading on SiO 2 • VO x sites weakly and strongly bound to AlO x clusters are formed in ternary system. • Weakly bound VO(OH)(OAl) 2 and mixed pods VO(OH)(OAl)(OSi) sites have OH groups. • VO(OAl) 3 and mixed pods VO(OAl) 2 (OSi), VO(OAl)(OSi) 2 are strongly bonded sites. [ABSTRACT FROM AUTHOR]

• A novel molecular coordination compound and one known compound have beeen synthesized and they were obtained from V 2 O 5 and 2,6-pyridinedicarboxylic acid (H 2 DPA). • They were characterized by IR spectroscopy, manganometric titration, magnetic susceptibility, thermogravimetric and single crystal XRD analyses. • The single-crystal XRD analysis revealed that compound 1 was a molecular consist of four-nuclear coordination compound. • The results of antimicrobial activity show that they have an antimicrobial effect against the microorganisms P. aeruginosa, E. coli, S. aureus, E. faecalis, L. monocytogenes, B.subtilis, C. albicans. A novel molecular coordination compound, [ V 4 IV O 4 (DPA) 4 (OH 2) 4 ]∙2H 2 O, 1 , and known [VIVO(DPA)(OH 2) 2 ].2H 2 O compound, 2 , were obtained from V 2 O 5 and 2,6-pyridine dicarboxylic acid (H 2 DPA) reactions with water or ethyl alcohol by using hydro/solvothermal synthetic methods. 1 was fully characterized by IR spectroscopy, manganometric titration, magnetic susceptibility, thermogravimetric and single crystal XRD analyses. The single-crystal XRD analysis revealed that it was a molecular consist of four-nuclear coordination compound. DPA ligand in 1 acted chelating and bridging modes through carboxylate groups. Four V(IV) ions exhibit a distorted octahedral coordination geometry {VNO 5 }. 1 and 2 were investigated for antimicrobial activity. The results of antimicrobial activity show that they have an antimicrobial effect against the microorganisms P. aeruginosa, E. coli, S. aureus, E. faecalis, L. monocytogenes, B.subtilis, C. albicans. [ABSTRACT FROM AUTHOR]

Optoelectronic devices play an essential part in our daily lives by seamlessly integrating optics and electronics, leading to technologies such as smartphones, solar cells, and optical communication. In this study, the structural and optoelectronic characteristics of the hexagonal vanadium silicide are determined using the density functional theory (DFT). The structural parameters such as the zero-pressure bulk modulus B 0 , its pressure derivative B 0 ′ ; equilibrium energy, and the volume of the primitive cell at equilibrium V 0 are compared with experiment results. The metallic character of VSi 2 is confirmed by calculating the density of states and band structure. Moreover, the optical properties like the dielectric function, reflectivity, energy loss function, refractive index, absorption coefficient, and optical conductivity are studied deeply, using the Drude model, within the energy interval from 0 to 14 eV and they are compared with experiment results of a polycrystalline and single crystal. However, the phonon dispersion spectrum shows the presence of imaginary modes, which indicates instability in the structure of vanadium silicide. The results indicate that the VSi 2 material has the potential to be used in many applications, including mirrors, glass coatings, optoelectronic devices, optical networks, electronics, optical communications, and waveguide components. • The optical properties exhibit a dominant behavior, especially at low energies (less than 1 eV) is attributed to the mechanism of interactions between free electrons in the system. • The optical properties of the VSi 2 compound were studied according to the polarizations of the parallel (E.||x) and perpendicular (E||z) electric fields, revealing low anisotropy in these properties and compared with experimental results. • The plasma frequency is found at 0.5 eV in both polarizations. • The reflectivity spectra share a remarkably similar and meta-like overall shape in our results of bulk state, compared to the experiment results of single crystals and polycrystalline films. • The VSi 2 compound is promising various applications, including mirrors, coatings for glasses, optoelectronic devices, optical networks, electronics, optical communications, and waveguide components. [ABSTRACT FROM AUTHOR]

[Display omitted] • The formation of catalytically active vanadia species over titania takes place at the expense of the terminal hydroxyl groups on the support. • The consumption of titania bridged hydroxyls results in the formation of polymeric vanadia and V 2 O 5 nano crystallites. • The intrinsic kinetic parameters of the kinetically relevant steps depend of the vanadia cluster size, vandia coverage, and the local environment surrounding the vanadia species. • The ability of the support to provide oxygen during the reoxidation step of the Mars-van Krevelen cycle plays a critical role for catalytic activity. Titanium oxide site requirements for the anchoring of catalytically active forms of dispersed vanadia species are investigated. Using a series of oxygen-modified titanium nitride materials, we systematically modify the available vanadia-anchoring moieties on the titanium-bearing support surface. This strategy in turn results in a very narrow size distribution of well-dispersed vanadia clusters anchored on the support. This synthesis technique ensures that only highly dispersed vanadia is present on the catalyst surface even at nominal monolayer coverages. A deeper insight into the catalytic behavior for ethanol partial oxidation of the active vanadia species is obtained by comparing intrinsic kinetic and thermodynamic parameters of kinetically relevant reaction steps (heat of ethanol adsorption, hydrogen abstraction activation energy, and the energetics of catalyst reoxidation). It is found that these parameters are dependent on the relative amount of oxygen in the titanium-bearing support and the resulting distribution of vanadia species, which validates the premise of a potential participation of lattice oxygen atoms of the titania support into the catalytic activity of active vanadia species. [ABSTRACT FROM AUTHOR]

The UV sensing in pure ZnO is due to oxygen adsorption/desorption process from the ZnO surface. Vanadium doping improves the UV sensitivity of ZnO. The enhancement in UV sensitivity in vanadium-substituted ZnO is attributed to trapping and de-trapping of electrons at V4+ and V5+-related defect states. The V4+ state has an extra electron than the V5+ state. A V4+ to V5+ transformation happens with excitation of this electron to the conduction band, while a reverse trapping process liberates a visible light. An analytic study of response phenomenon reveals this trapping and de-trapping process. [ABSTRACT FROM AUTHOR]

Mesoporous vanadium oxide nanospheres (MVONs) with small particle size and excellent peroxidase-like activities are synthesized via a self-template method for antibacterial application. By adjusting the amount of F127 in the synthesis (i.e. , 0.1 g, 0.2 g, 0.3 g), MVONs with various particle size (52–105 nm), specific surface area (31.3–63.7 m2 g−1) and zeta potential (−8.99–(−2.30) mV) are obtained. Based on these different characteristics, MVONs show different peroxidase-like activities. They can effectively transform the hydrogen peroxide into highly toxic oxygen radicals, and possess excellent antibacterial activity. [Display omitted] Mesoporous vanadium oxide nanospheres are a very promising nanozyme for antibacterial and chemical sensing. However, controllable synthesis of mesoporous vanadium oxide nanospheres with uniform structure and small diameter (<200 nm) remains challenging. Herein, mesoporous vanadium oxide nanospheres (MVONs) with a small, uniform and adjustable particle size (52–105 nm), large mesopore size (5.1–5.8 nm), and high specific surface area (up to 63.7 m2 g−1) are constructed via a self-template strategy using tannic acid, formaldehyde and vanadium compounds as a polymerizable ligand, cross-linking agent and metal source, respectively. The relationships between synthesis conditions and material nanostructure are systematically investigated. The particle size and peroxidase-like activity of MVONs can be easily changed by adding different amounts of Pluronic block copolymer F127. Owing to the mesoporous structure, high specific surface area and small particle size, MVONs can effectively convert H 2 O 2 into extremely toxic reactive oxygen species, and further kill Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus). This research establishes a universal, reliable method for synthesizing mesoporous vanadium oxide nanospheres, which might be used in catalysis, biosensors, and antibacterial treatment. [ABSTRACT FROM AUTHOR]

The direct hydroxylation of benzene is a green and economical-efficient alternative to the existing cumene process for phenol production. However, the undesired phenol selectivity at high benzene conversion hinders its wide application. Here, we develop a one-pot synthesis of protonated g-C3N4 supporting vanadia catalysts (V-pg-C3N4) for the efficient and selective hydroxylation of benzene. Characterizations suggest that protonating g-C3N4 in diluted HCl can boost the generation of amino groups (NH/NH2) without changing the bulk structure. The content of surface amino groups, which determines the dispersion of vanadia, can be easily regulated by the amount of HCl added in the preparation. Increasing the content of surface amino groups benefits the dispersion of vanadia, which eventually leads to improved H2O2 activation and benzene hydroxylation. The optimal catalyst, V-pg-C3N4-0.46, achieves 60% benzene conversion and 99.7% phenol selectivity at 60 oC with H2O2 as the oxidant. [ABSTRACT FROM AUTHOR]

Vanadia supported on well-defined ceria nanocubes are synthesized at various loadings using a liquid-phase chemical grafting technique and are compared to those prepared using traditional incipient wetness impregnation. Raman and IR characterization reveal that, as vanadia loading is increased to near monolayer coverage, vanadia deposited using grafting shows greatly enhanced dispersion (i.e., improved VOx monomer/dimer distribution). Methanol is used as a probe molecule to explore the redox behavior of the catalysts. IR and temperature programmed desorption of methanol show increased CO2 formation occurs on the bare ceria support and increasing the dispersion of vanadia promotes dehydrogenation to formaldehyde due to the inhibited oxygen vacancy formation on VOx/CeO2. Hydrogen temperature programmed reduction demonstrates that the catalyst reducibility and formation of surface oxygen vacancy are directly related to the degree of vanadia oligomerization. The samples prepared using grafting exhibit superior catalytic performance for methanol oxidative dehydrogenation to formaldehyde compared to the impregnated samples, due to the presence of highly dispersed VOx species (i.e., monomers and dimers). [ABSTRACT FROM AUTHOR]

The antifungal potentials of two vanadium oxalate compounds (C7H11N2)2[VO(C2O4)2(H2O)]·2H2O (compound 1) and {(CH6N3)2[VO(C2O4)2]}n (compound 2) against Penicillium expansum and Penicillium italicum were investigated. The compounds inhibited both fungi in well diffusion and plate growth inhibition assays and via volatile production methods. Compound 2 was able to reduce spore germination of P. expansum and P. italicum by 40.87% and 42.00%, respectively. Neither compound exhibited cytotoxicity in human cells. In vivo assays with stored apples showed a reduction in a blue mold by 49% and 25% by compounds 1 and 2, respectively. Both compounds were able to completely prevent blue mold in stored oranges. Microscopic examination demonstrated, that compound 2 caused drastic morphological effects on morphogenesis, and limit the spore germination of P. italicum on oranges and the destruction of P. expansum hyphae on apples. Both compounds inhibited biofilm by 78.48% and 73.83% and patulin reduction by 43.31% and 40%, respectively. Novelty impact statement: The present work highlights the successful use of two vanadium oxalate complexes as antifungal agents to reduce blue mold on apples and citrus. Both compounds are able to limit radial growth and spores germination as well as reduce biofilm and Patulin production and affect mycelium morphogenesis. [ABSTRACT FROM AUTHOR]

The varying oxidation states of vanadium has given vanadium phosphate-based compounds a very rich chemistry, that has resulted in increasing interest in them for varying applications such as energy storage systems, including supercapacitors. Among them is vanadyl phosphates that exist in several polymorphs and have seen lots of research on their applications in alkali metal rechargeable batteries. Layered VOPO 4 is of much interest due to its ability to undergo intercalation reaction. In this work, an organic molecule (triethylene glycol) was successfully intercalated into the layers of VOPO 4 in a two-step solvothermal reaction. This approach resulted in exfoliation of VOPO 4 layers leading to enlarged interlayer spacing, as well as enhancing the conductivity by reducing the band gap of the material. The intercalated material (TrEG-VOP) demonstrated an enhanced supercapacitor properties with capacitance 473 Fg-1 and capacitance retention of 80% against capacitance 400 Fg-1 and capacitance retention of 55% for the pristine (VOP) [ABSTRACT FROM AUTHOR]

A series of oxovanadium(V) compounds 1–4 were prepared and explored as stereodynamic chiroptical probes to detect a simulant of sarin known as diethyl chlorophosphate (DCP) without any interference from the competing analytes. Simultaneous CD cum UV/vis based bimodal instant recognition of DCP using optically active probes is unprecedented. Upon fabricating the vanadium compound with a polymer has yielded a chiroptical membrane, which showed a change in its dichroic as well as colorimetric signals on interaction with DCP vapour at 1 ppm. EPR and UV/vis studies revealed an irreversible change of the CD-active V(V) to the CD-silent ternary V(V) species in presence of DCP via a transient V(IV) species. Nucleophilic attack of the alkoxo oxygen of 1–4 to the electrophilic P atom of DCP resulted in the formation of ternary V(V) compounds as confirmed by 51V/31P NMR. [ABSTRACT FROM AUTHOR]

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Vanadium compounds have frequently been proposed as therapeutics, but their application has been hampered by the lack of information on the different V‐containing species that may form and how these interact with blood and cell proteins, and with enzymes. Herein, we report several resolved crystal structures of lysozyme with bound VIVO2+ and VIVOL2+, where L=2,2'‐bipyridine or 1,10‐phenanthroline (phen), and of trypsin with VIVO(picolinato)2 and VVO2(phen)+ moieties. Computational studies complete the refinement and shed light on the relevant role of hydrophobic interactions, hydrogen bonds, and microsolvation in stabilizating the structure. Noteworthy is that the trypsin−VVO2(phen) and trypsin−VIVO(OH)(phen) adducts correspond to similar energies, thus suggesting a possible interconversion under physiological/biological conditions. The obtained data support the relevance of hydrolysis of VIV and VV complexes in the several types of binding established with proteins and the formation of different adducts that might contribute to their pharmacological action, and significantly widen our knowledge of vanadium–protein interactions. [ABSTRACT FROM AUTHOR]

In modern dual-pressure nitric acid plants, the tail gas temperature usually exceeds 300 °C. The NH3-SCR catalyst used in this temperature range must be resistant to thermal deactivation, so commercial vanadium-based systems, such as V2O5-WO3 (MoO3)-TiO2, are most commonly used. However, selectivity of this material significantly decreases above 350 °C due to the increase in the rate of side reactions, such as oxidation of ammonia to NO and formation of N2O. Moreover, vanadium compounds are toxic for the environment. Thus, management of the used catalyst is complicated. One of the alternatives to commercial V2O5-TiO2 catalysts are natural zeolites. These materials are abundant in the environment and are thus relatively cheap and easily accessible. Therefore, the aim of the study was to design a novel iron-modified zeolite catalyst for the reduction of NOx emission from dual-pressure nitric acid plants via NH3-SCR. The aim of the study was to determine the influence of iron loading in the natural zeolite-supported catalyst on its catalytic performance in NOx conversion. The investigated support was firstly formed into pellets and then impregnated with various contents of Fe precursor. Physicochemical characteristics of the catalyst were determined by XRF, XRD, low-temperature N2 sorption, FT-IR, and UV–Vis. The catalytic performance of the catalyst formed into pellets was tested on a laboratory scale within the range of 250–450 °C using tail gases from a pilot nitric acid plant. The results of this study indicated that the presence of various iron species, including natural isolated Fe3+ and the introduced FexOy oligomers, contributed to efficient NOx reduction, especially in the high-temperature range, where the NOx conversion rate exceeded 90%. [ABSTRACT FROM AUTHOR]

The reaction of [(MenacnacDipp)Mn(μ-Cl)]2(2) (MenacnacDipp = HC(C(Me)NDipp)2; Dipp = 2,6-Pri2C6H3) with sodium triethylborohydride in a toluene—THF mixture afforded the complex [(MenacnacDipp)Mn(μ-H)2BEt2(THF)] (3). The reaction of 2 with Na[HBEt3] in toluene under THF-free conditions gave a mixture of products. The set and the ratio of these products in the resulting crystalline mixture were established by quantitative powder X-ray diffraction analysis: [(MenacnacDipp)Mn(μ-H)]2(1), [(MenacnacDipp)−Mn(μ-H)2BEt2] (4), and unreacted compound 2 in the ratio of 15:4:1 and traces of an unknown crystalline phase. The reaction of [(MenacnacDipp)VCl2] (5) with Na[HBEt3] yielded the compound [(MenacnacDipp)V(μ-H)(μ,κ1:1−C:C′−C2H4)BEt2] (6) containing the unusual ligand [HBEt2(CH2CH2)]2−. The vanadium analog of compound 3, [(MenacnacDipp)V(μ-H)2BEt2(THF)] (7), was isolated in one experiment. Besides. a small amount of the complex [(MenacnacDipp)V(μ-H)BEt3(THF)] (8) was detected in the mixture of crystalline products. The structures of compounds 3, 4, 6, 7, and 8 were determined by single-crystal X-ray diffraction. [ABSTRACT FROM AUTHOR]

The reaction of [(MenacnacDipp)Mn(μ-Cl)]2(2) (MenacnacDipp = HC(C(Me)NDipp)2; Dipp = 2,6-Pri2C6H3) with sodium triethylborohydride in a toluene—THF mixture afforded the complex [(MenacnacDipp)Mn(μ-H)2BEt2(THF)] (3). The reaction of 2 with Na[HBEt3] in toluene under THF-free conditions gave a mixture of products. The set and the ratio of these products in the resulting crystalline mixture were established by quantitative powder X-ray diffraction analysis: [(MenacnacDipp)Mn(μ-H)]2(1), [(MenacnacDipp)−Mn(μ-H)2BEt2] (4), and unreacted compound 2 in the ratio of 15:4:1 and traces of an unknown crystalline phase. The reaction of [(MenacnacDipp)VCl2] (5) with Na[HBEt3] yielded the compound [(MenacnacDipp)V(μ-H)(μ,κ1:1−C:C′−C2H4)BEt2] (6) containing the unusual ligand [HBEt2(CH2CH2)]2−. The vanadium analog of compound 3, [(MenacnacDipp)V(μ-H)2BEt2(THF)] (7), was isolated in one experiment. Besides. a small amount of the complex [(MenacnacDipp)V(μ-H)BEt3(THF)] (8) was detected in the mixture of crystalline products. The structures of compounds 3, 4, 6, 7, and 8 were determined by single-crystal X-ray diffraction. [ABSTRACT FROM AUTHOR]

These authors contributed equally: Yong Yin, Bingcheng Luo.Correction to: Nature Communicationshttps://doi.org/10.1038/s41467-024-47878-1, published online 27 April 2024In this article the author's name Bar Mosevitzky Lis was incorrectly written as Bar Mosevizky Lis. The original article has been corrected.By Yong Yin; Bingcheng Luo; Kezhi Li; Benjamin M. Moskowitz; Bar Mosevitzky Lis; Israel E. Wachs; Minghui Zhu; Ye Sun; Tianle Zhu and Xiang LiReported by Author; Author; Author; Author; Author; Author; Author; Author; Author; Author [Extracted from the article]

Vanadium has been reported to possess relevant therapeutic properties such as anti-diabetic and anti-tumoral. This study aimed at determining the effects of vanadium on experimentally induced colitis in rats. Forty-five male Wistar rats (103 ± 3.90 g, n=15) were used for this study and were divided into three groups. Group 1 (Untreated control) had nothing added to their drinking, while groups 2 and 3 received sodium metavanadate at a dose of 50 and 200 mg/L respectively in their drinking water for 10 weeks. Colitis was thereafter induced by intra colonic administration of 1.50 mL of 6% acetic acid. Animals were sacrificed on day 0 (pre-induction), three- and seven-days post induction. Blood samples were collected for haematological variables and the distal 8 cm of the colon was collected for macroscopic, histological and biochemical (malondialdehyde-MDA, superoxide dismutase-SOD, catalase-CAT, glutathione peroxidase- GPx and nitrite concentration- NO) assessment. Low dose vanadium proved beneficial in ameliorating acetic acid-induced colitis by improving both histopathological and haematological changes. Gross observation showed a faster healing rate in vanadium treated groups (50 and 200 mg/L) compared with untreated control at day 3 (40 and 26.20 vs. 2.50%) and day 7 (80 and 66.70 vs. 42%) respectively. Vanadium also appears to exert its beneficial effects on acetic acid-induced colitis via up regulation of antioxidant enzymes (SOD, CAT, GPx) and NO while decreasing the over production of MDA. Vanadium at small concentration functions as an essential trace element and may be able to promote healing process during ulcerative colitis. [ABSTRACT FROM AUTHOR]