Vanadium Level Research Articles

The Heat Treatment of Pink Zoisite

Natural pink zoisites owe their color to a high concentration of manganese paired with low concentrations of other coloring elements such as vanadium or titanium. Upon conventional heating, such stones typically suffer from the reduction of Mn3+ to the colorless Mn2+ species alongside the destruction of the brownish yellow color that is related to titanium. We have processed manganese containing zoisites under the high pressure of pure oxygen which allowed the manganese to remain oxidized, while the brownish yellow color component was still successfully removed. Depending on the vanadium level, the treated gems show a pink to purplish pink color. Detection of this treatment is not easy as the temperature is too low to result in a change in internal features, but a combination of UV-Vis-NIR spectroscopy and trace element chemistry provided by LA-ICP-MS give evidence of such treatment.

Marine anammox bacteria-driven nitrogen removal from saline wastewater under different vanadium (v) doses: Evaluation on performance and kinetics

This study used a sequencing batch reactor to investigate the nitrogen removal performance of marine anammox bacteria (MAB) from nitrogen-rich saline wastewater with addition of a transition element, vanadium (V(V)). The findings showed that the performance of nitrogen removal by MAB was enhanced by dosing proper amount of V (V) (i.e. 0.25–20 mg/L), but the effectiveness deteriorated at higher doses (>20 mg/L). Vanadium (V) level at 1 mg/L was found to be an optimal dose for complete removal of ammonia (NH4+-N) within only 160 min. Substrate conversion rates were improved and stayed at high for longer periods with lower vanadium doses (0.25–10 mg/L), which indicates that the MAB-mediated anammox reaction rate was accelerated by adding V(V). Moreover, V(V) was more preferential than partial nitrite (NO2−) to be used as the electron acceptor by MAB, thus the new marine anammox process is termed as Vammox. Kinetic analysis using remodified Logistic model, modified Boltzman and Gompertz models on the nitrogen removal processes in typical operational conditions with V(V) addition revealed that none of the three models was appropriate at higher V(V) doses (>20 mg/L). Nevertheless, the remodified Logistic model was most suitable at lower V(V) doses (≤20 mg/L).

Growth responses, accumulation, translocation and distribution of vanadium in tobacco and its potential in phytoremediation

The metal tolerance mechanism of plants is of great importance to explore the plant-based clean-up of environmental substrata contaminated by heavy metals. Indoor experiment of tobacco (Nicotiana tabacum L.) seedlings growing hydroponically in nutrient solution containing 0, 0.1, 0.5, 2.0, and 4.0 mg L−1 V was conducted. The results indicated that plant overall growth performance was significantly affected at ≥ 2.0 mg L−1 V. Oxidative stress degree as indicated by foliar O2−· and H2O2 content intensified markedly at ≥ 0.5 mg L−1 V treatments. In response, the plant activated its enzyme and non-enzyme protecting mechanism to cope with oxidative stress inflicted by vanadium. The activities of antioxidant enzymes, including SOD, POD, CAT, APX, and the concentration of non-enzyme antioxidants, e.g., AsA and GSH were all conspicuously (p < 0.5 or p < 0.1) enhanced at ≥ 0.5 mg L−1 V treatments. Vanadium accumulated in leaves, stems, and roots increased with increasing vanadium level. The majority of the absorbed vanadium retained in plant root, and minor portions were transferred to aerial parts. Vanadium concentration in plant tissues ordered as root ˃ stem ˃ leaf. Translocation factors (TF) in vanadium-treated tobaccos (TF « 1) were significantly lower than that of control (TF ˃ 1). In conclusion, although vanadium at ≥ 2.0 mg L−1 inhibited plant growth, tobacco exhibited a relatively good vanadium tolerance through self-adaptive regulation and has the potential as a phytostabilizer in decontaminating the environment contaminated by vanadium.

Effectiveness, stabilization, and potential feasible analysis of a biochar material on simultaneous remediation and quality improvement of vanadium contaminated soil

Biochar additions to soil have been proposed as an environment-friendly way to enhance the soil nutrients or to amend the contaminated soils; however, few studies have evaluated the effectiveness of biochars from an integrated perspective of soil remediation and quality improvement, especially for the soil contaminated by vanadium with increasing prevalence, complex species and chemistry, widespread toxicity to organisms. Herein, this gap is addressed by using a biochar to evaluate the effectiveness of both remediation and quality improvement of a vanadium contaminated soil. Based on the physicochemical and morphology properties, the optimal biochar with a good porous structure and abundant surface functional groups prepared by pyrolyzing rice straw at 650 °C and sieving through a 200 mesh (RS-T650-P0.075) was selected from 18 candidates. The increase of pH (1.72), organic matter content (3.80%), and available P content (9.17 mg kg−1) of soil and the decrease of bioavailable vanadium (225.59 ± 16.25 mg vanadium kg−1 soil) in soil during a 10-week experiment indicated an effective and stable improvement of soil quality and treatment for soil vanadium pollution, by high RS-T650-P0.075 application (3%) to soil contaminated at high exogenous vanadium level (1000 mg vanadium kg−1 soil). Analysis of the cost-benefit and environmental influence confirmed the potential feasibility for practical applicating the RS-T650-P0.075 to treat the vanadium contaminated soils. Overall, the RS-T650-P0.075 can be served as a cost-effective and ecofriendly amendment for both soil quality improvement and the vanadium contaminated soil remediation.

Experience of applying flow cytometry to assess immunologic reactivity in subjects with increased blood vanadium concentration

Environmental pollution with external vanadium results in its accumulation in human biological media and alters ability of human body to properly react to negative impact after exposure to haptens. Aim of the work was to assess immunologic reactivity in subjects bearing increased blood vanadium (hapten) level by using flow cytometry. There were examined adults bearing various blood vanadium concedntration. The test group was comprised by adult subjects (n = 50) having blood vanadium concentration exceeding that one for the upper limit of the reference level and mean reference group (n = 42) corresponding to reference range by 3.7- (р 0.001) and 4.3-fold, respectrively, It was found that subjects with excessively vanadium-contaminated serum were featured with stronger lymphocytes activation, increased count of effector helper T cells, lowered count of regulatory lymphocytes and decreased humoral immune arm, and suppressed p53-dependent control of cellular cycle. Thus, flow cytometry allows to assessing immunologic reactivity in subjects with varying level of blood exogenous chemicals as well as determining body adaptation potential to ewffects exerted by environmental chemical cues.

Mechanism of vanadium(IV) resistance of the strains isolated from a vanadium titanomagnetite mining region.

Microbial treatment for vanadium contamination of soils is a favorable and environment-friendly method. However, information of the resistant mechanism of the strains in soils to vanadium, especially to tetravalent vanadium [vanadium(IV)], is still limited. Herein, potential of the vanadium(IV) biosorption and biotransformation of the strains (4K1, 4K2, 4K3 and 4K4) which were capable of tolerating vanadium(IV) was determined. For biosorption, the bioadsorption and the bioabsorption of vanadium(IV) occur on the bacterial cell wall and within the cell, respectively, were taken into consideration. Comparison of the vanadium(IV) adsorbed on the bacterial cell walls and remained in the cells after sorption indicated the major bacterial vanadium(IV) sorption role of the bioadsorption which was at least one order of magnitude higher than the bioabsorption amount. Isotherm study using various isotherm models revealed a monolayer and a multilayer vanadium(IV) biosorption by 4K2 and the others (4K1, 4K3 and 4K4), respectively. Higher biosorption was observed in acidic conditions than in alkaline conditions, and the maximum biosorption was 2.41, 9.35, 7.76 and 8.44mgg-1 observed at pH 6 for 4K1, at pH 3 for 4K2, and at pH 4 for 4K3 and 4K4, respectively. At the present experimental range of the initial vanadium(IV) concentration, optimal biosorption capacity of the bacteria was observed at the vanadium(IV) level of 100-250mgL-1. Different biotransformation level of vanadium(IV) in soils by the stains was observed during a 28-d pot incubation of the soils mixed with the strains, which can be attributed to the discrepancy of both soil properties and bacterial species. Present study can help to fill up the gaps of the insufficient knowledge of the vanadium(IV) resistant mechanism of the strains in soils.

The detoxification effect of liquid digestate on vanadium toxicity to seed germination and seedling growth of dog's tail grass.

Dog's tail grass (Setaria viridis) presented strong tolerance and high accumulation of vanadium in field conditions. Liquid digestate containing high levels of nutrients could alleviate vanadium toxicity and accelerate the growth of dog's tail grass. To elucidate the detoxification potential and mechanism of liquid digestate, dog's tail grass was grown in soil solution containing 0.14-55.8 mg L-1 of vanadium. Parameters including germination index (GI), tolerance index (TI), seedlings' fresh weight, seedlings' vanadium accumulation, antioxidant enzymes activity, malonaldehyde (MDA) content, and V5+ species, were measured after addition of 1%, 5%, 10% and 15% liquid digestate. The results showed that a vanadium level of 10.9 mg L-1was a threshold value for toxicity; furthermore, the GI and TI decreased by 50% when vanadium content reached 36.8 mg L-1. The MDA content was reduced, and the other parameters were markedly enhanced, after addition of 5% and 10% liquid digestate with vanadium levels above 36.8 mg L-1. V5+ species was the dominant vanadium species in solution and the addition of liquid digestate reduced V5+ concentrations. The detoxification of vanadium by liquid digestate was a combined effect of direct reduction of V5+ species and plant nutrition.

Metal Ion Release During Growth-Friendly Instrumentation for Early-Onset Scoliosis: A Preliminary Study

BackgroundMetal ions released from spinal instruments can cause localized debris and distribute systemically to settle on distant organs. Children with early-onset deformities live with metallic implants for a substantial amount of time. No research focused on metal distribution in growth-friendly instrumentations. The aim of this study was to compare age-matched growing rod (GR) and magnetically controlled growing rod (MCGR) groups to noninstrumented controls. MethodsThe study was designed as a multicenter, prospective, cross-sectional case series. GR and MCGR applications of three institutions were included. A total of 52 children were enrolled. Blood samples were collected between December 2014 and February 2015. Biochemical serum analyses were performed to trace and quantify titanium, vanadium, aluminum, and boron. The GR group included 15 children. Mean age was 10.7 (range 6-15). MCGR group included 22 children. Mean age was 8.5 (range 2-13). Fifteen age-matched nonoperated children formed the control group. The mean age was 10.4 (range 5-15). One-way analysis of variance, Kruskal-Wallis, and Mann-Whitney U tests were used for comparisons. ResultsThe mean serum titanium level in control, GR, and MCGR groups were 2.8 ± 1.4, 7.3 ± 4.3, and 10.2 ± 6.8 μg/L, respectively. GR and MCGR group titanium levels were higher than controls' (p = .008 and p < .001). The mean serum vanadium level in control, GR, and MCGR groups were 0.2 ± 0.0, 0.2 ± 0.0, and 0.5 ± 0.5 μg/L, respectively. MCGR group vanadium level was higher than control (p < .001) and GR groups (p = .004). Mean serum levels in control, GR, and MCGR groups were, respectively, 5.4 ± 4.1, 8.1 ± 7.4, and 7.8 ± 5.1 μg/L for aluminum and 86.7 ± 2.7, 86.9 ± 2.5, and 85.0 ± 6.6 μg/L for boron. The distribution of aluminum and boron were similar across groups (p = .675 and p = .396). ConclusionsBoth GR and MCGR applications significantly release titanium and possibly aluminum. MCGR further releases vanadium. MCGR possibly releases more titanium than traditional GR. Time-dependent alterations of serum ion levels, structural properties of the MCGR device, and exposure caused by magnetic distraction processes warrant investigation.

An Evaluation of Vanadium Enrichment in the Eastern Shelf Sediments of the Turkish Black Sea

This paper presents an&#x0D; evaluation of the spatial distribution of vanadium level, its enrichment and&#x0D; possible sources in the bottom sediment along the shelf of the Turkish Black&#x0D; Sea. In April 2006, vanadium concentrations were measured along the measurement&#x0D; profiles (20, 50 and 100 m) using ICP-MS. The vanadium levels ranged from 40 to&#x0D; 315 µg g-1, usually within the range of typical and background&#x0D; values (Cf&amp;lt;1), except the one&#x0D; offshore the Yeşilırmak River (315.2 µg g-1), revealing significant&#x0D; riverine inputs and geographical conditions (Cf&amp;gt;3). The concentrations decrease gradually with water depth,&#x0D; implying the dominance of anthropogenic sources such as industrial wastes,&#x0D; agricultural effluents, sewage discharge, and port activities. The vanadium&#x0D; levels had not significant correlations with the physicochemical parameters&#x0D; (sediment texture, water content, TOC) and TPH level in the sediment. At the&#x0D; eastern basin, a serious vanadium enrichment (Cf&amp;gt;6-9) was observed in&#x0D; October 2010, implying some important regional and seasonal contributions;&#x0D; which may be natural or anthropogenic. Biogeochemical processes,&#x0D; eutrophication, wave-based erosion, abnormal current circulations, bottom&#x0D; morphology and influence of other substances in the environment may be other&#x0D; regulating factors to this enrichment. Continuous monitoring and further&#x0D; studies are required for a detailed description of vanadium mobility and for&#x0D; assessment of the main controlling processes associated with vanadium&#x0D; enrichment in the eastern Black Sea basin.

Magnetic stirrer induced dispersive ionic-liquid microextraction for the determination of vanadium in water and food samples prior to graphite furnace atomic absorption spectrometry

A new dispersive liquid–liquid microextraction, magnetic stirrer induced dispersive ionic-liquid microextraction (MS-IL-DLLME) was developed to quantify the trace level of vanadium in real water and food samples by graphite furnace atomic absorption spectrometry (GFAAS). In this extraction method magnetic stirrer was applied to obtained a dispersive medium of 1-butyl-3-methylimidazolium hexafluorophosphate [C4MIM][PF6] in aqueous solution of (real water samples and digested food samples) to increase phase transfer ratio, which significantly enhance the recovery of vanadium – 4-(2-pyridylazo) resorcinol (PAR) chelate. Variables having vital role on desired microextraction methods were optimised to obtain the maximum recovery of study analyte. Under the optimised experimental variables, enhancement factor (EF) and limit of detection (LOD) were achieved to be 125 and 18ngL−1, respectively. Validity and accuracy of the desired method was checked by analysis of certified reference materials (SLRS-4 Riverine water and NIST SRM 1515 Apple leaves). The relative standard deviation (RSD) for 10 replicate determinations at 0.5μgL−1 of vanadium level was found to be <5.0%. This method was successfully applied to real water and acid digested food samples.

Influence of Vanadium–organic Ligands Treatment on Selected Metal Levels in Kidneys of STZ Rats

The objective of the study was to investigate the effects of five organic vanadium complexes supplement and a small dose of insulin injection on V, Fe, Cu, Zn, Mn, Ca, and K level in the streptozotocin diabetic rat’s kidney during a 5-week treatment with the tested complexes. In all groups of animals, metal level in the lyophilized kidney organs was investigated by means of the proton induced X-ray emission method. Tissue vanadium level was naturally higher in vanadium-treated rats. The maximum level of vanadium was observed in the kidney ( {x_{text mean}} =16.6 upmu mathrm{g}/left. mathrm{g} right) . The influence of vanadium administration on other metal level in rat’s tissue was also investigated. Spectacular influence of vanadium action was observed on copper and zinc level in examined tissue.

Electronic structure of lead telluride-based alloys, doped with vanadium

The crystal structure, composition, galvanomagnetic properties in low magnetic fields (4.2 K ≤ T ≤ 300 K, B ≤ 0.07 T), and the Shubnikov–de Haas effect (T = 4.2 K, B ≤ 7 T) are studied in Pb1−x−ySnxVyTe (x = 0, 0.05–0.18) alloys synthesized by the Bridgman technique with variable vanadium impurity concentrations. It is shown that increasing the vanadium content leads to the formation of regions enriched in vanadium and of microscopic inclusions of compounds with compositions close to V3Te4. In Pb1−yVyTe stabilization of the Fermi level by a deep vanadium level, an insulator–metal transition, and a rise in the free electron concentration are observed as the vanadium content is increased. The variation in the free charge carrier concentration with increasing vanadium concentration in Pb1−yVyTe and Pb1−x−ySnxVyTe (x = 0.05–0.18) alloys is compared. Possible models for rearrangement of the electronic structure in Pb1−x−ySnxVyTe alloys with vanadium doping are discussed.

Rearrangement of electronic structure of Pb1-x-ySnxVyTe under pressure

The galvanomagnetic properties in weak magnetic fields (4.2≤T≤300 K, B≤0.07 T) and the Shubnikov-de Haas effect (T = 4.2 K, B≤7 T) in the single crystal Pb1-x-ySnxVyTe (x = 0.05-0.20, y≤0.01) alloys at atmospheric pressure and under hydrostatic compression up to 15 kbar have been investigated. We found that the increase of the vanadium impurity content leads to the p-n-conversion, transition to the insulating phase and to the pinning of Fermi level by the deep impurity level, lying under the bottom of the conduction band. Under pressure a decrease of the activation energy of the vanadium level, the n-p-inversion of the conductivity type at low temperatures and an insulator-metal transition occur. The pressure and the temperature coefficients of vanadium deep level energy are determined and the diagram of the electronic structure rearrangement for Pb1-x-ySnxVyTe under pressure is proposed.

Insulator-Metal Transition in Diluted Magnetic Semiconductor Pb1-x-ySnxVyTe under Pressure

The galvanomagnetic properties in weak magnetic fields (4.2T300 K, B0.07 T) as well as Shubnikov-de Haas effect (T=4.2 K, B7 T) in the single crystal Pb1-x-ySnxVyTe (x=0.20, y0.01) under hydrostatic compression up to 15 kbar have been investigated. It is shown that under pressure the decrease of activation energy of vanadium deep level, n-p-inversion of the conductivity type at low temperatures and insulator-metal transition take place. In the metallic phase sharp increase of the Hall mobility and appearance of Shubnikov-de Haas oscillations at helium temperature are observed. The pressure coefficient of vanadium level energy is determined and the diagram of the electronic structure rearrangement for Pb1-x-ySnxVyTe under pressure is proposed.

Galvanomagnetic properties and electronic structure of Pb1−x−ySnxVyTe under pressure

We study the galvanomagnetic properties in weak magnetic fields (4.2 ≤ T ≤ 300 K, B ≤ 0.07 T) and the Shubnikov-de Haas effect (T = 4.2 K, B ≤ 7 T) in single crystal Pb1−x−ySnxVyTe alloys under variation of alloy composition (x = 0.05–0.20, y ≤ 0.01) and hydrostatic compression up to 15 kbar. The increase of vanadium impurity content leads to the p-n-conversion and to a transition in the insulating phase due to the pinning of Fermi level by the donor-type deep vanadium impurity level situated under the bottom of the conduction band. We found that pressure induces a decrease of the activation energy of the vanadium level, the n-p-inversion of the conductivity type at low temperatures and an insulator–metal transition. In the metallic phase, a sharp increase of the Hall mobility (up to 3 × 105 cm2 V−1 s−1) and appearance of Shubnikov-de Haas oscillations are observed at helium temperature. The pressure and temperature coefficients of vanadium deep level energy are determined, and the diagram of the electronic structure rearrangement for Pb1−x−ySnxVyTe under pressure is proposed.

Optimising heat treatment requirements for improved toughness of V containing 3%NiCrMo steel

AbstractOne major field of application of medium carbon low alloy steels is military hardware, especially the production of mortars. In manufacturing, it is usually necessary to adhere to specific standards; however, since economic and technological requirements depend on using scrap extensively, it can be difficult to keep minor additions within the specification. Heat treatment will therefore play an important role in obtaining the required mechanical properties. The combined effect of vanadium level and heat treatment cycles on strength and toughness of type 4337V (3%NiCrMo) 'gun steel' has been investigated. Vanadium is added mainly as a grain refiner, but it is also a strong carbide former, and therefore likely to reduce toughness. Conventional heat treatment (normalising at 900°C followed by quenching from 850°C), a modified heat treatment (double normalising at 900 and 800°C, successively, before the conventional treatment), and thermomechanical treatment (quenching in oil directly from the forging...

Influence of V and N on Transformation Behavior and Mechanical Properties of Medium Carbon Forging Steels

The influence of vanadium and nitrogen on microstructure and mechanical properties of medium-carbon steels has been studied by means of metallography and mechanical testing. Vanadium addition to the low nitrogen steel suppresses the formation of ferrite-pearlite following the low reheating temperatures and microstructure consists of bainitic sheaves. Increasing nitrogen at the same vanadium level promotes the acicular ferrite formation. For high reheating temperatures, dominantly acicular ferrite structure in both the low nitrogen and the high nitrogen vanadium steels is obtained. The results suggest that vanadium in solid solution promotes the formation of bainite, whereas the effect of nitrogen is related to the precipitation of VN particles in austenite with high potency for intragranular nucleation of acicular ferrite and to the precipitation of V(C,N) particles in ferrite with high potency for precipitation strengthening. Addition of both vanadium and nitrogen considerably increases the strength level, while CVN20 impact energy increases on changing the microstructure from bainitic ferrite to the fine ferrite-pearlite and acicular ferrite.

Influence of Reheating Temperature and Vanadium Content on Transformation Behavior and Mechanical Properties of Medium Carbon Forging Steels

The influence of vanadium and nitrogen on microstructure and mechanical properties of medium-carbon steels has been studied by means of metallography and mechanical testing. Vanadium addition to the low nitrogen steel suppresses the formation of ferrite–pearlite following the low reheating temperatures and microstructure consists of bainitic sheaves. Increasing nitrogen at the same vanadium level promotes the acicular ferrite formation. For high reheating temperatures, dominantly acicular ferrite structure in both the low nitrogen and the high nitrogen vanadium steels is obtained. The results suggest that vanadium in solid solution promotes the formation of bainite. The effect of nitrogen is related to the precipitation of VN particles in austenite with high potency for intragranular nucleation of acicular ferrite and to the precipitation of V(C, N) particles in ferrite with high potency for precipitation strengthening. Addition of both vanadium and nitrogen considerably increases the strength level, while CVN20 impact energy increases on changing the microstructure from bainitic ferrite to the fine ferrite–pearlite and acicular ferrite.

Development of an on-line temperature-assisted ionic liquid dispersive microextraction system for sensitive determination of vanadium in environmental and biological samples

An original flow injection (FI) system was developed for on-line microextraction of Vanadium (V) based on room temperature ionic liquid (RTIL). Vanadium was complexed with 2-(5-bromo-2-pyridylazo)-5-diethylaminophenol (5-Br-PADAP) at pH 4.0. A 40 μL-volume of 1-butyl-3-methylimidazolium hexafluorophosphate ([C 4mim][PF 6]) RTIL was mixed with 5 mL of sample solution containing the V-5-Br-PADAP complex. Then, a fully on-line temperature-assisted dispersion procedure was developed, followed by, analyte microextraction; and final on-line separation of the RTIL phase with a florisil-containing microcolumn. Vanadium was removed from the microcolumn with a 10% (v/v) nitric acid (in acetone) solution, and finally measured by electrothermal atomic absorption spectrometry (ETAAS). The detection limit achieved after preconcentration of 5 mL of sample solution, was 4.8 ng L −1. The relative standard deviation (RSD) for 10 replicate determinations at 5 μg L −1 of vanadium level was 4.1%, calculated from the obtained peak heights. The calibration graph was linear, with a correlation coefficient of 0.9982 at levels from the detection limits up to 15 μg L −1. The method was successfully applied for the determination of vanadium in environmental and biological samples.

Effect of vanadium and titanium modification on the microstructure and mechanical properties of a microalloyed HSLA steel

DMR-249A is a low carbon microalloyed high-strength low-alloy (HSLA) steel. While DMR-249A plates of thickness less than 18 mm meet the specified room temperature yield strength (390 MPa) and Charpy impact toughness (78J at −60 °C) in the as-rolled condition, thicker plates require water quenching and tempering. Elimination of the quenching and tempering treatment can result in significant cost and energy savings besides offering increased productivity. Therefore, in the present work, modifications to the base DMR-249A steel composition have been investigated with the objective of producing thicker gage plates (24 mm) capable of meeting the specified properties in the normalized condition. Plates from three modified compositions i.e., containing 0.015 wt.% titanium and 0.06, 0.09 and 0.12 wt.% vanadium respectively and one composition with 0.10 wt.% vanadium, and without any titanium were investigated over a range of normalizing temperatures (875–1000 °C). In all cases, only the steel without titanium met the specified properties in the normalized condition. Microstructural investigations using scanning and transmission electron microscopy, as well as support evidence from calculations performed using ThermoCalc software, suggest that this is due to the presence of nanoscale vanadium rich carbonitride particles distributed throughout the matrix. These particles were absent in the titanium-containing steel at a similar vanadium level.