Various Concentrations Of Nickel Research Articles

Integrated sulfide alkali wastewater treatment using spent galvanic solutions

We identified the efficiency of spent Ni2+-containing galvanic solutions for removing sulfide ions from sulfide alkali wastewater. It was found that the removal of sulfide ions led to achieving 89.7 % of purification degree by the chemical oxygen demand value. We also studied how various concentrations of nickel (II) and copper (II) ions affect the oxidation intensity of pollutants in mixed wastewater with ambient oxygen and with ozone-air mixture. Optimal conditions were identified for cleaning sulfide alkali wastewater from hydrocarbons: Oxidation of organic components by ozone-air mixture for 30 minutes, containing 300 mg/dm3 of nickel (II) ions; implementing such conditions resulted in the greatest reduction of the chemical oxygen demand value (down to 798 mg of O/dm3. A comprehensive method for the purification of sulfur-alkaline wastewater is proposed, which includes the stages of removing readily volatile hydrocarbons by simple distillation, sulfide ions by reagent deposition using spent Ni2+-containing galvanic solutions, and soluble hydrocarbons by oxidation of ozone-air mixture with adding 300 mg/dm3 of nickel (II) ions contained in galvanic wastewater. Implementation of this technique led to achieving 96% of the wastewater purification degree by the chemical oxygen demand value, which allows discharging wastewater into biological treatment.

Strategy for enhancing the hydrogen evolution reaction properties of $$\hbox {MoS}_{\mathrm {2}}$$ by utilizing the ordered mesoporous carbon as support and modification with nickel

Surface modification of electrocatalyst suitable for yielding reduced overpotential with improved exchange current density at the interface is highly desired for hydrogen evolution reaction (HER). Herein, the present report demonstrates the HER performance of ordered mesoporous carbon (OMC)-supported nickel-modified $$\hbox {MoS}_{\mathrm {2}}$$ electrocatalysts [NiMoS(x)–OMC] synthesized by hydrothermal route. Inherent activity of pristine $$\hbox {MoS}_{\mathrm {2}}$$ was improved by two vital surface strategies utilizing OMC as the support matrix for the dispersed growth of active catalyst and surpassing the active sites formation via augmentation of various concentrations of nickel. Crystalline phase, heterostructure vibrations, morphological orientation and electrocatalytic property of the prepared catalysts are comprehensively studied using different spectroscopic methods. Linear sweep voltammetric analysis suggests that the HER from the pristine $$\hbox {MoS}_{\mathrm {2}}$$ could be amplified by introducing OMC as support matrix. Synergistic enrichment of Ni (3 and 5 wt%) on $$\hbox {MoS}_{\mathrm {2}}$$ –OMC matrix enables both the lowest onset potential (180 and 185 mV) and Tafel slope values (103 and 100 mV per decade), with retained stability promising for further optimization and scalability.

Origins of the nitrogen-related deep donor center and its preceding species in nitrogen-doped silicon determined by deep-level transient spectroscopy

High concentrations of a deep donor center (DDC) and substitutional nickel (Nis) are distinctively produced in the nitrogen-doped/nickel-diffused silicon crystals. To find out the structural origins of the DDC and the preexisting nitrogen–vacancy (N–V) complex that produces the DDC and Nis, we have measured the concentrations of these products by deep-level transient spectroscopy in the samples diffused with various concentrations of nickel. From the close examination of the depth profiles of the products and the anneal-out temperature of the DDC, this species is found to be the substitutional nitrogen and the structure molecule-like split nitrogen interstitials is suggested for the N–V complex.

Magnetic minerals of the chelyabinsk meteorite

Eight samples of the Chelyabinsk meteorite were studied using thermomagnetic and electron microprobe analyses; the hysteresis loop characteristics were also measured. The main magnetic minerals of the meteorite are represented by two groups of Fe-Ni alloys (native Fe minerals) with various concentrations of nickel and iron sulfides. A small number of magnetite balls were found. They are probably formed due to oxidation of troilite and other Fe sulfides as a result of melting of the meteorite due to passage through the Earth’s atmosphere. The observed effect of the primary hysteresis loop constriction is probably connected with prolonged annealing of a celestial body before its transition into the meteoroid state.

Effect of Different Concentrations of Nickel on Some secondary metabolites in Coriander (Coriandrum Sativum L.)

Nickel is a heavy metal that is toxic for humans, animals and plants. However, some plants are known as accumulator plants. In some plants, nickel has been introduced as beneficial element for growth and development. The aim of this study was to investigate the effect of different concentrations of nickel on some metabolites of Coriandrum Sativum L. The experiment was done under controlled conditions. Plant samples were kept in a growth chamber under standard conditions and treated with various concentrations of nickel for 12 weeks. Based on these results, leaf protein and sugar content decreased while the content of flavonoids, phenolic and flavonol increased.DOI: http://dx.doi.org/10.3126/ijls.v9i2.12059 International Journal of Life Sciences 9 (2) : 2015; 28-32

Effect of toxic components on microbial fuel cell-polarization curves and estimation of the type of toxic inhibition.

Polarization curves are of paramount importance for the detection of toxic components in microbial fuel cell (MFC) based biosensors. In this study, polarization curves were made under non-toxic conditions and under toxic conditions after the addition of various concentrations of nickel, bentazon, sodiumdodecyl sulfate and potassium ferricyanide. The experimental polarization curves show that toxic components have an effect on the electrochemically active bacteria in the cell. (Extended) Butler Volmer Monod (BVM) models were used to describe the polarization curves of the MFC under nontoxic and toxic conditions. It was possible to properly fit the (extended) BVM models using linear regression techniques to the polarization curves and to distinguish between different types of kinetic inhibitions. For each of the toxic components, the value of the kinetic inhibition constant Ki was also estimated from the experimental data. The value of Ki indicates the sensitivity of the sensor for a specific component and thus can be used for the selection of the biosensor for a toxic component.

Nickel skin levels in different occupations and an estimate of the threshold for reacting to a single open application of nickel in nickel-allergic subjects

Nickel is a frequent allergen throughout the world. However, the extent to which nickel is relevant as an occupational contact allergen as opposed to being simply a reflection of jewellery exposure has been unclear. Some thresholds for cutaneous nickel exposure to induce a dermatitis reaction in nickel-allergic individuals have been defined. Over recent years it has become possible to measure accurately the quantity of nickel on the skin of individuals in a number of occupations. To measure the quantities of nickel on the skin of the fingers in workers employed in occupations for which nickel has been suspected as a contact allergen. To define the threshold for a dermatitis reaction after the single application of a quantity of nickel to the skin of nickel-allergic individuals when read at 2days. We employed the 'finger immersion' technique for sample collection and induction coupled plasma mass spectrometry for the nickel measurement. Nickel platers, cashiers, sales assistants, caterers, healthcare assistants, office workers, dental nurses and hairdressers were studied (five in each group except for seven cashiers). A correction was made for the fact that the finger immersion method underestimates the amount of nickel on the fingertip. The threshold for reactivity to a single application of nickel was studied by the application of various concentrations of nickel (μgcm(-2) ) [0·05 (two subjects), 0·5 (two subjects), 2·5 (three subjects), 5·0 (21 subjects), 15 (19 subjects), 30 (19 subjects) and 45 (18 subjects)] in 21 subjects overall using Finn chambers on forearm skin. The reading was made at 2days and reactions were graded using the International Contact Dermatitis Research Group classification. Nickel levels on the fingers of platers, cashiers, sales assistants, caterers, and even office staff, were at or above the 0·035μgcm(-2) level at which 22% of nickel-allergic subjects will react (after applying a correction). The single open application of nickel study demonstrated a dose-response relationship, with no subjects reacting to ≤ 2·5μgcm(-2) , but increasing numbers reacting at the higher concentrations as follows: six of 21 (28%) at 5·0μgcm(-2) , six of 19 (31%) at 15μgcm(-2) , seven of 19 (37%) at 30μgcm(-2) and 11 of 18 (61%) at 45μgcm(-2) . This study confirms that nickel levels on the skin in coin handling occupations and some others are sufficient to induce an allergic contact dermatitis in some nickel-allergic subjects. A single application of 5μgcm(-2) when read at 2days induced a dermatitis reaction in six of 21 nickel-allergic subjects.

Impact of active transport and transpiration on nickel and cadmium accumulation in the leaves of the Ni-hyperaccumulator Leptoplax emarginata: a biophysical approach

Aims The primary aim of this study was to investigate the impact of active nickel and cadmium transport, transpiration and shoot biomass production on Ni and Cd accumulation in the leaves of the Ni-hyperaccumulator Leptoplax emarginata. A secondary objective was to observe the effects of various concentrations of nickel and cadmium in solutions on the plant growth and ecophysiological characteristics of these plants. Finally, the study sought to identify possible nickel and cadmium concentration gradients in solution as a function of the root distance.

Effect of nickel on the mineralization of hydrocarbons by indigenous microbiota in Kuwait soils

Assessment of nickel contents in soil samples in Kuwait indicated only a minor difference in concentration in hydrocarbon-contaminated (86 mg kg(-1) soil) and non-contaminated soils (84 mg kg(-1) soil). The potential inhibitory effects of nickel on the number of hydrocarbon degraders, and hydrocarbon utilization were investigated over a wide range of nickel concentrations to span concentrations observed in the soil. Nickel addition, as nickel sulphate, to soil samples reduced the number of hydrocarbon degraders in all samples by a wide range (15-96%) depending on concentration and the hydrocarbon substrate utilized. Similarly, the metabolic activities were affected as observed in mineralization (3-60%) of soils amended with various concentrations of nickel. The inhibitive effects of nickel on hexadecane and crude oil utilization were minimal but were significantly higher with naphthalene (P < 0.05) in both hydrocarbon-contaminated and non-contaminated soils. Polarographic determination of hydrocarbons induced oxygen uptake rate demonstrated the tendency of nickel to significantly inhibit (P < 0.05) the oxidation of polyaromatic hydrocarbons compared to aliphatic hydrocarbons.

Nickel accumulation and its effects on the survival rate of Spodoptera litura fabricius under continuous nickel stress

The artificial diets mixed with various concentrations of nickel were offered to the larvae of the phytophagous insect Spodoptera litura Fabricius for 3 generations. Nickel accumulations in the 6th instar larvae, pupae and newly emerged adults of the corresponding generations of S. litura were investigated by inductively Coupled Plasma-Atomic Emission Spectrometer (ICP-AES), and the effects of nickel accumulations on the survival rate of S. litura were also evaluated by individual rearing. The results showed that nickel accumulated in the 6th instar larvae, pupae and adults of S. litura, and the accumulated nickel in all the tested developmental stages within a generation increased with the increase of the nickel doses in the treated diets and showed significant dose-dependent relationship with the nickel doses in the artificial diets. The results also indicated that the nickel accumulations in the 6th instar larvae, pupae, and newly emerged adults from the 3rd generation were higher than those from the 2nd generation, which were also higher than those from the 1st generation. Nickel concentrations in pupae and adults were significantly lower than those in larvae, which indicated that the excessive nickel might be excreted during metamorphosis. Furthermore, larval survival rate, pupation rate and eclosion rate of S. litura in the tested three generations all decreased with the increase of the nickel doses in the treated diets.

Characterization of ceramic hydrogen separation membranes with varying nickel concentrations

Ceramic hydrogen separation membranes in the stoichiometric form BaCe 0.8Y 0.2O 3, doped with various concentrations of nickel, were characterized by utilizing X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), and atomic-force microscopy (AFM). Characterization was performed at room temperature, 550°C and 650°C, and after exposure to hydrogen. Migration of nickel to the surface and changes in both elemental composition and oxidation states were observed at elevated temperatures. The concentration of nickel significantly affects surface morphology and roughness.

Regulation of hydrogenase biosynthesis by nickel in Bradyrhizobium japonicum

The addition of 5 μM nickel to heterotropically growing hydrogen uptake constitutive mutants resulted in up to a 10-fold increase in hydrogen uptake activity. Strain SR wild type cells required nickel for the derepression of hydrogenase in media treated to remove contaminating nickel and produced increasing levels of hydrogenase activity as a function of increasing nickel concentration. Immunoblots of SR wild type cultures derepressed with various concentrations of nickel revealed that the amount of anti-hydrogenase cross-reactive material synthesized is dependent on the amount of nickel in the media. Studies using chloramphenicol demonstrated that protein synthesis, in addition to nickel, was required for the synthesis of hydrogenase; inactive (nickel-free) hydrogenase protein does not accumulate during derepression in the absence of nickel. Thus the acquisition of hydrogenase activity by adding nickel during the course of derepression is not the result of nickel being inserted into pre-formed hydrogenase. Rifampicin inhibition studies suggested that nickel is required for the transcription of hydrogenase related genes. It is proposed that nickel, in addition to its structural role in the enzyme, plays a role in the regulation of hydrogenase expression in Bradyrhizobium japonicum.

Antagonism by essential divalent metals and amino acids of nickel(II)-DNA binding in vitro

In vitro binding of nickel(II) to DNA and the effects of divalent essential metals calcium, magnesium, manganese, copper, and zinc, and of amino acids histidine, cysteine, glutamine, arginine, lysine, alanine, and glycine upon that binding were investigated. Samples of 0.156 mg of calf thymus DNA (0.078 mg/ml in 5 m m ammonium acetate buffer, pH = 7.4) were incubated for 1 hr at 24°C with various concentrations of nickel(II)acetate labeled with 63Ni (0.1 to 250 μ m) in the absence or presence of 50 μ m concentrations of the essential metal acetates, or with 100 μ m concentrations of the amino acids. Free and DNA-bound nickel(II) fractions were separated by gel filtration on Sephadex G-25 and quantified by liquid scintillation counting. Scatchard analysis revealed more than two types of nickel(II)-binding sites and a positive cooperativity of binding at the bound-Ni concentrations below 0.35 μ m. The high-affinity nickel(II)-binding sites at DNA were identified as phosphate groups. Their binding capacity equalled 0.043 μmol/mg DNA (approx, 1 mol Ni 70 mol of DNA bases). The apparent dissociation constant of nickel(II) from the high-affinity sites was 5.35 μ m. Double reciprocal plots showed the essential divalent metals to be competitive antagonists of nickel(II)-binding to the high-affinity sites, ranking Mg(II) ≥ Mn(II) > Ca(II) ≥ Cu(II) = Zn(II). Similarly, the amino acids antagonized nickel binding to DNA with a relative strength of His > Gln ≥ His Cys > Arg > Cys ≥ Gly = Ala ≥ Lys . The strongest inhibitors of nickel(II)-DNA binding in vitro appear to be magnesium and manganese, i.e., the same metals that are capable of attenuating nickel carcinogenicity in vivo.