Free Nickel Research Articles

Determination of Free Nickel Ion Concentrations Using the Ion Exchange Technique: Application to Aqueous Mining and Municipal Effluents

Free metal ion concentration is generally considered a useful indicator of a metal’s bioavailability and ecotoxicity to aquatic biota. This article reports the speciation of nickel in mining and municipal effluents from Sudbury (Ontario, Canada), and also in model solutions containing a fully characterized laurentian fulvic acid (LFA) at environmentally relevant concentrations. A column ion exchange technique (IET) using a cation exchange resin (Dowex 50W-X8) was applied to determine free nickel ion concentrations. In model solutions, reasonable correlation was found between the predictions of an equilibrium-based computer speciation code, Windermere Humic Aqueous Model (WHAM) VI, and the results obtained by IET at low nickel-to-fulvic acid ratios. However at higher mole ratios, the WHAM VI predicted higher free nickel ion concentrations than IET. Only three out of six effluent samples showed reasonable agreement between the IET and the WHAM VI results, indicating the need for further development of IET for application to effluent waters.

ホウ酸代替物質を使用したスルファミン酸ニッケル浴から得られためっき皮膜物性とその応用

Boric acid has been an essential substance in plating technology for obtaining good film properties and for improving bath life. However, there are restrict ions against Boron in waste water ; therefore the development of a boric acid free nickel electroplating bath was in demanded.In our previous paper, we attempted to develop a boric acid-free sulfamate Ni plating bath. We examined over 20 kinds of plating solutions with alternative chemicals, and found that acetic acid, propionic acid, Ni acetate, and citric acid were recognized as potential candidates to obtain similar film properties and appearance. This paper reports the evaluation of deposited film properties obtained using these four kinds of organic acid baths. Acetic acid, propionic acid, and Ni acetate, as replacements for boric acid, exhibited similar properties as those obtained by boric acid. The propionic acid bath showed less pit defects even after thick film formation without surfactants. Accordingly, it appears to be a favorable boric acid replacement for those applications that require thicker require films.

To Be Dinuclear or Not: Z‐DNA Induction by Nickel Complexes

The left-handed Z-DNA has been identified as a gene regulating element. Therefore the generation of Z-DNA through metal complexes might be an innovative way for the regulation of gene expression. Use of the new dinuclear complex N,N,N',N'-tetrakis-[2-(3,5-dimethylpyrazol-1-yl)ethyl]-1,3-propylenediamine-bis(nickel(II) dinitrate) (2) reversibly induced Z-DNA formation. However, when a 1:1 ratio of metal/dinucleating ligand was used as a control, the midpoint of the B- to Z-DNA transition was at the same nickel concentration as in case of the dinuclear complex. The novel mononuclear analogue, N-methyl-N,N-bis-[2-(3,5-dimethylpyrazol-1-yl)ethyl]amine-nickel(II)-dinitrate (3) was inducing the Z-DNA at a similar ratio versus nucleotides as free nickel(II) itself. For the first time, proton and nickel binding constants for the bis-[2-(pyrazol-1-yl)ethyl]amine ligand system are reported and discussed. Both nickel complexes 2 and 3 were structurally characterized by single crystal analysis. Furthermore, the synthesis of the two new ligands, N,N,N',N'-tetrakis-[2-(3,5-dimethylpyrazol-1-yl)ethyl]-1,2-propylenediamine (4) and N-methyl-N,N-bis-[2-(3,5-dimethylpyrazol-1-yl)ethyl]amine (5) is described. The two major synthetic pathways leading to polypyrazoyl amines in general are critically discussed with respect to yield, reproducibility and handling of the intermediates.

Ni Uptake by a Green Alga. 1. Validation of Equilibrium Models for Complexation Effects

Short-term (< 60 min) internalization fluxes (J(int)) by the green alga Chlamydomonas reinhardtii were measured in the presence of a variety of ligands forming hydrophilic (citric, diglycolic, or nitrilotriacetic acids), amphiphilic (Suwannee River fulvic and humic acids), and hydrophobic (oxine, diethyldithiocarbamate) Ni complexes. Free nickel concentrations, ranging from 10(-10) to 10(-3) M, were evaluated by thermodynamic modeling and by a resin exchange technique. Ni internalization appeared to occur via a single transport site that was characterized by a conditional stability constant (pH 6.0, I = 10(-2) M) of 10(5.1) M(-1). In the presence of humic substances, Ni uptake could be quantitatively predicted on the basis of Ni2+ concentrations for two algae: C. reinhardtii and Chlorella kesslerii. In the presence of the hydrophobic ligands, an increase in permeability was observed due to the formation of neutral, lipophilic complexes.

The permeation liquid membrane as a sensor for free nickel in aqueous samples

There are currently a limited number of techniques to study nickel speciation in aqueous samples. This work reports on the use of the permeation liquid membrane (PLM) for that objective. In this paper, the composition of the organic phase was studied to maximize the Ni flux (thus the sensitivity of the device) over a wide Ni2+ concentration range (50 nM to 100 microM) in order to verify its ability to determine free Ni2+ in the presence of Ni complexes. A mixture containing 1,10-didecyl-1,10-diaza-18-crown-6 ether (22DD) and di(2-ethylhexyl)phosphoric acid (D2EHPA) in toluene/phenylhexane was selected as the optimized organic phase for the PLM. The PLM was shown to be a reliable tool to measure free nickel concentrations down to 10(-7) M. The effect of pH on Ni transport was also studied. Fluxes below pH 6 were reduced significantly, i.e. an order of magnitude smaller than fluxes above pH 7.8. Finally, as part of a broader study examining the ability of trace metals to induce antibiotic resistance in bacteria, we used the PLM to quantify the formation, at pH = 7.2, of a weak complex between Ni and Imipenem (a member of the carbapenem class of beta-lactam antibiotics) or its hydrolysis product(s).

Determination of free heavy metal ion concentrations in soils around a cadmium rich zinc deposit

The study of heavy metal speciation is of interest for the evaluation of their ecotoxicological risk. Free heavy metal ion concentrations of Cu2+, Zn2+, Ni2+ and Cd2+ were studied at different soil to soil solution ratio (SSR) to discuss metal bioavailability and toxicity in circumstance. The samples were collected from two farmed soils, impacted by a cadmium rich zinc deposit, Guizhou, China. One is near a bridge (QBT for short), which is 15 km away from smelter and is regarded as polluted by fly ash from smelter, the other is located 300 m away from a smelting factory (BXT for short), and it is polluted badly by waste water from smelter. To determine the free heavy metal ion concentration, Donnan Membrane Technique (DMT) and ECOSAT program were used. The concentrations of free copper and zinc ions in QBT and all studied metal ions in BXT were nearly in direct ratio with the soil to soil solution ratio, and they increased with the increasing of SSR. The variational trends of the concentrations of free nickel and cadmium ions in QBT were contrary to those of copper and zinc ions. The measured and predicted results were compared and they agreed with each other. Individual sorbents contribution to metal binding was also predicted. The results suggest soil organic matter is the most important sorbents in the two soils, and hydrous ferric oxide takes the second place.

Electroless deposition and characterization of Ni–P–WC composite alloys

A composite coating Ni–P–WC was produced using an electroless deposition technique from citrate bath containing WC powder. The influence of plating parameters such as WC content, pH, temperature and stirring rate on the content of WC codeposited with Ni–P alloys were investigated. The maximum value of WC (50–55 V p) codeposited can be achieved at a particle content of 20 gL − 1 in the electrolyte, at pH 5.5–6, temperature 85–90 °C and stirring rate of 150 rpm. Surface morphology and microstructure of Ni–P–WC coatings were determined by means of SEM and X-ray diffraction. It was found that the phase structure of the solid solution cannot be varied by codeposition of WC particles in Ni–P alloys, and it only influences the growth of the crystal planes. The properties of the composite such as hardness and abrasion resistance were also examined and compared with WC free nickel deposited layer. The presence of WC particles in the deposit significantly was found to improve the hardness and abrasion resistance of composite coatings.

Fabrication of Nanosized Alumina Powders by a Simple Polymer Solution Route

The development of a free form bulk Nickel reinforced Alumina matrix nano composites using Air Plasma Spray and laser processing has been presented. The process consumes less time and requires further minimal machining and therefore is cost effective. The relative differences in using APS over laser processing in development of bulk metal-ceramic nanocomposites have been discussed. The process intricacies involved during processing such as material specific mandrel selection, plasma-particle interaction are highlighted. Electroless coating has been used to uniformly disperse Nickel in alumina matrix as a source material. The electroless Ni coated alumina particles are subjected to both laser processing and Air Plasma Spraying with optimized parameters. Consolidation by laser processing could not be achieved as the laser beam was reflective to Nickel. On the other hand, APS Ni-alumina nanocomposite with a cylindrical shape of 1.2" OD x 1" ID x 1.5" length has been fabricated with minimum or no surface defects. HRTEM pictures revealed the nanostructure retention thereby corroborating the fact that bulk nanostructures can be made using Air Plasma Spray. XRD analysis confirmed the phase transformation from alpha alumina to gamma alumina and oxidation of Ni to NiO. Subsequent reduction of NiO to metallic nickel using hydrogen atmosphere has also been demonstrated. Mechanical properties such as, hardness (1025 HV) and fracture toughness (5 MPa m1/2) for the nanocomposite are presented herein.

A new approach for the synthesis of K +-free nickel hexacyanoferrate

A Ni, Al hydrotalcite-like compound (Htlc) has been proven an useful host material for an alternative synthesis of a K +-free mixed hexacyanoferrate Ni 1.5Fe III(CN) 6, which is very difficult to obtain in bulk. The first stage of the procedure consists in the intercalation of hexacyanoferrate(III) inside the Htlc structure. The intercalated Htlc has been treated with a NiNO 3 solution. The obtained material has been characterized by XRD, XAS Raman and FT-IR spectroscopy. The voltammetric response of the compound obtained after the complete solubilization of the Htlc host shows a typical fingerprint of nickel hexacyanoferrate material with a very low level of potassium. Elemental analysis confirmed the absence of K + and thus the occurrence of K +-free nickel hexacyanoferrate (14% yield).

Comparative investigation of N, N′-bis-(dithiocarboxy)piperazine and diethyldithiocarbamate as precipitants for Ni(II) in simulated wastewater

The performances of a coordination polymerization precipitant, N,N′-bis-(dithiocarboxy)piperazine (BDP) were compared with the widely used heavy metal precipitant, diethyldithiocarbamate (DDTC), through the treatment of three kinds of nickel-containing wastewaters, NiSO 4, nickel citrate (NiCA) and Ni 2+-dye. Results indicated that both BDP and DDTC at their stiochiometric doses could reduce 50.00 mg l −1 free nickel(II) to lower than 1.0 mg l −1 (discharge limit of nickel ions in China) and 10% precipitants doses increase could treat NiCA containing 50.00 mg l −1 Ni 2+ to meet the discharge limit. But [NiBDP] n coordination polymerization precipitates had more rapid settling speed than Ni(DDTC) 2 precipitates. It was also observed that BDP could still partly remove Reactive Brilliant Red X-3B from Ni(II)-dye integrated wastewater through the adsorption of the precipitates [NiBDP] n , in addition to precipitating Ni(II). A 1:1 stiochiometric dose of BDP/Ni(II) could decrease Ni(II) from 50.00 to 0.87 mg l −1, and simultaneously reduce the dye from 30.00 to 19.52 mg l −1.

Selection of Novel Nickel‐binding Peptides from Flagella Displayed Secondary Peptide Library

Nickel (Ni) performs its biological or toxic functions in nickel-protein coordination form. Novel Ni-binding peptides were isolated from a random dodecapeptide library displayed on the flagella of Escherichia coli against immobilized ions. On the basis of isolated sequences rich in histidine residues, two secondary libraries were constructed respectively. By consequent selection, more Ni-chelating peptides were identified and the consensus motif RHXHR (where X was always H) was deduced. The result suggested that not only histidine, but also arginine, play an important role in Ni-binding. Furthermore, two selected clones (1035 and 2022) were chosen for further identification. They exhibited similar relative binding affinity, which was about nine times that of the original library derived clones and statistically much more significant than the positive control with polyhistidine insert. Free nickel ions could almost completely inhibit the binding of the clones 1035 and 2022 to immobilized nickel, implicating that the peptides were able to chelate nickel ions. These studies reveal that bacterial surface displayed peptide libraries may have promising future potential for the development of metal bioadsorbents. Furthermore, novel Ni-binding peptides may provide lead molecules for Ni-chelation and applications thereof.

Structure and corrosion resistance of nickel coatings containing tungsten and silicon powders

Ni + W + Si coatings were prepared by nickel deposition from a bath containing a suspension of tungsten and silicon powders. These coatings were obtained at galvanostatic conditions, at the current density of j dep = − 0.100 A cm − 2 and at the temperature of 338 K. For determination of the influence of phase composition and surface morphology of these coatings on changes in the corrosion resistance, these coatings were modified in an argon atmosphere by thermal treatment at 1373 K during 1 h. A scanning electron microscope was used for surface morphology characterization of the coatings. The chemical composition of the coatings was determined by EDS and phase composition investigations were conducted by X-ray diffraction. It was found that the as-deposited coatings consist of a three-phase structure, i.e., nickel, tungsten and silicon. The phase composition for the Ni + W + Si coatings after thermal treatment is markedly different. The main peaks corresponding to Ni and W coexist with the new phases: NiW, NiWSi and a solid solution of W in Ni. Electrochemical corrosion resistance investigations were carried out in 5 M KOH, using potentiodynamic and electrochemical impedance spectroscopy (EIS) methods. On the basis of these investigations it was found that the Ni + W + Si coatings after thermal treatment are more corrosion resistant in alkaline solution than the as-deposited coatings. The reasons for this are a reduction in the amount of free nickel and tungsten, the presence of new phases (in particular polymetallic silicides), and a decrease of the active surface area of the coatings after thermal treatment.

Characteristics of nickel sulphide reduction in Ni2+ free background and Watts nickel plating electrolytes

The electrochemical behaviour and composition of nickel sulphide coatings deposited on glassy carbon (GC) electrode by the successive ionic layer adsorption and reaction (SILAR) method using a nickel(II) ammonia complex and Na2S solutions have been studied in Ni2+ free background, Watts nickel plating and 0·05 M H2SO4 electrolytes by the cyclic voltammetry and X-ray photoelectron spectroscopy (XPS) methods. Analysis of XPS data suggests that the coating is a mixture of two sulphides where NiS dominates. In the Ni2+ free background solution at first the electrochemical reduction of the sulphur rich nickel sulphide to NiS occurs. After that the NiS to metallic Ni is reduced in the potential range of H2 evolution. During the cathodic reduction of the coating in Watts nickel plating electrolyte the sulphur is reduced in the potential range from 0·0 to −0·4 V, while at the potential values <−0·5 V the sulphur rich nickel sulphide and NiS reduction in the H2 evolution range and Ni plating occur.

Mechanisms for catalytic carbon nanofiber growth studied byab initiodensity functional theory calculations

Mechanisms and energetics of graphene growth catalyzed by nickel nanoclusters were studied using ab initio density functional theory calculations. It is demonstrated that nickel step-edge sites act as the preferential growth centers for graphene layers on the nickel surface. Carbon is transported from the deposition site at the free nickel surface to the perimeter of the growing graphene layer via surface or subsurface diffusion. Three different processes are identified to govern the growth of graphene layers, depending on the termination of the graphene perimeter at the nickel surface, and it is argued how these processes may lead to different nanofiber structures. The proposed growth model is found to be in good agreement with previous findings.

High Energy Density Processing of a Free Form Nickel–Alumina Nanocomposite

The development of a free form bulk Nickel reinforced Alumina matrix nano composites using Air Plasma Spray and laser processing has been presented. The process consumes less time and requires further minimal machining and therefore is cost effective. The relative differences in using APS over laser processing in development of bulk metal-ceramic nanocomposites have been discussed. The process intricacies involved during processing such as material specific mandrel selection, plasma-particle interaction are highlighted. Electroless coating has been used to uniformly disperse Nickel in alumina matrix as a source material. The electroless Ni coated alumina particles are subjected to both laser processing and Air Plasma Spraying with optimized parameters. Consolidation by laser processing could not be achieved as the laser beam was reflective to Nickel. On the other hand, APS Ni–alumina nanocomposite with a cylindrical shape of 1.2″ OD × 1″ ID × 1.5″ length has been fabricated with minimum or no surface defects. HRTEM pictures revealed the nanostructure retention thereby corroborating the fact that bulk nanostructures can be made using Air Plasma Spray. XRD analysis confirmed the phase transformation from alpha alumina to gamma alumina and oxidation of Ni to NiO. Subsequent reduction of NiO to metallic nickel using hydrogen atmosphere has also been demonstrated. Mechanical properties such as, hardness (1025 HV) and fracture toughness (5 MPa m1/2) for the nanocomposite are presented herein.

Controlling of Physicochemical Properties of Nickel-Substituted MCM-41 by Adjustment of the Synthesis Solution pH and Tetramethylammonium Silicate Concentration

The effect of initial synthesis solution pH and tetramethylammonium silicate concentration in the synthesis solution on the physical and chemical properties of MCM-41 was systematically investigated using N(2) physisorption, X-ray diffraction, temperature-programmed reduction, in situ Fourier transform IR, UV-vis, and X-ray absorption spectroscopies. pH and tetramethylammonium (TMA) fraction affect the porosity of MCM-41 and the reducibility of incorporated Ni cations; higher pH and TMA concentration produced more porosity with higher stability against reduction, which is attributed to more metal ions locating in the interior of the silica walls. The control of the pore diameter of mesoporous MCM-41 at the sub-nanometer scale may be accomplished by adjusting the pH and TMA fraction. pH may be used to control the surface free silanol group density and nickel reduction degree as well, and this is useful in the design of a specific catalyst for particular reactions, such as CO methanation, which requires highly dispersed, stable metallic clusters with controllable size.

Fabrication and characterization of electro-codeposited Ni/Zr-silicate composite coating

Ni–Zr-silicate (Ni–zircon) composite coating was electro-deposited on mild steel using Watt's nickel bath. Fine (5–10 μm) and coarse (40–60 μm) zircon particles were used. The aim of this study is to compare the effect of zircon addition to the electrolyte on the hardness and wear resistance properties of composite coatings. The results obtained in this study indicated that the codeposition of reinforced particles of zircon to Watt's nickel bath improved the hardness and wear resistance of mild steel samples compared with zircon free nickel bath. On the other hand, microstructure of Ni matrix was changed by the addition of the hard Zr-Silicate particles. It is confirmed that the wear resistance of codeposited layer increases with addition of 25 g/l of large Zr-silicate particles. Moreover, wear resistance increases as the amount of fine zircon particles (5–10 μm) increases.

Laser surface alloying of NiTi shape memory alloy with Mo for hardness improvement and reduction of Ni2+ ion release

Interests in applying NiTi shape memory alloys as metallic implant materials have grown immensely in recent years due to their unique shape memory, super-elastic and corrosion resistance properties. However, concern has been raised for its long-term applications inside the human body because of the risk of release of Ni2+ ions. The sources of Ni2+ ion are the free nickel elements at the surface and the results of fretting wear and corrosion of the metal systems. This paper aims at investigating the feasibility of using molybdenum to alloy with the free Ni on the surface of NiTi alloys and in the mean time improving the surface hardness of NiTi. To introduce Mo into the surface of NiTi metallurgically, laser surface alloying is one of the most feasible route. The mechanical properties of the alloyed surface were examined. A single point wear test was used to study the wear resistance of the samples. It was found that the microhardness and the wear resistance of the laser-alloyed surface were better than the untreated ones. The Ni2+ ion release rate of the laser surface alloying specimen was found to be ten times lower than the untreated one. The corrosion rate of the alloyed surface was an order of magnitude lower than that of the untreated sample.

Extremely large cavity assembled by self-interlocking of distorted biconcave porphyrins

X-Ray analyses of free base, zinc, and nickel complexes of 2,3;7,8;12,13;17,18-tetrakis(6,13-dihydro-6,13-pentaceno)-21H,23H-porphine revealed that the porphyrin chromophores adopted a heavily-saddled conformation by interlocking of the biconcave porphyrins in the crystals containing halobenzenes as crystalline solvents, while the ring was almost flat in the crystals obtained from benzene or from chlorobenzene and isopropanol.

Enhancing the first enzymatic step in the histidine biosynthesis pathway increases the free histidine pool and nickel tolerance in Arabidopsis thaliana

Naturally selected nickel (Ni) tolerance in Alyssum lesbiacum has been proposed to involve constitutively high levels of endogenous free histidine. Transgenic Arabidopsis thaliana expressing a Salmonella typhimurium ATP phosphoribosyl transferase enzyme ( StHisG) resistant to feedback inhibition by histidine contained approximately 2-fold higher histidine concentrations than wild type plants. Under exposure to a toxic Ni concentration, biomass production in StHisG expressing lines was between 14- and 40-fold higher than in wild-type plants. This suggested that enhancing the first step in the histidine biosynthesis pathway is sufficient to increase the endogenous free histidine pool and Ni tolerance in A. thaliana.