Nickel Ions In Solution Research Articles

Zeolite-Clinoptilolite conditioning for improved heavy metals ions removal: A preliminary assessment

The emerging problem of nickel allergy is increasingly widespread due to the increase in nickel content in everyday foods. The physicochemical structure of the zeolites makes it possible to adsorb nickel ions in solution. The properties of molecular sieves, together with those of a size and a chemical composition compatible with the human gastrointestinal tract, are present in a particular zeolite called clinoptilolite. In this work, a type of natural clinoptilolite was characterized before and after being subjected to two different conditioning processes with NaCl to increase its adsorption efficiency and specificity against nickel. The three forms of clinoptilolite, natural, conditioned, and biconditioned, were compared based on analysis of absolute density, X-ray diffraction pattern, granulometry, porosity, chemical composition, and grain morphology. Finally, nickel ion removal tests were performed in an aqueous solution that simulates the conditions of the gastrointestinal tract. The Ni2+ removal efficiency of natural clinoptilolite is 73.2%, while after conditioning it reaches 96.6%. Double conditioning with Na does not generate a considerable increase in removal efficiency which remains at 96.8%.

Effect of Ni ions on the DNA spectral properties and photostability

The optical absorption, fluorescence, phosphorescence in UV and visible spectral range, and effect of light irradiation on spectral properties of DNA with the presence of nickel ions are studied. The quantity of nickel ions varies from 1 ion per 500 base pairs of DNA to 2 ions per base pair. Three important features fixed: the shape of fluorescence and phosphorescence spectra of the DNA do not change in presence of Ni, but their intensity depends on the number of nickel ions in solution; phosphorescence intensity decreases more rapidly than fluorescence; the small decrease of DNA photodegradation rate in presence of Ni is observed. The average of triplet exciton path length evaluated from the dependence of phosphorescence/fluorescence intensity ratio on the relative concentration of nickel ions is 30–20 DNA pair sequence length. It was proposed that nickel ions interact in the outer side of DNA with the phosphate groups and do not penetrate intra macromolecular space.

Nickel Contamination from Caustic Etching of Silicon Wafers

Silicon etch rate with caustic is widely investigated due to its anisotropic etch behavior which is important for semiconductor device fabrication. In wafer manufacturing, caustic or acid etching is used to remove surface defects produced from prior processing steps. Prevention of metal deposition is an important consideration for use of caustic in silicon wafer manufacturing process (1). Deposition behavior of nickel on doped silicon wafer from caustic solution is investigated here. A number of process parameters like type of caustic, doping level, and process temperature on deposition behavior of nickel from KOH and NaOH solution are considered. The mechanism of nickel deposition is discussed along with prevention of deposition from caustic solution. Boron doped P-type silicon wafer of low and high resistivity and <100> orientations is used for the investigation. The wafers were etched approx. 48%-50% by wt. caustic solution at temperatures and duration indicated for investigation. The level of nickel concentration in caustic solution is less than 100 ppb. Surface nickel is investigated following treatment in caustic solutions followed by rinsing with DI water. For bulk measurements of nickel, the wafers were subjected to standard polishing and cleaning procedures following the indicated caustic etch treatment indicated below. Both surface and bulk contamination of silicon wafer by caustic solutions is investigated. Surface adsorption of nickel from these two caustic solutions is shown in Figure 1. Contamination is found to be higher with NaOH compared with KOH. Bulk contamination of nickel from each of these caustic solutions as a function of resistivity is shown in Figure 2. The amount of deposited nickel tends to increase with increasing doping level for both the NaOH and KOH used here. The increased level of nickel adsorption from NaOH is likely due to lower stability of the nickel ion in NaOH compared to KOH based caustic solution. This is explained by increased availability of water molecule in KOH based caustic compared to NaOH based solution (2). The impact of doping level on deposition is explained by higher reduction potential of boron compared to silicon which enhances the oxidation by OH ion as substrate resistivity is reduced. Furthermore, deposition of nickel ion from alkaline solution also favors the deposition on substrate due to higher reduction potential for the metal compared to silicon in solution (3). The amount of deposited nickel from caustic solution is also found to increase with solution temperature due to increase in metal diffusivity with increasing solution. Finally, the prevention of nickel deposition from the caustic solution is found to be effective with the addition of chelating agent like TTHA and DTPA in caustic solution due to higher stability index of nickel ion with these agents in high pH caustic solution. Addition of peroxide in caustic is also found to be effective in preventing nickel deposition by enhancing the stability of nickel ions in solution. References G. B. Larrabee, J. Electrochemical Soc., 108, 1130 (1961).H. Freiser and Q. Fernando, Ionic Equilibria in Analytical Chemistry, John Wiley and Sons Inc., New York, 1963.Yoshihiro, M, K. Uemura, K. Shimanoe and T. Sakon, J. Electrochem. Soc., Vol. 142 (9), 3104, 1995.

Cobalt Alloy Implant Debris Induces Inflammation and Bone Loss Primarily through Danger Signaling, Not TLR4 Activation: Implications for DAMP-ening Implant Related Inflammation

Cobalt alloy debris has been implicated as causative in the early failure of some designs of current total joint implants. The ability of implant debris to cause excessive inflammation via danger signaling (NLRP3 inflammasome) vs. pathogen associated pattern recognition receptors (e.g. Toll-like receptors; TLRs) remains controversial. Recently, specific non-conserved histidines on human TLR4 have been shown activated by cobalt and nickel ions in solution. However, whether this TLR activation is directly or indirectly an effect of metals or secondary endogenous alarmins (danger-associated molecular patterns, DAMPs) elicited by danger signaling, remains unknown and contentious. Our study indicates that in both a human macrophage cell line (THP-1) and primary human macrophages, as well as an in vivo murine model of inflammatory osteolysis, that Cobalt-alloy particle induced NLRP3 inflammasome danger signaling inflammatory responses were highly dominant relative to TLR4 activation, as measured respectively by IL-1β or TNF-α, IL-6, IL-10, tissue histology and quantitative bone loss measurement. Despite the lack of metal binding histidines H456 and H458 in murine TLR4, murine calvaria challenge with Cobalt alloy particles induced significant macrophage driven in vivo inflammation and bone loss inflammatory osteolysis, whereas LPS calvaria challenge alone did not. Additionally, no significant increase (p<0.05) in inflammation and inflammatory bone loss by LPS co-challenge with Cobalt vs. Cobalt alone was evident, even at high levels of LPS (i.e. levels commiserate with hematogenous levels in fatal sepsis, >500pg/mL). Therefore, not only do the results of this investigation support Cobalt alloy danger signaling induced inflammation, but under normal homeostasis low levels of hematogenous PAMPs (<2pg/mL) from Gram-negative bacteria, seem to have negligible contribution to the danger signaling responses elicited by Cobalt alloy metal implant debris. This suggests the unique nature of Cobalt alloy particle bioreactivity is strong enough to illicit danger signaling that secondarily activate concomitant TLR activation, and may in part explain Cobalt particulate associated inflammatory and toxicity-like reactions of specific orthopedic implants.

PREPARATION AND CHARACTERIZATION OF ELEC-TROLESS Ni COATING ON THE SURFACE OF MgO WITH POROUS STRUCTURE

Generally,the surface pretreatments such as sensitization and activation are necessary for depositing a nickel metal layer on oxide surface by electroless plating,however,for an oxide surface with porous structure it is possible that the pretreatment is not necessary.In this paper,only by use of the surface activity of porous structure,an electroless plated nickel layer can be prepared on the surface of microarc-oxidation-fabricated porous magnesium oxide film in a conventional electroless nickel plating solution,consisted of nickel sulfate as main salt and sodium hypophosphite as reducing agent.Furthermore,the phase,microstructure,electrical conductivity and corrosion resistance of the obtained nickel layer were characterized.The results indicate that the 5μm-thick nickel layer is composed of fine and homogeneously distributed nickel particles,at the same time the microstructure of nickel layer is dense.Nickel layer spreads into the micropores on the surface of porous magnesium oxide film,so that an interleaving interface is formed at nickel/oxide interface.XRD results reveal that the nickel layer contains crystalline Ni and amorphous Ni-P.Four-point probe measurement indicates that the nickel layer exhibits well electrical conductivity.Meanwhile,polarization curve reveals that corrosion potential elevates notably due to the presence of nickel layer.During electroless nickel plating the nickel ions in solution were reduced and deposited in the micropores of porous magnesium oxide film under the action of reducing agent ions,so as to generate tiny primary nickel particles, subsequently,these primary nickel particles continuously grew and spread,and finally formed an entire nickel layer on oxide surface.

The Ni(II)-Binding Properties of the Metallochaperone SlyD

Metallochaperones are essential for the safe and targeted delivery of necessary yet toxic metal cofactors to their respective protein partners. In this study we examine the nickel-binding properties of the Escherichia coli protein SlyD, a factor that contributes to optimal nickel accumulation in this organism. This protein is also required for E. coli energy metabolism because it participates in the nickel insertion step during [Ni-Fe]-hydrogenase metallocenter assembly. Our study demonstrates that SlyD is a multiple nickel ion binding protein. The analysis of noncovalent metal-protein complexes via electrospray ionization mass spectrometry revealed that SlyD binds up to seven nickel ions in a noncooperative manner with submicromolar affinity (<2 microM, upper limit) and that the protein exists in a dynamic mixture of metalloforms that is dependent on the availability of nickel ions in solution. Structural analysis indicates that this metallochaperone undergoes small but distinct changes in the structure upon metal binding and that the nickel-binding sites are assembled through beta-turn formation. Although the C-terminal metal-binding domain is primarily responsible for metal chelation, we find that metal binding also perturbs the structure of the N-terminal domains. An investigation of the nickel sites by using X-ray absorption spectroscopy shows that SlyD binds nickel ions by adapting several different geometries and coordination numbers. Finally, the characterization of SlyD mutants demonstrates that the cysteine residues in the C-terminal domain confer tighter affinity as well as increased binding capacity to SlyD. On the basis of the presented data a model for nickel binding to SlyD as well as its role in nickel homeostasis is discussed.

Preparation of fine nickel powders via reduction of nickel hydrazine complex precursors

Fine nickel(Ni) powders with controllable particle sizes were synthesized via the reduction of nickel hydrazine complex precursors of pure [Ni(N 2H 4) 2]Cl 2 and a mixture of [Ni(N 2H 4) 2]Cl 2 and [Ni(N 2H 4) 3]Cl 2 in aqueous solution. The mechanism of the formation of metallic Ni powders experiences the reduction of nickel hydroxide by hydrazine released from the ligand exchange reaction between nickel hydrazine complex and NaOH. In comparison with the method of preparing Ni powders from nickel salts, the method of making Ni powders via the reduction of nickel hydrazine complex precursors shows the advantages of using half dosage of hydrazine for complete reduction of nickel ions in solution, and the obtained Ni particles show less agglomeration and better dispersibility. Moreover, the average particle size of nickel powders can be controlled from 180 to 260 nm by adjusting the reaction molar ratio and concentration.

4-cyanoimidazolate: a new pseudo-cyanide?

Because of its exobidentate nature, pK(a), and electronic properties, 4-cyanoimidazole has been examined as a ligand and as a pseudo-cyanide. The ligand reacts readily as an anion with both cobalt and nickel ions in solution to form coordination polymers. The magnetic susceptibility and thermal stability of these materials are reported. 4-Cyanoimidazolate forms a hexakis complex with nickel, to form the first observed hexakis imidazolate nickelate complex.

Characterisation of electrodeposited nickel nanowires using NCA template

This paper reports on the growth of nanowires of nickel by electrodeposition in nano channel alumina (NCA) membranes. To make ohmic contact, one side of the NCA was sputtered with aluminium and nickel was electrodeposited from the other side. Nickel ions in solution migrate into the pores by the action of electrical potential, filling them approximately to 80% of solid-metal density. These ions form wires imbedded in the NCA matrix. Scanning electron microscopy (SEM) images were used to examine the growth mechanism of the nanowires. The images revealed that the wires started to grow from the aluminium backing plate, although a small number of wires grew from the middle of the pores. One possible reason of this partial pore fill-up could be the trapped air pocket inside the pores when the NCA was placed into the electrolyte. The mechanism of growth of the wires was studied by varying the electrochemical cell parameters temperature, pH and time. Purer nickel wire growth was observed with less nickel hydroxide species contamination at higher temperatures and at lower pH. X-ray diffraction spectra of FCC nickel nanowires were found to be polycrystalline and had a preferred orientation of (200) plane at higher bath temperature (60°C). Bulk magnetic properties of nickel filled nanoporous arrays were investigated by the vibrating sample magnetometer (VSM). The magnetization hysteresis at room temperature showed enhancement of coercivity for magnetic field applied parallel to the nanowires compared to that for perpendicular applied field. Magneto-impedance was measured as a function of applied magnetic field and wire diameter.

Limitations of Nickel Hypophosphite Electroless Nickel Processes

The effects of replenishment chemistry during electroless nickel deposition on solution volumes are investigated. Purging electroless nickel solutions is necessary to maintain a low concentration of orthophosphite ions in solution. Electroless nickel solutions that operate at high bath loadings require large volumes of nickel solution to maintain a constant concentration of nickel ions in solution. The low solubility of nickel in hypophosphorous acid dictates the high replenishment volume of the nickel solution. However, it is shown that the purge rate is too low compared to the replenishment feed rate particularly when high bath loadings are necessary in solution.

Charge Exchange Processes during the Open‐Circuit Deposition of Nickel on Silicon from Fluoride Solutions

The open‐circuit potential deposition of nickel on silicon from fluoride solutions has been studied under potentiostatic control for two extreme values of pH. At pH 1.2, nickel ions are unable to exchange charge with the silicon substrate, and thus deposition is not observed. At pH 8.0, nickel ions in solution can exchange electrons with both the conduction band and the valence band of the silicon substrate in order to be reduced and deposit on the surface. The results are interpreted in terms of the coupling between the anodic dissolution of silicon in fluoride media and two competing cathodic reactions, hydrogen evolution and nickel deposition. The role of silicon surface states as dissolution intermediates is recalled and their interplay with the cathodic reactions is discussed as a function of solution pH. Surface states must also be relevant in the deposition process from other metallic ion solutions of high technological interest whose energy levels lie within the silicon bandgap. © 2000 The Electrochemical Society. All rights reserved.

The Effect of Ozone on the Corrosion Behavior of Ni-Cr-Mo Alloys in Artificial Seawater

The effects of ozonated seawater on the corrosion behavior of Ni-Cr-Mo alloys C-276, C-22, 625 and 59 were studied and the results were compared with those obtained for aerated solutions. Corrosion rates and crevice corrosion information obtained from plate samples at intervals of 2, 4, 8, 16, 26, and 47 weeks were compared with electrochemical measurements of corrosion potential, linear polarization resistance (LPR), and cyclic polarization curves from concurrently immersed wire samples. It was observed that samples in ozonated seawater, in general, exhibited higher corrosion rates (5--34 {micro}m/yr), as measured by both LPR and weight change measurements, than those exposed to aerated seawater. These relatively low corrosion rates were accompanied by the precipitation of voluminous amounts of black flocculent corrosion product in the ozonated solution, identified as hydrated nickel chlorates formed from dissolved nickel ions in solution. The only adherent corrosion product observed on samples in ozonated solutions is characterized by the presence of a thin oxide film exhibiting interference coloration, which varied from alloy to alloy, and with time of exposure. Creviced samples of alloy C-276 in ozonated seawater showed preferential corrosion at the interface between creviced and uncreviced surfaces, with the creviced surface being completely protected, in contrastmore » to slight pitting damage observed in the crevice region of samples exposured to aerated seawater. Cyclic polarization curves of alloys C-276 and C-22 also suggested increased crevice corrosion susceptibility in ozonated seawater, as indicated by the presence of a hysteresis loop and an increase in the passive current density compared to those observed in aerated seawater.« less

Removal and recovery of nickel ion in sodium citrate solution with chelating resin containing triethylenetetramine side chain

AbstractRemoval and recovery of nickel ion in sodium citrate solution with the macroreticular chelating resin containing triethylenetetramine side chain was investigated. The resin (RMT) exhibited high affinity for nickel ion in a solution containing 100 mmol/dm3 of sodium citrate over the pH range of 7.4–11.5. The adsorption of nickel ion was above 98%. In the column method, the breakthrough capacity of the RMT for nickel ion was 3.0 g/dm3‐resin, when the solution containing 0.5 mmol/dm3 of nickel (II) nitrate and 100 mmol/dm3 of sodium citrate was passed through the RMT column at a space velocity of 7.5 h−1. The nickel ion adsorbed was eluted by allowing 1 mol/dm3 hydrochloric acid to pass through the column. The recycle of adsorption and elution was found to be satisfactory.

Determination of Trace Arsenic and Selenium in Copper and Nickel Powders by Hydride-Generation Atomic Absorption Spectrometry after Chelex Separation

Trace arsenic and selenium in copper or nickel powder were determined, after separation with Chelex 100 resin, by hydride-generation atomic absorption spectrometry in the presence of masking agents. When recoveries of arsenic or selenium were checked in the presence of copper or nickel ion in solution, they were quantitative. On the contrary, the recoveries of arsenic or selenium added to copper powder were not quantitative without masking agents, which may be due to partial elution of copper from the resin. Accuracies tested with an NBS Standard Reference Material were within the certified values.