Sorption of nickel on marl

Batch sorption experiments using nickel have been carried out on marl, a sedimentary, carbonaceous rock. All experiments were performed with a synthetic water of pH 7.3 and in an atmosphere of N₂/1% CO₂. Over the equilibrium nickel concentration range of 10^–11–10^–5M, sorption was linear and reversible with R_d of 819 ml g^–1. Owing to the linear sorption behavior, R_d was independent of rock/water ratio (r/w=1/5–1/100). The data suggested that at [Ni] lower than 10^–7M an isotope exchange mechanism operated, whereas at higher [Ni], sorption involved ion exchange. Sorption experiments on some of the components of marl indicated that nickel adsorbs mainly on the clay minerals and on the trace of iron hydroxide present; sorption on calcite and quartz was low.     

Characterization of an epithermal irradiation facility

An epithermal energy neutron irradiation facility has been used to perform instrumental activation analysis for iodine, silicon, nickel, zirconium, uranium and thorium. The facility, which is adjacent to the fuel of the University of Virginia 2.0 MW pool reactor, consists of a dry sample region surrounded by a fixed cadmium shield. A boron nitride capsule can be used to hold the sample in the cadmium facility to further enhance the reduction of thermal neutron activation. The neutron fluence rate is 2.2×10¹⁶ n·m^–2·s^–1 for fission spectrum energy neutrons (measured with Ni(n,p)Co) and 8.2·10¹⁵ n·m^–2·s^–1 for resonance energy neutrons (measured with gold).Iodine has been measured at concentrations as low as 0.1 mg/kg with 3% counting statistics in powdered infant formula and 0.15 mg/kg with 5% statistics in liquid infant formula. Silicon has been measured at concentrations of 0.2% in biological samples with counting statistics between 5 and 10% and in coal and soil at concentrations greater than 4% with better than 1% statistics. Nickel has been measured in coal and soil at the 20 mg/kg level and higher with 6% statistics. Zirconium has been determined at 600 mg/kg and greater in ceramics with counting errors less than 3%. Uranium and thorium have been measured at the 10 mg/kg level with 3% counting statistics.     

One electron oxidation of Ni(II)-iminodiacetate by carbonate radical

Reactions of carbonate radical (CO₃ ^–), generated by photolysis or by radiolysis of a carbonate solution with nickel(II)-iminodiacetate (Ni(II)IDA) were studied at pH 10.5 and ionic strength (I)==0.2 mol·dm^–3. The stable product arising from the ligand degradation in the complex is mainly glyxalic acid. Time-resolved spectroscopy and transient kinetics were studied using flash photolysis. From the kinetic data it was suggested that the carbonate radical initially reacts with Ni(III)IDA with a rate constant (2.4±0.4)·10⁶ dm³·mol^–1·s^–1 to form a Ni(II)IDA species which, however, undergoes a first-order transformation (k=2.7·10²·s^–1) to give a radical intermediate of the type Ni(II)RNHCHCO ₂ ^– ) which rapidly forms an adduct containing a Ni–C bond. This adduct decays very slowly to give rise to glyoxalic acid. From a consideration of equilibrium between Ni(II)IDA and Ni(III)IDA, the one electron reduction potential for the Ni(III)IDA/Ni(II)IDA couple was determined to be 1.467 V.     

Assessment of the essential element and heavy metal content of edible fish muscle

The aim of this work was to determine the concentrations of some essential and toxic elements in the muscle of ten species of commercial fish consumed in Portugal. We combined two different techniques for determination of the elements—energy-dispersive X-ray fluorescence (EDXRF) was used to quantify K, Ca, Fe, Zn, Se, Rb, and Sr and flame atomic-absorption spectrometry for analysis of Cr, Ni, Cu, Cd, Hg, and Pb. The latter technique was used because of its higher sensitivity, because these elements were not detected by EDXRF. The results obtained show a similar pattern for the trace elements. K and Ca are present at the highest concentrations in all the samples studied, from 0.6–1.3% and from 0.04–0.08%, respectively, followed by Zn, Fe, Sr, Se, and Rb. Sr is present at higher concentrations than Rb in all the species studied except meagre. Concentrations of the elements in octopus do not follow this pattern—Fe is present at a higher concentration than Zn. Low concentrations of Cr (0.66–1.5 g g^–1), Ni (0.11–0.24 g g^–1), Cd (0.01–0.08 g g^–1), Hg (0.49–2.74 g g^–1), and Pb (0.02–0.06 g g^–1) were observed in all the samples analysed. The concentration of Hg was highest in Helicolenus dactylopterus—5.4 g g^–1 in one sample.     

Decorating multi-walled carbon nanotubes with nickel nanoparticles for selective hydrogenation of citral

The nanocomposites of multi-walled carbon nanotubes (MWNTs) decorated with nickel nanoparticles were conveniently prepared by a chemical reduction of nickel salt in the present of poly(acrylic acid) grafted MWNTs (PAA-g-MWNTs). Due to the strong interaction between Ni²⁺ and –COOH, PAA-g-MWNTs became an excellent supporting material for Ni nanoparticles. The morphology and distribution of Ni nanoparticles on the surface of MWNTs were greatly influenced by the reduction temperatures, the experimental results also showed that the distribution of Ni nanoparticles was greatly improved while the MWNTs were modified by poly(acrylic acid) (PAA). The hydrogenation activity and selectivity of MWNTs decorated with Ni nanoparticles (Ni-MWNTs) for α, β-unsaturated aldehyde (citral) were also studied, and the experimental results showed that the citronellal, an important raw material for flavoring and perfumery industries, is the favorable product with a percentage as high as 86.9%, which is 7 times higher than that of catalyst by Ni-supported active carbon (Ni-AC).     

Intermediate molybdenum oxides involved in binary and ternary induced electrodeposition

The first stages of Co–Ni and Co–Ni–Mo deposition in sulphate–citrate medium at pH 4.0 were analysed. In both cases, the formation of non-hydrogenated nickel on the electrode before alloy deposition was detected by linear sweep voltammetry and inductively coupled plasma mass spectrometry. Co–Ni electrodeposition was anomalous since the Co/Ni ratio in the alloy was higher than the corresponding [Co(II)]/[Ni(II)] ratio in solution. The adsorption of Co(II) over the initial nickel could explain the anomalous codeposition, which persisted with the addition of molybdate to the Co–Ni bath. However, the formation of intermediate molybdenum oxides also took place. A mechanism has been proposed to describe the sequence of steps for Co–Ni–Mo electrodeposition. Under our conditions, the alloy is formed mainly from free Co²⁺ and Ni²⁺ cations, whereas molybdate is reduced firstly to molybdenum oxide from MoO₄(H₃Cit)²⁻ and, secondly, NiCit⁻ catalyses the subsequent reduction to molybdenum metal of the intermediate [MoO₂–NiCit⁻]_ads species.     

Kinetics and mechanism of ligand substitution of mono(polyamine)-nickel(II) complexes with 4-(2-pyridylazo)resorcinol

Summary The kinetics and mechanism of ligand substitution reactions of tetraethylenepentamine nickel(II), Ni (Teren), and triethylenetetraamine nickel(II), Ni(Trien), with 4-(2-pyridylazo)resorcinol (parH₂) have been studied spectrophotometrically at I=0.1 M (NaClO₄) at 25°C. In both systems two distinct reaction steps are observed. The rapid first step follows the rate law d[Ni(Polyamine)(ParH₂)]/dt=k₁ [Ni(Polyamine)] [ParH₂]. The formation of ternary complexes of Ni (Polyamine) with ParH₂ has been investigated under second order equal concentration conditions. The values of second order rate constants for the Trien and Teren reactions are (2.1±0.2)×10⁴ M^–1s^–1 and (7.8±0.6)×10³ M^–1s^–1 respectively at pH=9.0, I=0.1 M and 25°C.The rate law for the second step may be written as d[Ni(Par)₂]/dt=k₂[Ni(Polyamine)(ParH₂)]. Values of k₂ for the Trien and Teren systems are (2.5±0.1)×10^–4 s^–1 and (4.76±0.3)×10^–5 s^–1 respectively.     

Anwendung von Paraffinmembranen zur selektiven Bestimmung von Nickelionen

Zusammenfassung Auf Grund durchgeführter Untersuchungen mit Paraffin- und Gummimembranen wurde festgestellt, daß sich mit deren Hilfe Nickel auch in Gegenwart von Kobalt und Zink ohne vorherige Trennung potentiometrisch bestimmen läßt. Die Bestimmungsgrenze liegt bei 10^–6 Mol Ni/1 in reiner Lösung. Bei Gegenwart von Kobalt und Zink beträgt die untere Grenze der Nickelbestimmung 10^–2% der Kobalt- bzw. Zinkmenge.

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Summary On the basis of investigations made with paraffin- and rubber membranes, it was shown that with their help it is possible to determine nickel potentiometrically without prior separation even in the presence of cobalt and zinc. In pure solution, the limit of determination is 10^–6 mol Ni/1. In the presence of cobalt and zinc the lower limit of the nickel determination is 10^–2% of the quantity of cobalt or zinc.

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Résumé On a établi d'après les recherches effectuées en se servant de membranes de paraffine et de caoutchouc que l'on peut doser potentiométriquement le nickel même en présence de cobalt et de zinc, sans séparation préalable. La limite de dilution atteint 10^–6 mol Ni/1 en solution pure. En présence de cobalt et de zinc, la limite inférieure du dosage du nickel s'élève à 10^–2% de la quantité de cobalt ou de zinc.

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Herrn Prof. Dr.A. A. Benedetti-Pichler zum 70. Geburtstag gewidmet.     

Solid Phase Extractive Preconcentration of Cobalt and Nickel in Hair Samples Using Ethyl Xanthate Modified Benzophenone

The ethyl xanthate complexes of cobalt and nickel are quantitatively retained on benzophenone in the pH range of 8.0–10.0. The solid mixture consisting of metal complex together with benzophenone is dissolved in 5mL of dimethyl formamide, and the cobalt and nickel contents were determined by flame atomic absorption spectrometry. The calibration graphs are rectilinear over the concentration range of 0–75 (Co) and 0–100 (Ni) µgL^–1. The detection limits of flame AAS for cobalt and nickel are lowered by a factor of 200 due to the solid phase extraction preconcentration procedure. NIES CRM Human Hair No. 5 and IAEA Reference Hair HH-1 certified reference materials were used in order to verify the accuracy of the developed preconcentration method in analysing human hair samples. The results obtained were found to be in excellent agreement with certified values. Furthermore, hair samples collected from various inhabitants of different age groups and sex living in the Indian states of Andhra Pradesh and Tamil Nadu were successfully analysed by flame AAS in conjunction with the solid phase extraction preconcentration procedure developed for cobalt and nickel.     

EPR- und optische Spektren von Nickel(III)-serinat

Zusammenfassung DieRacah Parameter des Ni(Ser)₃, (HSer=rac. Serin) wurden nach der vollständigen Energie-Matrix für d⁷-Elektronen in trigonalem Feld berechnet. Beim Grundzustand²E (starkes Ligandenfeld) und C4 B wurden die WerteDq=1778 cm^–1 undB=490 cm^–1 erhalten. Das EPR-Spektrum und der Wert desg-Faktors weisen auf einen kovalenten Charakter der O-Ni-Bindung hin.

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EPR and optical spectra of nickel(III) serinate

TheRacah parameters of Ni(Ser)₃ (HSer=rac. serine) were calculated using the full energy matrix for d⁷-electrons in a trigonal field. The valuesD _q=1778 cm^–1 andB=490 cm^–1 were obtained at ground state²E and C4 B. The EPR-spectrum and the value of theg-factor show that the bonding O-Ni has a covalent character.

     

Mobility of Ni(II) Ions in Inorganic Ion Exchangers Based on Zirconium Hydroxophosphate

The mobility of Ni(II) ions in inorganic ion exchangers based on zirconium hydroxophosphate with varying phosphorus content was studied using electromigration and kinetic methods. It was found that the effective diffusion coefficient of nickel in the ion exchanger phase increased with increasing phosphorus content within the range 1·10^–13 to 2·10^–12 m²/s.     

Spectrophotometric determination of nickel(II), palladium(II) and copper(II) in presence of each other and other ions with 1-(o-carboxyphenyl)-3-hydroxy-3-phenyltriazene

Summary 1-(o-Carboxyphenyl)-3-hydroxy-3-phenyltriazene was found to be an excellent spectrophotometric reagent for the determination of nickel(II), palladium(II) and copper(II). At pH 6.8–8.3, 2.4–3.5 and 2.2–3.8, nickel, palladium and copper form greenish yellow, yellowish orange and light green complexes with maximum absorption at 410, 410, 400 nm, respectively. The systems obey Beer's law with optimum ranges from 0.25 to 2.0 ppm for Ni(II), 0.5–4.0 for Pd(II) and 0.5–4.0 for Cu(II); the elements form 11 complexes with the instability constants 2.1×10^–5, 1.5×10^–5 and 2.0×10^–5, resepctively. Effects of other anions and cations on the colour systems have been studied and procedures for the determination of Ni(II), Pd(II) and Cu(II) in presence of each other are described.

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Spektrophotometrische Bestimmung von Nickel(II), Palladium(II) und Kupfer(II) nebeneinander und in Gegenwart anderer Ionen mit Hilfe von 1-(o-Carboxyphenyl)-3-hydroxy-3-phenyltriazen

Zusammenfassung Ni, Pd und Cu bilden mit dem Reagens bei pH 6,8–8,3, 2,4–3,5 bzw. 2,2–3,8 grünlich-gelbe, gelblich-orange bzw. hellgrüne Komplexe mit Absorptionsmaxima bei 410, 410 bzw. 400 nm. Das Beersche Gesetz wird in den Bereichen 0,25–2,0, 0,5–4,0 bzw. 0,5–4,0 ppm befolgt. Die Elemente bilden 11-Komplexe mit den Instabilitätskonstanten 2,1 · 10^–5, 1,5 · 10^–5 bzw. 2,0 · 10^–5. Der Einfluß anderer Kationen und Anionen wurde untersucht und Arbeitsvorschriften werden angegeben.

     

多孔碳负载镍纳米颗粒的制备及催化氨硼烷水解制氢

合成了蜂窝状的分级多孔碳,并以多孔碳为载体通过浸渍-化学还原法制备碳载镍(Ni/C)作为催化氨硼烷水解制氢的催化剂。采用XRD、BET、SEM、Raman、TEM等手段对样品进行了表征并研究了Ni/C室温催化性能。结果显示,多孔碳比表面积高达737 m²·g^-1,具有部分石墨化结构;负载的非晶态镍纳米颗粒平均粒径约为10 nm,均匀分布在碳基材。碳载镍对氨硼烷水解反应具有良好的催化活性,镍负载量为30wt%时催化性能最佳,298 K温度下放氢速率达到1 304.67 mL·min^-1·g^-1,活化能为29.1 kJ·mol^-1,并且具备一定的催化稳定性,表明Ni/C可作为一种廉价高效的催化剂应用于催化氨硼烷水解制氢。     

Preconcentration and Determination of Trace Nickel Using 1-(2-Pyridylazo)-2-Naphtol (PAN) Immobilized on Surfactant-Coated Alumina

A microcolumn of alumina modified with sodium dodecyl sulfate (SDS) and 1-(2-pyridylazo)-2-naphthol (PAN) was prepared for the preconcentration of trace nickel from water samples for a flame atomic absorption spectrometry (FAAS) determination. Under optimized conditions (pH = 4.0; flow rate, 5 mL min^–1) nickel (II) was retained on the column. The nickel collected on the column was eluted with 5 mL of 0.5 M nitric acid. Recovery was greater than 96.7%. A concentration factor of 300 can be achieved by passing 1500 mL of sample through the microcolumn. The relative standard deviation (ten replicate analyses) at the 40 ng mL^–1 level for nickel was 2.4%, and the corresponding limit of detection (based on 3) was 0.06 ng mL^–1. The method was applied to the determination of Ni in waste and mineral waters.     

多孔碳负载镍纳米颗粒的制备及催化氨硼烷水解制氢

合成了蜂窝状的分级多孔碳,并以多孔碳为载体通过浸渍-化学还原法制备碳载镍(Ni/C)作为催化氨硼烷水解制氢的催化剂。采用XRD、BET、SEM、Raman、TEM等手段对样品进行了表征并研究了Ni/C室温催化性能。结果显示,多孔碳比表面积高达737 m2·g-1,具有部分石墨化结构;负载的非晶态镍纳米颗粒平均粒径约为10 nm,均匀分布在碳基材。碳载镍对氨硼烷水解反应具有良好的催化活性,镍负载量为30wt%时催化性能最佳,298 K温度下放氢速率达到1 304.67 m L·min-1·g-1,活化能为29.1 k J·mol-1,并且具备一定的催化稳定性,表明Ni/C可作为一种廉价高效的催化剂应用于催化氨硼烷水解制氢。     

Low level determination of thallium in biological and environmental reference materials by RNAA using several counting methods

A new RNAA procedure was developed capable of low level determination of thallium in biological and environmental samples. After high fluence neutron irradiation in a nuclear reactor, wet ashing of samples and T1(I) separation by solvent extraction with sodium diethyldithiocarbamate at pH 13, several types of counting were employed to compare their detection limits and to utilize the self-validation principle of NAA. The following measurement modes were used: High efficiency counting of -rays of²⁰²T1 and Hg X-rays produced on decay of²⁰⁴T1 using a well-type HPGe detector, combined ^– ray and ^–-counting of²⁰⁴T1 with the aid of a HPGe planar detector, and liquid scintillation counting and counting of Cerenkov radiation of ^–-particles of²⁰⁴T1. The lowest detection limit of 0.034 ng of T1 was achieved on liquid scintillation counting of²⁰⁴T1. The method was applied for the analysis of biological NIST SRMs 1515, 1573a, 1577b and environmental NIST SRM 1633a. Good agreement was found between the thallium certified value in SRM 1633a and values determined in this work by all counting modes. For SRM 1573a, results in agreement were obtained by two counting modes, while counting of Hg X-rays of²⁰⁴T1 was only used for SRMs 1515 and 1577b.     

Paramagnetic complexes of nickel(I) stabilized by norbornadiene

Nickel(I) compounds whose concentration was 10^–4–10^–6 of the total concentration of nickel added to the system were identified by EPR in the reaction of 2,5-norbornadiene with nickel homoligand allyl complexes Niall₂ (all is C₃H₅, 1-CH₃C₃H₄, or 2-CH₃C₃H₄). The Ni(I) complexes were stable at room temperature under oxygen-free conditions. It was shown that the paramagnetic complexes were in equilibrium with diamagnetic forms. The temperature dependence of the concentration of the paramagnetic species was determined. The structure of the paramagnetic nickel(I) complexes and the possible routes of their formation are discussed on the basis of the obtained data.Translated from Teoreticheskaya i Éksperimental'naya Khimiya, Vol. 26, No. 4, pp. 490–493, July–August, 1990.     

Cyclic voltammetric study of the catalytic behavior of nickel(I) salen electrogenerated at a glassy carbon electrode in an ionic liquid (1-butyl-3-methylimidazolium tetrafluoroborate, BMIMBF4)

Cyclic voltammetry has been employed to examine the electrochemistry of nickel(II) salen at a glassy carbon electrode in an ionic liquid (1-butyl-3-methylimidazolium tetrafluoroborate, BMIM⁺BF₄⁻). Residual water in the ionic liquid can be eliminated by introduction of activated molecular sieves into the electrochemical cell. Nickel(II) salen exhibits a one-electron, quasi-reversible reduction to nickel(I) salen, and the latter species serves as a catalyst for the cleavage of carbon–halogen bonds in iodoethane and 1,1,2-trichlorotrifluoroethane (Freon^® 113). In BMIM⁺BF₄⁻ the diffusion coefficient for nickel(II) salen at room temperature has been determined to be 1.8×10⁻⁸ cm² s⁻¹, which is more than 500 times smaller than that (1.0×10⁻⁵ cm² s⁻¹) in a typical organic solvent–electrolyte system such as dimethylformamide (DMF) containing 0.10 M tetramethylammonium tetrafluoroborate.     

Comparison of GC-ICP-MS and HPLC-ICP-MS for species-specific isotope dilution analysis of tributyltin in sediment after accelerated solvent extraction

This study describes a direct comparison of GC and HPLC hyphenated to ICP–MS determination of tributyltin (TBT) in sediment by species-specific isotope dilution analysis (SS-IDMS). The certified reference sediment PACS-2 (NRC, Canada) and a candidate reference sediment (P-18/HIPA-1) were extracted using an accelerated solvent extraction (ASE) procedure. For comparison of GC and LC methods an older bottle of PACS-2 was used, whilst a fresh bottle was taken for demonstration of the accuracy of the methods. The data obtained show good agreement between both methods for both the PACS-2 sediment (LC–ICP–IDMS 828±87 ng g^–1 TBT as Sn, GC–ICP–IDMS 848±39 ng g^–1 TBT as Sn) and the P-18/ HIPA-1 sediment (LC–ICP–IDMS 78.0±9.7 ng g^–1 TBT as Sn, GC–ICP–IDMS 79.2±3.8 ng g^–1 TBT as Sn). The analysis by GC–ICP–IDMS offers a greater signal-to-noise ratio and hence a superior detection limit of 0.03 pg TBT as Sn, in the sediment extracts compared to HPLC–ICP–IDMS (3 pg TBT as Sn). A comparison of the uncertainties associated with both methods indicates superior precision of the GC approach. This is related to the better reproducibility of the peak integration, which affects the isotope ratio measurements used for IDMS. The accuracy of the ASE method combined with HPLC–ICP–IDMS was demonstrated during the international interlaboratory comparison P-18 organised by the Comité Consultatif pour la Quantité de Matière (CCQM). The results obtained by GC–ICP–IDMS for a newly opened bottle of PACS-2 were 1087±77 ng g^–1 Sn for DBT and 876±51 ng g^–1 Sn for TBT (expanded uncertainties with a coverage factor of 2), which are in good agreement with the certified values of 1090±150 ng g^–1 Sn and 980±130 ng g^–1 Sn, respectively.     

A Catalytic Method for Determining Cadmium(II), Nickel(II), and Zinc(II) Inhibitor Metals

The inhibitory effect of Cd(II), Ni(II), and Zn(II) on the oxidation of 3,3′,5,5′ -tetramethylbenzidine with periodate was detected. The optimum reaction conditions were found, and the procedures were developed for determining 1 × 10⁻² to 10 μg/mL Cd(II), Ni(II), and Zn(II) in solution. The indicator reaction was performed on a number of supports. The maximum inhibitory effect was observed on silica gel-based plates for TLC. Procedures for determining 6 × 10⁻³ to 0.4 μg of these metals were developed. Silica gel plates with the immobilized reagent for cadmium (bromobenzothiazo) were used to preconcentrate cadmium. A selective test procedure was developed for determining 1 × 10⁻⁴ −3 × 10⁻³ μg/mL cadmium with the visual detection of the process rate. Upon the introduction of dimethylglyoxime into the indicator reaction, the inhibitory effect of nickel changed to its promoting effect and the detection limit for nickel was lowered. A procedure was developed for determining 3 × 10⁻⁴ −3 × 10⁻³ μg/mL nickel in solution and 7 × 10⁻³−4 × 10⁻¹ μg nickel on the surface of Sorbfil plates. An assumption was made about the reasons for the inhibitory effect of metal ions on the oxidation of aryl diamines with periodate.__________Translated from Zhurnal Analiticheskoi Khimii, Vol. 60, No. 6, 2005, pp. 662–669.Original Russian Text Copyright © 2005 by Beklemishev, Kiryushchenkov, Stoyan, Dolmanova.