Amount Of Ni2 Research Articles

Acetic acid gas sensors based on Ni2+ doped ZnO nanorods prepared by using the solvothermal method

Ni2+-doped ZnO nanorods with different doping concentrations are prepared via the solvothermal method. The doped ZnO nanorods are characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM), respectively. The amount of Ni2+ ions that enter the lattice of ZnO increases with increasing the Ni2+/Zn2+ molar ratio when the molar ratio of Ni2+/Zn2+ in the starting solution is lower than 3% and does not change obviously if the mole ratio of Ni2+/Zn2+ in the starting solution is in the range of 3–10 mol%. The effect of Ni2+ doping on the gas-sensing properties is investigated. The results reveal that the amount of Ni2+ has a great influence on the response (Ra/Rg) and the gas-sensing selectivity. The sensor based on 1 mol % Ni2+ doped ZnO nanorods (120 °C, 10 h) exhibits a high response to acetic acid vapor, in particular, the responses to 0.001 ppm and 0.01 ppm acetic acid vapor reach 1.6 and 2, respectively. The response time and the recovery time for 0.001 ppm acetic acid are only 4 s and 27 s, respectively.

Chemical and electrochemical recycling of the nickel, cobalt, zinc and manganese from the positives electrodes of spent Ni–MH batteries from mobile phones

Chemical and electrochemical recycling methods for the Ni, Co, Zn and Mn from the positives electrodes of spent Ni–MH batteries were developed. The materials recycled by chemical precipitation have the composition β-Ni(OH)2, Co(OH)2, Zn(OH)2 and Mn3O4. The powder retains sulphate, nitrate and carbonate anions from the mother solution as well as adsorbed water. Studies using cyclic voltammetry show that the current density decreases for scan rates greater than 10 mV s−1 because of the formation of hydroxide films. The amounts of Ni2+, Co2+, Zn2+ and Mn2+ were obtained by analysis of the solution using the inductively coupled plasma with optical emission spectroscopy technique, which demonstrated that the electrodeposition method exhibits anomalous behaviour. The amount of deposited nickel ions is related to the composition of the sulfamate bath. The presence of manganese in the electrodeposits is due to the precipitation of Mn(OH)2, and Zn(OH)42− does not undergo reduction in the investigated potential range. The electrodeposited material contains Ni, Co, CoO, Co(OH)2, and Mn3O4. A charge efficiency of 83.7% was attained for the electrodeposits formed by the application of −1.1 V vs. Ag/AgCl at a charge density of −90 C cm−2. The dissolution of the electrodeposits depends on the applied potential.

Probing Li-Ni Cation Disorder in Li1−xNi1+x−yAlyO2 Cathode Materials by Neutron Diffraction

Neutron diffraction is a unique technique to study Li-ion batteries because of its high sensitivity toward detecting lithium ions and ability to differentiate between different cations. This information is essential for understanding the subtle structure/property relationships of active electrode materials. In this study, neutron diffraction was utilized to probe the cation disorder in LiNiO2 with and without Al3+ substitution by different synthesis processes. The powder neutron diffraction revealed that a strong oxidizer rather than Al3+-doping greatly reduces Li+ and Ni2+ mixing. The amount of Ni2+ at Li-site is 6% for Li1−x(Ni0.75Al0.25)1+xO2 synthesized from excess LiOH, while it is only 0.6% for Li1−x(Ni0.75Al0.25)1+xO2 which was synthesized from excess Li2O2. The reduction of Ni2+ at Li-sites greatly improves electrochemical performance. The substitution of Al3+ stabilizes the hexagonal lattice of Li1−xNi1+x−yAlyO2 even for highly lithium-deficient phases.

A selective flotation-spectrophotometric method for the determination of nickel using dimethylglyoxime

A simple and selective method for separation and preconcentration of nickel has been developed. The method is based on the flotation of a complex of Ni and dimethylglyoxime (DMG) at the aqueous solution-n-hexane interface. The complex was separated and Ni determined spectrophotometrically by DMG after addition of oxidizing agent. The quantitative flotation of the complex was possible in the pH range of 9-12. The method is simple and free from the interference of all cations and anions and has a wide linear range. The procedure was successfully applied to the determination of trace amounts of nickel in well water and waste water in coating plant. The method's accuracy was investigated by using standard reference materials alloys (NIST 864) and by spiking the samples with different amounts of Ni2+.

Sorption kinetics, thermodynamics and competition of Ni2+ from aqueous solutions onto surface oxidized carbon nanotubes

Singlewalled carbon nanotubes (SWCNTs) and multiwalled carbon nanotubes (MWCNTs) were oxidized by NaClO solutions and were employed as sorbents to study their sorption kinetics and thermodynamics of Ni2+ from aqueous solutions. The amount of Ni2+ sorbed onto SWCNTs and MWCNTs increased with a rise in temperature. The sorption kinetics follows the pseudo-second-order rate law while the sorption thermodynamics indicates the endothermic and spontaneous nature. Under the same conditions, the SWCNTs and MWCNTs possess better performance of Ni2+ sorption than the commercially available granular activated carbon, reflecting that both CNTs are efficient Ni2+ sorbents in water and wastewater treatment. The competitive sorption of Ni2+ and Zn2+ onto SWCNTs and MWCNTs was also conducted and revealed that the sorption capacities of Ni2+ and Zn2+ without competition are much greater than those with competition. The competition which Zn2+ exerts on the sorption of Ni2+ is stronger than the competition exerted by Ni2+ on the sorption of Zn2+.

Effects of daily nickel intake on the bio-accumulation, body weight and length in tilapia (Oreochromis niloticus)

Nickel pollution is a serious environmental problem, and its effects may provoke alterations in the ecosystem and in organism of animals and humans. Dermatitis, eczema, and asthma are some illnesses caused by Ni2+ poisoning. In this work, fish fed either Ni2+-enriched pellets or commercial pellets were studied. The amount of Ni2+ in fish were measurements by adsorptive stripping voltammetry (AdSV) with dimethylglyoxime as a complexing agent. The analysis of Ni2+ in fish by AdSV established that its accumulation occurs principally in viscera (670.86 ± 5.82 µg g−1), in the head (697.12 ± 2.77 µg g−1) and in the muscle (405.82 ± 3.26 µg g−1), both after 12 months of experiments. Ni2+ adsorbs preferentially in organs such as the stomach, the intestine, and the kidneys and acts in the central nervous system as well. Tilapia growth and mass were significantly affected by Ni2+ poisoning. From statistical analysis, observed that the results for lengths, weights and metal concentration were different for each sampling at significance level of p < 0.05. The Ni2+ concentration in tilapia was enough to cause the death of tilapias; however, it did not occur because the presence of Zn2+ might act as protective agent of heavy metals.

Use of Phosphate Rock for the Removal of Ni2+ from Aqueous Solutions: Kinetic and Thermodynamics Studies

A study was carried out in batch conditions to examine the removal of nickel ions from an aqueous solution by phosphate rock. The effect of different sorption parameters, such as initial metal concentration, equilibration time, solution pH, and temperature on the amount of Ni2+ sorbed was studied and discussed. The sorption process followed pseudo-second-order kinetics with necessary time of 2h to reach equilibrium. The maximum removal obtained is at initial pH around 8. Nickel uptake was quantitatively evaluated using the Langmuir and Dubinin–Kaganer–Radushkevich model. The Langmuir adsorption isotherm constant corresponding to adsorption capacity, Q0, was found to be 7.63mg∕g. The possibility of metal recovery was investigated using several eluting agents. The desorbed amount of nickel decreased continuously with increasing pH, and increased with increasing Ca2+ concentration in leaching solution.

Removal of nickel(II) from aqueous solution by carbon nanotubes

AbstractSingle‐walled carbon nanotubes (SWCNTs) and multiwalled carbon nanotubes (MWCNTs) were oxidized by NaClO solutions and were employed as sorbents to study sorption characteristics of nickel(II) from aqueous solution. The surface properties of CNTs such as functional groups, total acidic sites and negatively charged carbons were greatly improved after oxidation, which made CNTs become more hydrophilic and resulted in sorption of more Ni2+. The amount of Ni2+ sorbed onto oxidized CNTs increased with a rise in agitation speed, initial Ni2+ concentration and solution pH in the range 1–8, but decreased with a rise in CNT mass and solution ionic strength. The sorption mechanisms are complicated and appear attributable to electrostatic forces and chemical interactions between the Ni2+ and the surface functional groups of the CNTs. The oxidized SWCNTs and MWCNTs have shorter equilibrium time and better Ni2+ sorption performance than the oxidized granular activated carbon, suggesting that both NaClO oxidized CNTs are efficient Ni2+ sorbents and that they possess good potential applications in water treatment. Copyright © 2006 Society of Chemical Industry

Porous dye affinity beads for nickel adsorption from aqueous solutions: A kinetic study

AbstractWe investigated a new adsorbent system, Reactive Red 120 attached poly(2‐hydroxyethyl methacrylate ethylene dimethacrylate) [poly(HEMA–EDMA)] beads, for the removal of Ni2+ ions from aqueous solutions. Poly(HEMA–EDMA) beads were prepared by the modified suspension copolymerization of 2‐hydroxyethyl methacrylate and ethylene dimethacrylate. Reactive Red 120 molecules were covalently attached to the beads. The beads (150–250 μm), having a swelling ratio of 55% and carrying 25.5 μmol of Reactive Red 120/g of polymer, were used in the removal of Ni2+ ions. The adsorption rate and capacity of the Reactive Red 120 attached poly(HEMA–EDMA) beads for Ni2+ ions was investigated in aqueous media containing different amounts of Ni2+ ions (5–35 mg/L) and having different pH values (2.0–7.0). Very high adsorption rates were observed at the beginning, and adsorption equilibria were then gradually achieved in about 60 min. The maximum adsorption of Ni2+ ions onto the Reactive Red 120 attached poly(HEMA–EDMA) beads was 2.83 mg/g at pH 6.0. The nonspecific adsorption of Ni2+ ions onto poly(HEMA–EDMA) beads was negligible (0.1 mg/g). The desorption of Ni2+ ions was studied with 0.1M HNO3. High desorption ratios (&gt;90%) were achieved. The intraparticle diffusion rate constants at various temperatures were calculated as k20°C = 0.565 mg/g min0.5, k30°C = 0.560 mg/g min0.5, and k40°C = 0.385 mg/g min0.5. Adsorption–desorption cycles showed the feasibility of repeated use of this novel adsorbent system. The equilibrium data fitted very well both Langmuir and Freundlich adsorption models. The pseudo‐first‐order kinetic model was used to describe the kinetic data. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100:5056–5065, 2006

無電解ニッケル‐リン‐ＰＴＦＥ複合めっき皮膜の抗菌性と生体物質に対する吸着親和性

The antibacterial activity for pathogenic and food-poisoning bacteria and affinity for biomaterial adsorption of electroless Ni-P-PTFE plated composite coating on stainless steel were studied. The antibacterial abilities of electrolytic Ni plated and electroless Ni-P plated coatings on stainless steel for Escherichia coli increased with decreasing their spontaneous electrode potentials, suggesting that the amount of Ni2+ dissolved from the plated coatings was correlated with the magnitude of antibacterial ability. Growth of pathogenic and food-poisoning bacteria, i. e., Escherichia spp. (coli and O157), Staphylococcus spp. (aureus and MRSA), Salmonella spp., Klebsialla spp., and Pseudomonas spp., was inhibited completely after being in contact with electroless Ni-P-PTFE plated coating for 24 h. The Ni-P and Ni-P-PTFE plated coatings showed high affinities for E. coli adhesion and bovine serum albumin (BSA) adsorption compared with those of stainless steel. Kinetic analysis of cleaning curves of BSA-fouled Ni-P and Ni-P-PTFE plated coatings showed that the first-order desorption rate constants for Ni-P and Ni-P-PTFE plated coatings were lower by one order of magnitude than those for stainless steel. These results indicated that Ni-P-PTFE plated coating had a significantly high antibacterial ability, whereas its surface was more susceptible to biofouling than stainless steel.

Structural and Electrochemical Characterization of the LiNi1-yTiyO2 Electrode Materials Obtained by Direct Solid-State Reactions

LiNi1-yTiyO2 (y ≤ 0.15) layered oxides were synthesized at high temperature by solid-state reactions. Rietveld refinements of their X-ray and neutron diffraction patterns showed that these phases were characterized by an α-NaFeO2-type structure with the following cationic distribution: (Li1-zNi2+z)3b(Ti4+tNi2+t+zNi3+1-z-2t)3aO2 [t = y(1 + z)]. The amount of Ni2+ ions in the lithium site increases with y. A magnetic study confirmed the presence of paramagnetic ions in the interslab space and, therefore, the cationic distribution. These materials used as positive electrode in lithium batteries show reversible behavior. A large decrease of the capacity is observed with increasing y, because of the presence of extra nickel ions in the lithium sites. For the “LixNi0.95Ti0.05O2” composition, 144 mA h/g are obtained in discharge at the 14th cycle at the C/20 rate. The “LixNi1-yTiyO2” phases were characterized for y = 0.05 and 0.10: the simultaneous presence of titanium ions in the slab and of a significant amo...

THE INFLUENCE OF ALUMINIUM AND ALUMINIUM OXIDE ON THE EFFECTS OF MECHANICAL ACTIVATION OF NICKEL HYDROXOCARBONATE

The chemical and physical processes occurring during the grinding of nickel hydroxocarbonate and mixtures of nickel hydroxocarbonate with aluminium and aluminium oxide were discussed. For mechanical treatment a planetary ball mill was used. The phase analyses of ground products were carried out using thermogravimetry and X-ray diffraction methods. The amount of Ni2(OH)2CO3 undecomposed and Al2O3⋅xH2O, xNiO, Ni0, NixAly alloys and remained Al0 in the systems strongly depends on the proportion of components and on the duration of grinding in a mill which was used in the study. The comparative results are presented.

Concurrent sorption of Ni2+ and Cu2+ by Chlorella vulgaris from a binary metal solution.

Kinetics and capacity of Ni2+ and Cu2+ sorption by Chlorella vulgaris were studied using single and binary metal solutions at various concentrations of these metal ions. The second-order rate law best described the kinetics of metal sorption from both single and binary metal systems. C. vulgaris preferentially sorbed Cu2+ over Ni2+ in the binary system. In comparison to the single metal system, the amounts of Ni2+ and Cu2+ sorbed at equilibrium (qe) were respectively 73% and 25%, and the initial rate of sorption (h) was ca. 50% in the case of the binary metal system. The test metals inhibited sorption of each other, thereby indicating competition between Ni2+ and Cu2+ for sorption onto non-specific binding sites. The present study showed that C. vulgaris has specific as well as non-specific sites for the binding of Ni2+ and Cu2+. Participation of these sites for sorption depended on the ratio of Ni2+ and CU2+ in solution. The maximum metal sorption capacity of C. vulgaris was 6.75 mmol g(-1) from the binary metal solution at the tested biomass concentration (100 mg dry weight l(-1)). Total metal sorption was enhanced with increasing total concentration of both the metals up to 1.6 mM, beyond which a decrease occurred. Two-dimensional contour plots were successfully used for the first time for the evaluation of metal sorption potential.

Influence of Ni2+ and Co2+ on Methanogenic Activity and the Amounts of Coenzymes Involved in Methanogenesis.

The requirement of Ni2+ and Co2+ addition on methanogenic activity and the coenzymes involved in methanogenesis were investigated in anaerobic continuous cultivation with synthetic wastewater using acetate as the sole carbon source. Addition of Ni2+ and Co2+ to the synthetic wastewater drastically increased the maximum dilution rate of the cultivation. The concentrations of coenzymes F430 and corrinoids in the biomass increased to 0.62 micromol-Ni/g-VSS and 0.67 micromol-Co/g-VSS, respectively with the increase of the dilution rate. Methanogenic activity of the culture broth also increased with an increase of dilution rate. However, without addition of Ni2+ and Co2+, F430 and corrinoids were not detected in the biomass and methanogenic activity was only a trace level at a dilution rate of 0.025 d(-1). When the amounts of Ni2+ and Co2+ added at a dilution rate of 0.6 d(-1) were lowered in steps, the concentrations of F430 and corrinoids in the biomass and methanogenic activity decreased with decreasing amounts of Ni2+ and Co2+ added. These results suggest that Ni2+ and Co2+ were required for the methane-producing reactions via increases of coenzymes F430 and corrinoids.

Layered double hydroxides with the hydrotalcite-type structure containing Cu2+, Ni2+ and Al3+

Layered double hydroxides (LDHs) with the hydrotalcite-like structure have been prepared containing different amounts of Ni2+, Cu2+ and Al3+ in the brucite-like layers by a coprecipitation method. The samples have been characterized by elemental chemical analysis, powder X-ray diffraction, differential thermal analysis and thermogravimetric analysis, FT-IR and UV–VIS diffuse reflectance spectroscopies, temperature-programmed reduction, and specific surface area and porosity assessment by N2 adsorption at −196 °C. The nature of the phase obtained, crystallinity of the HT-like phase and thermal behaviour of these materials were influenced by MII/Al atomic composition and concentration of bivalent metal ion. Calcination at 500 °C leads to mostly amorphous solids containing NiO, and also CuO (tenorite) for large Cu2+ contents (Cu/Ni molar ratio equal to 4). When the calcination temperature is increased to 850 °C, crystallization of well defined phases (NiO, CuO and NiAl2O4, depending on the relative amounts of Ni, Cu and Al) takes place. Reduction of Cu2+ species in these samples takes place at a lower temperature than that for Ni2+, while the temperature of reduction of nickel is increased with an increase in aluminium and copper content of the samples.

Partition of Microamounts of Some M2+ Ions During MgSO4.7H2O Crystallization

Partition coefficients (D) of trace amounts of Ni2+, Co2+, Zn2+, Cd2+, Cu2+, Mn2+, Ca2+, and Fe2+ have been determined during crystallization of MgSO4.7H2O. Their dependences on the ionic radii of the M2+ ions, solubilities and structures of the corresponding sulfates, as well as the abilities of the microcomponents to form solid solutions with MgSO4.7H2O have been analysed. The D values are in the range from &lt;0·005 (DCa) to 1·13 (DNi) and depend mainly on the ionic radii of the M2+ ions, as well as the structures of the corresponding sulfates and the ability to form solid solutions with the macrocomponent.

Effect of Me&lt;sup&gt;2+&lt;/sup&gt;(Me&lt;sup&gt;2+&lt;/sup&gt;=Ni&lt;sup&gt;2+&lt;/sup&gt;, Zn&lt;sup&gt;2+&lt;/sup&gt;) on Precipitation Reaction in Fe(NO&lt;sub&gt;3&lt;/sub&gt;)&lt;sub&gt;3&lt;/sub&gt;-Me(NO&lt;sub&gt;3&lt;/sub&gt;)&lt;sub&gt;2&lt;/sub&gt;-HNO&lt;sub&gt;3&lt;/sub&gt; Solutions

Effect of Me2+(Me2+=Ni2+, Zn2+) on the formation of precipitation in the Fe(NO3)3-Me(NO3)2-HNO3 solutions was determined on the basis of the potentiometric titration curve. By comparison of the titration curves obtained from Fe(NO3)3-Me(NO3)2 solutions with those of Me(NO3)2 solutions, it was found that the pH values of the plateau in the titration curve and its variation against the amount of added alkali depended on the nature of the respective cation. In the Fe(NO3)3-Ni(NO3)2 solution system, Ni2+ only reacted with Fe3+ untill the molar ratio of Ni2+ to Fe3+ in the precipitates becomes 2:1, but the reaction between Ni2+ and Ni2+ preferentially proceeded to produce Ni(OH)2 when the amount of Ni2+ in the precipitates increased further. In the Fe(NO3)3-Zn(NO3)2 solution system, Zn2+ reacted with Fe3+ to produce amorphous precipitate but the reaction between Zn2+ and Zn2+ simultaneously occurred to produce Zn5(NO3)2(OH)8⋅2H2O irrespective to the amount of Zn2+ in the precipitates. These precipitates were aged at 25 and 75°C. The precipitates obtained at 25°C were heat-treated at 500°C for 2h. The amount of crystalline McFe2O4 in these samples varied between the Fe(NO3)3-Ni(NO3)2 and the Fe(NO3)3-Zn(NO3)2 solution systems. By the aging and heating treatments, only Ni(OH)2 or NiO crystallized in the former system, whereas both ZnFe2O4 and ZnO crystallized in the latter system when the amounts of Me2+ in the precipitates increased.

Coprecipitation of Sr, Ni and U with CaCO3: An Experimental Study

AbstractAt the Finnish candidate sites for a nuclear waste repository, calcite (CaCO3) is a common fracture mineral that may participate in coprecipitation processes. The objective of this preliminary work was to study the coprecipitation of the trace elements Sr, Ni, and U with CaCO3 under controlled conditions. The experiments were made in a titration vessel at room temperature under pure N2 or a 0.1 % CO 2/N2 mixture. The water phase contained CaCl2 (0.01M) and NaCl (0.05 M) to which trace amounts of Ni2+, Sr2+ and UO22+ were initially added. CaCO3 was precipitated by the addition of Na2CO3 and the use of CaCO3 seed crystals. When about 10−4 mol of precipitate had formed, the solution and solid phases were analysed with ICPMS. The results seem to indicate that Ni coprecipitated with CaCO3 under the experimental conditions, while U did not. In the case of Sr, further data are needed in order to make any conclusions from the experiments.

Ca2+ influx into leech glial cells and neurones caused by pharmacologically distinct glutamate receptors

The effect of glutamatergic agonists on the intracellular free Ca2+ concentration ([Ca2+]i) of neuropile glial cells and Retzius neurones in intact segmental ganglia of the medicinal leech Hirudo medicinalis was investigated by using iontophoretically injected fura-2. In physiological Ringer solution the [Ca2+]i levels of both cell types were almost the same (glial cells: 58 +/- 30 nM, n = 51; Retzius neurones: 61 +/- 27 nM, n = 64). In both cell types glutamate, kainate, and quisqualate induced an increase in [Ca2+]i which was inhibited by 6,7-dinitroquinoxaline-2,3-dione (DNQX). This increase was caused by a Ca2+ influx from the extracellular space because the response was greatly diminished upon removal of extracellular Ca2+. The glutamate receptors of neuropile glial cells and Retzius neurones differed with respect to the relative effectiveness of the agonists used, as well as with regard to the inhibitory strength of DNQX. In Retzius neurones the agonist-induced [Ca2+]i increase was abolished after replacing extracellular Na+ by organic cations or by mM amounts of Ni2+, whereas in glial cells the [Ca2+]i increase was largely preserved under both conditions. It is concluded that in Retzius neurones the Ca2+ influx is predominantly mediated by voltage-dependent Ca2+ channels, whereas in neuropile glial cells the major influx occurs via the ion channels that are associated with the glutamate receptors.

Codeposition of SiC powders with nickel in a Watts bath

The effect of the silica layer of SiC powder on ionic adsorption was studied in a Watts nickel plating bath. PZC (point of zero charge) measurement suggested that SiC powder has a tendency to release H+ at pH > PZC (∼ 2.2), and the amount of Ni2+ adsorbed on the surface of the SiC increased with increased pH of the Watts bath. Experimental results showed that SiC powders not only catalyzed the adsorption of hydrogen atoms but also had a significant effect on hydrogen evolution during electrodeposition if the solution pH was less than or equal to 2.0 (∼PZC. Furthermore, SiC powders have a shielding effect which prevents OH− from being released into the solution under an applied potential, which results in more Ni(OH)2 in the deposited layer. SiC powders also promote further adsorption of intermediates of nickel on the electrode surface, as shown by impedance studies.