Nickel Concentration In Solution Research Articles

Selection of thermophiles for base metal sulfide concentrate leaching, Part II: Nickel-copper and nickel concentrates

The ferrous iron- and sulfur-oxidizing Acidithiomicrobium was the dominant iron-oxidizing bacterium in a mixed culture of moderate thermophiles in a bioreactor with a high concentration of nickel in solution (20gl−1) and a continuous feed of nickel concentrate. This is the first demonstration specifically indicating that this bacterium could be used for industrial processing of a base metal sulfide concentrate. However, its sensitivity to copper determined that it was replaced by Sulfobacillus thermosulfidooxidans in the mixed culture when the feed was a nickel-copper concentrate. The extraction of copper from the nickel-copper concentrate by moderate thermophiles, despite fine grinding of the feed, was relatively poor (50% at 49°C) compared to that achieved with high temperature archaea (92% at 77°C) in single, continuous reactors with 5% w/v concentrate feeds and residence times of 2.7 and 2.5days respectively.

Ecophysiology of nickel phytoaccumulation: a simplified biophysical approach

Solute active transport or exclusion by plants can be identified by the values of the Transpiration Stream Concentration Factor (TSCF=xylem:solution solute concentration ratio). The aim of this study was to estimate this parameter for Ni uptake by the Ni-hyperaccumulator Leptoplax emarginata or the Ni-excluder Triticum aestivum cultivar 'Fidel'. The Intact Plant TSCF for nickel (IPTSCF(Ni)) was calculated as the ratio between the nickel mass accumulation in the leaves and the nickel concentration in solution per volume of water transpired. Predominantly, Ni active transport occurred for L. emarginata, with IPTSCF(Ni) values of 4.7-7.2 and convective component proportions of the root Ni uptake flow of only 15-20% for a range of Ni concentrations in solutions of 2-16 µmol Ni l(-1), regardless of the growth period and the time of Ni uptake. Hyperaccumulator roots were permeable to both water and nickel (mean reflection coefficient for Ni, σ(Ni), of 0.06), which was mainly attributed to an absence of exodermis. Results provide a new view of the mechanisms of Ni hyperaccumulation. By contrast, the wheat excluder was characterized by an extremely low mean IPTSCF(Ni) value of 0.006, characterizing a predominantly Ni sequestration in roots. From a methodological viewpoint, the 'microscopic' TSCF(Ni), measured directly on excised plants was 2.4 times larger than its recommended 'macroscopic' IPTSCF(Ni) counterpart. Overall, IPTSCF and σ determined on intact transpiring plants appeared to be very useful biophysical parameters in the study of the mechanisms involved in metal uptake and accumulation by plants, and in their modelling.

Modelamento da extração de níquel por D2EHPA em meio sulfúrico

A extração do níquel, em um sistema NiSO4 - H2SO4 - H2O - D2EHPA - Isoparafina, foi estudada por um modelo termodinâmico com base em equações de balanço de massa e carga. Os coeficientes de atividade de todos os solutos, na fase aquosa, foram calculados pela equação de Davies modificada. Ao aplicar esse modelo, a concentração das espécies no equilíbrio foram calculadas a partir dos valores de concentração total de níquel em solução e pH. O metal extraído das espécies foi determinada a ser NiA2 (onde HA é D2EHPA) e a constante de equilíbrio da extração foi encontrado para ter um valor de 2,83 E-2 a partir do cálculo de regressão não-linear realizado com os dados experimentais. Os valores dos coeficientes de distribuição previstos pelo modelo, para a extração de níquel, tiveram uma boa concordância, quando comparados com resultados experimentais.

Application of quartz crystal nanobalance and principal component analysis for detection and determination of nickel in solution

Quartz crystal nanobalance (QCN) sensors are considered as powerful mass sensitive sensors to determine materials in the sub-nanogram level. In the first part of this study, a single piezoelectric QCN modified with polypyrrole (PPy) has been tested for detection and determination of nickel ions in the solution at room temperature. The developed method was successfully applied for detection of total nickel in samples taken from several hot springs located at the Northwest of Iran. The frequency shifts were linear with respect to the concentration of nickel in solution. Using this method, nickel can be measured in the range of 3–20 mg L− 1. A lower limit of detection of 0.79 mg L− 1 and a sensivity factor of 4.429 Hz/mg L− 1 were obtained. Some possible interference such as heavy metal ions (lead, mercury, and cadmium) was checked. No major interference was observed with the performance of the sensor except for mercury. To evaluate the ability of the PPy-modified QCN in discriminating between nickel ions and interfering mercury ions, a principal component analysis (PCA) was carried out. PCA was utilized to process the frequency response data of the single piezoelectric crystal at different times, considering different adsorption-desorption dynamics of nickel and interfering mercury ions on electrode. Using PCA, it was found that about 97.90% of the data variance could still be explained by two principal components (PC1 and PC2). The score plot of the data for the first two PCs showed that the PPy-modified QCN yields favorable identification and quantification performances for nickel ions. The accuracy of method for hot spring samples was evaluated and RSD of 4.10% was obtained.

Selective nickel and cobalt uptake from pressure sulfuric acid leach solutions using column resin sorption

Selective removal of Ni and Co, from a high pressure acid leach (HPAL) solution of a Brazilian laterite nickel ore that contains relatively high concentration of impurities, was carried out with an ion exchange chelating resin possessing iminodiacetic acid group (Amberlite IRC 748®). The resin was tested in column experiments. The experimental results showed that higher pH values improved the ion exchanger performance and higher nickel load capacities were achieved. Besides, increasing nickel concentration in solution, nickel uptake and selectivity were substantially improved. The breakthrough experimental curves also showed that many metals were immediately brokenthrough just after the initiation of the feed, while the breakthrough of Ni began later. These results suggested that it is feasible to purify HPAL solution recovering nickel selectively using the chelating resin Amberlite IRC748® if some specific conditions related to pH, flow rate and nickel concentration are applied. Removal of metals from the resin was successfully performed with HCl and H 2SO 4 solutions. Nickel was eluted concentrated more than 20 times its initial concentration in the feed solution, while only a trace amount of impurities was eluted.

Electrodeionisation 3: The removal of nickel ions from dilute solutions

The removal of nickel ions from dilute solutions using a process that combines an ion-exchange bed with electrodialysis has been studied. The main aspects include: the concentration of nickel ions in the diluate, the voltage over the cell and the current density distribution along the ion-exchange bed. The current density distribution provides insight into the state of the bed as it is simultaneously loaded with Ni2+ and regenerated with an electric potential difference applied perpendicular to it. A simple model is used to describe the state of the bed and the quantity of nickel removed from it as a function of time. Under specific conditions the precipitation of metal hydroxides is observed in the compartment containing the ion-exchange bed. The results show that hydroxide precipitation is related to the nickel concentration in solution and the electric potential gradient across the bed.

Effects of nickel concentration in the nutrient solution on the nitrogen assimilation and growth of tomato seedlings in hydroponic culture supplied with urea or nitrate as the sole nitrogen source

Both the beneficial and the adverse effects of nickel supplement on the N assimilation and growth of tomato plants were evaluated while either urea or nitrate was applied as the sole N source in the nutrient solution. The nickel concentration in the plant was related to that in the solution. Urea toxicity to the plants was reduced by the nickel supplement at 0.01 mgl –1, and no symptom of urea toxicity was observed in the plants when supplemented nickel was at 0.1 or 1 mg 1 –1. Both the plant growth and chlorophyll concentration in leaves of the urea-fed plants increased when nickel concentration in the solution was up to 0.1 mg 1 –1, but decreased by nickel at 1 mg 1 –1. The maximum growth of the urea-fed plants promoted by nickel supplement was still less than 80% of the nitrate-fed plants. Nickel supplement did not affect the growth of the nitrate-fed plants. The concentrations of leaf total-N in the urea-fed plants was enhanced by the nickel supplement, but was still lower than those in the nitrate-fed plants. At 0.1 mg 1 –1 nickel supplement, the concentrations of leaf urea-N and NH 4-N in the urea-fed plants were about one-sixth and four times, respectively, of those without nickel supplement. Urea assimilation increased with the nickel supplement up to 0.1 mg 1 –1. No effect of nickel supplement on the N assimilation in the nitrate-fed plants was found. Nickel supplement up to 0.1 mg 1 –1 reduced urea toxicity and enhanced chlorophyll concentration, plant growth, and urea hydrolysis. The symptom of nickel toxicity and the depression of plant growth were only observed with the nickel supplement up to 1 mg 1 –1.

Nickel biosorption by two chlorella species, C. Vulgaris (a commercial species) and C. Miniata (a local isolate)

The present study compared the efficiency of two unicellular green algae, Chlorella vulgaris (a commercial species from Carolina Biological Supplies Company) and WW1 (an indigenous species isolated from a local sewage treatment works, tentatively identified as Chlorella miniata) in removing Ni 2+ from nickel solutions with concentration ranges similar to that in electroplating effluents. The Ni 2+ removal efficiency of C. vulgaris (around 33–41%) was significantly lower than that of WW1 (more than 99%) in nickel solutions from 10 to 40 μg ml −1. The maximum Ni 2+ uptake by C. vulgaris and WW1 under the present batch experiment was 641.76 and 1367.62 μg g −1, respectively. According to Langmuir adsorption isotherms the nickel adsorption capacity of WW1 (2985.07 μg g −1) was two times greater than that of C. vulgaris (1282.05 μg g −1). These results demonstrated that WW1 was a more powerful Ni 2+ biosorbent than C. vulgaris. In both species, most Ni 2+ in solution was sequestered by the algal cells within the first few minutes of treatment. The cellular Ni 2+ concentration increased with the concentrations of nickel in solution. After treating Ni-containing wastewater for 24 h, both species were still capable of cell division, but the growth rate was reduced in proportion to the concentrations of nickel in the wastewaters.

Multiple metal stress in Triticum aestivum. Differentiation between additive, multiplicative, antagonistic, and synergistic effects

Aluminum toxicity is an important factor limiting plant growth in soils with pH below 5.0. Because metalliferous soils are commonly acidic, understanding plant growth dynamics on such soils may require insight into the interaction between aluminum and other phytotoxic metals. To investigate potential interactions in the phytotoxicity of nickel and aluminum, seedlings of Triticum aestivum L. cv. Neepawa were grown for 14 days in solution culture with varying concentrations of nickel (0–60 μM), with or without 40 μM aluminum. Increasing concentrations of nickel were observed in roots (232–2318 μg ∙ g−1) and leaves (25–152 μg ∙ g−1) with increasing nickel in solution, but concentrations were reduced with addition of aluminum as a second phytotoxic metal (roots: 125–1314 μg ∙ g−1; leaves: 20–108 μg ∙ g−1). Aluminum was only detectable in roots of seedlings grown with aluminum and declined with increasing nickel in the growth solution (1446–530 μg ∙ g−1). Addition of nickel to growth solutions reduced both root (0.981–0.193 g) and leaf (2.608–1.030 g) weights. Aluminum as a second phytotoxic metal further reduced root (0.698–0.194 g) and leaf (2.245–1.111 g) weights at low concentrations of nickel in solution. Analysis of variance of the root weight data indicated a significant nickel × aluminum interaction, but this may not have been indicative of a biological interaction. Root weight, both in the presence and absence of aluminum, decreased to a common minimum at high concentrations of nickel in the growth solution, possibly reflecting biomass present at the onset of experimental treatments and the lag time required for the expression of the phytotoxic growth response. When root growth relative to control was expressed as weight above the empirical minimum (the root weight index), results of the analysis of variance were different. Significant main effects of nickel were detected, while main effects due to aluminum and the nickel × aluminum interaction were not significant. Despite antagonistic effects observed with metal uptake and accumulation, such results suggest that the combined toxic effect of nickel and aluminum can be explained by a simple multiplicative model.

ChemInform Abstract: VOLTAMMETRIC EVALUATION OF ZINC ELECTROWINNING SOLUTION CONTAINING NICKEL

AbstractDer Einfluß von Ni2 ‐Zusätzen auf die zyklischen Voltammogramme von sauren ZnSO4‐Lösungen wird untersucht.

Voltammetric Evaluation of Zinc Electrowinning Solution Containing Nickel

The effect of nickel impurity in zinc sulfate electrowinning solutions was studied using voltammetry techniques. The reactions occurring at various points on the polarization curve are proposed and comparisons made for both pure electrolyte and those containing nickel. A nickel‐activated hydrogen evolution peak was found to occur at low current densities during the anodic sweep portion of the curve, the height of which was found to be proportional to the nickel concentration in solution. The influence of certain operating parameters such as zinc ion concentration, potential scan limit, and scan rate on the nickel activated peak was also determined.