Nickel Sulfate Solution Research Articles

Influence of the orientation of constructed blood vessels during the 3D printing on the measurement of the pseudo-oxygen saturation of an artificial blood substitute using conventional oxygen sensors: a test series

BackgroundThe development of phantoms to reduce animal testing or to validate new instruments or operation techniques is of increasing importance. For this reason, a blood circulation phantom was developed to test a newly designed retractor system with an integrated oxygen sensor. This phantom was used to evaluate the impact of the 3D printed blood vessel on the measurement of the oxygen saturation.MethodsA solution of nickel sulfate and copper sulfate was prepared as a substitute for real blood. The absorption spectra of these solutions were recorded and compared with those of blood. Subsequently, the oxygen sensor used was calibrated to the blood substitute. Additionally, blood vessels with a simplified geometry were designed and manufactured using inverted vat polymerization and an elastic material (Formlabs Elastic 50 A). To determine the orientation during the printing process, various vessels were printed. Measurements to assess the effects of disturbance (rotation of the vessels during measurements) on the sensor readouts were prepared.ResultsThe impact of disturbances was verified through the rotation of the 3D printed vessels. It was demonstrated that a direct measurement on the disturbances led to outliers and higher values. An optimal orientation was determined to be a lateral placement (90° or 270°) of the sensor. Regarding the orientation of the vessels within the printing space, an orientation of 45° yielded the best results, as the individual layers had the least impact on the light emitted and received by the oxygen sensor.ConclusionThe achieved results demonstrate the influence of the orientation of the vessel during 3D printing as well as the influence of the position of the vessel during the measurement using a conventional oxygen sensor.

Improvement of Silkworm (Bombyx mori L.) Growth and Cocoon Quality Using Nickel Sulfate Supplementation

The silkworm belongs to the order Lepidoptera and the family Bombycidae (Bombyx mori L.). The silkworm industry plays a crucial role in providing employment opportunities in India. This study investigated the effects of nickel sulfate supplementation on the growth and cocoon quality of silkworm (Bombyx mori L.). The experiment was conducted at a silkworm-rearing center in Palayamkottai, India, from December 2022 to January 2023. Silkworms were fed Victory-1 (V1) mulberry leaves soaked in different nickel sulfate solutions (100 ppm, 300 ppm, and 500 ppm). Larval weight, duration, cocoon weight, shell weight, shell ratio, and pupal weight were measured for 10 healthy silkworms with good quality cocoons selected from each treatment group. Compared to the control group, supplementation with 500-ppm nickel sulfate solution significantly improved silkworm growth performance (weight) and economic traits (cocoon weight and quality). GRAPHICAL ABSTRACT

Étude de l'adsorption des ions de Nickel sur des argiles naturelles locales dans les effluents hydrométallurgiques

This research focuses on the treatment of hydrometallurgical effluents, specifically studying the adsorption of metallic ions such as Nickel, Copper, Cobalt, Mercury, and lead on natural clays from the Democratic Republic of Congo (DRC). Twelve clay samples, six activated with a strong acid and six non-activated, were characterized using various techniques including X-Ray Diffraction, Fourier Transform Infrared Spectroscopy, X-Ray Fluorescence, Transmission Electron Microscopy, and chemical dosage. The characterization revealed that the clays are mixed with several clayey minerals, enriched in aluminum silicate; contain absorption and water retention sites, and exhibit heterogeneities at the interfaces between grains and exchangeable ions. Activating the clays increased their cation exchange capacities, removed impurities, and increased pore size and specific area. Two aqueous solutions were used in the experiments: a laboratory-prepared nickel sulfate solution and a hydrometallurgical aqueous solution from a factory, both initially containing 15 mgL-1 of Ni2+ ions. Results showed that the adsorption of Ni2+ ions increased with the quantity of clay in the solution. The activated clays adsorbed more ions than non-activated clays at the same Ni2+ ion concentration. Additionally, adsorption was weaker in the hydrometallurgical solution compared to the nickel sulfate solution, suggesting competition from other metallic ions. The optimal adsorption occurred with chemically activated clays containing high Na+, Fe2+, and Al3+ ion content and low K+ ion content. The Hill-Langmuir model was used to describe the adsorption results, revealing that minimal quantities of activated clay were needed to adsorb a large quantity of Ni2+ ions in the solution, whereas large quantities of non-activated clays were insufficient. In conclusion, the research demonstrates the potential of natural clays from the DRC to adsorb metallic ions from hydrometallurgical effluents, providing insights for effective treatment methods in the future. The model revealed that the clay samples A2a clay, A6a and A3na have the very elevated reactional sites concentrations.

Solvent extraction of cobalt from artificial nickel sulphate solution using PC-88A organic solution as extractant

In this research, an experiment was carried out to separate cobalt from artificial nickel sulfate solution containing cobalt ions by solvent extraction method using organic solvent 2-ethythexyl phosponic acid mono-2-ethylhexyl ester (PC-88A). The experiment was carried out on a laboratory scale. The experimental variables observed included the acidity of the solution (pH), shaking time, shaking speed, and ratio of aqueous and organic (A/O) volume and concentration of PC-88A extractant. The experimental results showed that at pH 6 as much as 95.68% of cobalt could be extracted with the PC-88A.

Кинетические характеристики процесса регенерационной утилизации отработанного раствора химического никелирования

Galvanic production in terms of the degree of negative impact on the environment occupies a leading position in the global industrial production; therefore, the introduction of regenerative recycling technology is receiving increasing attention. The aim of the present work is to determine the kinetic characteristics of the precipitation reaction in a solution of nickel sulfate with sodium hydroxide to develop a technology for the regeneration utilization of spent solutions of chemical nickel plating (SCNPS). The object of the study was the spent solution of chemical nickel plating of one of the industrial enterprises of Izhevsk. The experiment was carried out in the temperature range 293–333 K at various concentrations of sodium hydroxide (1.25–2.60 M) and nickel sulfate (0.037–0.06 M). To determine the order of the reaction, we plot graphs in the coordinates lg w – lg C(Ni) using the experimental data, where w is the reaction rate. The tangent of the slope of the obtained linear dependences with a high degree of approximation (R2 = 0.98) is close to 2, therefore, the order of the reaction of the deposition of SCNPS with sodium hydroxide is second. With a graphical method for determining the rate constant of a second-order reaction for the dependence 1/С = f(t), the tangent of the slope of the straight line corresponds to the calculated parameter. In the investigated temperature range the rate constant takes values from 5·10-4 to 9·10-4 dm3·mol-1·s-1. The activation energy of the precipitation reaction, determined by the Arrhenius equation by graphic and calculation methods, is 16.57 kJ·mol-1 and 16.44 kJ·mol-1, respectively. The low values of Ea indicate a weak dependence of the reaction rate on temperature. Consequently, the introduction of the technology for the regeneration utilization of SCNPS will not entail large expenditures of energy resources for heating the reaction masses.

Heavy metals mitigation and growth promoting effect of endophytic Agrococcus terreus (MW 979614) in maize plants under zinc and nickel contaminated soil.

Heavy metals such as iron, copper, manganese, cobalt, silver, zinc, nickel, and arsenic have accumulated in soils for a long time due to the dumping of industrial waste and sewage. Various techniques have been adapted to overcome metal toxicity in agricultural land but utilizing a biological application using potential microorganisms in heavy metals contaminated soil may be a successful approach to decontaminate heavy metals soil. Therefore, the current study aimed to isolate endophytic bacteria from a medicinal plant (Viburnum grandiflorum) and to investigate the growth-promoting and heavy metal detoxification potential of the isolated endophytic bacteria Agrococus tereus (GenBank accession number MW 979614) under nickel and zinc contamination. Zinc sulfate and nickel sulfate solutions were prepared at the rate of 100 mg/kg and 50 mg/kg in sterilized distilled water. The experiment was conducted using a completely random design (CRD) with three replicates for each treatment. Inoculation of seeds with A. tereus significantly increased the plant growth, nutrient uptake, and defense system. Treatment T4 (inoculated seeds), T5 (inoculated seeds + Zn100 mg/kg), and T6 (inoculated seeds + Ni 100 mg/kg) were effective, but T5 (inoculated seeds + Zn100 mg/kg) was the most pronounced and increased shoot length, root length, leaf width, plant height, fresh weight, moisture content, and proline by 49%, 38%, 89%, 31%, 113%, and 146%, respectively. Moreover the antioxidant enzymes peroxidase and super oxidase dismutase were accelerated by 211 and 68% in contaminated soil when plants were inoculated by A. tereus respectively. Similarly the inoculation of A. tereus also enhanced maize plants' absorption of Cu, Mn, Ni, Na, Cr, Fe, Ca, Mg, and K significantly. Results of the findings concluded that 100 mg/kg of Zn and Ni were toxic to maize growth, but seed inoculation with A. tereus helped the plants significantly in reducing zinc and nickel stress. The A. tereus strain may be employed as a potential strain for the detoxification of heavy metals.

Nickel sulfate solution fluoride separation with hydrous zirconium oxide

AbstractFluoride is an impurity in nickel sulfate production, which is required for electric vehicle batteries. Hydrous zirconium oxide (HZO) was evaluated for removing fluoride from nickel sulfate solution. Maximum fluoride removal occurred at pH value 4 and optimal pH value is 4–5, considering Zr solubility. Fluoride availability decreases with pH due to hydrogen fluoride and zirconium fluoride aqueous species. Fluoride removal is initially rapid, with 50 wt.% removal in 7 min, followed by slow removal up to 68 wt.% after 72 h and follows second order rate kinetics. Fluoride removal was dominated by an ion exchange mechanism and resulting Zr–F bonds were observed using Fourier-transform infrared spectroscopy. The presence of nickel sulfate decreased loading capacity compared to a salt-free solution. HZO maintained adsorption capacity through five cycles of loading and regeneration.

Electrodialysis Separation and Selective Concentration of Sulfuric Acid and Nickel Sulfate Mixed Solution Using Membranes Modified by Polyaniline

The paper discusses the electrodialysis treatment of mixed nickel sulfate and sulfuric acid solution using polyaniline surface-modified cation exchange membranes. The modified membranes are obtained on the basis of industrial cation-exchange MK-40 heterogeneous and MF-4SK homogeneous membranes by in situ oxidative polymerization of aniline under electrodialysis conditions. The conductive and diffusion characteristics of the initial and modified membranes in solutions of sulfuric acid and nickel sulfate are studied. It is shown that the modification of membranes with polyaniline leads to a decrease in their electrical conductivity and diffusion permeability while maintaining high selectivity. The diffusion permeability of cation-exchange membranes is higher in nickel sulfate solutions compared to sulfuric acid one, while an inverse dependence is found for anion-exchange membranes. The competitive transfer of sulfuric acid and nickel sulfate during electrodialysis separation and concentration of their mixture using initial and modified cation-exchange membranes paired with anion-exchange MA-41 membrane are studied. It is shown that the applying a polyaniline layer with positively charged groups on the surface of the MK-40 or MF-4SK cation-exchange membranes suppresses the transport of doubly charged nickel ions both in the separation and concentration modes over the entire range of current densities. The greatest repulsion effect is observed for homogeneous modified membranes, where the selective permeability coefficient P(H2SO4/NiSO4) increases from 0.7–1.7 to 32.5–19.7 depending on the current density. It is established that the use of polyaniline modified cation-exchange membranes permits to concentrate the solution containing 0.1 mol-eq/L (4.9 g/L) H2SO4 and 0.1 mol-eq/L (7.7 g/L) NiSO4, with simultaneous separation into sulfuric acid with concentration about 2.4 mol-eq/L (120 g/L) and nickel sulfate solutions. The content of nickel sulfate in the concentrate does not exceed 0.13 mol-eq/L (10 g/L).

A Preliminary Study of Cobalt Solvent Extraction from Nickel Sulphate Solution using Organic Extractant-PC-88A

In present study, a solvent extraction experiment has been done to separate cobalt from the nickel sulfate solution by using 2-ethythexyl phosponic acid mono-2-ethylhexyl ester (PC-88A) as extractant. The experiment was carried out on a laboratory scale by using a separating funnel to extract cobalt from the nickel sulfate solution with PC88A. The mixed solution was shake in separating funnel for a specified period of time, and after the solvent extraction experiment was finished the organic phase PC88 was separated from the nickel sulfate solution by decantation. The nickel and cobalt content in the aqueous nickel sulfate solution were then analyzed using Atomic absorption spectrophotometry (AAS). In this experiment, the variable for experiments were covering solution pH from 2 to 6, shaking time from 30 minutes to 120 minutes, shaking speed from 20 revolutions per minute (rpm) to 80 rpm, and the volumeratio of aqueous to organic phase (A:O ratio) was from 1:1 to 1:4. The effects that experimental variables to the cobalt extraction were observed in this experiment. The result of experiment at room temperature, solution pH 5, shaking speed 60 rpm, shaking time 90 minutes, A:O ratio 1:4 and concentration of PC- 88A 40% show 97.21% of cobalt can be extracted by PC-88A from nickel sulfate solution, thererfore it was necessary to conduct two stage extraction process to extract 100% of the cobalt from the nickel sulfate solution.

The effect of pH on X-ray-radiolysis-induced synthesis of nickel nanoparticles on lithium niobate substrates

Photochemical reactions in aqueous media induced by X-ray irradiation have been shown to enable the synthesis of functional structures ranging from nanometer to millimeter scales. Herein, we demonstrate the synthesis and immobilization of nanoscale/microscale Ni particles onto lithium niobate (LiNbO3) substrates directly by X-ray irradiation of nickel sulfate (NiSO4) solutions with pHs from 1 to 9 using a synchrotron radiation facility. We found that the size and composition of the synthesized particles strongly depends on the pH of the solution; as pH increases, oxidation is accelerated and particle size increases. The synthesized particles exhibit magnetic hysteresis and are found to have ferromagnetic properties. Our investigation reveals that pH regulation is essential for controlling the synthesis of particles and providing characteristic functionalities to the materials. The X-ray radiolysis technique enables a state-of-the-art nanoscale/microscale three-dimensional manufacturing process that can create functional structures comprising composite constituents such as metallic and plastic materials.

Electrochemical deposition of nickel from local nickel sulphate solution on copper substrate

In this work, nickel was deposited on copper substrate through electrodeposition which was abstracted from local sulphate salt. Nickel deposition on copper substrate was done in both presence of vitamin C and saccharin additive. Boric oxide was used as buffering agent and pH of the solution bath was maintained through sulfuric acid and ammonium hydroxide. Round shape deposition on copper substrate was observed in the presence of vitamin C, while columnar shape particles were observed in the presence of saccharin additive. Deposition of nickel was done through sulfate bath on copper substrate. Boric acid was used as buffering agent and direct current electrolysis were conduct throughout this experimental work. pH of the solution was kept constant with the help of diluted sulfuric acid and ammonium hydroxide. The deposited nickel particles were obtained in round shape in the presence of vitamin additive, while columnar shape particles obtained in saccharin additive. The experimental conditions were optimizing to get smooth, adherent, and acid resistance surface. This research work reported that, rate of sulfate bath deposition increases lineally with increase in temperature and pH of the solution.

The effect of Graphene content on the corrosion and mechanical properties of an electrodeposited Ni-Graphene coating

Ni-Graphene coatings were developed on a mild steel substrate by electrodeposition from an electrolyte solution of nickel sulphate. Graphene was utilised in the electrolyte at volume fractions of 0.25, 0.5, 0.75, and 1 g/l.The low volume proportion of graphene can boost ion and electron mobility, promote cathodic polarisation potential, and accelerate the formation of heterogeneous microstructure features.The electrochemical route was employed to investigate the influence of graphene content on the corrosion behaviour of electrodeposited coatings. The coating structure and surface morphology were measured using X-ray diffraction and scanning electron microscopy. Microhardness test, scratch test, AFM imaging and profilometry were conducted to study the mechanical characteristics of the coating. The corrosion rate dropped from 3.624 mil/year for the nickel sample to 1.891 mil/year for the Ni-Graphene sample with 1 g/l graphene concentration. For the Ni-Graphene coatings, a surface morphology resembling a bulged flake was observed in the SEM. The uniform distribution of graphene with improved roughness was achieved in the coating. The substrate and the adjacent layers were not affected by the scratch test.

Effect of Surfactant Type on Synthesis and Characteristics of Nanonickel Hydroxide

Nickel hydroxide has a vital role in various applications, especially as a support material for energy storage materials. Nickel hydroxide can be synthesized through the hydroxide precipitation method. However, the product formed by this method may be large or more than 100 nm because the agglomeration step can occur easily. This present work aims to study the effect of surfactant types in the synthesis and characterization of nickel hydroxide nanoparticle. Nickel sulfate (NiSO4) solution was used as a precursor solution, while 5M sodium hydroxide (NaOH) solution was used as a precipitation agent. The surfactants studied were alkyl benzene sulfonate (ABS), sodium dodecyl sulfate (SDS), cetyltrimethylammonium bromide (CTAB), and polyvinylpyrrolidone (PVP). The nickel hydroxide synthesis process was carried out at 50 oC for 1 hour. The surfactant concentration used was at the critical micelle concentration (CMC), where the CMC for ABS, SDS, CTAB, and PVP were 0.01; 0.05; 3; and 0.5 %w/v, respectively. The synthesis of nickel hydroxide nanoparticle was carried out successfully precipitated almost 100% of Ni2+ ions. The product characterization that has been carried out shows that ABS surfactant produces the best nickel hydroxide nanoparticle product where the particle size is 3.12–4.47 nm.

Synthesis of Cobalt-Nickel Nanoparticles via a Liquid-Phase Reduction Process

Cobalt-nickel nanoparticles (Co-Ni-NPs) show promising electrochemical performance in oxygen and hydrogen evolution reactions (OER and HER) due to their physicochemical properties such as electronic configuration and great electrochemical stability. Therefore, developing new economically and environmentally friendly methods of synthesizing Co-Ni-NPs has become a practical requirement. Co-Ni-NPs were produced by employing the liquid-phase reduction method. Nickel and cobalt sulfate solutions in hydrazine monohydrate with various mixing ratios were used as raw materials. Nickel plays an important role in the nucleation process via increasing the reduction reaction rate throughout the formation of Co-Ni-NPs. Furthermore, the acceleration of the Co-Ni-NPs formation process may be attributed to the partial dissolution of Ni(OH)2 in the presence of N2H4 and/or citrate-anions and the formation of the Ni-N2H4 or Ni-Cit complexes in contrast to Co(OH)2.

EVALUATION OF THE PHYTOREMEDIATION POTENTIAL OF Lemna minor AND Eichhornia crassipes IN WATERS CONTAMINATION WITH NICKEL (II)

BACKGROUND AND AIM: At present, human activities related to the consumption of energy and minerals have generated a negative environmental impact on aquatic ecosystems, with the nickel industry being one of those with the greatest impact on the environment. Phytoremediation is presented as a convenient technology for the stabilization of heavy metals and the improvement of water conditions, since aquatic plants can accumulate pollutants through different physical and biochemical pathways. METHODS: In this study, the bioremediation capacity of two types of aquatic macrophytes was evaluated: Lemna minor and Eichhornia crassipes upon contact with synthetic nickel sulfate solutions at a concentration of 0.5, 1.5, and 2.5 mg/L of nickel ion. Their phytoremediation effect was evaluated by calculating the bioconcentration factor, the percentage of removal, the kinetics of the removal capacity and their physical development during the process. RESULTS:The results showed that these species had a great phytoremediation potential. In addition, L. minor presented a maximum removal rate of 68%, compared to E. crassipes, which did not exceed 50% at the three concentrations studied. However, the latter macrophyte showed greater resistance to nickel affectations and obtained a higher removal capacity during the phytoremediation process, which was performed for 10 days. CONCLUSIONS:It can be concluded that the two macrophytes are presented as a good alternative for nickel removal in water body. KEYWORDS: Heavy metals, Water quality, Exposures

Improvement of continuous technology of electrochemical synthesis of nickel hydroxide by implementation of solution recycling

Nickel hydroxide is widely used in supercapacitors, alkaline batteries, for the electrocatalytic oxidation of organic contaminants, etc. Due to their electrochemical activity, Ni(OH)2 (α+β) samples with a layer structure synthesized in a slit diaphragm electrolyzer are the most promising. To improve the continuous technology of electrochemical synthesis of nickel hydroxide, the possibility of recycling the spent catholyte containing sodium sulfate was determined. For this, samples of nickel hydroxide were synthesized from a solution of nickel sulfate in the presence of sodium sulfate with concentrations of 40, 60, 80, 100, and 120 g/L. The crystal structure of the samples was studied by X-ray phase analysis; the electrochemical properties were studied by the method of cyclic voltammetry. It was shown that the base sample obtained without the presence of sodium sulfate was a monophase layered (α+β) structure with a high content of α-modification. The crystallinity of the sample was not high. It was revealed that the presence of sodium sulfate led to a decrease in the crystallinity of nickel hydroxide due to an increase in the electrical conductivity of the solution and a decrease in the voltage in the electrolyzer. Cyclic voltramperometry showed that synthesis in a slit diaphragm electrolyzer in the presence of Na2SO4 (40–80 g/L) did not lead to a significant change in the electrochemical activity of nickel hydroxide samples. An increase in the concentration of sodium sulfate in the catholyte to 100–120 g/L led to an increase in electrochemical activity – the specific current of the discharge peak was 3.7–3.9 A/g (compared to 2.1 A/g for the reference sample).A comprehensive analysis of the characteristics of nickel hydroxide samples synthesized in the presence of sodium sulfate revealed the possibility and prospects of recycling the spent catholyte in a continuous technology for producing Ni(OH)2 in a slit diaphragm electrolyzer. It was revealed that when introducing recycling, it was recommended to maintain a high concentration of sodium sulfate (80–100 g/L)

Characterization of the γ,α-alumina and its adsorption capability to adsorb nickel (ii) and magnesium (ii) from nickel sulfate as a result of solvent differences

This study discusses the characteristics phase of the alumina mixture, namely the γ, α-alumina as well as its ability to adsorb the nickel (II) and magnesium (II) from nickel sulfate due to solvent differences. The γ, α-alumina was synthesized under acidic conditions (pH = 5) from poly aluminum chloride that was calcined at 800 °C by the sol-gel method. The particle size of γ, α-alumina is 15.65 μm; BET specific surface area of 104.12 m2 g−1; mesopores volume of 0.284 mL g−1; and a shape type of IV isotherm curve. Such the characteristic belongs to an adsorbent. The solution of nickel sulfate as Solution (b) has a bigger total adsorption capacity than that of the Solution (a), namely 16.46 mg L−1 and 2.49 mg L−1 respectively. The alkaline buffer formation as the ammonium hydroxide and ammonium chloride in Solution (a) may result in reducing the adsorption capability of the γ,α-alumina. The magnesium concentration of nickel sulfate in Solution (a) is smaller than that of the nickel one, namely 118.36 mg L−1 for the Mg and 486.64 mg L−1 for the Ni. However, the Mg is still more adsorbed around 29.96 mg L−1 compared to the Ni (19.80 mg L−1).

PH-Controlled Growth of Ni-Fe Layered Double Hydroxide Electro-Catalyst for Water Oxidation with Exceptional Operational Stability

Ni-Fe layered double hydroxide (LDH) is a potential OER electro-catalyst in water electrolysis due to its layered open structure, rapid diffusion of reactant, good anion exchange and excellent hydroxyl adsorption. Its OER activity has been well reported at constant applied voltage. However, the water electrolyser utilizes renewable energy due to which it suffers irregular power supply that consequently affects its electrode activity. Therefore, the development of a stable Ni-Fe LDH under dynamic operation conditions is required. Herein, we performed pH-controlled growth of NiFe LDH (1:1) on Fe substrate in nickel sulfate solution by oxygen sparging. The prepared LDH requires a low OER overpotential of ~270 mV vs. Hg/HgO at 200 mA/cm2 in 1M KOH solution. Considering the potentiodynamic polarization curve of Ni-Fe LDH, its OER region is above 0.5 V (vs. Hg/HgO) and shutdown region is below 0.3 V (vs. Hg/HgO). The voltage fluctuation between both regions may result in phase change and structural distortion. Therefore, three stability regimes are important to consider for an actual operational stability test; upper OER regime I (constant 0.75 V (vs. Hg/HgO)), one-minute lower to upper OER regime II (0.5 to 0.75 V (vs. Hg/HgO)) and one-minute on-off regime III (0.3 to 0.75 V (vs. Hg/HgO)). The electrochemical characterization before and after each 12 hours regime showed no degradation and steady kinetics (38 mV/dec). The morphological and surface analysis using SEM, XRD, TEM and XPS confirmed that the LDH structure remained preserve after each regime.Fig. 1: Operational stability test of Ni-Fe LDH prepared by pH-controlled growth under three regimes and embedded IR-corrected polarization curve after each regime. Figure 1

A Facile Route to Efficient Water Oxidation Electrodes via Electrochemical Activation of Iron in Nickel Sulfate Solution

The oxygen evolution reaction (OER) is an important half reaction in many electrochemical energy conversion processes, such as water splitting and carbon dioxide reduction. However, new, scalable a...

Effect of nickel shell thickness of Ni-microsphere on microwave absorption properties of Ni-microsphere@MWCNTs hybrids

Magnetic nickel microspheres with core–shell structure were synthesized via depositing nickel metal on the polystyrene (PS) microspheres surface by the method of chemical platting, which were used to assemble a multiple-loss absorbers hybrids of Ni@MWCNTs. The nickel shell thickness of Ni-microspheres was controlled via regulating the platting solution concentration of nickel sulfate solution. XRD analysis indicated that the Ni@MWCNTs hybrids still retained the crystal structure of MWCNTs and nickel metal. The SEM results showed that the nickel shell thickness of Ni-microspheres was effectively regulated by altering the plating solution concentration. When the plating solution was 24 g/L, 12 g/L and 6 g/L, the nickel shell thickness of Ni-1, Ni-2 and Ni-3 microspheres were 55 nm, 45 nm and 20 nm, respectively. While the nickel shell thickness of Ni-2 microspheres was 45 nm, the Ni-2@MWCNTs hybrids presented the best microwave absorption (MA) property. At 11.20 GHz, the minimum reflection coefficient (RC(min)) value was −40.65 dB and the bandwidth of RL < -10 dB was 3.6 GHz, while the RC(min) of Ni-1@MWCNTs and Ni-3@MWCNTs were −17.83 dB and −27.52 dB, respectively. The results demonstrated that the nickel shell thickness of Ni-microspheres had a meaningful influence on the MA performance of Ni@MWCNTs hybrids.