Ni Ion Concentration Research Articles

Chemical modification of Pinus walliichiana sawdust: Application in membrane system for efficient purification of groundwater containing Cd(II) and Ni(II)

In the Sargodha region of Pakistan, the concentrations of Cd(II) and Ni(II) ions are very high as compared to WHO and US EPA standards and may be one of the leading reasons for water-borne diseases in the population of this area. In the current research work, an eco-friendly, low-cost, effective, and reusable filter membrane system is developed. The cellulose sawdust of Pinus walliichiana (PWC) was treated with succinic anhydride to form Pinus walliichiana cellulose succinate (PWCS) and finally converted to sodic form (PWCS-Na) by treating with saturated sodium bicarbonate. The PWCS and PWCS-Na as obtained were characterized using FTIR, pHZPC, SEM, PXRD, and Brunauer–Emmett–Teller (BET) analysis. The BET surface area of the PWCS-Na was found to be 579.5 m2/g. Maximum sorption capacity values in the batch study for Cd(II) (235.2 ± 10.3 mg g−1) and Ni(II) (195.6 ± 15.2 mg g−1) were observed at 298 K, pH 6, sorbent dosage of 30 mg, and metal ion concentration of 70 mg/L. The filter membrane system was designed and employed for the purification of the flowing water system. Theoretical calculations show that 1 L of filter membrane containing 138.0 g of the adsorbent PWCS-Na can purify 532.8 L solution with Cd(II) concentration 70 mg/L and 278.2 L solution of Ni(II) with concentration 70 mg/L. The regeneration study proved the efficient reusability of sorbent after five cycles with a slight change in sorption capacity.

Structural, magnetic and electrical studies on nickel doped copper ferrite synthesized using sol-gel method

Nickel doped copper ferrite nanoparticles NixCu1-xFe2O4(x = 0.1, 0.3, 0.5, 0.7, and 0.9) have been prepared through well known sol-gel technique. Numerous analytical methods, including the Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), vibrating sample magnetometer (VSM), and powder X-ray diffractometer (XRD), were used to analyze the synthesized materials. Synthesized sample XRD patterns reveal the single phase development of the spinel crystalline structure in the absence of any contaminant. The concentration of Ni ions rises with a corresponding decrease in crystallite size. Scanning electron microscopy (SEM) was also used to assess the microstructure. By using UV–Visible spectrometer an optical absorbance and through FTIR, two of ferrite's distinctive bands were verified. The M-H loops show that when the concentration of nickel ions increases, saturation magnetization varies. The Cyclic-Voltameter was used to perform the ionic electrochemical analysis. The NixCu1-xFe2O4 nanopowder's enhanced magnetic characteristics suggest that these substances would make good candidates for magnetic catalysts.

Binary adsorption of toxic nickel(II) and cadmium(II) ions from aqueous solution by acid modified chilli peppers

The acid-modified chilli peppers, a novel adsorbent, were prepared and used to absorb Ni(II) and Cd(II) ions from aqueous solution. Batch experiments with raw chilli peppers were compared with those of acid-modified chilli peppers. Batch experiments were conducted to evaluate the adsorption capacities of both sorbents under different conditions, including pH, concentration, contact time and temperature, in solutions. Bands with oxygen groups (-OH, -COOH, -C = O, -COC and -CO) on both sorbents were identified by Fourier transform infrared spectroscopy. Scanning electron micrographs of raw chilli peppers showed a morphology resembling spheres, while acid-modified chilli peppers showed a structure resembling a mesh of a mixture of different shapes, including squares and triangles. Maximum sorption capacities were achieved at pH 7, with the uptake of Ni(II) and Cd(II) ions dependent on pH.The highest adsorption capacities for raw chilli peppers and acid-modified chilli peppers were observed at 70 °C. The sorption capacities increased with increasing temperature. The concentration effect showed that as the concentration of Ni(II) and Cd(II) ions increased on raw chilli peppers and acid-modified chilli peppers, the adsorption capacity also increased. On raw chilli peppers, the rate of removal of Ni(II) and Cd(II) ions in solution was 60 min, while on acid-modified chilli peppers it took 80 min. The adsorption of Ni(II) and Cd(II) ions was best described by the Freundlich model with heterogeneous coverage and maximum capacities of 45.33 and 39.12 mg/g, respectively. The uptake of Ni(II) and Cd(II) ions was endothermic and showed positive values (∆Hº). Gibb′s free energy (∆Gº) for Cd(II) and Ni(II) ions on the activated carbon showed that the reaction was spontaneous. The change in entropy (ΔSo) of the reactions showed positive magnitudes for both pollutants, indicating a high degree of randomness in the solid-liquid phase. The kinetic model that best fitted the mechanism was pseudo-first order for Ni(II) and Cd(II) ions, indicating correlation numbers of R2 values of 0.9923–0.9995. Therefore, the acid-modified chilli peppers can be used as a viable alternative adsorbent for effective removal of Cd(II) and Ni(II) ions from aqueous solution.

Ferromagnetism behavior of Ni-doped Fe3O4 thin films synthesized by the SILAR technique

In this article, Ni-doped Fe3O4 thin films were synthesized by using the SILAR technique. The films were characterized through X-ray diffraction (XRD), Field emission scanning electron microscopy (FESEM), X-ray photoelectron spectroscopy (XPS), Raman, Photoluminescence and UV–Vis analysis. The XRD spectrum confirms the spinal structure of undoped and Ni-doped Fe3O4 thin films. The FESEM images show that Ni-doping has changed the morphology of thin films from a granular to a Spiky structure. The EDAX and XPS spectra show Fe, Ni and O elements are present in 1%Ni-doped Fe3O4 thin film. The vibrating sample magnetometer (VSM) studies showed ferromagnetism in undoped and Ni-doped Fe3O4 thin films. The ferromagnetism behavior of Ni-doped Fe3O4 thin films increases with the increase in Ni ion concentration.

Highly efficient nickel recovery from industrial wastewater via synergistic electrodeposition and electrocatalytic oxidation technique

This study was conducted to address water pollution concerns entwined with electroless nickel plating (ENP) industry. Its principal endeavor centers on the development and application of an innovative single-compartment technique to proficiently treat spent ENP baths. The research demonstrated the recovery of Nickel (Ni) from wastewater through synergistic interactions between electrocatalytic oxidation and electrodeposition processes. Electrochemical tests used a direct current power supply in constant current mode, with the positive pole on IrO2/Ti mesh and negative pole on stainless steel. Zero-valent nickel recovered on the electrodes was conclusively identified via SEM, XRD, and EDS analyses. This work carefully examined the impact of initial pH, initial Ni ion concentration, and current density (CD) on electrochemical recovery efficiency. The findings suggest that higher current densities positively influence the Ni recovery ratio. Additionally, through meticulous experiments, the viability of this approach for treating spent ENP baths has been confirmed. An impressive 98.88% recovery of Ni was achieved under specific conditions: CD 4.5 mA cm−2, experimental time 180 min, pH 4.5, electrodes spacing 1.5 cm, temperature 55 °C, and a dilution factor 10 times. The study demonstrated the process for Ni recovering from ENP wastewater through direct oxidation and subsequent decomposition, leading to liberation of free Ni ions. The recovered substance, identified as zero-valent nickel, adheres to the electrodes. The method employed in this research is described by its cost-effectiveness, user-friendliness, and low energy consumption. As a result, this study makes valuable contributions to both wastewater remediation and the sustainable utilization of Ni resources.

Functionalization Mesoporous Silica using Aminopropyltriethoxysilane (APTES) as Adsorbent for Removal Ni (II) from Aqueous Solution

<p>This study successfully synthesized mesoporous silica using the template methyl ester ricinoleate (MS-TMR) and further functionalized the MS-TMR surface with 3-aminopropyltriethoxysilane (APTES). The functionalization of MS-TMR with APTES was achieved through a 48-hour grafting method. For the adsorption experiments, 20 mg of both MS-TMR and MS-TMR-APTES adsorbents were employed to remove Ni(II) from aqueous solutions at a concentration of 30 mg/L and pH 6. The objective was to assess the adsorption capacity and to characterize the synthesized adsorbents. Characterization was conducted using Fourier Transform Infrared Spectroscopy (FTIR) and X-ray Diffraction (XRD). FTIR analysis revealed that the MS-TMR adsorbent possessed silanol (Si-OH) and siloxane (Si-O-Si) groups. Conversely, the MS-TMR-APTES adsorbent exhibited additional amine (N-H) and C-H groups after the APTES grafting. XRD results indicated that both samples were amorphous. The concentration of Ni(II) ions was determined using Atomic Absorption Spectroscopy (AAS), which facilitated the calculation of removal percentages and adsorption capacities. MS-TMR achieved a mere 3.54% removal of Ni(II) ions, corresponding to an adsorption capacity of 3.21 mg/g. In contrast, MS-TMR-APTES demonstrated significantly enhanced performance, removing 54.23% of Ni(II) ions with an adsorption capacity of 48.81 mg/g. The findings suggest that APTES-functionalized MS-TMR has considerable potential for removing Ni(II) ions and could be explored further for the adsorption of other heavy metal ions.</p>

Impact of Trace Nickel in the Electrolyte on the Electrochemistry of Positive Electrodes for Lithium-Ion Batteries

This study looks into the impact of Ni2+ ions as an electrolyte impurity on the electrochemical performance of NMC811 electrodes. The results indicate that the presence of Ni impurities in the electrolyte increases the polarization, primarily at the oxide-electrolyte interface. The influence on the metallic lithium counter electrode and the electrolyte conductivity can be neglected. The Ni impurities induce the formation of high impedance CEI layers on the oxide electrode, affected by both cations and anions of the impurity and impeding the current flow and cell performance. Ni impurities also enhance electrochemical side reactions, especially oxidation of the electrolyte, diminishing both, the Coulombic efficiency during cycling and the practical specific charge. The rates of these side reactions are related to the Ni2+ ion concentration. C-rate tests confirmed that a contaminated electrolyte reduces the practical specific charge due to the increased interfacial impedance of the CEI, especially at high discharge rates. The cycling performance of NMC811 electrodes in contaminated electrolytes showed that Ni impurities, especially NiCO3, promoted capacity fading during cycling and increased cell polarization. To optimize the performance of NMC-based oxide electrodes, controlling the concentration of Ni ions in the electrolyte is critical.

Facile Synthesis of Ni-Doped ZnO Nanoparticles Using Cashew Gum: Investigation of the Structural, Optical, and Photocatalytic Properties

This work adopted a green synthesis route using cashew tree gum as a mediating agent to obtain Ni-doped ZnO nanoparticles through the sol–gel method. Structural analysis confirmed the formation of the hexagonal wurtzite phase and distortions in the crystal lattice due to the inclusion of Ni cations, which increased the average crystallite size from 61.9 nm to 81.6 nm. These distortions resulted in the growth of point defects in the structure, which influenced the samples’ optical properties, causing slight reductions in the band gaps and significant increases in the Urbach energy. The fitting of the photoluminescence spectra confirmed an increase in the concentration of zinc vacancy defects (VZn) and monovacancies (Vo) as Zn cations were replaced by Ni cations in the ZnO structure. The percentage of VZn defects for the pure compound was 11%, increasing to 40% and 47% for the samples doped with 1% and 3% of Ni cations, respectively. In contrast, the highest percentage of VO defects is recorded for the material with the lowest Ni ions concentration, comprising about 60%. The influence of dopant concentration was also reflected in the photocatalytic performance. Among the samples tested, the Zn0.99Ni0.01O compound presented the best result in MB degradation, reaching an efficiency of 98.4%. Thus, the recovered material underwent reuse tests, revealing an efficiency of 98.2% in dye degradation, confirming the stability of the photocatalyst. Furthermore, the use of different inhibitors indicated that •OH radicals are the main ones involved in removing the pollutant. This work is valuable because it presents an ecological synthesis using cashew gum, a natural polysaccharide that has been little explored in the literature.

Deep insights into novel hexa-coordinated phenoxy-bridged trinuclear Ni(II) asymmetric salamo-like complexes affected by different types of combined solvents

By changing different types of combined solvents, two novel trinuclear Ni(II) complexes, [Ni3(L)2(NO3)2(MeOH)2] (1) and [Ni3(L)2(NO3)2]2 (2) were constructed from an asymmetric salamo-type ligand H2L and Ni(NO3)2·6H2O, respectively. The specific coordination modes of the two complexes have been clearly confirmed by X-ray single-crystal data. The results manifested that the complexes 1 and 2 possess similar coordination structures with solvent methanol molecules involved in coordination in complex 1, however, no coordinated solvent molecule appears in complex 2. The ligand (L)2− units were shown to be involved in coordination with Ni(II) atoms by analysis of infrared and UV–vis absorption spectroscopy. DFT and Hirshfeld surfaces analyses were performed on the complexes. Fluorescent strengths of both complexes were markedly lower compared to the ligand H2L and decreased gradually with increasing concentration of Ni(II) ions, which indicated the charge transfer from H2L to Ni(II) ions involved in the coordination.

Decoding Natural Strategy: Oxygen-Evolution Reaction on the Surface of Nickel Oxyhydroxide at Extremely Low Overpotential.

Although nickel (hydr)oxides in the absence of other metal ions are conventionally deemed inefficient catalysts for the oxygen-evolution reaction (OER) under alkaline conditions, this study reveals that nickel oxyhydroxide displays an OER activity at the associated peak for Ni(II) to Ni(III) oxidation postcharge accumulation. This occurs with only 90-120 mV overpotentials (at a low current density) and a Tafel slope of 297 mV/decade in a 0.10 M KOH solution. In the initial seconds, the Faraday efficiency lingers at a relatively low 20%, which can be attributed to charge storage. Nonetheless, as the duration extends to reach the 200 s mark, the efficiency notably escalates, exceeding 80%. Additionally, a mechanism for the OER in this low-overpotential zone is proposed, grounded in our investigation of the Ni(II) to Ni(III) peak and the OER region through in situ Raman spectroscopy. Taking into account the quantity of oxygen generated and the concentrations of redox-active Ni ions in the region of the redox peak, a turnover frequency of at a potential of 4.3 × 10-4 s-1 at 1.37 V was calculated. The documented reduction in overpotential during the OER may be ascribed to the complex interplay between the process of the OER and charge accumulation. The convergence of these reciprocally influencing factors facilitates a notably low overpotential in the OER. Our findings bear substantial implications for developing highly efficient and stable electrocatalysts for the OER in water-splitting applications.

Studying the Corrosion Effect of Fixed Orthodontic Appliances on Thyroid Hormones

This study aimed to determine the nickel (Ni), and chromium (Cr) ions amounts and investigate their potential effects on thyroid hormones in patients' saliva who were receiving treatment with fixed orthodontic appliances (FOA). In this study, 42 FOA volunteers participated, and all samples were obtained from a specialized center for manufacturing and orthodontics in Bab Al-Moadham, Baghdad, Iraq. According to the findings, individuals with fixed orthodontics have significantly higher levels of the thyroid hormones (P<0.05) FT3 and FT4 than those who did not have orthodontic treatment, whereas there were no significant changes in TSH (P=0.599). Additionally, the amounts of Ni+2 and Cr+3 were considerably higher in the individuals receiving metallic orthodontic treatment (P <0.0001). The findings of this investigation support the hypothesis that corrosion metals from the FOA have a meaningful impact on the concentration of Ni and Cr ions and, consequently, on the thyroid and salivary functioning of the patient group.

Galvanic Deposition of Calcium Phosphate/Bioglass Composite Coating on AISI 316L

Calcium phosphate/Bioglass composite coatings on AISI 316L were investigated with regard to their potential role as a beneficial coating for orthopedic implants. These coatings were realized by the galvanic co-deposition of calcium phosphate compounds and Bioglass particles. A different amount of Bioglass 45S5 was used to study its effect on the performance of the composite coatings. The morphology and chemical composition of the coatings were investigated before and after their aging in simulated body fluid. The coatings uniformly covered the AISI 316L substrate and consisted of a brushite and hydroxyapatite mixture. Both phases were detected using X-ray diffraction and Raman spectroscopy. Additionally, both analyses revealed that brushite is the primary phase. The presence of Bioglass was verified through energy-dispersive X-ray spectroscopy, which showed the presence of a silicon peak. During aging in simulated body fluid, the coating was subject to a dynamic equilibrium of dissolution/reprecipitation with total conversion in only the hydroxyapatite phase. Corrosion tests performed in simulated body fluid at different aging times revealed that the coatings made with 1 g/L of Bioglass performed best. These samples have a corrosion potential of −0.068V vs. Ag/AgCl and a corrosion current density of 8.87 × 10−7 A/cm2. These values are better than those measured for bare AISI 316L (−0.187 V vs. Ag/AgCl and 2.52 × 10−6 A/cm2, respectively) and remained superior to pure steel for all 21 days of aging. This behavior indicated the good protection of the coating against corrosion phenomena, which was further confirmed by the very low concentration of Ni ions (0.076 ppm) released in the aging solution after 21 days of immersion. Furthermore, the absence of cytotoxicity, verified through cell viability assays with MC3T3-E1 osteoblastic cells, proves the biocompatibility of the coatings.

Reformed dielectric features in single phase orthorhombic nickel vanadate complex oxides and the significance of the lattice dynamics in the optoelectrical features

V(1-x)2Ni3xO5-δ compounds are prepared by high-temperature solid-state reactions for mole fractions x = 0.04, 0.05, and 0.06. Micro-Raman spectrum with an excitation wavelength of 540 nm reveals 12 well-resolved phonon modes corresponding to the orthorhombic alpha-polymorphic phase of Vanadium Pentoxide and an extra vibrational mode excited by the tetravalent vanadium cation. A sharp absorption edge is observed from 500 nm to 650 nm in the diffuse reflectance spectrum with the rate of absorption increasing slightly, directly proportional to the x value. Kubelka-Munk plots reveal band gap reduction due to the negative Moss-Burstein shift that is attributed to the Ni2+ occupancy at the lattice sites creating electron deficiency. Frequency-dependent AC conductivity, studied in the frequency range 1 KHz to 1 MHz at room temperature exhibited DC-like conductivity in the low-frequency region, and the Jonsher Power Law fit gives the σdc values increasing with Ni ion concentration. AC conductivity at 1MHZ shows an elevation from 1.6 × 10−03 Sm−1 through 4.8 × 10−03 Sm−1 reaching 13.6 × 10−03 Sm−1 by increasing the concentration of Ni2+ ions. The dielectric constant at 250 °C, is observed to increase from 395, through 1447 to 2614, for mole fractions 0.04,0.05 and 0.06 respectively making this multivalent vanadate system a potential candidate for optoelectric and solid oxide fuel cell applications.

Adsorption of nickel(II) ions from aqueous solutions using Malatya clay: Equilibrium, kinetic, and thermodynamic studies

AbstractThis paper evaluates Malatya clay (MC) for the removal of Ni(II) ions from aqueous solutions. For adsorption efficiency, the impacts of several factors, such as pH, starting metal ion concentration, and contact duration, were examined. The optimal initial Ni(II) ion concentration was determined to be 5 mg/L, the adsorption contact duration was 360 min, and the solution's pH was 6.27. Using scanning electron microscopy, energy dispersive spectroscopy, and Fourier transform infrared spectroscopy, the surface characteristics of Malatya clay were examined. The isotherm data fit the Langmuir isotherm model, indicating chemical adsorption and likely irreversibility of the process, according to the results. At 298, 308, and 318 K, the adsorption capacities of Ni(II) were determined to be 10.267, 11.834, and 12.285 mg/g, respectively. Adsorption kinetic data revealed that the adsorption of Ni(II) metal ions followed the pseudo‐second‐order kinetic model. According to thermodynamic studies, Ni(II) ion adsorption on the MC is spontaneous and endothermic. MC has proven to be an effective and alternative material for the removal of Ni(II) ions from aqueous media due to its excellent removal ability, availability, and low cost, as well as its features such as being able to be used without any chemical treatment and being environmentally friendly.

Chromoionophoric Probe-anchored Mesoporous Silica Nanospheres for Rapid and Reliable Naked-eye Detection of Ni(II) Ions in Petroleum Products and Removal from Electroplating Wastewater.

This paper presents the expansion of an optical, chemical sensor that can rapidly and reliably detect, quantify, and remove Ni(II) ions in oil products and electroplating wastewater sources. The sensor is based on mesoporous silica nanospheres (MSNs) that have an extraordinary surface area, uniform surface morphology, and capacious porosity, making them an excellent substrate for the anchoring of the chromoionophoic probe,3'-{(1E,1'E)-[(4-chloro-1,2 phenylene)bis (azaneylylidene)]-bis(methaneylylidene)}bis(2-hydroxybenzoic acid) (CPAMHP). The CPAMHP probe is highly selective and sensitive to Ni(II), enabling it to be used in naked-eye colorimetric recognition of Ni(II) ions. The MSNs provide several accessible exhibited sites for uniform anchoring of CPAMHP probe molecules, making it a viable chemical sensor even with the use of naked-eye sensing. The surface characters and structural analysis of the MSNs and CPAMHP sensor samples were examined using various techniques. The CPAMHP probe-anchored MSNs exhibit a clear and vivid color shift from pale yellow to green upon exposure to various concentrations of Ni(II) ions, with a reaction time down to approximately one minute. Furthermore, the MSNs can serve as a base to retrieve extremely trace amounts of Ni(II) ions, making the CPAMHP sensor a dual-functional device. The calculated limit of recognition for Ni(II) ions using the fabricated CPAMHP sensor samples is 0.318 ppb (5.43 x 10-9 M). The results suggest that the proposed sensor is a promising tool for the sensitive and reliable detection of Ni(II) ions in petroleum products and for removing Ni(II) ions in electroplating wastewater; the data indicate an excellent removal of Ni (II) up to 96.8%, highlighting the high accuracy and precision of our CPAMHP sensor. This article is protected by copyright. All rights reserved.

Electrochemical sensing platform based on Zeolite/Graphite/Dimethylglyoxime nanocomposite for highly selective and ultrasensitive determination of nickel

In this work, the fabrication and analytical application of a novel, unique, mercury-free, and user-friendly voltammetric sensor of Ni(II) based on glassy carbon electrode (GCE) modified with zeolite(MOR)/graphite(G)/dimethylglyoxime(DMG) composite (MOR/G/DMG-GCE) and the voltammetric procedure for highly selective, ultra-trace determination of nickel ions were reported for the first time. Deposition of a thin layer of the chemically active MOR/G/DMG nanocomposite enables the selective and effective accumulation of Ni(II) ions in the form of the DMG-Ni(II) complex. In 0.1 mol L−1 ammonia buffer (pH 9.0), the MOR/G/DMG-GCE exhibited linear response in the Ni(II) ions concentration range of 0.86 − 19.61 µg L−1 and 0.57 − 15.75 µg L−1, for the accumulation time of 30 s and 60 s, respectively. For 60 s of accumulation time, the limit of detection (S/N = 3) was 0.18 µg L−1 (3.04 nM), and sensitivity of 0.202 µA L µg−1 was achieved. The developed protocol was validated by the analysis of wastewater certified reference materials. Its practical usefulness was confirmed by the determination of nickel released from metallic jewelry submerged in artificial sweat and stainless steel pot during water boiling. The obtained results were verified by electrothermal atomic absorption spectroscopy as a reference method.

Application of amino-hypophosphite polyampholyte for purification of wastewater containing Ni(ii) ions.

This study investigated the sorption of Ni(ii) ions from an aqueous solution using novel, synthetic amino-hypophosphite polyampholyte resin (AHP) in a batch adsorption system. The removal of Ni(ii) ions was determined as a function of pH (2.0-8.0), initial concentration of Ni(ii) ions (2.0-20.0 mM), resin dosage (1.0-10.0 g dm-3), contact time (0.04-24 h), and temperature (298-318 K). Moreover, continuous fixed-bed column sorption was also studied using model solutions and actual wastewater from the galvanising plant. The batch sorption experimental data showed that the maximum pH for efficient Ni(ii) ion removal was about 5.0. An equilibrium was reached after about 24 hours. The kinetics results were fitted using pseudo-first-order (PFO), pseudo-second-order (PSO), liquid film (LFD), and intraparticle diffusion (IPD) models. Freundlich and Langmuir isotherm models were applied for sorption equilibrium data. The maximum sorption capacity was obtained from the Langmuir equation to be 2.39, 2.52, and 2.62 mmol g-1 at 298, 308, and 318 K, respectively. The thermodynamic parameters for the sorption of Ni(ii) ions on AHP imply the endothermic and spontaneous character of the process. The experimental results demonstrated that amino-hypophosphite polyampholyte resin could be used to effectively remove Ni(ii) ions from model solutions and real wastewater.

Highly Dispersed Ni Nanoclusters Spontaneously Formed on Hydrogen Boride Sheets.

Hydrogen boride (HB) sheets are two-dimensional materials comprising a negatively charged hexagonal boron network and positively charged hydrogen atoms with a stoichiometric ratio of 1:1. Herein, we report the spontaneous formation of highly dispersed Ni nanoclusters on HB sheets. The spontaneous reduction reaction of Ni ions by the HB sheets was monitored by in-situ measurements with an ultraviolet-visible spectrometer. Acetonitrile solutions of Ni complexes and acetonitrile dispersions of the HB sheets were mixed in several molar ratios (the HB:Ni molar ratio was varied from 100:0.5 to 100:20), and the changes in the absorbance were measured over time. In all cases, the results suggest that Ni metal clusters grow on the HB sheets, considering the increase in absorbance with time. The absorbance peak position shifts to the higher wavelength as the Ni ion concentration increases. Transmission electron microscopy images of the post-reaction products indicate the formation of Ni nanoclusters, with sizes of a few nanometers, on the HB sheets, regardless of the preparation conditions. These highly dispersed Ni nanoclusters supported on HB sheets will be used for catalytic and plasmonic applications and as hydrogen storage materials.

Boosting large-current–density water oxidation activity and stability by phytic acid-assisted rapid electrochemical corrosion

Corrosion engineering is an efficient strategy to achieve durable oxygen evolution reaction (OER) catalysts at high current densities beyond 500 mA cm−2. However, the spontaneous electrochemical corrosion has a slow reaction rate, and most of them need to add large amounts of salts (such as NaCl) to accelerate the corrosion process. In this report, a novel and effective phytic acid (PA)-assisted in situ electrochemical corrosion strategy is demonstrated to accelerate the the corrosion process and form bimetallic active catalysts to show excellent OER performance at large current densities. In situ rapid electrochemical corrosion of nickel foam substrate and PA ligands etching realize localized high concentrations of Ni and Fe ions. High concentrations of metal ions will combine with hydroxyl to effectively form defects-enriched NiFe layered double hydroxides porous nanosheets tightly anchoring on the underneath substrate. Remarkably, the activated electrode exhibits excellent OER catalytic activities with ultralow overpotentials of 289 and 315 mV to reach high current densities of 500 and 1000 mA cm−2, respectively. When coupled with Ni-Mo-N hydrogen evolution reaction catalysts, the two-electrode cell merely requires 1.87 V to deliver 1000 mA cm−2. The ligands-assisted rapid electrochemical corrosion strategy provides a fresh perspective for facile, cost-effective, and scale-up production of superior OER catalysts at large current densities.

Toxic Metals in Some Decorative Cosmetics and Nail Products

Cosmetic marketing is one of the most profitable and fast increasing markets in Kurdistan Region of Iraq. In recent years, the use of cosmetics has witnessed a rapid increase, especially with the emergence of social media and its impact on this trade. The market is full of different cosmetic brands and nail products. Moderate and low-quality brands of cosmetic samples that available in the local markets were selected to investigate their heavy metals and chemical composition. Samples from face foundation, eye shadow, and nail polish products were taken and examined to evaluate the concentration of metals, that is, Hg, Pb, Cd, As, Mn, Cr, Ni, Co, Fe, Zn, Cu, and Al ions, using X-ray diffraction and X-ray fluorescence techniques. The examination results show high concentrations of Fe and Al metals in the lipstick samples whereas the Hg, Cd, Cr, and Ni were out of detection limit. Moreover, the results show contamination of Hg heavy metal in one of the examined nail polishes brands, whereas the rest of foundation and eye shadow samples show a higher concentration of Al and Fe. Curcumin, as a natural bio-friendly chelate, has been used to deplete metal ions using ultraviolet-visible Spectrophotometer.