Nickel Impurities Research Articles

Effect of Nickel Impurities in Pyrite on Catalytic Degradation of Thiosulfate

The effects of nickel content in nickel-bearing pyrite on photocatalytic properties, light absorption properties, and oxidative decomposition of thiosulfate were studied. The leaching experiments show that the consumption of thiosulfate in the Cu2+-ethylenediamine (en)-S2O32− system increases with an increase in nickel content in nickel-bearing pyrite. The consumption of Cu(en)22+ initially increases and then decreases with an increase in leaching time. There is a clear correlation between the change trend in its consumption and the doping amount of nickel in pyrite. The XPS results show that in the Cu2+-ethylenediamine (en)-S2O32− leaching gold system (temperature 25 °C, time 35 h, solution: 0.1 mol/L S2O32−, 5 mmol/L Cu(en)22+, 200 mL solution), the nickel of pyrite-containing nickel can be transferred to the leaching solution and becomes nickel ion. In this leaching system, Cu(II), which was originally complexed with en, is reduced to Cu(I) in a short time. The consumption of Cu(en)22+ increased rapidly in the 5 h period and then decreased gradually after 5 h. The results showed that the presence of free Ni2+ in the solution facilitated the conversion of bivalent copper ions to monovalent copper ions. Free Ni2+ ions can compete with Cu2+ ions for en ligands. When ethylenediamine complexes with Ni2+, the decomposition of Cu(en)22+ into Cu(en)+ and en occurs more rapidly. And the en, which was originally to be oxidized with Cu(en)+ to form Cu(en)22+, forms Ni(en)22+. As a result, the concentration of Cu(en)22+ continues to decrease in a short period of time.

Development of a Hydrometallurgical Process for the Extraction of Cobalt, Manganese, and Nickel from Acid Mine Drainage Treatment By-Product

Critical minerals (CMs) are pivotal in modern industries, such as telecommunications, defense, medicine, and aerospace, contributing significantly to regional and global economic growth. However, the reliance on external sources for 26 out of 50 identified CMs raises concerns about supply chain vulnerabilities. To address this, the research focused on developing a hydrometallurgical process for extracting cobalt, manganese, and nickel from acid mine drainage (AMD) treatment by-products, emphasizing the need to diversify CM supply chains within the United States (US). A solution composed of an REE solvent extraction raffinate loaded with cobalt, manganese, nickel, and various impurity metals was utilized as a feedstock in this study. The developed hydrometallurgical process involved initial sodium hydroxide precipitation to remove impurities like aluminum and iron from an SX raffinate solution generated during the extraction of rare earth elements (REEs). Precipitation stages were performed in a pH region ranging from 2 to 12 to identify the optimum pH values, achieving a tradeoff between recovery and impurity removal. A subsequent precipitation process at pH 5–10 yielded a product rich in CMs, such as manganese, cobalt, and nickel. Further separation steps involved nitric acid washing, resulting in a Mn product with a purity of 47.9% by weight and a solution with extractable concentrations of cobalt and nickel. Stagewise precipitation with sodium sulfide subsequently produced three solid products: cobalt and nickel product at pH 1–5, manganese product at pH 5–10, and magnesium at pH 10–12. The study also explored other separation approaches, including solvent extraction, to enhance the separation of nickel from cobalt. Overall, the developed hydrometallurgical process generated the following products with varying degrees of purities: cobalt (9.92 wt.%), nickel (14 wt.%), manganese (47.9 wt.%), and magnesium (27.49 wt.%). This research aimed to contribute to the sustainable extraction of CMs from secondary sources, reducing the US’ reliance on imports and promoting a more resilient supply chain for these crucial elements.

Frequency response of nanoscale core-shell of silicon wires doped with boron and nickel

In this work, silicon microcrystals doped with a boron impurity to concentrations corresponding to the metal-dielectric transition in silicon of 5.5·1018 cm−3 and a nickel impurity in the temperature range of 4.2 ÷ 70 K under alternating current in the frequency range of 0.010 ÷ 250 kHz were studied. The features of the frequency response of silicon microcrystals are determined. On the basis of Nyquist diagrams, an equivalent conductivity scheme at low temperatures is proposed. The frequency response of the samples was evaluated and the mechanisms of charge carrier flow were proposed depending on the observation conditions. Conduction mechanisms from quantum mechanical tunneling (QMT) to superlinear power law (SLPL), which can be implemented in crystals, are considered.

Оценка термодинамических свойств химических соединений в системах Me-Si-O, Fe-Si-B, Fe-Cr-B и в некоторых системах, используемых для получения покрытий

A comparative analysis was performed for evaluating thermodynamic properties of a number of condensed and gas-phase compounds formed in the Me-Si-O, (Me = Al, Ba, Pb, Fe, Cr, Fe, Ni, Mn, Mo), Fe-Cr-B and Fe-Si-B systems, including those with impurities of oxygen, manganese, nickel, molybdenum and aluminium, and in some systems used for coatings production. The data on the enthalpies of the formation and on the coefficients of 1 ÷ 7 equations for the calculation of the temperature dependences of isobaric-isothermal potential, entropy and heat capacity for 84 compounds were obtained. The results of the comparative correlation analysis of thermodynamic properties for a number of condensed and gas-phase compounds formed in the Me-Si-O, (Me = Al, Ba, Pb, Fe, Cr, Fe, Ni, Mn, Mo) and Fe-Cr-B, Fe-Si-B systems, including those with impurities of oxygen, manganese, nickel, molybdenum and aluminium, and in some systems used for coatings were obtained. The correlation dependences of thermodynamic properties had a multiple correlation coefficient – R = 0.98 and standard deviations for heat capacity σ ~ 4.8 % (for gas-phase compounds σ ~ 0.6 %), entropy σ ~ 5.8 %, the enthalpy of formation σ < 8 %, oxide systems σ ~ 3 % and silicates σ ~ 2 %. As a result, the enthalpies of formation and 1 ÷ 7 – coefficients of the equations for calculating the temperature dependences of isobaricisothermal potential, entropy and heat capacity for 84 condensed and gas-phase substances were estimated. The obtained thermodynamic data were tested in the thermodynamic analyses of the formation of compounds in various systems and showed satisfactory agreement with experimental results.

ТЕХНОЛОГИЯ ПОЛУЧЕНИЯ МОНОГИДРАТА СУЛЬФАТА ЦИНКА

The article presents the results of studies on the production of zinc sulfate monohydrate. Zinc sulfate hydrates are chemical compounds used in various industries. They are used in agriculture to increase yields, as well as in the production of paints, medicines, beer and other products. The main element is zinc, which contributes to the active growth and development of plants. Powders, zinc oxide production waste with zinc content from 75 to 99% and 25% sulfuric acid were used as study objects. The content of basic elements was determined by ICP spectroscopy. Based on the data obtained, a production scheme was developed, including the following stages: preliminary preparation of components, chemical interaction, purification of the resulting zinc sulfate solution, evaporation of the solution, drying. Zinc-containing raw materials must be crushed beforehand. In order to increase the rate of interaction between the components, the zinc-containing powders are premixed with water. The amount of concentrated sulfuric acid injected is adjusted so that a 25% solution is formed after dilution with water. During the reaction of the interaction of the components at temperatures above 70°C, strong foaming is observed, indicating the presence of metallic zinc (Zn) in addition to ZnO particles. Hydrogen peroxide can be used to purify zinc sulfate solution from impurities of iron, copper, cadmium and nickel. Evaporation is carried out with periodic stirring for 1-2 hours, at a temperature of 70 to 90°C. The filtered zinc sulfate monohydrate precipitate is dried at 105°C to constant weight. The zinc sulfate monohydrate powder obtained according to the developed scheme can be further used as a fertilizer or feed additive.

Oxygen-Evolution Reaction Performance of Nickel (Hydr)Oxide in Alkaline Media: Iron and Nickel Impurities

Oxygen-Evolution Reaction Performance of Nickel (Hydr)Oxide in Alkaline Media: Iron and Nickel Impurities

Identification of the Fe[formula omitted]O[formula omitted]–Fe[formula omitted]O[formula omitted] reaction in liquid lead–bismuth eutectic

Liquid lead–bismuth eutectic (LBE) is a heavy metal alloy with great potential as a coolant and spallation target material for Generation IV nuclear reactors. For LBE technology to be widely accepted as reliable, a comprehensive understanding of LBE coolant chemistry is crucial. Specifically, precise determination of chemical interactions between corrosion products and dissolved oxygen in LBE is essential. For that purpose, the thermal cycling method is used in the present research, in which a well-controlled batch of LBE is repeatedly cooled while a potentiometric oxygen sensor monitors the dissolved oxygen concentration.According to the literature, magnetite (Fe3O4) is confirmed to be an important oxide to describe oxygen–iron interaction in LBE. However, thermal cycling experiments indicate the presence of another oxide, besides Fe3O4, participating in LBE bulk chemistry under conditions relevant for LBE-cooled reactors (200 °C–400 °C, 10−8 wt.%–10−5 wt.% dissolved oxygen concentration). By varying iron impurity content, nickel impurity content and cooling rate in the experiments, the oxide has been identified as hematite (Fe2O3). Thermodynamic equilibrium calculations show that Fe2O3 formation through the reaction of Fe3O4 with dissolved oxygen can explain the observed oxygen trends. As Fe2O3 could form during LBE cooling, an oxygen control strategy should take into account additional oxygen consumption in the reactor cold leg.

The Effect of Thermal Annealing on the Electrophysical Properties of Samples n-Si<Ni,Сu>

This paper presents the results of studies of the effect of isothermal annealing at temperatures T = 673¸1473 K in the time interval 5¸60 minutes on the electrical properties of silicon, simultaneously alloyed with nickel and copper. Samples of n-Si<Ni,Cu> were obtained on the basis of the starting material - single-crystal silicon, grown by the Czochralski method with the initial resistivity r = 0.3 Ohm×cm. Diffusion was carried out at a temperature of 1523 K for 2 hours. After that, the samples were cooled at a rate of 0.1 K/s. The morphological parameters of impurity nickel and copper atom clusters formed in the bulk of silicon were measured by electron probe microanalysis on a modern Superprobe JXA-8800R setup. As it turned out, in the volume of n-Si<Ni,Cu> samples, clusters of impurity atoms with different geometric shapes are formed, the sizes of which reach up to 500 nm. The electrical properties of the samples were studied by the Hall effect method using an Ecopia HMS-7000 instrument. It was revealed that under the influence of thermal annealing (TA) at T≥1273 K, impurity clusters decompose, which leads to an increase in the resistivity of n‑Si<Ni,Cu> samples. After exposure to TA at Т=1273 K for 15 minutes, the density of impurity nanoaccumulations of acicular and lenticular shapes sharply decreases in the sample volume. Under the influence of TA at T = 1473 K for 10 minutes in the volume of the sample, the decay of impurity nanoclusters with a spherical shape is observed. Also presented are the results of changes in the density of impurity clusters, as well as structural analyzes of the samples before and after exposure to thermal annealing.

Increasing the Efficiency of Silicon Solar Elements by Doping with Nickel

It is shown that in the near-surface region of the solar cells (SCs) the concentration of nickel atoms is higher than in the bulk by 2–3 orders of magnitude, therefore, the gettering rate in the near-surface region is higher. Optimal modes of gettering by nickel clusters (i.e., nickel diffusion – Т = 800–850 °С, additional thermal annealing – Т = 750–800 °С) and the structure of a silicon SC were experimentally determined, which makes it possible to increase the efficiency of silicon SCs by 25–30% relative to the control. The physical mechanisms of the influence of the processes of diffusion of impurity nickel atoms and additional thermal annealing on the state of nickel atoms in the near-surface region and the SCs base and, accordingly, on the parameters of the SC are revealed. Physical models of the structure of a cluster of nickel atoms in silicon and the process of fast diffusing impurities gettering by clusters of nickel atoms are created. The binding energy of fast dissusing impurities atoms with a nickel cluster is estimated to be ~ 1.39 eV. The calculation shows that doping with nickel can increase the lifetime of minority charge carriers by 2–4 times, and the collection coefficient by 1.4–2 times. The experiment showed an increase in the minority charge carriers lifetime up to 2 times and an increase in efficiency by 25–30%.

Clusters of impurity nickel atoms and their migration in the crystal lattice of silicon

Clusters of impurity nickel atoms and their migration in the crystal lattice of silicon

Waste-free processing of waste nickel slags

The paper considers one of possible options for the waste-free processing of dumped masses of nickel slags, accumulated over the years of operation of some enterprises. This process includes the use of hydroand pyrometallurgical processing, which results in three products: iron sulfate, ferrosilicon with a small admixture of aluminum, and slag from the ferrosilicon smelting. The slag has a hardness of 7-7.5 Mohs and can be used as an abrasive powder for sandblasting, or as a raw material for production of high alumina cement. The resulting iron sulfate can subsequently be purified from the copper, nickel, magnesium, and aluminum impurities and brought to the existing GOST compositional requirements. The resulting ferrosilicon, whose silicon content is similar to that of the marked ferrosilicon FS 75 with an aluminum admixture, can be used for deoxidation and silicon alloying of all existing grades of steels and cast irons. In this case, specifications drawn up with participation of a consumer enterprise can be a regulatory document for such ferrosilicon. The slag obtained during the ferrosilicon smelting can also be defined within the framework of these specifications for the abrasive powder producing enterprises.

Thermal Susceptibility of Nickel in the Manufacture of Softeners

The chemical industry includes a wide range of factories focused on obtaining final products as: (i) plastics; (ii) chemical fibers; (iii) rubber; (iv) perfumery and cosmetic products; and (v) cleaning products. Although the level of safety in the activities and installations of this sector is very high, the use of dangerous substances implies an increased risk of suffering an accident involving the emission of hazardous substances, as well as endangering the safety of workers. In the case of the manufacture of softeners, the presence of isopropanol (C3H8O), and dimethyl sulfate (CH3)2SO4), have been reported to be the accident cause in most of the cases. The European accident database (eMars) reported an accident in which the presence of impurities of nickel (Ni) in the hydrogenated tallow used as raw material for softener production may have increased thermal reactivity and the chances of spontaneous combustion. This paper analyzes the results obtained with the Maciejasz Index (MI) to understand the thermal susceptibility of these substances in liquid state. The results show that combinations of nickel (hydrogenated tallow catalyst) with other liquid substances (isopropanol, dimethyl sulfate, and sulfuric acid) are not sufficiently reactive with oxygen to cause a spontaneous combustion.

Effect of nickel impurity on structural, magnetic and electronic properties of WX2MLs (X = S, Se): An ab-initio study

We have studied the spin dependent structural, electronic and magnetic properties of pristine and Ni doped WX2 (X = S, Se) 2D monolayers by using density functional theory (DFT). The doping process improves and control the electronic and magnetic properties of TMDCs which is essential for application in electronics, optoelectronics and spintronics. WX2MLs with Ni impurity shows ferromagnetic behaviour. Spin resolved energy band gap have been observed. The Ni doped WSe2 exhibits the characteristics of half metal with 0.88 (D) and 0.02 (D) eV energy band gap for up and down spin respectively. The WS2ML with Nickel impurity shows 1.03 (I) and 0.17 (D) eV energy band gap for up and down spin respectively. The total magnetic moment of both Ni doped WX2MLs is found to be approximately 4µB which is due to local effect of the dopant. The exclusive combination of magnetic response and narrow bandgap which expedite the application of spintronics and yields magnetic semiconductors.

Technology of synthesis and electronic structure of triple barium–strontium–calcium carbonates for cathodes of microwave devices

Objectives. Triple barium–strontium–calcium carbonates of various grades are widely used for depositing oxide coatings on cathodes of electrovacuum devices. Of all types of cathodes used in electrovacuum devices, oxide cathodes are among the most common, due to combining efficiency, durability, operation at relatively low temperatures, and a relatively low cost. The aims of this work were to: create a technology for the synthesis of triple barium–strontium–calcium carbonates with nonequilibrium phase compositions that comprise the triple carbonate proper and a pure barium carbonate phase; develop a quality control procedure for such a carbonate for using it as a component of the cathode material for microwave devices; study how the electronic structure of barium oxide crystallites is affected by doping microimpurities from other phases of the cathode material.Methods. The study used precision X-ray diffraction analysis and electron spectroscopy.Results. A technology was developed for the co-precipitation of triple barium–strontium–calcium carbonates from their nitrate salts. Under optimal precipitation conditions, this produces triple carbonate powders with nonequilibrium phase compositions. Electron spectroscopy showed that the parameters of the electronic structure of the crystallites are significantly affected by doping impurities of calcium, strontium, and nickel in barium oxide crystallites formed by heat treatment of triple carbonates.Conclusions. Calcium and strontium have a synergistic effect on the doping of barium oxide with the two other chemical elements. As well as efficiently controlling the quality of the nonequilibrium phase composition of triple carbonates, which is formed during the synthesis of triple carbonates by the titration method, precision X-ray diffraction analysis can be used to efficiently control the processes of agglomeration of nanoparticles or recrystallization of nanostructured phases formed during the synthesis of triple carbonates.

The Study of Nickel Impurity Segregation on LSNT Perovskite Open Surfaces by Ab Initio Molecular Dynamics

The Study of Nickel Impurity Segregation on LSNT Perovskite Open Surfaces by Ab Initio Molecular Dynamics

Quality and safety investigation of commonly used topical cosmetic preparations

Cosmetic and personal care products are considered an essential part of our daily care routine; hence, these products must be stable and safe for human use. This study aimed to assess the quality and safety of the most common cosmetic preparations. To select the products to be tested, a cross-sectional survey was distributed featuring the most used types and brands of products. Based on 447 responses from both males and females with different ages and education levels, 21 products from different brands were selected and tested in terms of microbial load, heavy metal content, and organoleptic properties. Microbial contamination was investigated using the aerobic plate count method. Lead (Pb), aluminum (Al), cadmium (Cd), cobalt (Co), chromium (Cr), copper (Cu), manganese (Mn), nickel (Ni), zinc (Zn), iron (Fe), and arsenic (As) impurities were analyzed using an inductively coupled plasma mass spectrometer. The products included sunblock, lip balm, hand cream, hair cream, shampoo, cleanser, baby oil, baby powder, bar soap, hair dye, makeup, deodorant, hair serum, shaving gel, and toothpaste. Microbial contamination was found in 14 of the products, ranging between 1467.5 and 299.5 cfu/ml. The most commonly isolated microorganisms were Staphylococcus aureus and Bacillus species. Most of the tested products showed metal impurities, with toothpaste having the highest concentrations of Pb, Cr, As, Cu and Ni. The samples did not show lumps or discoloration, did not have characteristic odors, and had pH values ranging from 6.90 to 8.10. The continuous usage of such products could lead to serious negative consequences. As a result, ensuring the quality of cosmetic products is critical. Regulatory authorities are required to enforce strict legislation on cosmetic manufacturing to assess and ensure the quality and safety of the products before they reach consumers.

Reduction of White Spot Defects in CMOS Image Sensors Fabricated Using Epitaxial Silicon Wafer with Proximity Gettering Sinks by CH2P Molecular Ion Implantation.

Using a new implantation technique with multielement molecular ions consisting of carbon, hydrogen, and phosphorus, namely, CH2P molecular ions, we developed an epitaxial silicon wafer with proximity gettering sinks under the epitaxial silicon layer to improve the gettering capability for metallic impurities. A complementary metal-oxide-semiconductor (CMOS) image sensor fabricated with this novel epitaxial silicon wafer has a markedly reduced number of white spot defects, as determined by dark current spectroscopy (DCS). In addition, the amount of nickel impurities gettered in the CH2P-molecular-ion-implanted region of this CMOS image sensor is higher than that gettered in the C3H5-molecular-ion-implanted region; and this implanted region is formed by high-density black pointed defects and deactivated phosphorus after epitaxial growth. From the obtained results, the CH2P-molecular-ion-implanted region has two types of complexes acting as gettering sinks. One includes carbon-related complexes such as aggregated C-I, and the other includes phosphorus-related complexes such as P4-V. These complexes have a high binding energy to metallic impurities. Therefore, CH2P-molecular-ion-implanted epitaxial silicon wafers have a high gettering capability for metallic impurities and contribute to improving the device performance of CMOS image sensors. (This manuscript is an extension from a paper presented at the 6th IEEE Electron Devices Technology & Manufacturing Conference (EDTM 2022)).

(Invited, Digital Presentation) In-Situ Prussian Blue Formation on Intrinsic Iron-Containing MWCNT As a Template and Its Scanning Electrochemical Microscopic Interrogation and Hydrogen Peroxide Electrocatalysis

Prussian blue (PB; iron (III) hexacyanoferrate), is a mixed-valent polynuclear complex widely used in electrochromic display, biosensors, ion-selective electrodes, electrocatalysis and energy storage systems like batteries and fuel cells [1,2]. For the PB preparation, an electrochemical deposition using an equimolar concentration of Fe2+ and Fe(CN)6 3- in 0.1 M KCl-electrolyte condition was reported. In another case, a template approach, wherein either Fe2+ (or ironic species) or Fe[(CN)6]3- immobilized on the electrode surface followed by interaction with counter ion were reported [3]. For instance, a deliberately added ironic species (>20 wt.%) into a multiwalled carbon nanotube (MWCNT) modified electrode has been utilized as a template for the PB functionalized MWCNT preparation by potential cycling of the precursor electrode with Fe[(CN)6]3- [3]. Meanwhile, an intrinsic iron species that originated from its catalytic source has been referred an influencing parameter in altering the electronic conductivity of the MWCNT (MWCNT-Fe*, Fe*-Instrinsic iron) [4]. Our group has utilized the pristine MWCNT as a template for in-situ preparation MWCNT@Fe*(bpy)3 2+ and as an electro-Fenton catalyst for electroanalytical applications [5]. However, the in-situ derivation of iron impurity (2-4 wt.%) into the Prussian blue complex has not been explored yet. The inaccessibility of the iron and its low concentrations are the likely reason for the limitation. This report demonstrates an in-situ electrochemical PB formation using MWCNT-Fe* modified glassy carbon electrode as a template and Fe(CN)6 3- as a counter ionic species. This modified electrode (GCE/MWCNT-Fe@PB) showed a characteristic redox peak for the high-spin ironic state of PB at about 0.2 V vs Ag/AgCl in addition with a post-peak at 0.3 V vs Ag/AgCl [Figure 1A]. The nickel impurity in the pristine MWCNT is suspected to be involved in the complexation with Fe(CN)6 3- ion along with the ironic species.In-situ formation of PB on MWCNT-Fe* was probed using the scanning electrochemical microscope technique (SECM). In a typical experiment, MWCNT-Fe* modified GCE was taken as a base-electrode along with 5 mM Fe(CN)6 3- in pH 2 KCl-HCl electrolyte and the potentials were set as 0.1 V and 0.5 V vs Ag/AgCl accordingly to reduce FeIII(CN)6 3- + e-® FeII(CN)6 4- and parallely reoxidize it as FeII(CN)6 4- ® FeIII(CN)6 3- + e- on the Pt-tip surface (Figure 1B). The FeII(CN)6 4- ion formed as an intermediate species interacts chemically with Fe2+ ion that might be stripped out from the MWCNT-Fe* on the interface for the in-situ PB formation [Figure 1C]. An island-like morphology with average particle size, few micrometers of PB crystallites on the MWCNT-Fe* surface was noticed. Typical SECM surface imaging of a controlled carbon, carbon nanofiber (CNF), which doesn’t have any metal impurity, was displayed in Figure 1D. A feature-less surface morphology was noticed under the identical imaging condition. Physico-electrochemical characterization of GCE/MWCNT-PB modified electrode using Raman, FT-IR, UV visible spectroscopy and Field emission scanning electron microscopy (FESEM) supported the formation of a hybrid complex on MWCNT-Fe* electrode surface. It has been confirmed that intrinsic iron content was responsible for the PB-formation. As an independent electroanalytical study, the selective electrocatalytic reduction of H2O2 was carried out using a newly developed MWCNT-PB system [Figure 1B]. As an electroanalytical application, amperometric i-t sensing of H2O2 was carried out, which showed a calibration plot wth linearity upto ~5mM of H2O2 at an operating potential, 0.1 V vs Ag/AgCl in pH 2 solution. There is no interference by common biochemical such as ascorbic acid (AA), uric acid (UA), dopamine (DA), cysteine (CySH), nitrite, nitrate and glucose etc.In conclusion, we have prepared a Prussian blue functionalized MWCNT modified glassy carbon electrode using an intrinsic iron-containing MWCNT as a template in an acidic solution. The in-situ formation of PB on the MWCNT-Fe* has been probed and imaged using the scanning electrochemical microscope technique. The selective electrocatalytic and electroanalytical applications of the GCE/MWCNT-Fe@PB towards H2O2 have been demonstrated. This study will provide unique info about the intrinsic iron in the MWCNT and its in-situ derivatization process. Acknowledgement The authors acknowledge the Department of Science and Technology – Science and Engineering Research Board and Technology Development Program, DST-SERB-EMR/2016/002818, IDP/MED/04/2017 and CRG/2021/001048 Schemes for the funding. References A.A. Karyakin, Electroanalysis, 13, 813 (2001).J. Chen, L. Wei, A. Mahmood, Z. Pei, Z. Zhou, X. Chen and Y. Chen, Energy Storage Mater., 25, 585 (2020).R. Shanmugam, P. Barathi and A.S. Kumar, Colloids Surf. A: Physicochem. Eng. Aspects, 452, 129 (2014).C.E.Banks, A.Crossley, C.Salter, S.J.Wilkins, R.G.Compton, R. Angew. Chem., Int. Ed. 45, 2533 (2006)P. Mayuri and A.S. Kumar, Langmuir, 31, 5945 (2015). Figure 1

The study of structural, optical and electrochromic properties of WO3:Co:Ni thin films deposited by spray pyrolysis

In this study, WO3:Ni (0 at.%, 10 at.%, 20 at.%, and 30 at.%) and WO3:Co20 at.%: Ni (0%, 5%, 10%, 20%, and 30%) thin films were deposited on glass substrates by pyrolysis spray technique and then annealed at T = 500 °C. For the preparation of thin films, the initial solution of 0.1 M tungsten oxide and the precursors of nickel sulfate and 6-hydrate cobalt chloride were used. After preparing thin films, the effect of the presence of Ni impurities on the structural, morphology, optical and electrochromic properties of WO3:Ni and WO3:Co 20 at.%–Ni thin films was studied. The results of the X-ray diffraction showed that the structure of thin films after annealing has a polycrystalline structure with the combined phases of CoWO4, NiWO4, and W17O49 with monoclinic and hexagonal structures. As the amount of Ni impurities increases, the grain size of the WO3:Ni thin films increases and ranges from 8 to 36 nm. Also, for WO3 thin films:Co20 at.%:Ni, the CoWO4 and NiWO4 phases have been seen and the grain size was in the range from 35 to 39 nm. The voltametric cycle diagrams of WO3:Ni and WO3:Co20 at.%:Ni thin films showed that the electrochromic behavior improves with increasing nickel impurity. The morphology of the thin films was studied by field emission electron microscopy (FESEM). Also, the energy band gap of thin films with the addition of nickel and cobalt impurities was calculated using UV–Vis diagrams. The energy gap is decreased for both WO3:Ni and WO3:Co (20%):Ni thin films.

From the Limit Test for Trace Elements Control to the Elemental Impurities Analysis by Inductively Coupled Plasma Optical Emission Spectrometry: Application on Six Samples of Metronidazole API

IntroductionThe objective of this work was to control the inorganic impurities by the trace elements and sulfuric ashs limit tests and to analyze the elemental impurties by Inductively Coupled Plasma Optical Emission Spectrometry (ICP OES) wich is a novel method based on security data in six samples of Metronidazole API, collected from six pharmaceutical industries installed in Algeria. Materials and MethodsFor the trace elements and sulfuric ashs limit tests, a muffle furnace and a sand bath were used for samples calcination and each sample was processed according to the limit tests of European Pharmacopoeia eighth edition (Eur Ph 8 th ed). For the elemental impurities analysis, an ICP OES device was used for analysis of trace elements in diverse samples and each sample was processed according to the new procedures of American Pharmacopoeia USP 40-NF 35. ResultsThe results of trace elements and sulfuric ashs limit tests showed that all samples were conform except M1 sample wich contained more than 20 ppm of trace elements. The ICP OES elemental impurities analysis showed that the content of class 1 elements (Cd, Pb, As and Hg) and class 3 elements (Cu, Sn and Cr) of all samples was in the required limits. The content of class 2 elements (Co, Ni and Ag) was in the required limits in all samples except M3 sample which had Nickel content (3.5 ppm) exceeded the authorized limit for the parenteral route (2 ppm). Knowing that Nickel interferes very weakly with Osmium, this may be explained by the fact that this sample was intended to be put into oral forms. ConclusionThe highlighting of Nickel impurity exceeding safety standards confirm that trace elements test is neither specific nor exact, so it's recommended to manufacturers and quality control laboratories to apply the new procedures based on safety data which are well described in the new chapters (232) and (233) of USP or the general chapter 2.4.20 of Eur Ph.