Nickel In Solution Research Articles

Using liquid extraction to clean JSC «Kola MMC» nickel production solutions from impurities

Studies of the extractive recovery of Ca(II), Mg(II) и B(III) impurities from nickel production solutions at JSC «Kola Mining and Smelting Company» were conducted. As extraction agents, we used di-(2-ethylhexyl)phosphoric acid (D2EHPA), di-(2,4,4-trime-thylpentyl)phosphinic acid (Cyanex 272), trialkylamine (TAA), tributyl phosphate (TBP), aliphatic alcohols: octanol-1, 2-ethylhexanol and a by-product of its production – heavy product of 2-ethylhexanol distillation (TPRD). In order to assess the effect of conditions used to extract impurities from solutions, laboratory studies on the effect of aqueous phase acidity, extraction agent concentration, composition of organic impurities on their extractability were conducted. According to the research results, it was found that the optimal concentration of individual extraction agents is 20 vol.% each in the Escaid 100 solvent, and the mixture composition is 15 vol.% D2EHPA + 5 vol.% Cyanex 272 at Ca(II) and Mg(II) extraction. Individual D2EHPA predominantly extracts calcium (II): extraction of 62 % Ca(II) and 15 % Mg(II). When using Cyanex 272, the extraction of magnesium (II) predominates: extraction of 59 % Mg(II) and 20 % Ca(II). It was found that the extraction mixture has higher performance than individual extraction agents for Ca(II) and Mg(II) extraction from nickel solutions in the pH range of 3.0÷3.5, at which Ni(II) coextraction is negligible. With increasing pH values, Ca(II) extraction decreases due to the increasing extraction of nickel and the displacement of calcium by it from the organic phase. It was established that a mixture of 40 % TAA + + 60 % 2-octanone and heavy product of 2-ethylhexanol distillation exhibits high extraction ability with respect to B(III): the degree of boron extraction is 60.7 and 74.5 %, respectively. The paper provides the results of the extraction purification of the nickel electrolyte from JSC «Kola Mining and Smelting Company» with an extraction mixture in the Ni-form to exclude pH adjustment at each stage of the process. Based on the results of the studies conducted, a flowchart is recommended for obtaining pure NiSO4 solutions with a residual total B(III), Ca(II), Mg(II) and Cl– content of £0.010 g/dm3 .

Study of nickel adsorption on NaCl-modified natural zeolite using response surface methodology and kinetics modeling

In this study, a natural Algerian zeolite of the mordenite type was activated and tested for nickel adsorption in aqueous solution. Na-mordenite was characterized by different techniques, such as X-Ray Diffraction (XRD) and Scanning Electron Microscopy (SEM). Brunauer-Emmett-Teller (BET) analysis shows that this mineral was a micro-meso-macroporous material with a high specific surface area (SBET = 124.95 m2/g) and a total pore volume of 0.45 cm3/g. Box-Behnken Design (BBD) was used to optimize the adsorption process. The optimal conditions predicted by the model were: initial concentration −10 mg/L; adsorbent content −0.32 g/L; and pH of nickel solution −5.27. Under these conditions, the experimental value of nickel removal (R = 95.13%) was in good agreement with the predicted value (R = 96.71%). Kinetic and isotherm studies revealed that the Avrami kinetic model and Redlich-Peterson isotherm best expressed the experimental data. Based on the X-Ray Fluorescence results and zeta potential measurements, the mechanism of nickel adsorption by Na-mordenite appears to be an electrostatic and ion-exchange process.

Lignocellulosic Materials Used as Biosorbents for the Capture of Nickel (II) in Aqueous Solution

Four lignocellulosic materials (walnut shell, chestnut shell, pine wood and burnt pine wood) were analyzed as biosorbents to remove nickel ions in aqueous solution. The optimal pH condition was determined. Due to this, a range of different pHs (3.0 to 7.5) was tested. The adsorption isotherms and kinetics were established. To plot Langmuir and Freundlich isotherms, batch adsorption tests were made with variable nickel concentrations (5 to 200 mg L−1). The pseudo-first order, pseudo-second order, Elovich and intraparticle diffusion models were used to describe the kinetics, batch adsorption tests were carried out with 25 mg L−1 of nickel solution and agitation time varied from 10 to 1440 min. The specific surface area of the different materials was between 3.97 and 4.85 m2g−1 with the exception for wood with 1.74 m2g−1. The pore size was 26.54 nm for wood and varied between 5.40 and 7.33 nm for the remaining materials. The diffractograms analysis showed that all the lignocellulosic materials presented some crystalline domains with the exception of burnt pine wood which was completely amorphous. The best pH was found to be around 5.0. At this pH the adsorption was higher for chestnut shells, walnut shells, burnt pine wood and wood, respectively. All samples fitted the Langmuir model well, with R2 of 0.994 to 0.998. The sorption kinetics was well described by the pseudo-second order equation with R2 between 0.996 and 1.00. No significative differences on the surface of the materials before and after adsorption could be observed by SEM. Finally, all materials tested were able to remove nickel ions in aqueous solution.

Reactivity with tin and corrosion resistance of electroless Ni-P and Ni-P-Re coatings plated on copper

The electroless plated nickel (Ni-P) layers are widely applied in the electronics industry (ENIG coatings), where the quality of interconnections is directly related to the nickel solution and the resultant chemical composition (phosphorus content) of the coating. Depending on the concentration of phosphorus within the coating, the layer can be either fully amorphous or with nano Ni crystallites or crystalline. This translates into an increase of the temperature of its thermal stability, which directly impacts the processes occurring at elevated temperatures during the soldering process or later during the use of the final product (heating/cooling conditions). This work shows how the metallization/solder zone is transformed after their reaction, where, as the solder material pure tin was used, being the main component of currently used lead-free solder of SAC type. In the electronics industry, the typically used coatings have a phosphorous content in the range of 6–8 wt.%. Therefore, the coatings of also such compositions have been studied. The newly electroless plated coatings were first characterized in terms of surface morphology and chemical composition. Then, the interfacial reactivity between liquid Sn and coatings was studied using the sessile drop method, and the resulting substrate/coating/solder reaction zone was examined by scanning and transmission electron microscopy. The main goal of the research was to determine the quality of the interface, the width of the newly formed zones, and the presence of NixPy phases as well as the intermetallic phases formed as a result of the reaction. The addition of rhenium to Ni-P coatings inhibited the formation of the Ni2SnP phase in each of the tested phosphorus content ranges (low, medium, and high phosphorus), also after thermal cycles. Thus, no undesirable phenomenon of intermetallic phase detachment from the layer/solder interface was observed. Studies have shown that the corrosion resistance of samples increases as the pH of the solution from which the test coatings are deposited decreases, and the addition of rhenium to Ni-P coatings always improve their corrosion resistance.

Влияние плазменного высокочастотного индукционного разряда на физико-химические свойства дисперсной системы Ti – Fe – Ni, полученной электрохимическим способом

The Ti – Fe – Ni dispersed system was synthesized by the method of contact exchange on the surface of dispersed titanium in an aqueous chloride-containing solution of iron and nickel. The morphology and composition of the surface, as well as the actual phase composition of the Ti – Fe – Ni dispersed system before and after plasma treatment, have been studied by X-ray phase analysis, scanning electron microscopy and Auger spectroscopy. It is shown that on the surface of titanium microparticles, separate spherical subindividuals and their agglomerates are formed, characterized by nanosizes (100 – 200 nm). It was also found that the Ti – Fe – Ni system contains highly distorted metallic phases of iron and nickel, as well as a hydride phase of TiH2, which practically do not undergo phase transformations as a result of the passage of low-pressure argon through an inductively coupled plasma discharge. It is shown that the metallic phases of titanium, iron, and nickel are characterized by the presence of a thin oxide film on the particle surface, and the total content of the oxide phase in the samples does not exceed 1.5 wt. %. The treatment of the Ti – Fe – Ni system microparticles by high frequency induction discharge in low-pressureargon leads to small changes in the content of phases, the lattice constant and the microstructure of the system under study.It indicates a certain solubility of elements in each other and a greater crystallinity of the phases relative to those in particles untreated by plasma.

Efficiency definition of the deposition process of electrochromic Ni(OH)2-PVA films formed on a metal substrate from concentrated solutions

Electrochemical devices based on nickel hydroxide electrodes are used in different areas. The main ones are chemical current sources, variable transparency “smart” windows, devices for carrying out electrocatalytic reactions, sensors for determining various substances. In this regard, methods of nickel hydroxide synthesis are of great interest, especially those that allow forming nickel hydroxide directly on the surface of electrodes. One of these methods is electrochemical deposition with cathodic current polarization. The available information on nickel hydroxide synthesis from nickel solutions was considered. It was shown that the available data mainly covered information on dilute solutions from 0.01 to 0.25 mol/L Ni(NO3)2. In addition, no comparison was found in the literature for the efficiency of the cathodic formation of Ni(OH)2 at different concentrations of nickel nitrate. To eliminate the lack of information, the dependence of the current efficiency on the concentration of nickel nitrate in the electrodeposition solution was determined at a constant cathode current density of 0.625 mA/cm2. The resulting dependence decreased nonlinearly with increasing concentration. The nickel hydroxide deposit formed in this case had an X-ray amorphous structure, and it depended little on the Ni(NO3)2 concentration. In addition, the current efficiency reached zero at concentrations of 1.5 mol/L Ni(NO3)2 and higher. However, with polyvinyl alcohol in the solution and at Ni(NO3)2 concentrations of 1.5 and 2 mol/L, electrochemically and electrochromically active Ni(OH)2 films were deposited. The current efficiency calculated indirectly for 1.5 and 2 mol/L Ni(NO3)2 solutions was 3.2 and 2.3 %, respectively. Thus, it was concluded that polyvinyl alcohol affected the mechanism of nickel hydroxide electrodeposition from aqueous solutions of nickel nitrate.

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.

MAKING PROTOTYPE OF ELECTRO PLATING EQUIPMENT FOR HOME INDUSTRYOME INDUSTRI

Corrosion is an electrochemical reaction process that is natural and takes place by itself, corrosion cannot be prevented or stopped but can only be controlled using the Electro Plating method. Electroplating is a process that produces a thin layer of metal on top of another metal surface by electrolysis or electroplating using direct current (DC) and chemical solutions (electrolytes). The process of giving this protective layer aims to protect the metal from corrosion, in this study, will make a prototype electro plating tool for small industry or Home Industry, the completeness of the components needed to make a prototype electro plating tool is an AC transformer matic 30-50 A 12V, ampere meter, volt meter, fuse and switch, then nickel solution serves to provide strength, metal resistance from rust and chrome solution serves to provide resistance to corrosion and gives a glossy white color so it looks better, to produce a strong coating. With the occurrence of the anode, cathode, and electrolyte solution which are used entirely as related to coating materials, especially metals are illustrated as, the cathode can be interpreted as the workpiece to be coated, connected to the negative pole of the electric current source and the electrolyte in the form of a solution whose molecules can be dissolved. in water and decomposes into positively or negatively charged particles and the deposition in the process is due to the presence of ions in the electrolyte and will settle on the cathode and the process of coating the metal occursPlease write your abstract in English version here.

Получение сульфата никеля из полупродуктов Кольской ГМК

The article studies the possibilities of obtaining pure nickel sulfate from the filtrate of the cobalt purification of the nickel electrolyte of JSC "Kola MMC". Methods of purification of nickel solutions using sedimentation and extraction methods that remove impurities of sodium, chloridones, micro-impurities of calcium and magnesium are considered.

Textile-based triboelectric nanogenerators via electroless plating for fabricating electrode material: Study of the relationship between electrostatic-charge density and strain in dielectric material

Textile-based cotton was developed to fabricate the support for triboelectric nanogenerators (TENGs), which would facilitate the improvement of the device wearability and comfort. But, it is difficult to achieve the fabrication of metal textile-based cotton for electrode materials using traditional technology. In this regard, a textile-based TENGs via electroless plating on cotton surface for fabricating electrode material was established, the output performances under different external forces were studied comprehensively to obtain a full understanding of the relationship between the density of electrostatic charge (δ) and strain of polydimethylsiloxane (PDMS) dielectric material. Results showed that active groups on the rough cotton surface would facilitate the adsorption of Pd2+, and then reduce of Ni2+ to Ni atom in electroless nickel solution. As a result, core-sheath micronfiber yarn with weave structure was fabricated. It is flexible, lightweight, flexible with typical performance of TENGs electrode. The device had stable and excellent performances, and a maximum open-circuit voltage of about 8.3 V was observed from stress of 3.8 kPa or strain of 1.7 × 10−6 on PDMS layer. More importantly, a new calculation method for the PDMS strain of formation δ was proposed by equation of state. It was also revealed that the δ and PDMS strain represented a linear regression relation when the device under weigh mass of 0.22–0.52 kg, stress of 0.69–1.63 kPa and strain of 0.3–0.72 × 10−6. Nevertheless, further increasing stress, actual δ value is firstly higher and then lower than the theoretical value due to fabric fiber deformation.

Selective Metallization on CFRP Composites by Laser Radiation and Electroless Plating

Selective metallization of carbon fiber-reinforced polymer composites (CFRP) was conducted by laser ablation with 1064 nm laser radiation and electroless plating in nickel solution. A rough caterpillar-like structure and polar surface with high property of absorption and anchoring for active seeds were produced by laser ablation. The laser treatment produce had a pronounced influence on nickel deposition. After immersed in nickel solution for 150s, a homogeneous and dense nickel film was selectively deposited on the laser treatment area of CFRP by electroless plating successfully. The Ni plating exhibited excellent adhesion on the CFRP. The technique in this study would widespread the application of CFRP in the area of spacecraft microwave components and waveguide antenna.

Plasma-solution synthesis of particles containing transition metals

The paper proposes a new method for the synthesis of powders containing transition metals using a plasma-solution system. The reactor was an H-shaped glass cell, the two parts of which were separated by a cellophane membrane. A discharge consisting of two discharges - with a liquid cathode and a liquid anode - a high voltage is applied to titanium electrodes located above the surface of the solution. Aqueous solutions of zinc, iron, cadmium, cobalt, nickel, and copper nitrates were used as the liquid phase. Under the action of the discharge on the liquid anode, in the region of contact of the discharge with the solution the formation of a colloidal suspension was observed. The kinetics of the process of synthesis of solid-phase particles in solution under the action of a discharge have been studied. The chemical composition and morphology of the formed solid phase have been established. The mechanisms of chemical reactions occurring in the solution under the action of plasma, and the mechanisms of formation of transition metal oxides in the process of calcining the synthesized powders have been proposed.

Electrospun Polyacrylonitrile/Lignin/Poly(Ethylene Glycol)-Based Porous Activated Carbon Nanofiber for Removal of Nickel(II) Ion from Aqueous Solution.

The issue of heavy metal contamination has caused a great deal of concern among water quality experts today, as it contributes to water pollution. Activated carbon nanofibers (ACNFs) showed a significant ability in removing heavy metals from the wastewater. In this study, polyacrylonitrile (PAN) was blended and electrospun with an abundant and inexpensive biopolymer, lignin and a water soluble polymer, poly(ethylene glycol) (PEG), by using an electrospinning technique to form nanofibers. The electrospun nanofibers were then investigated as a precursor for the production of porous ACNFs to study the removal of nickel(II) ions by adsorption technique. PEG was added to act as a porogen and to create the porous structure of carbon nanofibers (CNFs). CNFs were prepared by thermal treatment of the electrospun nanofibers and followed by activation of CNFs by thermal and acid treatment on CNFs. Attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR) spectral analysis of the ACNFs showed a strong absorption peak of the C-O functional group, indicating the increase in the oxygenated compound. Field emission scanning electron microscopy (FESEM) images concluded that the ACNFs have more porous and compact fibers with a smaller fiber diameter of 263 ± 11 nm, while the CNFs are less compact and have slightly larger fiber diameter of 323 ± 6 nm. The adsorption study showed that the ACNFs possessed a much higher adsorption capacity of 18.09 mg/g compared with the CNFs, which the amount adsorbed was achieved only at 2.7 mg/g. The optimum adsorption conditions that gave the highest percentage of 60% for nickel(II) ions removal were 50 mg of adsorbent dosage, 100 ppm of nickel(II) solution, pH 3, and a contact time of 60 min. The study demonstrated that the fabrication of ACNFs from PAN/lignin/PEG electrospun nanofibers have potential as adsorbents for the removal of heavy metal contaminants.

Creep of single-crystals of nickel-base γ-alloy at temperatures between 1150 °C and 1288 °C

A γ-analogue of the superalloy CMSX-4 that does not contain the strengthening γ′-phase and only consists of the γ-solid solution of nickel has been designed, solidified as single-crystals of different orientations, and tested under creep conditions in the temperature range between 1150 and 1288 °C. The tests have revealed a very high creep anisotropy of this alloy, as was previously found for CMSX-4 at supersolvus temperature of 1288 °C. This creep anisotropy could be explained by the dominance of 011111 octahedral slip. Furthermore, the analysis of the creep data has yielded a high value of the creep activation energy, Qc≈442 kJ/mol, which correlates with the high activation energy of Re diffusion in Ni. This supports the hypothesis that dislocation motion in the γ-matrix of Re-containing superalloys is controlled by the diffusion of the Re atoms segregating at the dislocation core. The Norton stress exponent n is close to 5, which is a typical value for pure metals and their alloys. The absence of γ′-reprecipitation after high-temperature creep tests facilitates microstructural investigations. It has been shown by EBSD that creep deformation results in an increasing misorientation of the existing low angle boundaries. In addition, according to TEM, new low angle boundaries appear due to reactions of the a/2011 mobile dislocations and knitting of new networks.

Design of a scheelite production pilot plant for the treatment of spent electroless nickel plating solutions in Field Service Solution S.A.S.: an alternative source for tungsten recycling

In this contribution, the design considerations to assemble a pilot-plant for tungsten recovery and further conversion into synthetic scheeliteas raw material, as an eco-friendly improvement for the current electroless nickel process in Field Service Solution (FES) S. A. S., arepresented. This low-cost methodology scale-up aims to provide an alternative treatment for spent electroless nickel solutions (Ni-P-W) asa secondary tungsten source. The plant is projected to treat up to 750 L of industrial waste per week, achieving a maximum scheeliteproduction of 9.1 kg per week. This prototype serves as a model of eco-sustainability in the nickel-plating industry by controlling thedisposal of heavy metals and by facilitating the production of other tungsten derivatives and their feasible reuse in the process.

Surface Roughness and Hardness Characteristic of 2024 Aluminum Alloy by Electroplating Ni-Cr

Aluminum alloy 2024 is widely applied to aircraft because it has excellent mechanical properties. However, the application requires better properties on the surface. However, in its application, sometimes better properties are needed on the surface. This experiment aimed to evaluate the effect of electroplating time duration (nickel solution: 15 and 20 minutes, and chromium solution: 10, 15, and 20 minutes) on surface roughness. Investigate surface hardness due to variations in electroplating time: 10, 15, 20, 20, 25, 30, and 35 minutes. The results show that the time duration can affect the surface roughness after electroplating coating compared to untreated samples. On the other hand, electroplating on 2024 alloy with time variations, initially the surface hardness value increases with increasing time duration and reaches the highest at 25 minutes (electroplating time), then the hardness value decreases with increasing treatment time duration.

Extraction of trace elements from platinum group metal concentrates in hydrothermal conditions

Concentrates of platinum group metals, despite the high proportion of precious metals, contain significant amounts of impurity non-ferrous elements, the presence of which negatively affects the technology of refining and leads to an increase in the cost of marketable products. In this connection, it is promising to develop approaches for the most complete, deep removal of base elements from concentrates received for processing. In doing so, an extremely important requirement is the complete prevention of the noble metals passing into the solution, since otherwise they “get smeared”, and the process chain is complicated. In the present work, there are data on the features of the composition of concentrates of four platinum group metals, and the possibilities of removing nonprecious metals from them under autoclave conditions are studied. It was found that concentrates, in which platinum metals are represented mainly by platinum and palladium (K1-K3), slightly dissolve in water both at 25 оС in open systems and at elevated temperatures (180 оС). They are characterized by rather high silver contents, and their solubility is due to the presence of a water-soluble form of silver sulfate in them. The transition to the solution of other noble metals (NM) was not detected. In the case of a concentrate enriched with rhodium, iridium and ruthenium (K4), anomalous solubility in water was observed, which was 25.1 and 23.8% at 25 оС and 180 оС, respectively. As this takes place, noble metals at 25 оС significantly passed into solution (34.3%), and under autoclave conditions, the degree of dissolution decreased by 15 times. The use of formic acid was supposed, on the one hand, to ensure the dissolution of metals which are placed below hydrogen in the electrochemical series (iron, nickel and cobalt), and on the other hand, to prevent the dissolution of noble metals. The degree of extraction of noble and impurity non-ferrous metals into the solution from rich concentrates at 120 оС and 180 оС during their treatment with aqueous solutions of formic acid was established. The use of 10% formic acid provides a transition into the solution of iron (90%) and nickel (55%), and is accompanied by a decrease in the mass of the C1 concentrate by about 6%. NM do not pass into the solution in this case. For C2, the mass reduction is 10.1% due to the removal of 94% iron and 82% nickel at a temperature of 180 оС. The total concentration of platinum group metals in the solution does not exceed 2 mg/L. When processing C3, among all the noble metals iridium noticeably passes into the solution (3.5 mg/l), and out of impurity elements 45% nickel and 47.5% iron dissolve with a total weight loss of the concentrate of 8%. As for C4, selectivity of separation of NM and impurity base elements was not achieved; significant amounts of rhodium, ruthenium and iridium were found in the solution.This research was partially carried out under a state assignment of the Institute of Chemistry and Chemical Technology of the Siberian Branch of the RAS (Project: 0287-2021-0014) using the equipment of the Krasnoyarsk Regional Shared Knowledge Centre of the Federal Research Center “Krasnoyarsk Scientific Center of the Siberian Branch of the RAS”. The authors would like to thank Ms Zhizhaeva, a holder of PhD degree in Engineering, for conducting electron microscopy and X-ray studies.

Selective Cobalt Precipitation for the Synthesis of Precursors for Cathode Materials of Li-Ion Batteries

Due to the increase in energy storage for consumer electronics, stationary application and above all for electrical vehicles, the manufacturing of Li-ion batteries has dramatically increased in the past few years. Unfortunately, cathode materials still often use cobalt, and consequently, an increase of 10% per year of the world’s cobalt consumption has been observed. Li-ion batteries represent 60% of the use of extracted cobalt today (more than 80% expected in 2030), which is classified as a critical material since 2011 by the European Commission. Battery grade cobalt is produced by only few countries. 60% is provided by the Democratic Republic of Congo. In order to avoid reliance on cobalt supplying, European industry should have to develop alternative solution.We present here a new way to extract cobalt from a solution of battery-waste materials. Through a one-step process, it is possible to recover the cobalt, selectively, in a solution composed in majority of cobalt, nickel and manganese.The goal of the process is to form a cobalt-based Metal Organic Framework compounds (MOF) from a multi-metals based solution. The contact of a well-designed ligand with model multi-metallic solution of nickel, manganese and cobalt, under specific conditions, creates a precipitate, which is recovered by centrifugation or filtration. The XRD analysis of the resulting material demonstrates a crystalline structure, and its ICP analysis shows up to 99% of cobalt composition of the metallic nodes of the material. The same process with a real battery waste solution enables the formation of a precipitate made of 94% of cobalt (among the metallic centers).The resulting MOF can be used as a precursor for synthetizing cathode materials. In order to complete the described closed-loop concept, it is indeed possible to assemble a coin-cell from those products. The well define crystalline structure of the MOF makes them suitable for other industrial application, such as separation or catalysis (open-loop concept).We are focusing on better understanding of this selectivity process. Density Functional Theory (DFT) calculations are performed, as a tool to evaluate the energy of the different complexes in solution at all states of the nucleation and growth of the MOF. Moreover, the ligand used can form a MOF with each of the metals present in solution. Some nickel and manganese phases (more or less soluble) are involved during the process as a function of the reaction conditions. Identifying their nature and formation is another axis for the understanding of the presented work. Modelling these phenomena could help to determine the reaction that occurs, how the selectivity happens, and why the growing material is made of cobalt only (no other metal).

English

BACKGROUND It is of outmost importance to know the effects of nickel on a cellular level. The objective of this systematic review was to analyse the factors affecting nickel release, the amount of nickel being released in commercially available NiTi wires and to also analyse the blood / periodontal evaluation after orthodontic treatment in conventional and nickel free brackets. METHODS For this systematic review, relevant articles were searched in PubMed, MedLine, Cochrane, EMBASE and Google Scholar databases, along with a complimentary manual search of all orthodontic journals from January 1980 till the year 2019 December. The study included in vitro and in vivo studies. 14 articles were included in this systematic review. RESULTS 160 articles were obtained initially. 41 were obtained by a manual search. 186 articles were excluded based on the inclusion criteria and 14 articles were found to be eligible. CONCLUSION This systematic review shows that nickel solution at a minimal concentration could damage human gingival fibroblast. As the carcinogenic effect of nickel has been already confirmed, other alloys that do not contain the heavy metal nickel can be used or standardization of the amount of nickel leach out from the appliance should be considered. KEY WORDS NiTi, Nickel Release, Periodontal Tissue or Periodontium, Cytotoxicity, Orthodontics

Preparation of solutions of copper and nickel en and dien complexes- an illustration of the Jahn-Teller effect

With the advent of methods that effectively solve the problems of modeling metal ions in the gas, water, and solid phases, computational tools are becoming increasingly important in chemical research. here we consider both quantum and classical strategies for modeling systems containing metal ions that have been developed over the past few decades. This experiment was performed to study solutions of copper (II) and Nickel (II) complexes containing the following ligands, such as ammonia, diene, ene, and water in molar ratios, and to characterize the visible spectrum of the prepared solutions. The research was divided into three parts. In the first part, Nickel complexes were prepared and their formulas were determined using the job method. The second part of the experiment was performed to obtain EN-complexes of copper (II), and in the last part diene complexes were obtained. Dien and en were used as ligands.