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Magnetic paper sheets were prepared from bleached sugarcane bagasse fibers and cobalt ferrite nanoparticles by lumen loading method. Sugarcane bagasse is an important fibrous raw material widely used worldwide for papermaking, whereas cobalt ferrite nanoparticles is an appropriate material for fibers modification given their magnetic properties. Cobalt ferrite nanoparticles were synthetized by coprecipitation method and coated with silica by hydrolysis and condensation of tetraethyl orthosilicate (TEOS) molecules. Then, silica coated magnetic nanoparticles were functionalized with polyethylenimine (PEI), as retention aid, by electrostatic bonding. It was observed that the loading degree of magnetic fibers depends on nanoparticles concentration and PEI dosage, which was determined by thermogravimetric analysis (TGA). Scanning electron microscope (SEM) shows the deposition of coated nanoparticles on the surface and into macropores of fibers. All samples exhibited ferromagnetic behavior. The coercivity values of magnetic fibers are higher than 0.2 kOe. This indicates that these fibers could be used to produce paper for magnetic recording purposes. Magnetic papers with 10 and 20% of modified fibers were manufactured. Brightness and tensile index of papers were decreased with the rise of loading degree. CIEL*a*b analysis shows the color differences between unmodified and modified papers. [ABSTRACT FROM AUTHOR]

The catalytic combustion of diesel soot is addressed with flexible and structured "paper catalysts". Two different series of catalysts were prepared either by drip impregnation or by a spray method to deposit a mixture of Co, Ba, and K or a mixture of Co and Ce onto SiO2-Al2O3 ceramic paper matrixes. In every case, CeO2 nanoparticles were added to bind the ceramic fibers. SEM images showed that the impregnation method generated catalytic particles concentrated as large chunks (> 10 μm), mainly at ceramic fiber crossings, whereas the spray method produced smaller catalytic particles (< 1 μm) well distributed throughout the ceramic paper. Besides, Co-Ba-K particles appeared better dispersed on the surface of ceramic fibers than Co-Ce due to the presence of K. Additionally, FTIR spectra showed the formation of O22− and O2− species associated with CeO2 (binder) on the samples containing potassium which gave the Co-Ba-K-ceramic paper good catalytic properties, thus making the Co-Ba-K drop impregnated the best catalyst both considering activity and stability. Successive temperature programmed oxidation (TPO) runs up to 700 °C caused the formation of cobalt silicates in the catalytic ceramic paper prepared by the spray method, as indicated by TPR. The formation of these species was probably favored by the smaller size of cobalt particulates and their higher dispersion in the catalysts prepared by the spray method. This provoked the partial loss of the redox properties of Co3O4. TPR experiments also indicated the formation of BaCoO3 in Ba-containing ceramic paper, which could help in maintaining the catalyst activity after several TPO runs through the capacity of this mixed perovskite-type oxide to trap and release NOx. [ABSTRACT FROM AUTHOR]

Highly dispersed Cobalt doped ZnS nanostructures were successfully fabricated on the surfaces of graphene sheets via a simple hydrothermal method. X-ray diffraction (XRD), X-ray photocurrent spectroscopy (XPS), Raman spectroscopy (RS), Fourier transform infrared spectroscopy (FTIR) and Scanning electron microscopy (SEM) were utilized to analyze the structural characteristics of the cobalt doped ZnS decorated with graphene Co x Zn 1 - x S rGO nanostructures (NSs). UV-visible optical absorption (UV-vis) studies were conducted to investigate their optical properties. In laboratory studies utilizing water and visible light, the photocatalytic activity of Co x Zn 1 - x S rGO NSs at (x = 0, 1, 2, 4 and 6 atm.%) were evaluated. Graphite Oxide (GO) was successfully transformed into sheets of graphene and Co x Zn 1 - x S rGO NSs possessed a crystalline structure according to the findings of XRD, RS and FTIR analysis. SEM investigation showed graphene sheets enhanced with ZnS NSs possessed cuboidal, spheroidal form of structure and displayed a paper like appearance. UV-vis confirmed a noticeable rapid increase in transmittance along the UV wavelength area and confirmed a highly transparent NSs in the wavelength range of (180-800 nm). Calculations using density functional theory (DFT) revealed that the Co NSs have more negative conduction bands than ZnS, allowing for effective electron transfer from cobalt to ZnS and exhibiting a band gap decrease as Co content increased. The Co 0.04 Zn 0.96 S rGO NSs sample had the highest photocatalytic activity, measured at 7648.9 μ mol h - 1 . A combination of improved dispersion properties, greater surface area, increased absorption and enhanced transfer of photogenerated electrons, Co x Zn 1 - x S rGO NSs increased the photocatalytic hydrogen generation activity. [ABSTRACT FROM AUTHOR]

The paper presents the results of testing the purification of real liquid radioactive waste from radionuclides, bottom residues of the Kola and Beloyarsk nuclear power plants (NPP), as well as low-level wastewater from the radiochemical building of the Institute of Physical Chemistry and Electrochemistry RAS (IPCE RAS) using the method of nanofiltration (NF) using a polymer membrane manufactured by the Russian company "RM Nanotech." It has been shown that in the case of single-stage NF purification of bottoms of the Kola NPP, the coefficient of purification from 60Co is 2.8, while no purification from 137Cs practically occurs. When cleaning the bottom residues of the Beloyarsk NPP from 60Co using a five-stage scheme, a coefficient of purification from 60Co equal to 388 was obtained. The combination of nanofiltration purification and selective sorption of cesium on the ferrocyanide sorbent Temoksid-35 makes it possible to obtain a dry salt residue that is not related to radioactive waste. When using the method of nanofiltration for the treatment of low-level wastewater of the Institute of Physical Chemistry and Electrochemistry of the Russian Academy of Sciences, the degree of purification was, %: 137Сs ~ 75; 90Sr ~ 91; 241Am ~ 99.5; 152Eu ~ 91; 239Pu ~ 99.5. [ABSTRACT FROM AUTHOR]

Electrochemical conversion of CO2 to alcohols is one of the most challenging methods of conversion and storage of electrical energy in the form of high-energy fuels. The challenge lies in the catalyst design to enable its real-life implementation. Herein, we demonstrate the synthesis and characterization of a cobalt(III) triphenylphosphine corrole complex, which contains three polyethylene glycol residues attached at the meso-phenyl groups. Electron-donation and therefore reduction of the cobalt from cobalt(III) to cobalt(I) is accompanied by removal of the axial ligand, thus resulting in a square-planar cobalt(I) complex. The cobalt(I) as an electron-rich supernucleophilic d8-configurated metal centre, where two electrons occupy and fill up the antibonding dz2 orbital. This orbital possesses high affinity towards electrophiles, allowing for such electronically configurated metals reactions with carbon dioxide. Herein, we report the potential dependent heterogeneous electroreduction of CO2 to ethanol or methanol of an immobilized cobalt A3-corrole catalyst system. In moderately acidic aqueous medium (pH = 6.0), the cobalt corrole modified carbon paper electrode exhibits a Faradaic Efficiency (FE%) of 48 % towards ethanol production. Electrochemical conversion of carbon dioxide to ethanol is one of the most challenging energy conversion reactions. Here the authors show selective electroreduction of carbon dioxide to ethanol by using a functionalized cobalt A3-corrole catalyst immobilized on a carbon paper electrode. [ABSTRACT FROM AUTHOR]

The world's dependency on cobalt mines in Congo and cobalt refineries in China is seen as serious security issues with potentially dangerous implications for the energy transition. However, Chinese refineries have a similar supply security issue as most of its cobalt concentrates are imported. Most supply security studies take a country perspective on market concentration and supply risks. However, control of the mines and refineries lies with the producing companies, not the governments of the countries where they are located. This paper analyses the corporate structure of the cobalt industry at the mine and the refinery stages over a longer time period to establish changes in the level of corporate concentration and to put the situation in 2018 in perspective. The level of corporate concentration at the mine stage is low and does not raise concerns for market failures or a lack of competitiveness. Corporate concentration of refined cobalt depends on the Chinese government's influence over Chinese production: if the state control over individual refineries is assumed to be strong, the corporate concentration is high. Mine stage supply security could be strengthened by improving the general political stability in the DRC to make the country more attractive for investors other than the present ones. Increased local beneficiation would strongly benefit Congo and reduce China's influence. This is a long and complicated process and its success is not at all certain. At the refinery stage, the solution is much easier: reliability of supply could be improved by constructing refineries in countries outside China. [ABSTRACT FROM AUTHOR]

Designing a stable, efficient, highly selective, and low-cost dehydrogenation catalyst, using formic acid to produce hydrogen energy, is challenging even today. This paper reports a facile preparation method of constructing Pd–Co alloy-composite catalyst for hydrogen production using formic acid by heterogeneous catalyst decomposition. The results demonstrate that introducing a nonprecious cobalt metal could significantly reduce precious palladium metal usage. Moreover, the particle size reduces from 13.50 nm (without Co) to 3.4 nm (with Co). More importantly, the Pd2+ amount in the catalyst affect the catalytic decomposition of formic acid to produce hydrogen. Additionally, Pd0.9Co0.1/C650 exhibits excellent catalytic activity and cyclic catalytic stability and it is one of the best non-precious metal doped Pd-based catalysts. The development of a synthetic method with the addition of nonprecious metal in this paper opens up a new avenue for cheap and efficient catalysts for application scenarios of hydrogen production. H2 production by formic acid dehydrogenation. [ABSTRACT FROM AUTHOR]

Decontamination of suspected packages, such as sealed envelopes, liquids and tools that are likely contaminated with biological agents is of great importance. In this study, we aimed to determine the gamma radiation dose required for the decontamination of paper, fabric and liquid materials without causing any damage to the structure of these materials. Each study group included 11 pieces of paper, fabric and sterile saline contaminated with 0.8 × 105 virulent Bacillus anthracis (B. anthracis) spores. These specimens were exposed to doses of 5.49, 11.58, 17.21, 21.75, 27 and 33.1 kilogray (kGy) of gamma radiation from a cobalt-60 source. After irradiation of all the samples, a viability assessment of the B. anthracis spores was performed. It was found that full decontamination was achieved with 11.58 kGy on the paper samples and 17.21 kGy on the fabric and liquid samples. It was concluded that a dose of 20 kGy of gamma radiation may be recommended for the inactivation of B. anthracis for some surfaces when especially sensitive and valuable materials cannot be wet decontaminated were exposed. In addition, serologic and molecular assays of the suspected packets can be performed for forensic purposes without damaging existing evidence in a bioterror incident. [ABSTRACT FROM AUTHOR]

In this paper, according to the reaction principle and material balance, the coefficient calculation rule is established to construct the valuable element allocation model with Java programs in the hydrometallurgy process of cobalt-rich slag. Thus, the ratio of distribution in each process containing acid leaching, copper deposition, ferromanganese precipitation, and cobalt deposition are forecast quantitatively, accompanied by the recovery rate of the valuable element. Compared with the expanding process of cobalt-rich slag, the correctness and applicability of the model for the distribution and ratio of the valuable element are investigated, and the weak link can be improved according to the specific situation of the process. The recovery rate of cobalt is 95.38 %, and the content of cobalt in the cobalt product is 44.93 % in the cobalt deposition. Ultimately, the valuable element allocation model can quantitatively predict the experimental results, indicating that it can be used for simulating and optimizing the control of the hydrometallurgy process of cobalt-rich slag. This can improve the recovery rate of valuable elements in such hydrometallurgical processes. [ABSTRACT FROM AUTHOR]

The objective of this paper is to contribute to a better understanding of the deformation mechanisms of a rolled polycrystalline cobalt sheet. In order to achieve this goal, a particular attention is given to the strain-induced phase transformation and the forming parameters on which it may depend such as the plastic anisotropy or the loading path. In situ phase quantification by X-ray diffraction during tensile tests, on samples cut out from a cold rolled sheet material in three different directions (at 0°, 45° and 90° from the rolling direction), has enabled to study the influence of plastic anisotropy on the strain-induced phase transformation of metastable retained Face Centered Cubic phase to Hexagonal Close Packed phase. Results show that the martensitic phase transformation can be activated by basal slip in the first stage of plasticity but it also indicates that the latter is delayed when sample is strained in tension for an angle of 45° to the rolling direction. Post mortem analyses on a stamped sample by the Nakazima test have revealed that the phase transformation continues for higher strain levels. A particular interest is paid to the coupling between strain-hardening mechanisms and phase transformation and is discussed given the plastic anisotropy of cobalt aggregate. [ABSTRACT FROM AUTHOR]

Cobalt recycling is important for solving environmental problems such as resource shortage and pollution emissions. This paper quantifies the positive significance of cobalt recycling on resource replenishment and pollution emission by using the substance flow analysis and life cycle analysis. The results show that the proportion of recycled cobalt supplied as cobalt raw material is 7.1%, which improves the supply structure of the resource. Meanwhile, the environmental impact of recycling cobalt using the combined treatment process is low. The environmental impact of mining cobalt from mines is about 4.03–41.53 times that of recycling cobalt from cobaltiferous waste materials. However, the overall cobalt recycling is not ideal. First, the cobalt recycling rate is growing slowly. From 1994 to 2020, 245,132 t of cobalt-containing final products entered waste management in China. However, only 79,593 t of cobalt have been recycled, with a recycling rate of 32.47%. Secondly, many recycling enterprises only carry out recycling for a certain type of cobaltiferous waste materials due to the non-uniform cobalt recycling process. Finally, China's cobalt recycling policy does not divide the recycling channels for cobalt waste and does not regulate the specific process. In the future, China should set up separate recycling systems for cobaltiferous waste materials according to different categories and consider adopting combined treatment processes. China can only promote the sustainable use of cobalt if it ensures stable and orderly cobalt recycling in terms of policy and technology. [ABSTRACT FROM AUTHOR]

This paper describes mineral prospectivity research conducted in Finland to predict favorable areas for cobalt exploration using the "fuzzy logic overlay" method in a GIS platform and public geodata of the Geological Survey of Finland. Cobalt occurs infrequently as a core product in mineral deposits. Therefore, we decided to construct separate conceptual mineral prospectivity models within the Northern Fennoscandian Shield, Finland, for four deposit types: (1) "Orthomagmatic Ni–Cu–Co sulfide deposits," (2) "Outokumpu-type mantle peridotite-associated volcanogenic massive sulfide (VMS)-style Cu–Co–Zn–Ni–Ag–Au deposits," (3) "Talvivaara black shale-hosted Ni–Zn–Cu–Co-type deposits" and (4) "Kuusamo-type (orogenic gold with atypical metal association) Au–Co–Cu–U–LREE deposits". In addition, we created a model combining till geochemical data with data derived from bedrock drilling and mineral indications, including boulders and outcrops. The mineral prospectivity models were statistically tested with the "receiver operating characteristics" method using exploration drilling data from known mineral deposits as validation sites. In addition, the predictive performance of the models was evaluated by using success rate curves, where the number of previously identified deposits was compared with the area coverage of the predicted highly favorable areas. These results indicate that the knowledge-driven mineral prospectivity method using parameters derived from mineral systems models is effective in defining favorable exploration target areas at the regional scale. This study's innovation lies in its comprehension of the process of evaluating mineral prospectivity when the commodity of interest is not the primary commodity within the mineral system. [ABSTRACT FROM AUTHOR]

Hydrogenation of carbon monoxide (Fischer–Tropsch synthesis) is a promising route to ultraclean motor fuels, base oils and petrochemicals on the basis of non-petroleum feed such as natural gas, coal and biomass. Although cobalt-based industrial catalysts for this process are in operation for many years, they still need to be improved in terms of specific activity and selectivity to target hydrocarbons. This paper describes the effect of catalyst support coating with carbon on the formation of cobalt active phase and catalytic performance in CO hydrogenation. Carbonization of Mg–Al spinel was performed by impregnating with aqueous glucose solution followed by thermal treatment in inert atmosphere. Thus prepared carbonized material was used for cobalt deposition by incipient wetness impregnation method. The catalysts were characterized by N2 adsorption–desorption, scanning electron microscopy, thermoanalytical measurements combined with mass spectrometry of released gases, X-ray diffraction and in situ magnetic measurements during activation in H2 flow. Catalytic performance in Fischer–Tropsch synthesis was assessed at T = 210 °C, P = 20 bar. The size of Co3O4 crystallites in calcined catalysts and metallic cobalt in activated catalysts decreases with carbon content in the support. Cobalt precursor is reduced completely to metal within 2 h in typical activation conditions for FTS cobalt catalysts: H2 flow, 450 °C. Activity in CO hydrogenation decreases while selectivity to higher hydrocarbons increases with carbon content. High proportion of olefins in synthesized light hydrocarbons (> 65%) is a remarkable feature of the elaborated catalysts. [ABSTRACT FROM AUTHOR]

In this paper, we present a study on the synthesis and electrochemical characterization of nitrogen-doped reduced graphene aerogel (NrGA) prepared through the hydrothermal reduction of graphene oxide (GO) suspension with urea as a nitrogen dopant source. Five samples (rGA, NrGA08, NrGA16, NrGA32, NrGA48) with varying concentrations of urea were prepared to investigate the effect of urea concentration on electrochemical performance. All samples were characterized using XRD, FT-IR, Raman, BET, FESEM, and XPS. The specific surface area of the samples ranged from 110 to 344 m2/g, with the highest value observed for NrGA48. Raman spectroscopy showed the generation of disorder in the structure with the insertion of nitrogen atoms. The electrochemical performance of the sample has been investigated through linear sweep voltammetry, cyclic voltammetry, chronoamperometry, and RDE. The NrGA32 sample exhibited superior electrochemical performance compared to the other samples, and was therefore chosen as the optimized N-doped sample to investigate the effect of cobalt phthalocyanine (CoPC) as a redox mediator. The addition of CoPC significantly improved the electrochemical properties of NrGA32, increasing the electron transfer number from 3.5 to 3.85, enhancing the oxygen reduction current, and shifting the onset potential from 0.480 to 0.700 V vs. SHE. [ABSTRACT FROM AUTHOR]

The paper presents the results of cobalt corrosion tests in air at different temperature and humidity values. It was demonstrated that corrosion losses in cobalt at temperatures of 20 and 30 °C and relative humidity of 70, 80, and 95% are insignificant. However, the rate of cobalt corrosion sharply increases at an air temperature of 50 °C, especially at 95% relative humidity. A conclusion about the intensity of the cobalt corrosion processes under these conditions can also be derived from the sample appearance: after testing at 50 °C and 70% humidity, the samples turn black, while at 50 °C and 95% humidity they become covered with black, oily, and easily crumbling flakes, which represent the products of cobalt corrosion. It was found that corrosion film formed on the cobalt surface consists of the eutectic Co–CoO mixture of variable composition and CoO·Co(OH)2·H2O complex oxide. At increased corrosion test temperatures, the surface film of hydrated cobalt oxide becomes thicker, develops microcracks, and leads to the formation of cobalt hydroxide flakes, which exhibit weak adhesion to the substrate and crumble. [ABSTRACT FROM AUTHOR]

Solving the crash risk problem of corporate stock price caused by information asymmetry can mitigate the negative externality of its carbon emission to become green, low-carbon, and high-quality development. Green finance generally profoundly impacts micro-corporate economics and macro-financial systems but remains a giant puzzle of whether they can effectively resolve the crash risk. This paper examined the impact of green financial development on the stock price crash risk using the sample data of non-financial listed companies in Shanghai and Shenzhen A stock market in China from 2009 to 2020. We found that green financial development significantly inhibits the stock price crash risk; this is more obvious in listed companies with a high level of asymmetric information. And companies in high-level regions of green financial development attracted more attention from institutional investors and analysts. As a result, they disclosed more information about their operational status, thus reducing the crash risk of corporate stock price from the torrential public pressure of lousy environmental details. Therefore, this study will help continuously discuss the costs, benefits, and value promotion of green finance for synergy between corporate performance and environmental performance to improve ESG capabilities. [ABSTRACT FROM AUTHOR]

Published data on hydrodesulfurization and hydrodenitrogenation of model petroleum compounds in the presence of molybdenum and tungsten phosphides are analyzed. The majority of papers in which these catalysts are compared to traditional sulfide catalysts demonstrate higher activity of the phosphide catalysts. The influence exerted on the activity of phosphide catalysts in these processes by the feed composition (presence of sulfur- and nitrogen-containing compounds), catalyst synthesis conditions and active phase content, reaction conditions, and promoter is described. When performing the synthesis at high temperatures or using large amounts of the active phase deposited onto an Al-containing support, the catalyst activity can decrease owing to the formation of AlPO4. The promotion of molybdenum and tungsten phosphides with nickel or cobalt enhances the catalyst activity. The major cause of phosphide deactivation is the presence of nitrogen-containing compounds in the feed, whereas the presence of sulfur-containing compounds, on the contrary, in most cases leads to an increase in the catalyst activity owing to the formation of the phosphosulfide phase. [ABSTRACT FROM AUTHOR]

In this paper, the chemical composition of 7Mo-alloyed super austenitic stainless steel was optimized and the principle of composition designing of Fe-24Cr-(22-x)Ni-7Mo-xCo (x = 0, 2, 4) alloys was discussed. Thermodynamic calculation, as well as microstructure observation, was carried out to investigate the precipitation behavior of Fe-24Cr-(22-x)Ni-7Mo-xCo alloys aged at 700–1100 °C. The results demonstrated that none of second phase was detected at 700 °C aging and at least three different types of precipitates, σ phase, χ phase and M23C6 were identified after aging at 800–1100 °C for 2 h. At all aging temperature, the intermetallic σ was determined as the dominant second phase. For alloys of 22Ni, 20Ni2Co and 18Ni4Co, the area fraction of precipitates increased first and then decreased with temperature increasing from 700 to 1100 °C. The 1000 °C was determined as the most sensitive temperature for this alloy. Furthermore, the area fractions of second phase of 20Ni2Co (x = 2) at all temperatures were lower than that of 22Ni (x = 0) and 18Ni4Co (x = 4). In addition, the characteristics of cellular precipitates growing have been disclosed in this paper. Compared with nickel-based alloy, the addition of cobalt did not affect the misfit between σ phase and austenite matrix, which is probably due to the high content of nitrogen in Fe-24Cr-(22-x)Ni-7Mo-xCo alloys. [ABSTRACT FROM AUTHOR]

When preparing tungsten-cobalt gradient alloy under nitriding conditions, TiC becomes a very important additive because it can effectively promote the formation of gradient structure. However, doping TiC often causes a large number of defects such as holes, cracks, and impurity segregation in the tungsten-cobalt cemented carbide matrix. The paper is mainly studied the improvement of microstructure and mechanical properties of Ti-containing cemented carbide by doping appropriate amount of NbC or VC. The results show that: doping with NbC or VC can refine the grains of the hard phase, effectively control the microstructure and mechanical properties of the alloy, significantly improve its compactness, and increase the hardness and transverse fracture strength of the alloy. However, the fracture toughness is reduced. When the doping amount is less than 0.6% (mass fraction), VC effects on improving the hardness and transverse fracture strength more obviously than NbC; when the doping amount is equal to 0.6% (mass fraction), the difference between VC and NbC in improving the transverse rupture strength is not significant. Comparing the two additive contents studied in this paper, when the VC content is 0.6% (mass fraction), the performance of cemented carbide is better, with a hardness of 1836 HV30kgf, a fracture toughness of 8.85 MPa·m1/2, and a transverse fracture strength of 1888 MPa. [ABSTRACT FROM AUTHOR]

Detection of water impurities is an important issue in many applications, especially in the medical field. In this paper, a fiber optic sensor based on surface plasmon resonance has been numerically simulated and is used for detecting 10% glucose (called dextrose 10%). This sensor consists of two layers, the first layer is metal such as cobalt, nickel, platinum, and silver and the second layer is barium titanate. The sensor performance parameters were calculated using the normalized transmitted power in three different values of 300, 600, and 900 microns of fiber core diameter. Ag/BaTiO3 with 900 microns fiber core is the most qualified structure. In the second part of the research, the effect of aluminum–silver alloy has been investigated to enhance the quality factor of Ag/BaTiO3. The combination ratio of Ag–Al (0.1:0.9) was the best choice to increase the quality factor of the sensor from 62.46 (RIU-1) to 88.0 (RIU-1). [ABSTRACT FROM AUTHOR]

By adjusting the coordination environment of single-atom catalysts, the enzyme-like activity can be finely tuned for highly sensitive biosensing. Herein, we demonstrated that coordinatively unsaturated cobalt-nitrogen sites doped within porous carbon (SA-CoN3) could serve as highly efficient oxidase mimic. Compared with the typical planar four-coordination structure (SA-CoN4), the as-obtained single-atom Co nanozymes anchored by three nitrogen atoms are found to display much higher oxidase-like catalytic efficiency. Combined theoretical and experimental analysis revealed that the coordinatively unsaturated Co sites could facilitate adsorption and activation of O2 molecule and thus improve their oxidase-like activity. Based on the enhanced oxidase-like activity of SA-CoN3, a paper/smartphone sensor for organophosphorus pesticides (OPs) was successfully constructed and used to quantify glyphosate in environmental and food samples with a low detection limit of 0.66 µM. This work not only highlights the important role of coordination unsaturation of SA nanozymes for promoting oxidase-like activity, but also provides an easy and cost-effective way to conduct effective quantification of OPs in the field. [ABSTRACT FROM AUTHOR]

Nowadays, two-dimensional transition metal chalcogenides have become attractive materials for flexible wearable devices because of their intriguing chemistry characteristics and sensitivity to external stimuli. However, the growth of two-dimensional materials on polymer surfaces is generally carried out by the time-consuming and costly chemical vapor deposition method. Reducing the manufacturing and integration costs while improving the device performance remains to be challenging. Herein, we report a simple liquid metal-assisted hydrothermal method for the growth of two-dimensional nanomaterials on the polymer surface. Specifically, a layer of liquid metal was coated on commercial tape, while layered cobalt sulfide was grown on its surface by a simple one-step hydrothermal method. Different kinds of flexible sensors can be prepared, such as bending sensor, pressure sensor, and humidity sensor, which can be used to detect motion, writing, breathing, and other signals. This strategy can also be assigned to sensing signals on different objects, which may further expand and enrich the application of two-dimensional materials in sensing. [ABSTRACT FROM AUTHOR]

Tailoring the band structure of photocatalysts by elemental doping to enhance redox ability and carrier separation kinetics is a promising strategy for designing high-efficiency catalysts for uranium (U(VI)) photoreduction. Herein, we report enhanced visible-light spectral absorption by tuning the energy bandgap of flower-like ZnO microspheres by doping Co. Accordingly, Co doping narrows the bandgap and increases the photogenerated carrier concentration, thereby promoting the U(VI) photocatalytic reduction. Especially, the removal ratio of U(VI) by Co-doped ZnO microspheres reaches 98.4% with a remarkable adsorption capacity of 1645 mg/g for U(VI) uptake in 400 ppm U(VI) solution. In addition, the Co-doped ZnO microspheres present desired U(VI) reduction ratio in a wide range of U(VI) concentrations, as well as excellent reusability, and resistance to ion interference during photocatalysis. This paper provides a feasible strategy for enhancing the photocatalytic reduction of uranium by introducing metal element doping on the metal oxide surface. [ABSTRACT FROM AUTHOR]

The possibility of processing cobalt-chrome parts by additive manufacturing opens the way to the production of complex net-shaped parts able to withstand high loads and at the same time resist the corrosive environment or thermal loads. However, the surface morphology typical of additive manufactured parts could be detrimental to the fatigue life, and finishing operations become necessary. In this paper, the adoption of abrasive fluidized bed (AFB) processing as a finishing solution is explored, and the effect of the main process parameters, namely the abrasive type, treatment time, and rotational speed, on morphological features and fatigue life is investigated. Field emission gun-scanning electron microscopy and contact gauge profilometry showed an improvement in sample finishing due to the AFB process. The advantages in surface properties were related to an increase in fatigue life. The experimental results show that AFB has a beneficial effect both on the finishing and fatigue behavior of additively manufactured components; a smoother surface was obtained, and the crack initiation during fatigue tests was retarded. [ABSTRACT FROM AUTHOR]

Research efforts on the development of hardmetals with a gradient structure, i.e., a structure that changes smoothly over the cross-section or volume of a sample, have been analyzed. These materials are called functionally graded hardmetals and are characterized by increased wear resistance at set hardness. Three approaches to the development of functionally graded hardmetals that are implemented in Ukraine, Europe, and the USA are discussed. These approaches are based on one phenomenon, such as the migration of molten cobalt from one to another hardmetal region that differs in the size of tungsten carbide particles, liquid phase amount, and carbon content. The approaches differ by process features in preparing and sintering the samples that acquire a gradient structure. In addition, different methods to produce hardmetals with a gradient structure are described. New capabilities of the extrusion process for the production of parts with uneven cross-sectional structure are studied. Conditions of obtaining long-length products from hardmetals with a cellular or 'honeycomb' structure by extrusion of structural elements through a die with openings of specific shape are presented. [ABSTRACT FROM AUTHOR]

Synthesis of high-color intensity blue pigments and using less amount of cobalt is intended in many papers. We also tried to study a highly intensified blue pigment using the least amount of cobalt in experimental and theoretical methods. In this work, the Zn(2−x)CoxSiO4 [x = 0, 0.056, and 0.167] structures were synthesized by the conventional ceramic method. Theoretical calculations were performed using DFT, DFT + U, and many-body Fxc kernel for the long-range correction (LRC) model. We studied the structural, electronic, and optical properties of the structures. A good match was observed between the experimental and theoretical results for all doped and undoped samples. The calculations of electronic properties revealed a decrease in the gap and Fermi energies of the theoretical samples as the doping concentration increased. The optical analysis, which utilizes UV–Vis spectroscopy and CIE L*a*b* calorimetric methods, showed a high blue color intensity (b* = − 49.3, − 46.71) obtained for pigments. Additionally, a comparison was made between the gap energy and color of the experimental and the theoretical samples. These findings highlight the capability of DFT, DFT + U, and Fxc kernel for the LRC model for ceramic pigments. [ABSTRACT FROM AUTHOR]

The increased adoption of lithium-iron-phosphate batteries, in response to the need to reduce the battery manufacturing process's dependence on scarce minerals and create a resilient and ethical supply chain, comes with many challenges. The design of an effective and high-performing battery management system (BMS) for such technology is one of those challenges. In this work, a physics-based model describing the two-phase transition operation of an iron-phosphate positive electrode—in a graphite anode battery—is integrated with a machine-learning model to capture the hysteresis and path-dependent behavior during transient operation. The machine-learning component of the proposed "hybrid" model is built upon the knowledge of the electrochemical internal states of the battery during charge and discharge operation over several driving profiles. The hybrid model is experimentally validated over 15 h of driving, and it is shown that the machine-learning component is responsible for a small percentage of the total battery behavior (i.e., it compensates for voltage hysteresis). The proposed modeling strategy can be used for battery performance analysis, synthetic data generation, and the development of reduced-order models for BMS design. [ABSTRACT FROM AUTHOR]

In this paper, the removal of nickel and cobalt by decylic acid from aqueous sulfate solution was carried out at 25°C. Synergistic extraction of cobalt and nickel with the mixed extractants of decylic acid and Cyanex 921 was also conducted to efficiently separate these metals. The synergistic effect on the extraction of Ni(II) by mixtures of decylic acid and Cyanex 921 in chloroform had been explained through the formation of the complexes NiL2(S) and NiL2(HL)S. The composition of the extracted complexes for the cobalt was shown to be CoL2 (HL)2S and CoL2(HL)2S2. An important synergistic extraction of cobalt with the synergistic enhancement coefficient of 30 was obtained by the addition of Cyanex 921 to decylic acid, whilst the extraction of nickel was petite affected. The greatest separation factor for cobalt and nickel of 36 was obtained with 0.01 M Cyanex 921 at pH 7.63. [ABSTRACT FROM AUTHOR]

In this paper, nitric acid-modified activated carbon was used as an electrode in the electrosorption process for the removal of Co2+, Mn2+, and Ni2+ from wastewater. The effects of applied voltage, initial pH, and coexisting ions on removal efficiency were investigated. The adsorption process was evaluated by adsorption isotherm models. The results indicated that the electrosorption process was consistent with the Langmuir model, proving that the electrosorption process was a monolayer adsorption process. The maximum adsorption capacities of Co2+, Mn2+, and Ni2+ were 131.58 mg/g, 102.04 mg/g, and 103.09 mg/g. Electrochemical tests revealed that the specific capacitance of AC-HNO3 was 54.11 F/g when the scanning rate was 5 mV/s, while the specific capacitance of AC was 36.51 F/g. The Fourier transform infrared spectroscopy (FT-IR) and X-ray photoelectron spectroscopy (XPS) confirmed that the content of oxygen groups on the surface of activated carbon increased after modification, which provided more adsorption sites for electrosorption. When the selected concentration of HCl was used as the eluent, the elution efficiency of Co2+, Mn2+, and Ni2+ could reach 94.23%, 93.65%, and 90.61%. The removal efficiency could reach more than 95% after three cycles. The results of the study can be used as a reference significance for the removal of cobalt, manganese, and nickel ions from heavy metal wastewater by electrosorption. [ABSTRACT FROM AUTHOR]

Nano Co–Cu alloy is an important catalyst, which has an important practical value in the field of the petrochemical industry. In order to prepare carbon-coated Co–Cu alloy composites efficiently and conveniently, a gaseous detonation method was explored in the present paper. The mixture of cobalt acetylacetonate and copper acetylacetonate was used as a carbon source and metal source, and the mixture gas of hydrogen–oxygen and benzene–oxygen was used as an explosion source, respectively, to study the influence of explosion source on the phase and morphology of the nanopowders. The TEM and XRD analysis results indicated that the carbon-coated Co–Cu alloy composites were composed of CNTs and carbon-coated Co–Cu/Cu nanoparticles with core–shell structure. The explosion source would affect the morphology of the carbon-coated Co–Cu alloy composites but have little impact on the phase. The higher combustion heat of combustible gas would contribute to the preparation of carbon-coated Co–Cu/Cu nanoparticles with a core–shell structure and a larger particle size. The present study provides a novel means for the preparation of carbon-coated Co–Cu alloy nanomaterials. [ABSTRACT FROM AUTHOR]

In this paper, we have studied the impact of the pressure on the magnetic, elastic, and mechanical properties of the cobalt Co and cobalt hydride CoH using the full-potential linearized augmented plane wave (FPLAPW) method within the generalized gradient approximation (GGA). The obtained results show an excellent agreement with the available experimental and theoretical data at zero pressure, whereas for pressures up to 20 GPa, the results obtained are considered the first quantitative theoretical prediction for cobalt and cobalt hydride. The calculated electronic properties and spin magnetic moment proved that the metallic and ferromagnetic aspects are preserved for both Co and CoH under different pressure values. Moreover, the results achieved for the elastic constants Cij and the mechanical properties (bulk modulus B, shear modulus G, Young's modulus Y, and Poisson's ratio ν) verified that studied systems are mechanically stable under the tested pressure range. Besides, the discussed results reveal the enhancement in the ductility for both Co and CoH with increasing pressure. [ABSTRACT FROM AUTHOR]

This paper examines a multistep physicochemical process underlying the recycling of spent cobalt-containing current sources, which comprises an opening step in a shredder, secondary comminution in a rotor knife mill, and mechanical comminution of electrode materials in a ball mill, followed by chemical leaching and extraction, and allows the yield of cobalt compounds to be raised. In describing the combination of mechanical comminution and chemical leaching processes, we rely on results of studies of mechanochemical decomposition processes in the case of alkali metals [1]. To analyze the influence of a combination of mechanical and technological factors on the effectiveness of the preparation of required products, we derive governing dimensionless criteria and criterial relations using similarity and dimension theory methods. [ABSTRACT FROM AUTHOR]

The cobalt market is a market that has frequent supply shortages and crises. This paper looks at the changes in the cobalt market from the period of the 1970s to 2018 to gain insights into how the cobalt market is responding and adjusting to periods of supply shortages. Particular concern has arisen due to the potential large increase in the need for cobalt in lithium-ion batteries for electric vehicles. Is the supply of cobalt able to grow at the necessary rate to match the projected increase in the production of electric vehicles? The paper finds that some cobalt market adjustments have occurred over the time period in response to supply risk, but these adjustments have not significantly offset the cobalt market characteristics that largely drive its behavior: by-product supply, the large amount of low-cost material in the DR Congo, and the technical advantages of using cobalt in its applications over potential substitutes. The ramifications for post-2018 are probably more of the same behavior. The cobalt market will continue to make incremental adjustments over time as periodic short-run price spikes occur with the corresponding supply "crisis." The move of the cobalt market to a dominant end use may make the market even more cyclical and prone to supply crises. [ABSTRACT FROM AUTHOR]

The paper presents a new low-temperature method for the synthesis of fine powders of double phosphates LiCoPO4 and LiNiPO4 using a low-waste technology. It has been shown that the morphology and particle size distribution of the synthesized materials are determined by the type of precursor used. The resulting compounds are characterized by chemical analysis, X-ray powder diffraction analysis, scanning electron microscopy, cyclic voltammetry, and cyclic chronopotentiometry. The new approach to the synthesis of submicron powders of lithium and transition metal (nickel or cobalt) double phosphates is more efficient than the existing conventional methods. [ABSTRACT FROM AUTHOR]

There is a tremendous increase in the demand for converting biomaterials into high-quality industrially manufactured human body parts, also known as medical implants. Drug delivery systems, bone plates, screws, cranial, and dental devices are the popular examples of these implants - the potential alternatives for human life survival. However, the processing techniques of an engineered implant largely determine its preciseness, surface characteristics, and interactive ability with the adjacent tissue(s) in a particular biological environment. Moreover, the high cost-effective manufacturing of an implant under tight tolerances remains a challenge. In this regard, several subtractive or additive manufacturing techniques are employed to manufacture patient-specific implants, depending primarily on the required biocompatibility, bioactivity, surface integrity, and fatigue strength. The present paper reviews numerous non-degradable and degradable metallic implant biomaterials such as stainless steel (SS), titanium (Ti)-based, cobalt (Co)-based, nickel-titanium (NiTi), and magnesium (Mg)-based alloys, followed by their processing via traditional turning, drilling, and milling including the high-speed multi-axis CNC machining, and non-traditional abrasive water jet machining (AWJM), laser beam machining (LBM), ultrasonic machining (USM), and electric discharge machining (EDM) types of subtractive manufacturing techniques. However, the review further funnels down its primary focus on Mg, NiTi, and Ti-based alloys on the basis of the increasing trend of their implant applications in the last decade due to some of their outstanding properties. In the recent years, the incorporation of cryogenic coolant-assisted traditional subtraction of biomaterials has gained researchers' attention due to its sustainability, environment-friendly nature, performance, and superior biocompatible and functional outcomes fitting for medical applications. However, some of the latest studies reported that the medical implant manufacturing requirements could be more remarkably met using the non-traditional subtractive manufacturing approaches. Altogether, cryogenic machining among the traditional routes and EDM among the non-traditional means along with their variants, were identified as some of the most effective subtractive manufacturing techniques for achieving the dimensionally accurate and biocompatible metallic medical implants with significantly modified surfaces. [ABSTRACT FROM AUTHOR]

Cobalt chromium-layered double hydroxides (CoCr-LDHs) were electrodeposited on to carbon paper by potentiostatic method from the respective cobalt and chromium ion sources. The electrodeposited CoCr-LDHs were characterized by x-ray diffraction (XRD), Fourier transferred infrared (FT-IR) spectroscopy, scanning electron microscope (SEM), energy-dispersive x-ray analysis (EDX) and x-ray fluorescence (XRF) elemental mapping. The XRD and IR data confirmed that the deposits were CoCr-LDH with carbonate and nitrate ions in the basal space. The SEM observations confirmed that the CoCr-LDH surface had distinct morphology consisting of aggregate size of about 100 nm. For the first time, the supercapacitor characteristics of the CoCr-LDHs were assessed in three-electrode configuration in 1 M KOH or two-electrode (asymmetric capacitor device with reduced graphene-oxide (RGO)). It turned out that the asymmetric capacitor consisted of the CoCr-LDH and the RGO exhibited higher energy density with excellent power density. The higher energy density and power density of the asymmetric capacitor device is believed to be due to the unique LDH morphology in addition to the Faradaic and non-Faradaic contributions. It was demonstrated that the two asymmetric capacitor devices connected in series could light an LED bulb. [ABSTRACT FROM AUTHOR]

The experimental data reported in this paper suggest that titanium(IV) oxyhydroxyphosphate-based ion-exchange materials are potentially attractive for extraction of heavy metal cations from solutions. We have studied the time-dependent ion exchange activity of titanium phosphates for Zn2+, Co2+, and Ni2+ cations in relation to the liquid : solid ratio, temperature, and equilibrium pH of the cation exchange process. The results demonstrate that the selectivity of an ion exchanger for metal cations is determined by the ionic radii of the metals. Conditions for effective use of titanium phosphate materials for extraction of Zn2+, Co2+, and Ni2+ cations from solutions (liquid : solid ratio, temperature, and pH) have been optimized experimentally. [ABSTRACT FROM AUTHOR]

Iron is the most important of all metals and ∼ 98% of it, in the form of iron ore/pellets, is used as the key raw material in making steel, with its per-capita consumption often seen as an Index for a nation's Prosperity. Salient aspects of the industries of iron ore mining and steel-production are presented. These include deposit-types and grades of iron-ore, iron ore minerals with Fe-contents, major producing-exporting-importing countries, international/national prices of iron ore; and major producing countries of steel, international/national production figures, processes of steel-making, including recent hydrogen-energy based green steel/iron ore under de-carbonisation. The less available high-grade Fe ore (>63.5% Fe), as compared to that of the benchmark or standard grade (62% Fe) and low-grade (< 59% Fe) iron ores, has many beneficial features in steel-making, carries a premium price of US $ 1–2/tonne for every 1% increase in Fe-grade over that of the standard grade and, hence, is much sought after. In this communication, two low-cost, potential alternatives to the highgrade Fe ore for steel-making are proposed from the mineral sand industry. These are: (i) placer magnetite-sand, with an example from the coastal Nizampatnam heavy mineral sand deposit in Andhra Pradesh, and (ii) by-product Fe, generated during the beneficiation of ilmenite-sand for high Ti-products such as synthetic rutile/anatase, titanium dioxide pigment, Ti-sponge, Ti-metal etc. A brief account of the mineral sand deposits, including the processes to obtain the above proposed alternatives and the consequent multiple benefits for both the steel and mineral sand industries, is presented in this paper. [ABSTRACT FROM AUTHOR]

This paper presents the results of a study of the physical properties of a hydrophobic deep eutectic solvent (HDES) based on Aliquat 336 and thymol. A solid–liquid phase diagram was built based on the glass temperatures of the Aliquat 336/thymol mixture in different molar ratios. For the first time, the temperature dependences of the density, viscosity, and refractive index of the suggested HDES have been studied. A study of the extraction of Co(II) and Ni(II) ions was carried out under various conditions with HDES Aliquat 336/thymol as an extractant: the influence of the concentration of hydrochloric acid, the concentration of ammonium/lithium/sodium chloride, and the volumetric ratio of phases was studied. The mechanism of the extraction of Co(II) ions by the proposed HDES has been established. Based on the obtained experimental data, it was shown that a Co/Ni pair can be separated from hydrochloric acid solutions with the proposed HDES. [ABSTRACT FROM AUTHOR]

In this paper, detailed results of the development (i.e., preparation and characterization using standard techniques) of self-standing, lightweight, flexible polymer (PVDF)-cobalt ferrite (CoFe2O4) nano-composite (PCFNC) thin films have been reported. The occurrence of major electroactive β-phase with small spherulite phase has been detected on the introduction of nano-cobalt ferrite particle in the ferroelectric PVDF polymer using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and atomic force microscope (AFM) techniques. The ambient temperature relative permittivity of PCFNC found to be nearly 80 with a tangent loss of 0.6 suggests the suitability of the composite for a flexible and lightweight capacitor device. Analysis of Impedance spectroscopy data confirms the contributions of grains and grain boundaries to the resistive and capacitive characteristics of the material. The frequency dependence of ac conductivity follows Jonscher's power law and is found to be in the order of 10−5Ω.m−1. The optical bandgap of the composite is found to be 3.66 eV which has better thermal stability as compared to that of PVDF thin film. The room temperature ferromagnetic hysteresis behaviour displays a saturation magnetization of 4emu/gm. The ferroelectric hysteresis loop provides an invariable saturation polarization of 6μC/cm2 at an applied frequency while the coercive field decreases with rising frequency. The first-order room temperature magneto-electric coupling coefficient of the composite is found to be 198 mV/cm. Oe at zero DC bias magnetic field. This unique field sensing characteristic suggests the potential application of the developed material in multifunctional devices, particularly as a field sensor. [ABSTRACT FROM AUTHOR]

Extensive irrigation by the effluents released from a paper mill near Nanjangud have led to the accumulation of heavy metals in the soil and different parts of the paddy crops. In this paper, the physicochemical characteristics of paper mill effluents and the accumulation ofheavy metals (Cu, Zn, Pb, Co, Cd, Cr, and Ni) in the soil and different parts (root, leaf, and seed) of the paddy crops growing in the irrigated area are described and compared with the soil and paddy cropsirrigated by natural waters (unpolluted). Chemical and biological oxygen demands of wastewater were found to be 437 and 1070 ppm respectively, which are beyond the tolerance limits set by Indian standards. The total dissolved and suspended solids are 1754 and 900 ppm respectively. The concentration of heavy metals (except Zn) in the seeds is remarkably less than that in the roots and leaves of the paddy crops.The heavy metal uptake by plants shows the greatest accumulation of Cu, Cr, Co, and Pb in the roots; Cd and Ni in the leaves; and Zn in the seeds of rice. The heavy metal content of the soil and their totaluptake by paddy roots has the relation: Pb>Zn>Cu>Cd and Pb>Cu>Zn>Cd.Survival of paddy crops irrigated by polluted waters indicates tolerance to toxic heavy metals. In conclusion, since in many tropical countries the common diet of people is rice, the accumulation of toxic heavy metals in rice may lead to health disorders. [ABSTRACT FROM AUTHOR]

This paper describes for the first time two processing routes—the precursor method and the two-step wet chemical process—for the synthesis of magnetic cobalt ferrite using the Tamarindus indica fruit extract. These green approaches are eco-friendly, safe and efficient alternatives to classical chemical methods. The aqueous extract from tamarind fruit contains numerous metabolites (organic acids, aminoacids). All these bioactive components are able to chelate metal ions leading to the formation of the multimetallic complex (precursor of cobalt ferrite). The obtained precursor was characterized by Fourier transform infrared spectroscopy (FTIR), thermal analysis, X-ray diffraction analysis (XRD) and magnetic measurements. The structure, morphology and magnetic behavior of the cobalt ferrite samples prepared through both synthesis routes were investigated by various characterization techniques: FTIR, XRD, scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS), Mössbauer spectroscopy and magnetic measurements. XRD data confirmed that a cubic spinel structure was obtained for both ferrite powders with average crystallite size of 13 and 5 nm, respectively. The microstructure study by SEM revealed the formation of nanocrystallites assemblies using the precursor method and carbon-rich particles forming granulated micron-sized agglomerates, embedding ferrite nanocrystallites obtained through the two-step wet chemical process. Mössbauer spectroscopy results evidenced relaxation processes in the CoFe2O4 samples at room temperature, and the main characteristics of the involved sublattices were derived. The magnetic investigation revealed a typical magnetic behavior for a spinel, with CoFe2O4 nanoparticles ferrimagnetic at low temperature and superparamagnetic at room temperature. [ABSTRACT FROM AUTHOR]

This paper describes the realization and characterization of La 0.8 Pb 0.1 Ca 0.1 Fe 1 - x Co x O 3 gas-based sensors. La 0.8 Pb 0.1 Ca 0.1 Fe 1 - x Co x O 3 (0.00 ≤ x ≤ 0.20) thin films are prepared using the drop-coating method over a Si / SiO 2 substrate with inter-digitated Pt -electrodes. The sensors, thus, produced exhibit a good sensitivity to ozone at low concentration. The substitution of iron atoms by cobalt ones increases the sensor responses "S," from 1.716 for x = 0.00 to 6.584 to x = 0.20 for an ozone concentration equal to 400 ppb . In addition, the substitution of iron by cobalt induces a decrease in the sensor-operating temperature from 270 ∘ C for the parent compound (x = 0.00) to 170 ∘ C for x = 0.20 . [ABSTRACT FROM AUTHOR]

With the rapid promotion of new energy vehicles, in-use electric vehicle batteries (EVBs) are becoming an important component of urban mining. This paper analyzed the metal stocks in EVBs in China from 2009 to 2019 using a bottom-up method, which focused on the in-use stock of seven main metals, namely, nickel, cobalt, manganese, lithium, copper, aluminum, and iron, in primary use stage and secondary use stage of three EVB types, namely, lithium nickel manganese cobalt oxide battery (NMC), lithium iron phosphate battery (LFP), and lithium manganese oxide battery (LMO). It was found that the rapid development of electric vehicles (EVs) contributed to a dramatic increase in in-use metal stocks from 0.7 kt in 2009 to 1.1 Mt in 2019. To assess the increase, three scenarios simulating metal stocks in EVBs from 2020 to 2030 were analyzed, namely, baseline, NMC-dominated, and LFP-dominated, and results indicated that metal stocks will reach 20.6 Mt, 23.2 Mt, and 17.9 Mt, respectively, by 2030. Across the scenarios there is little proportional difference in metal stocks between the two use stages. The proportion of the three EVB types correlates to the development trend of EVB technology under each corresponding scenario. Besides, the in-use metal stocks in EVBs have high implied recycling potential and environmental benefit. The recycling potential of these seven metals is 1.0 Mt in 2019, and it will reach 20.0 Mt, 22.6 Mt, and 17.4 Mt, respectively, in 2030 under the three scenarios. The results reveal the current status and evolution characteristics of metal stocks in EVBs in China, and provide data for material flow analysis and life cycle management of EVBs. [ABSTRACT FROM AUTHOR]

This paper lays down the history of the advances in cobalt production technology from natural copper–nickel and recyclable raw materials at the Severonikel combine at AO Kol'skaya GMK over an 80-year period. The high role of extraction processes for the production of commercial salts and high-quality electrolytic metal is shown. Ways to further improve the quality of cobalt are presented, as is the need to extend the assortment. [ABSTRACT FROM AUTHOR]

Copper and cobalt usually coexist in the leachate of waste lithium ion batteries, sea nodules and other copper ore or by-product. Conventional methods for the separation of copper and cobalt hardly avoid some defects, such as longer extraction time, co-extraction and too many stages. In this paper, a microfluidic extraction procedure for simultaneously separating copper (Cu2+) and cobalt (Co2+) ions in a microchannel was investigated. In addition, some key operation parameters, such as initial pH, volume flow rate and extractant concentration, were optimized by a method of response surface methodology (RSM). The result showed that under the optimized operation parameters of initial pH of 2.5, volume flow rate of 0.035mLmin-1 and extractant concentration of 17.36%, the extraction rate of copper could be as high as 96.73%, with a low cobalt extraction rate, which was only 2.41%. [ABSTRACT FROM AUTHOR]

In this paper, the induced effect of annealing temperature on structural and magnetic response of nano-crystalline cobalt ferrite prepared via sol–gel auto-combustion method using metal nitrates and citric acid has been reported. The X-ray diffraction pattern confirms the formation of cubic spinel structure of the annealed nano-crystalline cobalt ferrite belonging to the Fd3m space group. From the X-ray diffraction pattern it is observed that lattice parameter and crystallite size increase from 8.3801 to 8.3937 Å and 26.38 to 56.53 nm, respectively, with the increasing annealing temperature up to 1000 °C. The A1g and Eg modes in the Raman spectra and the vibrational frequencies of metal–oxygen (M–O) ions in the FTIR spectra also confirm the existence of the cubic spinel structure of nano-crystalline cobalt ferrites. The shift in the peak position of the Raman spectra shows the migration of Fe3+/Co2+ ions between the tetrahedral and octahedral sites. The magnetization response shows that saturation magnetization increases from 53.17 emu/g (2.13 μB/f.u.) to 77.94 emu/g (3.27 μB/f.u.), while coercivity lies between 1838.32 and 679.15 Oe with the increasing annealing temperature up to 1000 °C. [ABSTRACT FROM AUTHOR]

This study focused on the purification of ethylene from acetylene using a catalyst made of cobalt deposited on a carbon-containing material, such as clay. Cobalt catalysts with different mass fractions were carbonized at a temperature of 550 °C, activated with 5% and 10% nitric acid and tested for the hydrogenation of acetylene to ethylene. The physicochemical properties were investigated by means of X-ray powder diffraction (XRD), scanning electron microscope (SEM) and TG/DSC. The reaction products were analyzed using a Chrom-3700 gas chromatograph and gas chromatography–mass spectrometry (Agilent 7890A/5975C). The conversion of a 7% Co/CL-10 catalyst, carbonized at 550 °C, was 82% at 100 °C, and reached 95% at 140 °C. Side reactions were activated when the temperature rose above 140 °C, which reduced the ethylene yield. The carbonized catalysts exhibited more activity than traditional impregnated catalysts that had not been subjected to carbonization. This paper outlines a simple method for preparing Co/CL-10 catalysts with high catalytic activities for the selective hydrogenation of acetylene, using the carbonization process on a chemically-activated carrier clay. [ABSTRACT FROM AUTHOR]

Purpose: In the booming electric vehicle market, the demand for refined cobalt is showing a blowout growth. China is the largest cobalt-refiner and cobalt-importer in the world. However, the life cycle inventory and potential environmental impact from cobalt refining in China have not been clearly illustrated. This paper builds a comprehensive inventory to support the data needs of downstream users of cobalt sulfate. A "cradle-to-gate" life cycle assessment was conducted to provide theoretical support to stakeholders. Methods: A life cycle assessment was performed based on ISO 14040 to evaluate the potential environmental impact and recognize the key processes. The system boundary of this study contains four stages of cobalt sulfate production: mining, beneficiation, primary extraction, and refining. Except for the experimental data used in the primary extraction stage, all relevant data are actual operating data. The normalization value was calculated based on the latest released global emission and extraction data. Results and discussion: Normalization results show that the potential impacts of cobalt refining were mainly concentrated in the fossil depletion and freshwater ecotoxicity categories. The beneficiation stage and the refining stage account for 72% and 26% of the total normalization value, respectively. The beneficiation stage needs to consume a lot of chemicals and energy to increase the cobalt content, due to the low grade of cobalt ore in China. Compared with cobalt concentrate, the use of cobalt-containing waste (e.g., cobalt waste from EV batteries) can ease endpoint impact by up to 73%. With the application of the target electricity structure in 2050, the potential impact of China's cobalt sulfate production on global warming, fossil depletion, and particulates formation can be reduced by 24%, 22%, and 26%, respectively. Conclusion: Findings indicate that the chemical inputs and electricity consumption are primary sources of potential environmental impact in China's cobalt sulfate production. Promoting the development of urban mines can reduce excessive consumption of chemicals and energy in the beneficiation stage. The environmental benefits of transforming the electricity structure and using more renewable energy to reduce dependence on coal-based power in the cobalt refining industry were revealed. [ABSTRACT FROM AUTHOR]

This paper introduces for the first time the preparation of cobalt aluminate (CoAl2O4) nanoparticles through a solution combustion method using a Mentha piperita leaves extract. The active constituents present in the mentha leaves extract act as both a chelating and a reducing agent. The isolated precursor was characterized by FTIR, UV–Vis, thermal analysis and XPS. Various techniques (XRD, SEM and TEM, XPS, FTIR and UV–Vis) were also used to characterize the cobalt aluminate spinel from the point of view of structure, morphology and surface chemistry. XRD confirmed the formation of a single-phase, crystalline cubic spinel structure with mean crystalline domain size of 19.5 nm. The TEM analysis showed rhombic and rectangular CoAl2O4 nanoparticles with unimodal particle size distribution and average particle size of about 35 nm. The characteristic peaks of the CoAl2O4 spinel were highlighted by the FTIR spectrum. The tetrahedral configuration of Co2+ ions in the CoAl2O4 spinel structure was illustrated by the absorbance and XPS spectra. Furthermore, XPS spectra reveal both tetrahedral and octahedral configurations of Al3+ ions. To evaluate the catalytic properties of the cobalt aluminate, the photocatalytic degradation of methylene blue (MB) was carried out under visible light irradiation. [ABSTRACT FROM AUTHOR]