Ratio Of Copper Research Articles

Effect of Grain Size on Adiabatic Shear Susceptibility of Copper

The effect of grain size on adiabatic shear susceptibility of copper was investigated in this paper. Moreover, the results show that the critical time and critical strain corresponding to the stress collapse point decrease with the increase of grain size at the same strain rate, while the widths of adiabatic shear bands (ASBs) increase as grain size increases, indicating that the adiabatic shear susceptibility of copper increases with the increase of grain size. The electron backscatter diffraction (EBSD) experiment shows that the fraction of twin boundaries in large-grain copper is higher than that in small-grain copper before loading. Furthermore, the larger the grain size is, the easier twin will be produced in large-grain copper during deformation, which leads to the twin boundary ratio of large-grain copper will be further higher than that of small-grain copper. The higher fraction of twin boundaries makes large-grain copper have a stronger strain rate hardening effect and thermal softening effect than small-grain copper. Considering that their strain hardening effects are similar, the enhancement of thermal softening caused by the increase of twin boundary ratio exceeds the enhancement of strain hardening effect and strain rate hardening effect, indicating that large-grain copper has a higher adiabatic shear susceptibility.

Innovative Electrochemical Processing for Copper Removal from Carbon Saturated Iron Melt Using Na2S-FeS Molten Sulfide

Innovative electrochemical processing was proposed in this paper to remove residual copper from carbon saturated iron melt. A direct current electric field was applied to treat the copper-bearing molten iron with molten sulfide flux between a cathode immersed in the sulfide flux and an anode immersed in the molten iron, and a better decopperization effect was achieved with the action of the electric field. Including the copper removal ratio increased to 94%, the distribution ratio of copper between the sulfide and iron increased by about four times, and the sulfur content in the iron melt was decreased by about 50%. Electrochemical tests were carried out to study the reasons for those effects. The results indicated that the electrodeposition of Cu+ on the cathode promotes the mass transfer of Cu from iron melt to molten sulfide, and the excess S2− in the iron melt was oxidized to volatile sulfur on the anode. The molten sulfide has been widely concerned in pyrometallurgy for its potential to remove copper from iron-based melts, and this study verified that molten sulfide could also be used as an electrolyte for electrorefining of iron-based melts.

Structural and magnetic characterizations of NixCu0.8-x Zn0.2Fe2O4 spinel ferrites

The Ni-Cu-Zn ferrites are one of the most exciting spinel oxides so far because of its diverse applications. In the current study, the ratio of nickel and copper was varied keeping the concentration of zinc constant primarily aiming to examine its effect on cation distribution as well as structural and magnetic properties. The samples were synthesized via the conventional solid state sintering method at a temperature of 1050 °C then subjected to neutron diffraction studies. The magnetic properties were measured using a vibrating sample magnetometer (VSM) which complements the magnetic measurements from the neutron diffraction experiments. The ferromagnetic behaviors of these Ni-Cu-Zn ferrites were explained using the Y-K model and the canting of the magnetic moments were also measured. The lattice parameter ‘a’ was seen to reduce which results from the replacement of large Cu+ ions (0.73 with the smaller ionic radius of (0.69 ). To accommodate a large number of cations in the spinel lattice, the oxygen atoms restructure themselves as a result oxygen position parameter increased. The net magnetic moment per unit formula decreases as the Ni content is increased up to a level, after which the net moment increased.

Ion Beam Generation in a Vacuum Arc Ion Source with a Multicomponent Cathode

Vacuum arc ion sources are widely used for modifying the properties of various surfaces using ion implantation. The use of cathodes consisting of multicomponent compounds in these sources makes it possible to obtain beams of complex compositions, which expands their technological capabilities. An ion beam generated in a vacuum arc ion source with a two-component cathode made of a copper-chromium composite is studied under the conditions of a magnetic field applied to the discharge gap. It is shown that the charge state distribution of copper and chromium ions in the beam depends on their ratio in the cathode material, and the fractions of these ions in the beam correspond to their atomic content in the cathode. It is shown that the ratio of copper and chromium ions in the plasma, and, accordingly, in the ion beam, is independent of the magnetic field and corresponds to their atomic ratio in the cathode.

Relationship between the rate of a decreased oral function and the nutrient intake in community-dwelling older persons: An examination using oral function-related items in a questionnaire for latter-stage elderly people

To determine the rate of a decreased oral function using questions from the Kihon checklist corresponding to the Questionnaire for Latter-stage Elderly People and to clarify nutrient intake in older persons. This study targeted 511 older people (217 men, 294 women, average age 73.1±5.6 years old). Their oral function was evaluated using questions on the masticatory function and swallowing function from the Kihon checklist, corresponding to questions on the oral function in the Questionnaire for Latter-stage Elderly People. Participants who had at least one symptom measured were defined as the applicable group (AG). In addition, to evaluate the nutrient intake of the participants, interviews were conducted using the Food Frequency Questionnaire Based on Food Groups. The rate of inclusion in the AG was 32.9% for the total sample, 28.2% for early-stage elderly people, and 40.1% for latter-stage elderly people. The AG rates did not differ significantly between men and women. For latter-stage elderly people, the protein-energy ratio and intakes of total energy, protein, pantothenic acid, folic acid, vitamin B6, niacin, vitamin K, copper, zinc, phosphorus, magnesium, potassium, and total dietary fiber were significantly lower in the AG than in the non-AG. The evaluation of placement in the AG through questions on the oral function from the Kihon checklist corresponding to the Questionnaire for Latter-stage Elderly People demonstrated that the rate of a decreased oral function was higher in latter-stage elderly people than in early-stage elderly people. In addition, the latter-stage elderly people in the AG had a lower nutrient intake.

Scalable synthesis of Cu\u2013Sb\u2013S phases from reactive melts of metal xanthates and effect of cationic manipulation on structural and optical properties

We report a simple, economical and low temperature route for phase-pure synthesis of two distinct phases of Cu–Sb–S, chalcostibite (CuSbS2) and tetrahedrite (Cu12Sb4S13) nanostructures. Both compounds were prepared by the decomposition of a mixture of bis(O-ethylxanthato)copper(II) and tris(O-ethylxanthato)antimony(III), without the use of solvent or capping ligands. By tuning the molar ratio of copper and antimony xanthates, single-phases of either chalcostibite or tetrahedrite were obtained. The tetrahedrite phase exists in a cubic structure, where the Cu and Sb atoms are present in different coordination environments, and tuning of band gap energy was investigated by the incorporation of multivalent cationic dopants, i.e. by the formation of Zn-doped tetrahedrites Cu12−xZnxSb4S13 (x = 0.25, 0.5, 0.75, 1, 1.2 and 1.5) and the Bi-doped tetrahedrites Cu12Sb4−xBixS13 (x = 0.08, 0.15, 0.25, 0.32, 0.4 and 0.5). Powder X-ray diffraction (p-XRD) confirms single-phase of cubic tetrahedrite structures for both of the doped series. The only exception was for Cu12Sb4−xBixS13 with x = 0.5, which showed a secondary phase, implying that this value is above the solubility limit of Bi in Cu12Sb4S13 (12%). A linear increase in the lattice parameter a in both Zn- and Bi-doped tetrahedrite samples was observed with increasing dopant concentration. The estimated elemental compositions from EDX data are in line with the stoichiometric ratio expected for the compounds formed. The morphologies of samples were investigated using SEM and TEM, revealing the formation of smaller particle sizes upon incorporation of Zn. Incorporation of Zn or Bi into Cu12Sb4S13 led to an increase in band gap energy. The estimated band gap energies of Cu12−xZnxSb4S13 films ranges from 1.49 to 1.6 eV, while the band gaps of Cu12Sb4−xBixS13 films increases from 1.49 to 1.72 eV with increasing x.

Cu, Ni and multi-walled carbon-nanotube-modified graphite felt electrode for nitrate electroreduction in water

A three-dimensional bimetal carbon-based electrode, CuNi/multi-walled carbon nanotube/graphite felt (CuNi/M/GF), was designed for the electrochemical reduction of nitrate. Multi-walled carbon nanotubes (MWCNTs) served as the interlayer and skeleton, which increased the electrochemical reduction activity of GF to nitrate. CuNi/M/GF with different atomic ratios of copper and nickel was prepared by adjusting the electrodeposition potential. The performance of the CuNi/M/GF, Cu foam, Ni foam, M/GF and GF in a dual-chamber cell and single-chamber cell was evaluated for different concentrations of chlorine, current density, energy consumption and degradation. In a solution of 100 mg/L NO3−-N, the removal of NO3−-N and total nitrogen (TN) by the optimal electrode in a single-chamber cell (SCC) can reach 99%. Aeration in the dual-chamber cell cathode can blow out more than 99% of the ammonia nitrogen that is converted from NO3−-N. More than 95% of the TN in a 100 ml, 700 mg/L NO3−-N solution was removed within 6 h. CuNi/M/GF showed excellent corrosion resistance and stability in the cyclic tests. CuNi–1.3/M/GF is more resistant to corrosion in the DCC than in the SCC which may be attributed to contact of the cathode with the oxidizing substance in the SCC. The application of CuNi/M/GF in practical wastewater that contained a high concentration of NaCl and nitrate-N shows that the electrode has considerable application prospects in TN removal.

Effect of thermal annealing on the optoelectronic properties of Cu-Fe-O thin films deposited by reactive magnetron co-sputtering

In this work, the influences of the temperature and the air residual pressure during post-annealing treatment on the structural, optical and electrical properties of copper iron oxide thin films were investigated. The films were co-sputtered from metallic Cu and Fe targets in the presence of argon and oxygen gas mixture. The powers dissipated on the metallic targets were adjusted to fix the Cu/Fe metallic ratio close to 1 in the films. The as-deposited thin films were initially amorphous, and they were annealed under different oxidizing conditions as a function of the temperatures (380, 450 and 550°C) and of the air residual pressures (secondary vacuum, primary vacuum, and air atmosphere corresponding to the air residual pressures of 10−4, 10−1 and 105 Pa respectively). Spinel CuFe2O4 were clearly detected by X-ray diffraction analysis after air-annealing. With the diminishing of the air residual pressure, the films are reduced. It was shown that the delafossite CuFeO2 phase growth is possible in a limited range of temperature and pressure and is accompanied by the crystallization of phase mixture in which the nature of secondary phases depends on the air residual pressure. The optical and electrical properties of Cu-Fe-O thin films were then detailed and discussed according to the structural evolution with the treatment conditions.

OXIDATION OF ETHANOL OVER BINARY COPPER-TUNGSTEN OXIDE CATALYSTS

The oxidation reaction of ethanol on binary copper-tungsten oxide catalysts has been studied. It was shown that at temperatures up to 300°C, acetaldehyde is practically the only product of the ethanol oxidation reaction on copper-tungsten oxide catalysts. At higher temperatures, in addition to acetaldehyde, acetone, carbon dioxide and ethylene are also formed. It is found that the isomerization of butene-1 on the Cu-W-O catalysts begins from a temperature of 200°C and with an increase in temperature, the yield of butenes-2 increases and at 350°C reaches its maximum. It was shown that the dependence of the yields of butenes-2 on the atomic ratio of copper to tungsten has the form of a curve with a maximum on the sample Ti-W=3-7. On this sample, the maximum yield of butenes-2 reaches 57%. It is found that with an increase in the degree of isomerization, the yields of acetaldehyde and ethylene increase, and the yield of the product of deep oxidation decreases, which is due to formation of carbon dioxide at sites of basic nature. Keywords: Ethanol oxidation, isomerization, binary catalysts, tungsten oxide, copper oxide, acetaldehyde.

Zinc and copper accumulation in zander scales in the Novosibirsk reservoir

One of the most important environmental issues is the pollution of water basins with chemicals, in particular with heavy metals, which do not dissolve in water, and pass through the food chaininto the body of aquatic organisms, and then the final consumer, humans. The features of the contentof copper and zinc, their variability in the scales of pike perch (Sander lucioperca) of the Novosibirsk reservoir were studied. 33 samples of scales were taken for analysis. The concentration of the studied metals was measured applying the atomic emission spectral method with inductively coupledplasma on an iCAP-6500 spectrometer from Thermo Scientific. A high phenotypic variability in theconcentration of copper and zinc in pike perch scales was found. It was revealed that the concentration of copper in the scales of the pike perch of the Novosibirsk reservoir is 1.8 times lower than inthe muscles, and the content of zinc is 4.8 times higher. The extreme ratio for copper was 1:24, forzinc 1:6. The content of zinc and copper was in a ratio of 48:1. The average population values of theconcentration level of copper (1.69 mg / kg) and zinc (93.3 mg / kg) in the scales of the pike perchof the Novosibirsk reservoir were established. A high level of positive correlation (r = 0.859) wasrevealed between essential elements. The obtained data on the level of copper and zinc concentrationin scales can be used as reference values. The distribution of heavy metals in zander scales is uneven.Expansion of parameters for assessing living organisms by chemical composition enables to assessmore accurately the interior of animals. The data obtained can be used for intravital assessment ofthe interior of zander and in environmental studies. There is a tendency towards an increase in thelevel of heavy metals in the water body of the Novosibirsk Reservoir.

Investigation on Metal Adornments From Ancient Eastern Europe

This study focuses on the investigation of certain bronze adornment objects from the First Iron Age (the so-called middle Hallstatt period), dating to the ninth–eighth c. BC. These objects are part of a bronze and iron hoard (labeled Cx 116) discovered in the present Romanian territory, at Tărtăria–Podu Tărtăriei vest archaeological site, in Alba County. Along with a second hoard of bronze and iron objects, this represents a unique discovery for the present Romanian territory, namely, for the inner Carpathian area and the Lower and Middle Danube Basin, where no such votive discovery had been made by archaeological excavations. The objects, approximately 450 bronze and iron objects—weapons, tools, adornments, and harnesses—were found in the two hoards, in the Southern ditch, which outlines the archaeological site. Digital radiography has been used to assess the physical state of the objects and to identify potential specific craftsmanship details. It showed a fairly good preservation status, with incipient corrosion processes located in the core of some of the objects and some specific traces of the crafting process and subsequent mechanical defects were highlighted. The relatively good state of preservation of the objects can result from the fact that they had been protected from the humid environment by the ceramic vessel they were placed in. XRF and LIBS were used to identify the materials and to stratigraphically evaluate the objects. XRF scanned the surface of the objects, revealing elements related to both the raw material—a copper alloy with tin and lead, together with trace elements related to the specific mining location of the ores, and the depositional environment of the objects–such as iron. LIBS allowed a more in-depth stratigraphic analysis, which indicated a higher copper ratio—compared to iron—as the kinetic series advance, fact that sustains the idea that the major iron input was coming from the depositional environment. Both XRF and LIBS results were consistent with high elemental variability, probably due to the nature of the original material and the influence of the deposition soil conditions.

Augmentation of weld penetration by flux assisted TIG welding and its distinct variants for oxygen free copper

A comparative study to investigate the influences of single component fluxes on the depth-to-width ratio (DWR) of oxygen free copper was carried out with novel variants of tungsten inert gas (TIG) welding namely Activated TIG (A-TIG), Flux Bounded TIG (FB-TIG) and Flux Zoned TIG (FB-TIG) processes. The experiments to identify the fluxes delivering the higher DWRs in A-TIG welding among thirteen distinct fluxes were followed by the trials with FB-TIG and FZ-TIG employing those identified DWR fluxes. The fluxes which outperformed with all the techniques were MoO3 & MgO. Reversed Marangoni and arc constriction mechanisms were perceived to be opt for such an increase in DWR. Metallurgical characterization of the weldment indicated distinct grain morphologies and certain defects as well in the weld zones. The FZ-TIG welding is postulated to surpass all the techniques in terms of bringing about the upmost weld penetration.

Catalytic Asymmetric Mannich‐Type Reaction Enabled by Efficient Dienolization of α,β‐Unsaturated Pyrazoleamides†

Main observation and conclusion(E)‐α,β‐Unsaturated pyrazoleamides undergo facile dienolization to furnish copper(I)‐(1Z,3Z)‐dienolates as the major in the presence of a copper(I)‐(R)‐DTBM‐SEGPHOS catalyst and Et3N, which react with aldimines to afford syn‐vinylogous products as the major diastereoisomers in high regio‐ and enantioselectivities. In some cases, the diastereoselectivity is low, possibly due to the low ratio of copper(I)‐(1Z,3Z)‐dienolates to copper(I)‐(1Z,3E)‐dienolates. (Z)‐Allylcopper(I) species is proposed as effective intermediates, which may form an equilibrium with copper(I)‐(1Z,3Z)‐dienolates. Interestingly, the present methodology is a nice complement to our previous report, in which (E)‐β,γ‐unsaturated pyrazoleamides were employed as the prenucleophiles in the copper(I)‐catalyzed asymmetric vinylogous Mannich‐Type reaction and anti‐vinylogous products were obtained. In the previous reaction, copper(I)‐ (1Z,3E)‐dienolates were generated through α‐deprotonation, which might form an equilibrium with (E)‐allylcopper(I) species. Therefore, it is realized in the presence of a copper(I) catalyst that (E)‐α,β‐unsaturated pyrazoleamides lead to syn‐products and (E)‐β,γ‐unsaturated pyrazoleamides lead to anti‐products. Finally, by use of (E)‐β,γ‐unsaturated pyrazoleamide, (E)‐α,β‐unsaturated pyrazoleamide, (R)‐DTBM‐SEGPHOS, and (S)‐DTBM‐SEGPHOS, the stereodivergent synthesis of all four stereoisomers is successfully carried out. Then by following a three‐step reaction sequence, all four stereoisomers of N‐Boc‐2‐Ph‐3‐Me‐piperidine are synthesized in good yields, which potentially serve as common structure units in pharmaceutically active compounds.

Profile of Joel D. Blum

Joel D. Blum uses isotopes to solve an unusually wide range of research problems. Renowned for innovative approaches, Blum, a professor of earth and environmental sciences at the University of Michigan, was among the first scientists to apply methods developed largely for lunar and planetary studies to answer longstanding questions about ecology and the environment. His research group has also developed methods for making high-precision measurements of metallic element isotope ratios in terrestrial, aquatic, and atmospheric systems. Elected to the National Academy of Sciences in 2020, Blum used mercury isotopic signatures to investigate the world’s deepest ocean trenches, and the findings are reported in his Inaugural Article (1). Blum and his colleagues found that anthropogenic mercury reaches these remote areas primarily via sinking fish carcasses, an insight that could aid global mercury pollution reduction efforts. Joel Blum. Image credit: Alec Tremaine (photographer). Born in Cleveland, Ohio, Blum was influenced by his parents. His father, who was a professor of applied social science at Case Western Reserve University, inspired Blum’s interest in research. His mother, an avid outdoorswoman, shared her enjoyment of hiking, skiing, and other activities. Blum says, “As a family, we camped and hiked and traveled every summer. Not surprisingly, my brother Alex became a geologist.” For his undergraduate studies, Blum attended Case Western Reserve University, where he initially majored in political science. He decided, however, that geology was more compatible with one of his favorite pastimes, mountain climbing, and added a geology double major. After earning a Bachelor’s degree in 1981, Blum went to the University of Alaska, Fairbanks, for a Master’s degree in geological science. Desiring to stay in Alaska, Blum took a job as an exploration geologist for a mining company in 1982. He then became a project supervisor for the Alaska Department of Natural Resources, …

Assessment of kitchen wastewater quality for irrigation

In this study, the potential reuse of kitchen wastewater (KWW) in irrigation was analyzed to reduce the present freshwater demand. To know the suitability of KWW for irrigation, the samples were first collected from an educational institute in India and then characterized according to its physical, chemical, and bacteriological properties. The characterized data were then compared with the standard limit for irrigation Food and Agriculture Organization (FAO in Water quality for agriculture. Irrigation and drainage paper 29, M56, 1994) and the US Salinity Laboratory (USSL). Apart from the above irrigation standards, the characterized data were also compared with sodium adsorption ratio (SAR), residual sodium carbonate, sodium percentage (Na%), magnesium hazard (MH), Kelly’s ratio (KR), and permeability index to get better clarity. From the characterization, it was found that carbonate, fluoride, chromium, and Escherichia coli were absent, whereas parameters like pH, chloride, iron, copper, magnesium, lead, nickel, sodium, calcium, zinc, aluminum, and sodium adsorption ratio were within the permissible limit. The result obtained from the USSL classification system suggested that 30.77% of KWW samples are safe for irrigation. Moreover, its quality was found to be safe for irrigation based on SAR, Na%, KR, and MH. For better decision making of KWW reuse in irrigation, the output of Mamdani fuzzy inference system (MFIS) was compared with the USSL classification system. The overall agreement between USSL and MFIS was found to be 55.6% for KWW.

On Generalization of Fibonacci, Lucas and Mulatu Numbers

Fibonacci numbers, Lucas numbers and Mulatu numbers are built in the same method. The three numbers differ in the first term, while the second term is entirely the same. The next terms are the sum of two successive terms. In this article, generalizations of Fibonacci, Lucas and Mulatu (GFLM) numbers are built which are generalizations of the three types of numbers. The Binet formula is then built for the GFLM numbers, and determines the golden ratio, silver ratio and Bronze ratio of the GFLM numbers. This article also presents generalizations of these three types of ratios, called Metallic ratios. In the last part we state the Metallic ratio in the form of continued fraction and nested radicals.

The Influence of the Incorporation Method and Mass Ratio of Copper on the Antibacterial Activity of MCM-41

This work deals with the use for the first time of waste spent glass as a new source of silicon and aluminum in the synthesis of highly ordered MCM-41 nanomaterials and also treats the method (namely direct and indirect) of its activation by copper under different mass ratios Si/Cu 60; 80 and 100. The evaluation of the activation method efficiency is tested against Gram-negative (E. coli) and Gram-positive (S. aureus and Bacillus cunis). The ordered MCM-41 nanomaterials were prepared by hydrothermal synthesis using the waste spent glass as silicon and aluminum sources. The silicon and aluminum needed for the synthesis of MCM-41 are extracted from waste spent glass by the alkaline fusion process. The copper is added to the MCM by two mentioned methods separately to obtain Cu-MCM-41. The resulting MCM were characterized by X-ray fluorescence (XRF), Inductively Coupled Plasma Optical Emission spectroscopy (ICP-OES), X-ray diffraction (XRD), Nitrogen adsorption-desorption, and Fourier transformed Infra-red spectroscopy (FTIR). Evaluation data revealed that the ordered mesoporous Cu-MCM-41 nanomaterials by both methods under different mass ratios Si/Cu are obtained. The high crystalline order is attributed to the mass ratio Si/Cu 100 for both methods. It is also noted that the specific surface areas of all mass ratios in both methods are up to 1000 m2 g−1. No relationship is found between surface area and substitution method or metal content. Indeed, the efficiency of copper incorporation method of Cu-MCM-41 synthesized under molar ratio (Si/C = 100) in their two different states calcined and un-calcined are applied as antibacterial inhibitors against Gram-negative (E. coli) and Gram-positive (S. aureus and Bacillus cunis). The results obtained by the application of Cu-MCM-41 materials as antibacterial inhibitors appear to be very promising. However, the indirect method shows a slight improvement in antibacterial inhibition compared to the direct method.

Copper interferes with selenoprotein synthesis and activity

Selenium and copper are essential trace elements for humans, needed for the biosynthesis of enzymes contributing to redox homeostasis and redox-dependent signaling pathways. Selenium is incorporated as selenocysteine into the active site of redox-relevant selenoproteins including glutathione peroxidases (GPX) and thioredoxin reductases (TXNRD). Copper-dependent enzymes mediate electron transfer and other redox reactions. As selenoprotein expression can be modulated e.g. by H2O2, we tested the hypothesis that copper status affects selenoprotein expression. To this end, hepatocarcinoma HepG2 cells and mice were exposed to a variable copper and selenium supply in a physiologically relevant concentration range, and transcript and protein expression as well as GPX and TXNRD activities were compared. Copper suppressed selenoprotein mRNA levels of GPX1 and SELENOW, downregulated GPX and TXNRD activities and decreased UGA recoding efficiency in reporter cells. The interfering effects were successfully suppressed by applying the copper chelators bathocuproinedisulfonic acid or tetrathiomolybdate. In mice, a decreased copper supply moderately decreased the copper status and negatively affected hepatic TXNRD activity. We conclude that there is a hitherto unknown interrelationship between copper and selenium status, and that copper negatively affects selenoprotein expression and activity most probably via limiting UGA recoding. This interference may be of physiological relevance during aging, where a particular shift in the selenium to copper ratio has been reported. An increased concentration of copper in face of a downregulated selenoprotein expression may synergize and negatively affect the cellular redox homeostasis contributing to disease processes.

A new solution route for the synthesis of CuFeO2 and Mg-doped CuFeO2 as catalysts for dye degradation and CO2 conversion

In this study, CuFeO2 and Mg-doped CuFeO2 powders are synthesized by using a novel chemical solution route under an ambient atmosphere. By regulating the pH of the reaction solution, on the basis of Pourbaix diagrams, and the stoichiometric ratio of copper to iron ions, delafossite CuFeO2 powders are formed at 363 K in an aqueous solution. Mg-doped CuFeO2 powders are also synthesized by using the same chemical route with the trace addition of Mg(II) ions. From the powder X-ray diffraction results, all diffraction peaks are of the delafossite structure with dominated 3R phase and few 2H phase. X-ray photoelectron spectroscopy measurements show that the chemical environments of the Cu and Fe ions are consistent with the binding energies of Cu(I) and Fe(III) in the delafossite structure of CuFeO2. The UV–vis spectra show that the CuFeO2 and Mg-doped CuFeO2 powders are both able to absorb light with wavelengths ranging from 300 to 700 nm. The calculated optical band gaps of the CuFeO2 and Mg-doped CuFeO2 powders are 1.35 and 1.5 eV, respectively. With regard to the application of the powders in the photodegradation of 50 ppm methylene blue, the results suggest that at an incident light irradiation of AM 1.5G, the photodegradation efficiency of the Mg-doped CuFeO2 powder is remarkably better than that of the CuFeO2 powder, which can be attributed to its higher carrier concentration. Furthermore, at an external bias of −1.2 V, these delafossite catalysts are able to convert CO2 to ethylene glycol through an electrocatalytic reaction.

Hydrometallurgical stepwise recovery of copper and zinc from smelting slag of waste brass in ammonium chloride solution

A new process for recycling zinc and copper from the smelting slag of waste brass was investigated in this study. The zinc and copper present in the smelting slag were dissolved in a ZnCl2–NH4Cl solution system. To recycle copper, the lixivium was purified by a novel method termed as electrochemistry and chemistry synergetic (ECS) purification. After deep purification of the ECS-treated lixivium by zinc powder cementation, zinc in the lixivium was extracted by electrowinning to obtain a zinc plate. The effects of the leaching temperature, reaction time, and liquid–solid ratio on the extraction percentages of zinc and copper were examined. The results revealed that the extraction percentages of zinc and copper were 88.37% and 90.85%, respectively, at a leaching temperature of 95 °C, reaction time of 90 min, and liquid–solid ratio of 8:1 mL/g. Further, effects of the current density, temperature, and reaction time on the recovery ratio of copper by ECS method were examined. The results revealed that 98.51% of copper could be extracted from the lixivium and that the purity of the extracted copper was 96.7% at a temperature of 70 °C and cathode current density of 75 A/m2 after a reaction for 4 h. In the deep purification process, 0.3 g/L zinc powder was used to completely remove impurities from the ECS-treated lixivium. In the zinc electrowinning process, a current efficiency of 95.79% was achieved at 70 °C and 400 A/m2; the purity of the obtained zinc product was greater than 99.95%, and the direct energy consumption was 2966.59 kW·h/t-Zn.