Transfer Of Cu Research Articles

Zinc-modulated bidirectional copper transfer across the blood-brain barrier in a porcine brain capillary endothelial cell culture model system

The blood-brain barrier (BBB) serves as a crucial interface, regulating the transfer of trace elements (TEs) such as copper (Cu) and zinc (Zn) between the bloodstream and the brain. Cu and Zn are essential for maintaining neural function and enzymatic processes. Understanding the interplay of Cu and Zn with the BBB is crucial for elucidating their roles in neurological health and disease. This study investigates the bidirectional transfer of Cu across the BBB and examines the impact of Zn supplementation on this process using a porcine brain capillary endothelial cell (PBCEC) model. Transendothelial electrical resistance (TEER) and capacitance measurements confirmed barrier integrity upon TE exposure, while quantification of Cu and Zn concentrations via inductively coupled plasma-tandem mass spectrometry (ICP-MS/MS) in the culture medium provided essential baseline data. Transfer studies revealed significant increases in basolateral (brain side) Cu concentrations after apical (blood side) Cu incubation, with additional Zn supplementation reducing Cu transfer from apical to basolateral compartments. Conversely, Zn incubation showed no effect on basolateral-to-apical Cu transfer. Surprisingly, it was found that Cu also transferred significantly to the apical compartments when incubated basolaterally, and with slightly higher permeability coefficients than vice versa, indicating a potential role of PBCECs in regulating Cu transport both from blood to brain and from brain to blood. These findings suggest a bidirectional Cu trafficking across PBCECs, only slightly influenced unidirectionally by Zn supplementation, highlighting the intricate interplay between TEs at the BBB. Importantly, no alterations in barrier integrity were observed, underscoring the physiological relevance of the experimental conditions. Overall, this study sheds light on the complex dynamics of Cu and Zn transfer at the BBB, emphasizing the need for comprehensive investigations into TE interactions for a deeper understanding of brain TE homeostasis.

Active lattice oxygen trigger for propane total oxidation: [MnO6] tunnel-restrained Cu2+ chain in α-MnO2

The elimination of propane is particularly important in volatile organic compounds (VOCs) emissions control. We designed a special Cu-type α-MnO2 with tunnel-restrained Cu2+ chain for propane total oxidation. It can effectively elevate the reaction rate and reduce the apparent activation energy. Cu2+ mainly stabilizes as tunnel [CuO4] configurations, changing the charge distribution and ligand field inside the tunnel, compared to the original ionic [KO8] and [KO12] in α-MnO2. The covalency between Cu−O as well as exacerbated Jahn-Teller distortion of [MnO6] occur. The resulting charge transfer of Cu−O−Mn units via bridging O atoms further affects the outside-tunnel properties, specifically, facilitating oxygen vacancy formation and lattice oxygen activation. Moreover, abundant oxygen vacancies can promote the dehydrogenation of propane to generate alcohol at low temperatures. The above intermediates undergo successively oxidation with activated lattice oxygen to produce C3~C1 carboxylates as temperature elevates.

Electrocatalytically enhanced Cu(II)/peroxymonosulfate (PMS) oxidation: Focus on electrically-induced sustained Cu(II)/Cu(I)/Cu(III) cycling and suppression of singlet oxygen (1O2) production

Numerous azo dyes are discharged into industrial wastewater annually, posing significant threats to ecology and human health. In this study, an applied electric field was implemented in a trace copper-activated peroxymonosulfate system (EC/Cu(II)/PMS), achieving high removal efficiency (95.40 %) of Congo red (CR). The electron-donating effect of the cathode greatly enhanced the redox cycling of Cu(II)/Cu(I). Almost complete activation of PMS occurred during the entire reaction with an electrical consumption of merely 0.85 kWh/m3. Using electron paramagnetic resonance (EPR), quenching experiments, and chemical probes, the reactive substance that dominate CR removal, including Cu(III), sulfate radical (SO4•−), hydroxyl radical (HO∙), and singlet oxygen (1O2), were investigated. Cu(III) was identified as the main reactive substance, contributing over 90 %, and was primarily formed through double electron transfer of Cu(I). HO∙ can emerge as a secondary oxide of Cu(III). SO4•− originated mainly from the electroactivation of PMS. It was noted that 1O2 can be physically quenched by water, and thus 1O2 was considered as a side reaction product of PMS. Applying an electric field lowered the overall production of 1O2 and markedly mitigated the inefficient consumption of PMS. Moreover, the degradation pathways proposed for CR, based on mass spectrometry analysis, were in agreement with the predictions made by density functional theory (DFT). The toxicological characteristics of both CR and its intermediates were comprehensively analyzed as well. The study presents a straightforward and efficient strategy for PMS activation with versatile application potential for dye wastewater treatment.

Metasomatized mantle facilitates the genesis of magmatic nickel–copper sulfide deposits in orogenic belts: A copper isotope perspective

The role of metasomatized mantle in the genesis of magmatic Ni–Cu sulfide deposits in orogenic belts remains vigorously debated. The greatest challenge in clarifying uncertainties is how to track the behavior of metals during metasomatic processes in the mantle. Copper isotopes can shed new light on this enigmatic topic as the transfer of Cu during metasomatic processes can significantly fractionate Cu isotopes. In this regard, we have characterized the Cu isotope and trace-element compositions of fertile and barren mafic–ultramafic intrusions, and coeval basalts in the Eastern Tianshan, Central Asian Orogenic Belt (CAOB). Fertile mafic–ultramafic intrusions are characterized by elevated and highly variable Ba/Nb (40–756, average of 172) and Ba/La (16–219, average of 48) ratios, and exhibit δ65Cu values (−0.97 ‰ to +0.57 ‰) that vary over 1.54 ‰. In contrast, barren intrusions and coeval Permian basalts are characterized by relatively low and invariable Ba/Nb (2–95, average of 29) and Ba/La (0.9–26, average of 8) ratios, and have δ65Cu values that are comparatively less variable (−0.06 ‰ to +0.49 ‰ for δ65Cu) and more similar to bulk silicate Earth (BSE, δ65Cu = 0.06 ± 0.20 ‰). The difference in Cu isotope compositions of fertile and barren intrusions, alongside the variability in Ba enrichment, suggests that a high degree of mantle metasomatism promotes the fertilization of primary magmas in metals and, thus, represents one of the first stages in the development of magmatic Ni–Cu sulfide deposits in convergent margins.

Valence state effect of Cu on photocatalytic CO2 reduction

Copper (Cu) is extensively employed in photocatalytic CO2 reduction reactions for the production of high-value products. The valence state of transition metals plays a pivotal role in influencing the catalytic process. However, due to the complex valence state changes of Cu in the CO2 reduction reaction, research on its valence state effect is lacking. The current work is to prepare a series of TiO2/CuX with stable Cu valence composition using different copper halides (CuX and CuX2, X = Br or Cl) as precursors. The results show that the CuBr2 loading leads to Cu+/Cu2+ mixed cocatalyst and exhibits the highest activity for CO2 photoreduction. The CH4 evolution rate of the TiO2/CuBr2 catalyst is as high as 100.59 μmol h−1 g−1, which is 6.6 times that of pristine TiO2. The CH4 selectivity reaches 77%. The enhanced catalytic activity and selectivity can be ascribed to the efficient surface adsorption, activation, excellent carrier separation, and transfer of Cu+/Cu2+ mixed cocatalyst. Our findings provide a reference for designing highly active Cu-based photocatalysts.

Entropy analysis of slip flow second-grade Cu − EO and TiO 2 − EO nanofluids using Modified Buongiorno model

The current research investigates the magnetohydrodynamic (MHD) slip flow of second-grade nanofluids past a permeable stretching sheet in a porous medium. The flow analysis is accomplished considering thermophoresis, Brownian diffusion, chemical reaction, and elastic deformation. The implementation of the Modified Buongiorno model (MBM) on second-grade nanofluid is the novel aspect of the study. The formulated coupled nonlinear equations are non-dimensionalized, applying suitable similarity transformation. Numerical resolution of the resulting equations is achieved via MATLAB solver bvp4c. In our problem, two different groups of nanofluids, Cu − EO and TiO 2 − EO, have been considered. The development of profiles of nanofluid velocity, temperature, concentration, entropy generation and Bejan number, with the flow parameters, is elaborated graphically. Tabulated values of skin friction, Nusselt number, and Sherwood number are illustrated. The principal outcomes of this study demonstrate a higher rate of heat transfer of Cu − EO nanofluid than TiO 2 − EO nanofluid. The Nusselt number significantly decelerates, and the Sherwood number accelerates due to the combined influence of the Brownian diffusion and thermophoresis parameters. The second-grade parameter and nanoparticle volume fraction boost the skin friction magnitude. Furthermore, the entropy generation increases due to the Brinkman number and concentration diffusion parameter. The present research can be utilized to enhance the effectiveness of cooling systems in automobile engines, nuclear reactors, and heat exchangers. For the validation of our result, a comparative study is made with the previous authors and concludes in good agreement.

Se supplementation to an in vitro blood-brain barrier does not affect Cu transfer into the brain

BackgroundDyshomeostasis of copper (Cu) accompanied by Cu accumulation in certain brain areas has been associated with neurodegenerative diseases. One proposed toxic mode of action following Cu overload is oxidative stress associated with neuronal damage, whereas Selenium (Se) is assumed to play here a protective role. This study investigates the relationship between adequate Se supplementation and the respective consequences for Cu transfer into the brain applying an in vitro model of the blood-brain barrier (BBB). MethodsPrimary porcine brain capillary endothelial cells (PBCECs) seeded on Transwell® inserts were supplemented with selenite starting at cultivation in both compartments. After apical application of 15 or 50 µM CuSO4, transfer of Cu to the basolateral compartment, the brain facing side, was assessed by ICP-MS/MS. ResultsIncubation with Cu did not negatively affect the barrier properties, whereas Se had a positive effect. Additionally, Se status improved after selenite supplementation. Transfer of Cu was not affected by selenite supplementation. Under Se-deficient conditions, Cu permeability coefficients decreased with increasing Cu concentrations. ConclusionThe results of this study do not indicate that under suboptimal Se supplementation more Cu transfers across the BBB to the brain.

Positive effect of Ca addition on the risk of Cu and Zn in digestate as biofertilizer

The addition of Ca in anaerobic digestion will passivate the heavy metals in digestate. The effects of CaCl2, Ca(OH)2 and CaCO3 addition on the anaerobic digestion process and the speciation changes of Cu and Zn in solid fraction of anaerobic digestate (SFD) after digestion were studied. Then the effects of Ca-containing solid fraction digestate (SFD-Ca) application on the speciation changes of Cu and Zn in soil and the effects of ryegrass on the enrichment of Cu and Zn were also explored through pot experiments. The results indicated that: The addition of Ca(OH)2 was beneficial to the transfer of Cu and Zn from the liquid fraction of anaerobic digestate (LFD) to SFD, and the transfer effect was the best. The transfer amount of Cu and Zn increased by about 10.0% and 4.2%, respectively, compared with the blank group. The SFD-Ca promoted the increase of biomass, inhibited the enrichment of Cu and Zn by ryegrass, and the effect of a high concentration of Ca(OH)2 was the best. Ryegrass biomass increased by 19.7%, and the enrichment of Cu and Zn decreased by 39.3% and 31.1%, respectively. High concentration of Ca(OH)2-containing solid fraction digestate (SFD-Ca(OH)2) had the best passivation effect on Cu and Zn in soil, the residual state of Cu and Zn in soil increased by 4.3% and 7.8%, respectively. Adding a high concentration of Ca(OH)2 had a positive effect on ryegrass biomass and reduced the risk of Cu and Zn when SFD was used as biofertilizer.

Mhd Stagnation Point Flow and Heat Transfer of Cu –Water Nanofluid over A Stretching Sheet

A comprehensive study of Magnetohydrodynamics flow (stagnation Point) with heat transferal properties of Cu–Water nanofluid along a stretched sheet in the existence of a transverse magnetic field is analyzed. The governing equalities along with their conditions on boundary points are firstly converted to ordinary differential equations of non-linear category by similarity transformations. Lastly finite difference discretization is utilized. The flow and heat transfer parameters, namely: stretching parameter, magnetic parameter, the Prandtl number and solid volume fraction are investigated by tablular and graphical representation.

Sources, transfers and the fate of heavy metals in soil-wheat systems: The case of lead (Pb)/zinc (Zn) smelting region

Heavy metals (HMs) from smelters pose severe challenges to the environmental soil quality of surrounding farmlands, and threaten human health through the food chain. This study explored the environmental effects of smelting activities on farmland soil, and additionally assessed the enrichment, transfer and health risk of HMs in soil-wheat systems. Multiple characterization results were combined to demonstrate that HMs from smelter waste were transferred to the surrounding soil. It was determined that the enrichment of HMs in soil-wheat systems is mainly controlled by the total HM concentration and pH in soil. Furthermore, the priority pollutant in soil-wheat systems was found to be Cd, and Cd affected the transfer of Cu, Mn and Pb from soil to wheat roots. Interestingly, the -OH stretching, C-H stretching, N-H amide and C-O bending were involved in detoxifying HMs in wheat. The mean values of non-carcinogenic and carcinogenic risks by consuming wheat grain were 9.1, 1.4E-02 (adults) and 11.3, 3.3E-03 (children), respectively, indicating a noteworthy health risk. This study highlighted the critical issues arising from Pb/Zn smelting activities on agricultural soils. Notwithstanding, to ensure food security, the affected regions could opt to follow up on the type of crops grown.

Label-free electrochemical aptasensor for rapid detection of SARS-CoV-2 spike glycoprotein based on the composite of Cu(OH)2 nanorods arrays as a high-performance surface substrate

The development of advanced electrode materials and the combination of aptamer with them have improved dramatically the performance of aptasensors. Herein, a new architecture based on copper hydroxide nanorods (Cu(OH)2 NRs) are directly grown on the surface of screen printed carbon electrode (SPCE) using a two-step in situ, very simple and fast strategy and was used as a high-performance substrate for immobilization of aptamer strings, as well as an electrochemical probe to development a label-free electrochemical aptasensor for SARS-CoV-2 spike glycoprotein measurement. The Cu(OH)2 NRs was characterized using X-ray Diffraction (XRD) and electron microscopy (FESEM). In the presence of SARS-CoV-2 spike glycoprotein, a decrease in Cu(OH)2 NRs-associated peak current was observed that can be owing to the target-aptamer complexes formation and thus blocking the electron transfer of Cu(OH)2 NRs on the surface of electrode. This strategy exhibited wide dynamic range in of 0.1 fg mL−1 to 1.2 µg mL−1 and with a high sensitivity of 1974.43 μA mM−1 cm−2 and low detection limit of 0.03 ± 0.01 fg mL−1 of SARS-CoV-2 spike glycoprotein deprived of any cross-reactivity in the presence of possible interference species. In addition, the good reproducibility, repeatability, high stability and excellent feasibility in real samples of saliva and viral transport medium (VTM) were found from the provided aptasensor. Also, the aptasensor efficiency was evaluated by real samples of sick and healthy individuals and compared with the standard polymerase chain reaction (PCR) method and acceptable results were observed.

Trophic transfer of copper decreases the condition index in Crassostrea gigas spat in concomitance with a change in the microalgal fatty acid profile and enhanced oyster energy demand

Due to new usages and sources, copper (Cu) concentrations are increasing in the Arcachon Basin, an important shellfish production area in France. In the present paper, the trophic transfer of Cu was studied between a microalga, Tetraselmis suecica, and Crassostrea gigas (Pacific oyster) spat. An experimental approach was developed to assess Cu exposure, transfer and toxicity on both phytoplankton and spat. Exposure of microalgal cultures to Cu for 7–8 days (3.1 ± 0.1, 15.7 ± 0.2 and 50.4 ± 1.0 μg Cu·L−1 for the control, Cu15 and Cu50 conditions, respectively) led to concentrations in microalgae (28.3 ± 0.9 and 110.7 ± 11.9 mg Cu·kg dry weight−1 for Cu15 and Cu50, respectively) close to those measured in the field. Despite Cu accumulation, the physiology of the microalgae remained poorly affected. Exposed cultures could only be discriminated from controls by a higher relative content in intracellular reactive oxygen species, and a lower relative content in lipids together with a reduced metabolic activity. By contrast, the fatty acid profile of microalgae was modified, with a particularly relevant lower content of the essential polyunsaturated fatty acid 22:6n-3 (docosahexaenoic acid [DHA]). Following 21 days of spat feeding with Cu15 and Cu50 microalgal cultures, trophic transfer of Cu was observed with a high initial Cu concentration in spat tissues. No effect was observed on oxidative stress endpoints. Cu exposure was responsible for a decrease in the spat condition index, an outcome that could be related to an insufficient DHA supply and extra energy demand as suggested by the overexpression of genes involved in energy metabolism, ATP synthesis and glycogen catabolism.

Copper mobilization in the lower continental crust beneath cratonic margins, a Cu isotope perspective

Lower crustal sulfide-bearing cumulates beneath the convergent plate margins represent a major copper reservoir. However, how Cu is mobilized and migrated in the lower crust is still a matter of debate. Here, we analyzed the Cu elemental and isotopic compositions of well-characterized lower crustal xenoliths from the north margin of the North China Craton to decode Cu mobilization in the lower continental crust beneath cratonic margins. The mafic lower crustal rocks have experienced varying degrees of sulfide accumulation, with Cu contents ranging from 15 to 112 ppm. The majority of lower crustal xenoliths have variable and generally low (compared to the Bulk Silicate Earth) δ65Cu (the permil deviation of the 65Cu/63Cu ratio from the NIST 976 standard) values ranging from −3.17‰ to 0.13‰ (n = 24). Many intragranular and interstitial sulfide grains in these lower crustal xenoliths were partially dissolved and oxidized along the mineral fractures and boundaries. Oxidative dissolution of sulfide will preferentially release 65Cu into the liquids, leaving the residual sulfides enriched in the light isotope, implying that oxidized melt-rock interactions could account for the light Cu isotopic compositions of the lower crustal xenoliths. Sulfide accumulation and oxidative dissolution are responsible for the enrichment, mobilization, and transfer of Cu in the lower continental crust beneath cratonic margins.

Photoluminescence characteristics of NaCl: Cu sintered dose tablets under X/γ irradiation

In this paper, NaCl: Cu circular dose tablets with a size of 5×1.8mm are prepared by sintering pure NaCl and CuCl powder as raw materials. They are placed in a four-element shell and sealed with plastic film to overcome the moisture absorption of the material. Their photoluminescence characteristics are studied by using an Inlight 200 automatic photoluminescence measurement system. The results show that the X-ray characteristic peaks of NaCl: Cu sintered at 650 ℃ and 400 ℃ appear at 27°, 32°, 45°, 56°, 66°, 75° and 84° respectively. Compared with the data given by XRD standard card of pure NaCl crystal (pdf-#88-2300), those peaks of the sample sintered at 650 ℃ are more consistent with the data given by the standard card. In the scanning electron microscope image, it can be seen that the grains are wholly welded and closely connected, and the characteristic grains in the sintering process have good welding effect. After Cu<sup>+</sup> ion doping, the lattice structure of NaCl is slightly deformed. After high-temperature sintering, the mass transfer of Cu<sup>+</sup> ions occurs at an atomic level in NaCl, and the particles are combined into a coherent solid structure. For X/γ-rays, the photoluminescence response of NaCl:Cu dose sheet to low-energy rays is higher than that of the same kind of rays with high energy. When using NaCl:Cu dose sheet to calculate the cumulative photoluminescence dose, it is necessary to consider the ray category and ray energy of the radiation source at the radiation site. The photoluminescence curve of NaCl:Cu dose sheet has typical exponential attenuation characteristics. The deflection angle of dose sheet has influence on the measured value: the greatest influence extent is 13.5%. With the increase of deflection angle of dose sheet, the area irradiated by γ-ray decreases, and the response of internal lattices to γ-ray decreases slightly. The uniformity of NaCl: Cu raw material particle sizes has a great influence on the distribution consistency of photoluminescence response of dose tablets. The decrease of sample particle size during tablet pressing can improve the contact surface area between NaCl and CuCl. The increase of contact surface area can improve the diffusion and transfer efficiency of Cu<sup>+</sup> ions, increase the number of dose traps in the crystal, and make the overall count higher. When the particle sizes are more uniform, the Cu<sup>+</sup> ion transferefficiencies and quantities of different dose tablets are close, the difference in the number of dose traps is reduced, and the photoluminescence sensitivities are closer. The coefficient of variation of the repeatability test experiment is 2.28%. The consistency of the repeated measurement data is good. The lattice structure and lattice defects of the material are not changed in the process of photoluminescence measurement and photoannealing. In a dose range of 1-1000mgy, with the increase of irradiation dose, the photoluminescence response of NaCl: Cu and NaCl dose tablets gradually increase and show a good linear relationship. The photoluminescence response of NaCl: Cu is 2-to-4 times higher than that of NaCl dose tablets. The NaCl: Cu dose tablets prepared by the sintering method can be used as dosimeters for monitoring personal or environmental dose.

Biosorption of Cu(II), Pb(II) from electroplating industry effluents by treated shrimp shell

The current investigation focuses on a systematic study of application of treated shrimp shell waste (TSSW) as a potential biosorbent in removal of Cu(II) and Pb(II) from hazardous industrial effluents. The surface characterization and morphological studies indicated that biosorption is owing to ion complexation and exchange, and chemical adsorption mechanism. The effects of pH (1–10), time dependency (1–60 min), initial concentration of Cu(II) and Pb(II) (20–100 mg L−1), TSSW loading (0.1–0.5 g) and temperature (303–333 K) on biosorption efficiency using TSSW were examined through experiments. The experimental discoveries indicated that maximum biosorption efficacies were 96.42% at pH 5, 40 min for Cu (II) and 89.77% at pH 6, 30 min for Pb(II), 20 mg L−1 concentration, 0.1 g loading and 303 K temperature. Langmuir, Freundlich, Temkin, and Dubinin - Radushkevich isotherm models were used to examine experimental findings and the Langmuir model was well fitted one. The maximum Cu(II), Pb(II) removal capacities by TSSW were 22.67, 15.32 mg g−1 according to Langmuir model. Pseudo second order model was excellent suited to kinetics which shows that chemisorption was involved for the transfer of Cu(II), Pb(II) to TSSW surface with three different intra particle diffusional stages. Hence, this study revealed that TSSW has a great potential to be an environment friendly and economic biosorbent for removal of Cu(II) and Pb(II) containing industrial effluent.

The Effect of Ozone-Electric Treatment on the Enrichment and Transfer of Heavy Metal Cu in Sludge

In order to explore a safe, effective way to use sludge as agricultural fertilizer it is necessary to effectively separate and remove the heavy metals embedded in sludge. In the study, the ozone-electric two-stage treatment was used to transform heavy metal copper in the sludge, and then the treated sludge was used for maize production and the transferring of Cu in cultivation medium and plants, and the enrichment effect of Cu in plant were investigated. According to composition of culture substance, five treatments were set in maize planting experiments: CK, Agricultural soil without addition; T1, Agricultural soil supplemented with raw sludge; T2, Agricultural soil treated with ozone sludge; T3, Agricultural soil with ozone treated and electric treated sludge; T4, Agricultural soil added with common organic fertilizer. The results showed that in different treatments, the Cu content of organs showed the order of root> stem> leaf> cob> grain. Comparing root Cu content, the lowest was in T1 treatment, which was 11.60 mg/kg, while the lowest of grain Cu content was found in CK treatment, which was 1.36 mg/kg. In the upper, middle and lower soil layers, the highest and lowest Cu content was in T4 and CK, respectively. In both middle and lower soil layers, the Cu content of T1, T2 and T3 sludge treatments had a trend of T1>T2>T3; the difference of the Cu enrichment ability between different organs is not significant in the same soil layer. From each treatment, the Cu enrichment ability of plant of CK was higher than that of other treatments. According to the ability of Cu transferring to the above-ground part of plant, treatments are ranked as CK>T3>T4>T1>T2. The transferring of Cu from soil to plant was mainly affected by fertilizer level and the transferring rate of Cu from soil to stem, leaf and root was relatively high, but it was hardly affected by sludge. In summary, after ozone-electro treatment, the application of sludge does not significantly affect the Cu content in maize, and the Cu content in each treatment does not exceed the limit value of agricultural production.

Effect of copper core diameter on heat transfer and horizontal flame spread behaviors over electrical wire

The laboratory polyethylene wire with different core diameters of 3 mm, 5 mm, 6 mm, 7 mm, 8 mm, 10 mm and 12 mm was used to study the flame spread characteristics. The flame spread could be divided into initial oscillation stage, stable oscillation stage and burn-out stage. With the increase of the copper core diameter, the flame width and flame area increased firstly and then decreased. For wires with intermediate copper core diameters of 6 mm, 7 mm, 8 mm and 10 mm, the relationship between flame area and core diameter was established as A~dc, the total mass loss rate k with the copper core diameter dc followed as k~dc, and the combustion mass loss rate and dripping mass loss rate gradually equaled to each other at stable oscillation stage. By analyzing the temperature field during the process of flame spread, the temperature gradient was almost same for diameters from 3 mm to 10 mm, which demonstrated the radiation heat would be influenced by flame height. Combined with the increased flame spread, the dominant conduction heat transfer mechanism was built. When the diameter was 12 mm, the smaller conduction heat transfer, which illustrated the core material Cu played an cool effect on flame, thus the dominant heat transfer of Cu was changed from a heat source to a heat sink.

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.

Growth and accumulation of Cu and Zn by <i>Commelina communis </i>under Cu, Zn and their combined pollution

A pot experiment was carried out to investigate the growth, accumulation and transfer of Cu and Zn in Commelina communis, which were cultivated under single and combined pollution of Cu and Zn. The results showed that, with increasing single and combined concentration of Cu and Zn, the biomass of Commelina communis initially increased and then decreased. The Cu tolerance and accumulation capacity of Commelina communis was superior to Zn. With an increasing Cu and Zn concentration, the relative electronic conductivity and malondialdehyde increased and the chlorophyll content declined. Moreover, the low concentration level of Cu and Zn had a synergistic effect, which low-dose Zn significantly facilitated the adsorption of Cu in Commelina communis. While high-dose Cu and Zn tend to antagonistic effects, causing an inhibition to Cu accumulation of plant. Comprehensively, Commelina communis was a potential hyper-accumulator for Cu and could be applied to the heavy metal contaminated environments.

CTAB-capped copper nanoparticles coated on N doped carbon layer and encapsulated in ZIF-67: a highly-efficient ORR catalyst

The development of cathode materials with high cost-effectiveness, reliable performance, and good oxygen reduction activity are important to develop the next generation rechargeable metal-air battery system. Herein, we have developed a novel technique for synthesizing a catalyst with superior activity and durability for oxygen reduction reaction (ORR). Porous carbon with doped Cu nanoparticles was prepared by pyrolyzing Cu-containing ZIF-67 (Cu/ZIF-67). The findings show that Cu0.5%/Co-NC-900 exhibits superior ORR performance with an onset potential (Eo) of 0.98 V and a half-wave potential (E1/2) of 0.85 V, superior to all other prepared as well commercial Pt/C (20 wt.%, Eo 0.96 V and E1/2 0.82 V) catalysts in an alkaline solution. The excellent ORR performance of Cu0.5%/Co-NC-900 is due to the synergistic contribution to gradual mass transfer of Cu, Co and N doping structure, high pyridine content, and porous multilayer structure. This novel and rational metal doping strategy will dramatically enhance electrocatalyst operation and provide a template for new metal-doped porous carbon or catalyst designs.