Dongguashan deposit is a large porphyry-skarn copper(gold) deposit in Tongling ore district. The Qingshanjiao intermediate acid intrusion of Yanshanian had a direct genetic relationship with mineralization. The magm...Dongguashan deposit is a large porphyry-skarn copper(gold) deposit in Tongling ore district. The Qingshanjiao intermediate acid intrusion of Yanshanian had a direct genetic relationship with mineralization. The magma origin, rock-forming dynamic background and rock-forming process were studied, and the rock-forming mechanism of Qingshanjiao intrusion was discussed, based on geological characteristics, detailed observation of petrography and systematic investigation of petrochemistry, trace elements and REE geochemistry characteristics of Qingshanjiao intrusion. The results show that Qingshanjiao rock body belongs to high-K calc-alkaline series with higher LREE elements, Th, Rb and Sr abundance, but depleted in HREE elements, Ba, Nb and Ta. The primary magma originated from the mantle-crust mixtures which were caused by basaltic magma of mantle mixing with syenite magma of partial melting of the lower crust, and the formation environment of Qingshanjiao intrusion was emplaced in the transitional environment from compression to extension. The Harker diagram and hybrid structures of plagioclase and potassium feldspar indicate that the fractional crystallization occurred in the process of magmatic evolution. The petrochemistry, trace elements and REE geochemistry characteristics indicate that the magma was contaminated by crustal material during the rock-forming. These results suggested that the Qingshanjiao intrusion was formed by fractional crystallization and assimilation and hybridization of mantle-crust magma in the transitional environment from compression to extensional.展开更多
Flotation reagents have a complex behaviour in the beneficiation of base minerals in clayey ores.Interaction effects of reagents on the efficiency of copper flotation for a highly clayey low-grade sulphide ore were in...Flotation reagents have a complex behaviour in the beneficiation of base minerals in clayey ores.Interaction effects of reagents on the efficiency of copper flotation for a highly clayey low-grade sulphide ore were investigated using a central composite design.Preliminary results showed that sodium-isopropyl-xanthate(SIPX)and O-isopropyl-N-ethyl-thionocarbamate(IPETC)were found to be the most efficient collectors in the presence of lime as the pH regulator.The effects of dosage of collectors(SIPX and IPETC)and the dosage of methyl-isobutyl-carbonyl(MIBC)as frother on the separation efficiency were evaluated at different pH levels.Based on the analysis of variance(ANOVA),the interaction effects of the collector−pH and collector−frother were significant for the separation efficiency.At the low level of collector dosage,increasing pH from 9 to 11 enhanced copper separation efficiency from 81%to 86%for IPETC and from 77%to 86%for SIPX.Results of ANOVA showed that the maximum copper separation efficiency(88.7%)was obtained at the dosages of 8.6 g/t SIPX,7 g/t IPETC and 20 g/t MIBC at pH 11.Finally,it was concluded that a mixture of SIPX and IPETC collectors was more suitable to treat highly clayey sulphide ores.展开更多
A single-factor experiment of copper ion adsorption on pure palygorskite was carried out to understand the Cu2+ sorption of palygorskite—an important clay mineral in soil and sedimentary rock. In addition, pH of the ...A single-factor experiment of copper ion adsorption on pure palygorskite was carried out to understand the Cu2+ sorption of palygorskite—an important clay mineral in soil and sedimentary rock. In addition, pH of the solution and the surface microstructure of palygorskite were investigated before and after adsorption. The experimental results indicated that efficiency of Cu2+ removal was related to the oscillation rate of the specimen shaker, sorption time, initial pH value and the amount of adsorbent added. Palygorskite induced Cu2+ hydrolysis and interaction between copper hydroxide colloids and palygorskite surfaces, as observed with transmission electron microscopy (TEM), were the main contributions to palygorskite removal of Cu2+. This mechanism was different from adsorption at the mineral-water interface. It was proposed that surface hydrolysis of palygorskite raised the alkalinity of the palygorskite-water interface and suspension system. Thus, the induced pH of the solution was then high enough for Cu2+ hydrolysis on the mineral surface and in solution.展开更多
Magnetotactic bacteria (MTB) as biosorbents for the adsorption of Au(Ⅲ) and Cu(Ⅱ) ions from aqueous solution have been investigated. The optimum adsorption conditions for both metal ions were the initial pH sc...Magnetotactic bacteria (MTB) as biosorbents for the adsorption of Au(Ⅲ) and Cu(Ⅱ) ions from aqueous solution have been investigated. The optimum adsorption conditions for both metal ions were the initial pH scope of 1-5.5 for Au(Ⅲ) and 2.0-4.5 for Cu(Ⅱ), room temperature, biomass concentration of 10.0g.L^-1 and sorotion du-ration more than 10 min. When the initial metal concentration were within 500mg.L^-1, the maximum biosorption capacity of 1.0g of MTB (dry mass basis) for Au(Ⅲ) and Cu(Ⅱ) were calculated as 505.2mg of Au(Ⅲ) and 493.1mg of.Cu(Ⅱ) by Langmuir model in single system, respectively. The isotherm equilibrium of Au(Ⅲ) and Cu(Ⅱ) ions in the Au-Cu binary system reflected a unique phenomenon that the adsorption of Au(Ⅲ) was rein-forced and that of Cu(Ⅱ) prohibited, compared respectively-with their performances in the single metal system.When the,concentration of-Au(Ⅲ) and Cu(Ⅱ). were below 80mg.L^-1, the waste waterafter MTB treating, wasbelow 1.0mg.L^-1, which is in conformity with Environmental Performance Standards (EPS) of Canada. Besides, all the kinetic data were fitted well to the pseudo second-order kinetic model with a high correlation coefficient (R^2〉0.999).展开更多
Allelopathic effects of submerged macrophytes against algae are affected by many environmental factors which can only be measured one by one by traditional methods. Box-Behnken design of response surface methodology w...Allelopathic effects of submerged macrophytes against algae are affected by many environmental factors which can only be measured one by one by traditional methods. Box-Behnken design of response surface methodology was used to optimize three environmental factors (temperature, light intensity and total dissolved solids) of allelopathic effects of Potarnogeton pectinatus against Microcystis aeruginosa at the same time. By solving the regression equation and analyzing the response surface contour plots, the optimal conditions of the relatively inhibitory rate of Microcystis aeruginosa were that the temperature was 23℃, the light intensity was 2 700 lx and the total dissolved solids were 4 415 mg/L. Under these conditions, the optimal value of relatively inhibitory rate of Microcystis aeruginosa was 81.9%. According to validation experiments, the results of analysis indicated that the experimental values fitted well with the predicted ones.展开更多
The effects of sorbed phosphate on the kinetics of Cu ̄2+ secondary adsorption on three major types ofsoils in southern and Central China were studied using the batch method and flow (or miscible displacement)techniqu...The effects of sorbed phosphate on the kinetics of Cu ̄2+ secondary adsorption on three major types ofsoils in southern and Central China were studied using the batch method and flow (or miscible displacement)techniques. Both of the methods showed that diffusions were the ratedetermining steps in the Cu ̄2+ adsorp-tion by the soils. By the flow method, the course of Cu ̄2+ adsorption kinetics consisted of two steps-sn initialrapid process and a later slow process of Cu ̄2+ adsorption; while by the batch method, the 90% of Cu ̄2+adsorption reaction was found to finish within first 1 minute. The results obtained using the flow method alsoindicated that for red soil and yellow-brown soil, Cu ̄2+ adsorptions during the initial reaction periods wererestrained when the soils sorbed phosphate, whereas the adsorption reactions were stimulated at the finaltime. For grey Chao soil, sorbed phosphate retarded the Cu ̄2+ adsorption in the whole reaction period. Theresults obtained using the batch method and flow techniques all implied that the different effects of sorbedphosphate would be attributed to its effects on Cu ̄2+ ion diffusion in soil solution.展开更多
The microstructure,corrosion and cavitation erosion(CE)behaviors of the as-cast and four different heat treated nickel aluminum bronzes(NABs)in 3.5 wt.%NaCl solution were investigated.The results show that after annea...The microstructure,corrosion and cavitation erosion(CE)behaviors of the as-cast and four different heat treated nickel aluminum bronzes(NABs)in 3.5 wt.%NaCl solution were investigated.The results show that after annealing,β′transformed into the eutectoid microstructure,and moreκIV precipitated fromα.Less eutectoid microstructure and moreβ′were obtained after normalizing.The quenched NAB mainly consisted ofαandβ′phases,and fine,acicularαandκphases precipitated insideβ′after subsequent aging.The largest proportion of the eutectoid microstructure,which underwent severe selective phase corrosion,was responsible for the lowest corrosion resistance of the annealed NAB.The quenched NAB possessed the most protective film and hence the highest corrosion resistance.The mechanical attack was primarily responsible for the CE damage for the as-cast,annealed and normarlized NABs.The quenched and quenched+aged NABs exhibited superior CE resistance because of the high hardness.The CE−corrosion synergy dominantly caused CE degradation,and it was largely attributed to corrosion-enhanced-CE.展开更多
The galvanic corrosion behaviour of alumiuium 3004 - ∝ brass with different area ratios was studied in the tropical marine atmosphere at Tuticorin harbour over a period of 426 days. The area ratios, viz. AAluminiurn...The galvanic corrosion behaviour of alumiuium 3004 - ∝ brass with different area ratios was studied in the tropical marine atmosphere at Tuticorin harbour over a period of 426 days. The area ratios, viz. AAluminiurn:A∝ brass, studied were 0.125, 0.25, 0.5, 1, 2, 4 and 8. The galvanic corrosion behaviour of the metals was studied in terms of the relative increase in the corrosion rate of aluminium due to galvanic coupling with oc brass, the relative decrease in the corrosion rate of ∝ brass due to galvanic coupling with aluminium, and the susceptibility of aluminium to pitting owing to galvanic coupling with ∝ brass. The galvanic potential and galvanic current of the system were monitored. Pits of different dimensions ranging from mild etchings to perforations were experienced on the borders arid the surfaces of the interface of aluminium in contact with ∝ brass. The corrosion products resulting from galvanic corrosion were analysed using XRD and the pitting on aluminium as a result of galvanic corrosion was highlighted in terms of pit depth, size and density of pit, using a high resolution microscope. The most favourable area ratio of aluminium - ∝ brass in marine atmosphere in terms of gravimetric corrosion rate is 8:1 and the most unfavourable area ratio of aluminium - ∝ brass is 1:4.展开更多
In the search for new anti-tumor agents, exploiting features such as the flexibility of coordination modes of metals have become an alternative strategy for synthesizing pharmaceuticals. It has been shown that the Cu...In the search for new anti-tumor agents, exploiting features such as the flexibility of coordination modes of metals have become an alternative strategy for synthesizing pharmaceuticals. It has been shown that the CuDP (copper(II), doxycycline, and 1,10-phenanthroline) complex cleaves DNA strands by an oxidative mechanism and by intercalating the major groove, resulting in a cytotoxic action. The objective of this study was to assess the mutageinc/recombinogenic effects of the CuDP complex in vivo using the SMART (Somatic Mutation and Recombination Test) in Drosophila melanogaster. Treatments were carried out with third instar larvae at the standard cross and high bioactivation cross using three concentrations of CuDP (6.92, 13.84 or 27.67 mM). The mutagenic doxorubicin (0.4 mM) was used as a positive control and reverse osmosis water as a negative control. For each compound, marked trans-heterozygous and balanced heterozygous individuals were analyzed to determine the mutational and recombinogenic events occurring in the cells, We found that CuDP significantly increased the frequencies of mutant cells in both standard and high bioactivation crosses, mostly by induction of recombination. These data show that CuDP is a direct recombinogenic agent that is independent of bioactivation,展开更多
The exploration of efficient electrocatalysts for the reduction of CO2 to C2H4 is of significant importance but is also a challenging subject.Cu-based bimetallic catalysts are extremely promising for efficient CO2 red...The exploration of efficient electrocatalysts for the reduction of CO2 to C2H4 is of significant importance but is also a challenging subject.Cu-based bimetallic catalysts are extremely promising for efficient CO2 reduction.In this work,we synthesize a series of porous bimetallic Cu–Sb alloys with different compositions for the catalytic reduction of CO2 to C2H4.It is demonstrated that the alloy catalysts are much more efficient than the pure Cu catalyst.The performance of the alloy catalysts depended strongly on the composition.Further,the alloy with a Cu:Sb ratio of 10:1 yielded the best results;it exhibited a high C2H4 Faradaic efficiency of 49.7%and a high current density of 28.5 mA cm?2 at?1.19 V vs.a reversible hydrogen electrode(RHE)in 0.1 M KCl solution.To the best of our knowledge,the electrocatalytic reduction of CO2 to C2H4 using Cu–Sb alloys as catalysts has not been reported.The excellent performance of the porous alloy catalyst is attributed to its favorable electronic configuration,large surface area,high CO2 adsorption rate,and fast charge transfer rate.展开更多
Nano particles are finding their way into the environment through deliberate and accidental actions, ecotoxicological properties and the risks of these nano particles have yet not been fully characterized. In this pre...Nano particles are finding their way into the environment through deliberate and accidental actions, ecotoxicological properties and the risks of these nano particles have yet not been fully characterized. In this present investigation, experiments were carried out to know the effect of Cu oxide-nano particles (〈 50 nm) on germination and growth of seeds of soybean and chickpea. In both the crops, germination was not checked up to 2,000 ppm Cu (applied through Cu oxide-nano particles), but the root growth was prevented above 500 ppm Cu. With increasing concentration of NPs, the elongation of the roots was severely inhibited as compared to that in control. In many cases root necrosis was occurred. Massive adsorption of Cu oxide-nano particles into the root system was responsible for the toxicity. A parallel experiment was also carried out to know the effect of copper sulphate solution on seed germination, above 200 ppm Cu, it restricted the germination of seeds, because of high salinity.展开更多
Due to the elevated ecological awareness nowadays the consumption of products of organic agriculture is increasing. Organic farming means excluding the use of synthetic inputs, such as synthetic fertilizers and pestic...Due to the elevated ecological awareness nowadays the consumption of products of organic agriculture is increasing. Organic farming means excluding the use of synthetic inputs, such as synthetic fertilizers and pesticides or genetically modified organisms, but there are only a few regulations regarding heavy metal concentrations in soils. Thus a not negligible uptake of metals from the soil where the apple trees are grown may occur. Furthermore inorganic copper compounds being traditional fertilizers for apple trees are not considered as synthetic fertilizers, thus they are still used in organic apple farming for soil or foliar application. Thus also apples produced by organic agriculture may contain toxic elements, such as cadmium, chromium, copper, and lead. The concentrations of these elements were determined in whole apples, as well as in the flesh and peel in order to estimate the possible risk for human health. Prior to analysis using ICP-AES samples underwent a microwave assisted digestion. The LODs obtained are below the recommended maximum levels in vegetables/fruits by WHO. In all samples no Cu, Cr, and Pb could be detected. Only Ca was found in the peel of about a third of samples investigated in concentrations between LOD and LOQ (1-3 μg/g).展开更多
Crop nutrition has a significant effect on disease incidence, resistance or tolerance of various crops. There is currently a lack of reliable recent UK-based research about the effect of copper, zinc and boron on dise...Crop nutrition has a significant effect on disease incidence, resistance or tolerance of various crops. There is currently a lack of reliable recent UK-based research about the effect of copper, zinc and boron on disease incidence, green leaf area (GLA), green leaf retention (GLR) and grain yield of winter wheat, spring wheat and spring barley. Data analysis showed that these trace elements had positive effects on GLR. These positive effects may have been due to the role of copper, zinc and boron in the production of defence related compounds (phenolics and lignin), which may have reduced the disease incidence resulting in prolonged GLR. Grain yield was significantly enhanced by the application of these trace elements on the crop grown on high pH calcareous soil, which can be partly attributed to enhanced GLR. Also trace elements have a positive role in reproductive growth, flowering and male fertility. On average, zinc was found to be the most consistent trace element in terms of enhancing GLR and grain yield. Across all trials, it was noted that for every 10% increase in GLA from trace elements, grain yields increased by 4.2% in 2012-2013, by 4.4% in 2013-2014 in winter wheat and by 3.9% in spring wheat in 2014. These are remarkably consistent and indicate that increasing GLA by 10% by early dough stage was associated with a yield improvement of about 4%. These trace elements also had a positive effect on grain protein content (GPC). This research concluded that the trace elements had positive effects in enhancing GLA and yield. It can be speculated that with the use of these trace elements, there may be more scope for using less robust or reduced rates of fungicides to control foliar diseases, which may help to maximize farm profits.展开更多
With the increased use of copper (Cu)-based antifouling (AF) paints, copper has become a potential threat to marine organisms. Experiments were performed to investigate the effects of copper on larvae of the barna...With the increased use of copper (Cu)-based antifouling (AF) paints, copper has become a potential threat to marine organisms. Experiments were performed to investigate the effects of copper on larvae of the barnacle Chthamalus challengeri. These experiments attempted to identify a more sensitive index to monitor copper pollution in marine environments. The 24 h LC_50 ranged from 156.07 μg/L (nauplius Ⅱ) to 817.15μg/L (cypris) and the no observed effect concentration (NOEC) ranged from 81.75 μg/L (nauplius Ⅱ) to 571.04 μg/L (cypris). The cypris settlement rate declined significantly when copper concentrations 〉135 μg/L. No cypris was found in the copper concentration of 60 and 75 μg/L treatment groups stressed for 22 d. Nauplius Ⅱ moulting was not affected by exposure to copper for 24 h; however, when extended to 48 h, the percent moulted in 75 μg/L treatment group was declined to 37.12%, which was significant lower (P〈0.05) than that in the control group. The phototaxis of nauplius II decreased significantly when copper concentrations _〉45 μg/L. Despite an initial significant increase at copper concentrations of 30 μg/L, ammonia excretion rate decreased when copper concentrations ≥60 μg/L. These results suggested that: (1) nauplius Ⅱ could not develop to the cypris when the copper concentration ≥60 μg/L; (2) cypris settlement is more susceptible to copper than cypris mortality rate; (3) nauplius II is the most sensitive larval stage; (4) nauplius II ammonia excretion rate is the most sensitive index to copper and might be as the indicator for copper pollution monitoring.展开更多
基金Project(20091100704)supported by the Special Funds for Scientific Research of Land and Natural Resources,ChinaProject(2015CX008)supported by the Innovation Driven Plan of Central South University,China
文摘Dongguashan deposit is a large porphyry-skarn copper(gold) deposit in Tongling ore district. The Qingshanjiao intermediate acid intrusion of Yanshanian had a direct genetic relationship with mineralization. The magma origin, rock-forming dynamic background and rock-forming process were studied, and the rock-forming mechanism of Qingshanjiao intrusion was discussed, based on geological characteristics, detailed observation of petrography and systematic investigation of petrochemistry, trace elements and REE geochemistry characteristics of Qingshanjiao intrusion. The results show that Qingshanjiao rock body belongs to high-K calc-alkaline series with higher LREE elements, Th, Rb and Sr abundance, but depleted in HREE elements, Ba, Nb and Ta. The primary magma originated from the mantle-crust mixtures which were caused by basaltic magma of mantle mixing with syenite magma of partial melting of the lower crust, and the formation environment of Qingshanjiao intrusion was emplaced in the transitional environment from compression to extension. The Harker diagram and hybrid structures of plagioclase and potassium feldspar indicate that the fractional crystallization occurred in the process of magmatic evolution. The petrochemistry, trace elements and REE geochemistry characteristics indicate that the magma was contaminated by crustal material during the rock-forming. These results suggested that the Qingshanjiao intrusion was formed by fractional crystallization and assimilation and hybridization of mantle-crust magma in the transitional environment from compression to extensional.
文摘Flotation reagents have a complex behaviour in the beneficiation of base minerals in clayey ores.Interaction effects of reagents on the efficiency of copper flotation for a highly clayey low-grade sulphide ore were investigated using a central composite design.Preliminary results showed that sodium-isopropyl-xanthate(SIPX)and O-isopropyl-N-ethyl-thionocarbamate(IPETC)were found to be the most efficient collectors in the presence of lime as the pH regulator.The effects of dosage of collectors(SIPX and IPETC)and the dosage of methyl-isobutyl-carbonyl(MIBC)as frother on the separation efficiency were evaluated at different pH levels.Based on the analysis of variance(ANOVA),the interaction effects of the collector−pH and collector−frother were significant for the separation efficiency.At the low level of collector dosage,increasing pH from 9 to 11 enhanced copper separation efficiency from 81%to 86%for IPETC and from 77%to 86%for SIPX.Results of ANOVA showed that the maximum copper separation efficiency(88.7%)was obtained at the dosages of 8.6 g/t SIPX,7 g/t IPETC and 20 g/t MIBC at pH 11.Finally,it was concluded that a mixture of SIPX and IPETC collectors was more suitable to treat highly clayey sulphide ores.
基金1 Project supported by the National Natural Science Foundation of China (Nos. 40472026 and 40072017).
文摘A single-factor experiment of copper ion adsorption on pure palygorskite was carried out to understand the Cu2+ sorption of palygorskite—an important clay mineral in soil and sedimentary rock. In addition, pH of the solution and the surface microstructure of palygorskite were investigated before and after adsorption. The experimental results indicated that efficiency of Cu2+ removal was related to the oscillation rate of the specimen shaker, sorption time, initial pH value and the amount of adsorbent added. Palygorskite induced Cu2+ hydrolysis and interaction between copper hydroxide colloids and palygorskite surfaces, as observed with transmission electron microscopy (TEM), were the main contributions to palygorskite removal of Cu2+. This mechanism was different from adsorption at the mineral-water interface. It was proposed that surface hydrolysis of palygorskite raised the alkalinity of the palygorskite-water interface and suspension system. Thus, the induced pH of the solution was then high enough for Cu2+ hydrolysis on the mineral surface and in solution.
基金Supported by the National Natural Science Foundation of China (No.20206024) and the Natural Science Foundation of Tianjin (No.07JCYBJC06800).
文摘Magnetotactic bacteria (MTB) as biosorbents for the adsorption of Au(Ⅲ) and Cu(Ⅱ) ions from aqueous solution have been investigated. The optimum adsorption conditions for both metal ions were the initial pH scope of 1-5.5 for Au(Ⅲ) and 2.0-4.5 for Cu(Ⅱ), room temperature, biomass concentration of 10.0g.L^-1 and sorotion du-ration more than 10 min. When the initial metal concentration were within 500mg.L^-1, the maximum biosorption capacity of 1.0g of MTB (dry mass basis) for Au(Ⅲ) and Cu(Ⅱ) were calculated as 505.2mg of Au(Ⅲ) and 493.1mg of.Cu(Ⅱ) by Langmuir model in single system, respectively. The isotherm equilibrium of Au(Ⅲ) and Cu(Ⅱ) ions in the Au-Cu binary system reflected a unique phenomenon that the adsorption of Au(Ⅲ) was rein-forced and that of Cu(Ⅱ) prohibited, compared respectively-with their performances in the single metal system.When the,concentration of-Au(Ⅲ) and Cu(Ⅱ). were below 80mg.L^-1, the waste waterafter MTB treating, wasbelow 1.0mg.L^-1, which is in conformity with Environmental Performance Standards (EPS) of Canada. Besides, all the kinetic data were fitted well to the pseudo second-order kinetic model with a high correlation coefficient (R^2〉0.999).
基金Supported by the National Key Technology Research and Development Program of the Ministry of Science and Technology of China(No.2012BAC13B05)Science and Technology Foundation of Beijing Municipal Research Institute of Environmental Protection(No.2013B05)
文摘Allelopathic effects of submerged macrophytes against algae are affected by many environmental factors which can only be measured one by one by traditional methods. Box-Behnken design of response surface methodology was used to optimize three environmental factors (temperature, light intensity and total dissolved solids) of allelopathic effects of Potarnogeton pectinatus against Microcystis aeruginosa at the same time. By solving the regression equation and analyzing the response surface contour plots, the optimal conditions of the relatively inhibitory rate of Microcystis aeruginosa were that the temperature was 23℃, the light intensity was 2 700 lx and the total dissolved solids were 4 415 mg/L. Under these conditions, the optimal value of relatively inhibitory rate of Microcystis aeruginosa was 81.9%. According to validation experiments, the results of analysis indicated that the experimental values fitted well with the predicted ones.
文摘The effects of sorbed phosphate on the kinetics of Cu ̄2+ secondary adsorption on three major types ofsoils in southern and Central China were studied using the batch method and flow (or miscible displacement)techniques. Both of the methods showed that diffusions were the ratedetermining steps in the Cu ̄2+ adsorp-tion by the soils. By the flow method, the course of Cu ̄2+ adsorption kinetics consisted of two steps-sn initialrapid process and a later slow process of Cu ̄2+ adsorption; while by the batch method, the 90% of Cu ̄2+adsorption reaction was found to finish within first 1 minute. The results obtained using the flow method alsoindicated that for red soil and yellow-brown soil, Cu ̄2+ adsorptions during the initial reaction periods wererestrained when the soils sorbed phosphate, whereas the adsorption reactions were stimulated at the finaltime. For grey Chao soil, sorbed phosphate retarded the Cu ̄2+ adsorption in the whole reaction period. Theresults obtained using the batch method and flow techniques all implied that the different effects of sorbedphosphate would be attributed to its effects on Cu ̄2+ ion diffusion in soil solution.
基金financially supported by the Fundamental Research Funds for the Central Universities of China (Nos. B210203049, B210204005)the Natural Science Foundation of Jiangsu Province, China (No. BK20191161)+1 种基金the Changzhou Sci & Tech Program, China (No. CJ20210154)the National Natural Science Foundation of China (Nos. 51601058, 51879089)
文摘The microstructure,corrosion and cavitation erosion(CE)behaviors of the as-cast and four different heat treated nickel aluminum bronzes(NABs)in 3.5 wt.%NaCl solution were investigated.The results show that after annealing,β′transformed into the eutectoid microstructure,and moreκIV precipitated fromα.Less eutectoid microstructure and moreβ′were obtained after normalizing.The quenched NAB mainly consisted ofαandβ′phases,and fine,acicularαandκphases precipitated insideβ′after subsequent aging.The largest proportion of the eutectoid microstructure,which underwent severe selective phase corrosion,was responsible for the lowest corrosion resistance of the annealed NAB.The quenched NAB possessed the most protective film and hence the highest corrosion resistance.The mechanical attack was primarily responsible for the CE damage for the as-cast,annealed and normarlized NABs.The quenched and quenched+aged NABs exhibited superior CE resistance because of the high hardness.The CE−corrosion synergy dominantly caused CE degradation,and it was largely attributed to corrosion-enhanced-CE.
基金Supported by the CSIR-CECRI under project No.MLP 0008
文摘The galvanic corrosion behaviour of alumiuium 3004 - ∝ brass with different area ratios was studied in the tropical marine atmosphere at Tuticorin harbour over a period of 426 days. The area ratios, viz. AAluminiurn:A∝ brass, studied were 0.125, 0.25, 0.5, 1, 2, 4 and 8. The galvanic corrosion behaviour of the metals was studied in terms of the relative increase in the corrosion rate of aluminium due to galvanic coupling with oc brass, the relative decrease in the corrosion rate of ∝ brass due to galvanic coupling with aluminium, and the susceptibility of aluminium to pitting owing to galvanic coupling with ∝ brass. The galvanic potential and galvanic current of the system were monitored. Pits of different dimensions ranging from mild etchings to perforations were experienced on the borders arid the surfaces of the interface of aluminium in contact with ∝ brass. The corrosion products resulting from galvanic corrosion were analysed using XRD and the pitting on aluminium as a result of galvanic corrosion was highlighted in terms of pit depth, size and density of pit, using a high resolution microscope. The most favourable area ratio of aluminium - ∝ brass in marine atmosphere in terms of gravimetric corrosion rate is 8:1 and the most unfavourable area ratio of aluminium - ∝ brass is 1:4.
文摘In the search for new anti-tumor agents, exploiting features such as the flexibility of coordination modes of metals have become an alternative strategy for synthesizing pharmaceuticals. It has been shown that the CuDP (copper(II), doxycycline, and 1,10-phenanthroline) complex cleaves DNA strands by an oxidative mechanism and by intercalating the major groove, resulting in a cytotoxic action. The objective of this study was to assess the mutageinc/recombinogenic effects of the CuDP complex in vivo using the SMART (Somatic Mutation and Recombination Test) in Drosophila melanogaster. Treatments were carried out with third instar larvae at the standard cross and high bioactivation cross using three concentrations of CuDP (6.92, 13.84 or 27.67 mM). The mutagenic doxorubicin (0.4 mM) was used as a positive control and reverse osmosis water as a negative control. For each compound, marked trans-heterozygous and balanced heterozygous individuals were analyzed to determine the mutational and recombinogenic events occurring in the cells, We found that CuDP significantly increased the frequencies of mutant cells in both standard and high bioactivation crosses, mostly by induction of recombination. These data show that CuDP is a direct recombinogenic agent that is independent of bioactivation,
文摘The exploration of efficient electrocatalysts for the reduction of CO2 to C2H4 is of significant importance but is also a challenging subject.Cu-based bimetallic catalysts are extremely promising for efficient CO2 reduction.In this work,we synthesize a series of porous bimetallic Cu–Sb alloys with different compositions for the catalytic reduction of CO2 to C2H4.It is demonstrated that the alloy catalysts are much more efficient than the pure Cu catalyst.The performance of the alloy catalysts depended strongly on the composition.Further,the alloy with a Cu:Sb ratio of 10:1 yielded the best results;it exhibited a high C2H4 Faradaic efficiency of 49.7%and a high current density of 28.5 mA cm?2 at?1.19 V vs.a reversible hydrogen electrode(RHE)in 0.1 M KCl solution.To the best of our knowledge,the electrocatalytic reduction of CO2 to C2H4 using Cu–Sb alloys as catalysts has not been reported.The excellent performance of the porous alloy catalyst is attributed to its favorable electronic configuration,large surface area,high CO2 adsorption rate,and fast charge transfer rate.
文摘Nano particles are finding their way into the environment through deliberate and accidental actions, ecotoxicological properties and the risks of these nano particles have yet not been fully characterized. In this present investigation, experiments were carried out to know the effect of Cu oxide-nano particles (〈 50 nm) on germination and growth of seeds of soybean and chickpea. In both the crops, germination was not checked up to 2,000 ppm Cu (applied through Cu oxide-nano particles), but the root growth was prevented above 500 ppm Cu. With increasing concentration of NPs, the elongation of the roots was severely inhibited as compared to that in control. In many cases root necrosis was occurred. Massive adsorption of Cu oxide-nano particles into the root system was responsible for the toxicity. A parallel experiment was also carried out to know the effect of copper sulphate solution on seed germination, above 200 ppm Cu, it restricted the germination of seeds, because of high salinity.
文摘Due to the elevated ecological awareness nowadays the consumption of products of organic agriculture is increasing. Organic farming means excluding the use of synthetic inputs, such as synthetic fertilizers and pesticides or genetically modified organisms, but there are only a few regulations regarding heavy metal concentrations in soils. Thus a not negligible uptake of metals from the soil where the apple trees are grown may occur. Furthermore inorganic copper compounds being traditional fertilizers for apple trees are not considered as synthetic fertilizers, thus they are still used in organic apple farming for soil or foliar application. Thus also apples produced by organic agriculture may contain toxic elements, such as cadmium, chromium, copper, and lead. The concentrations of these elements were determined in whole apples, as well as in the flesh and peel in order to estimate the possible risk for human health. Prior to analysis using ICP-AES samples underwent a microwave assisted digestion. The LODs obtained are below the recommended maximum levels in vegetables/fruits by WHO. In all samples no Cu, Cr, and Pb could be detected. Only Ca was found in the peel of about a third of samples investigated in concentrations between LOD and LOQ (1-3 μg/g).
文摘Crop nutrition has a significant effect on disease incidence, resistance or tolerance of various crops. There is currently a lack of reliable recent UK-based research about the effect of copper, zinc and boron on disease incidence, green leaf area (GLA), green leaf retention (GLR) and grain yield of winter wheat, spring wheat and spring barley. Data analysis showed that these trace elements had positive effects on GLR. These positive effects may have been due to the role of copper, zinc and boron in the production of defence related compounds (phenolics and lignin), which may have reduced the disease incidence resulting in prolonged GLR. Grain yield was significantly enhanced by the application of these trace elements on the crop grown on high pH calcareous soil, which can be partly attributed to enhanced GLR. Also trace elements have a positive role in reproductive growth, flowering and male fertility. On average, zinc was found to be the most consistent trace element in terms of enhancing GLR and grain yield. Across all trials, it was noted that for every 10% increase in GLA from trace elements, grain yields increased by 4.2% in 2012-2013, by 4.4% in 2013-2014 in winter wheat and by 3.9% in spring wheat in 2014. These are remarkably consistent and indicate that increasing GLA by 10% by early dough stage was associated with a yield improvement of about 4%. These trace elements also had a positive effect on grain protein content (GPC). This research concluded that the trace elements had positive effects in enhancing GLA and yield. It can be speculated that with the use of these trace elements, there may be more scope for using less robust or reduced rates of fungicides to control foliar diseases, which may help to maximize farm profits.
基金Supported by the National Natural Science Foundation of China(No.3107045820)the State Oceanic Administration Public Welfare Project(Nos.201305009,201305009-4,201005007)
文摘With the increased use of copper (Cu)-based antifouling (AF) paints, copper has become a potential threat to marine organisms. Experiments were performed to investigate the effects of copper on larvae of the barnacle Chthamalus challengeri. These experiments attempted to identify a more sensitive index to monitor copper pollution in marine environments. The 24 h LC_50 ranged from 156.07 μg/L (nauplius Ⅱ) to 817.15μg/L (cypris) and the no observed effect concentration (NOEC) ranged from 81.75 μg/L (nauplius Ⅱ) to 571.04 μg/L (cypris). The cypris settlement rate declined significantly when copper concentrations 〉135 μg/L. No cypris was found in the copper concentration of 60 and 75 μg/L treatment groups stressed for 22 d. Nauplius Ⅱ moulting was not affected by exposure to copper for 24 h; however, when extended to 48 h, the percent moulted in 75 μg/L treatment group was declined to 37.12%, which was significant lower (P〈0.05) than that in the control group. The phototaxis of nauplius II decreased significantly when copper concentrations _〉45 μg/L. Despite an initial significant increase at copper concentrations of 30 μg/L, ammonia excretion rate decreased when copper concentrations ≥60 μg/L. These results suggested that: (1) nauplius Ⅱ could not develop to the cypris when the copper concentration ≥60 μg/L; (2) cypris settlement is more susceptible to copper than cypris mortality rate; (3) nauplius II is the most sensitive larval stage; (4) nauplius II ammonia excretion rate is the most sensitive index to copper and might be as the indicator for copper pollution monitoring.