Simultaneous determination of impurity metal ions in high concentration zinc solution is very important for zinc hydrometallurgy,and the purpose is to establish a method for determining the trace Cu^2+,Cd^2+,Ni^2+and ...Simultaneous determination of impurity metal ions in high concentration zinc solution is very important for zinc hydrometallurgy,and the purpose is to establish a method for determining the trace Cu^2+,Cd^2+,Ni^2+and Co^2+in zinc electrolytes at the same time using the second derivative waves of single sweep oscillopolarography.Factors affecting the derivative waves of the ions were researched in a medium of dimethylglyoxime(DMG)-sodium citrate-sodium tetraborate.The results indicated that the interferences of a high concentration of Zn^2+and most other coexisting ions on the determination can be eliminated;when the Cu^2+,Cd^2+,Ni^2+and Co^2+are in the ranges of1×10^-7-3×10^-4,6×10^-7-2×10^-4,2×10^-8-1×10^-5and1×10^-8-3×10^-5mol/L,respectively,the relationships between the peak currents of the second derivative waves and the concentrations are linear;the detection limits to determine the Cu^2+,Cd^2+,Ni^2+and Co^2+are8×10^-8,2×10^-7,6×10^-9and4×10^-9mol/L,respectively.Without any sample pretreatment,the method was used to directly determine the trace Cu^2+,Cd^2+,Ni^2+and Co^2+in actual zinc electrolytes with satisfactory results.The method is simple,sensitive and rapid.展开更多
We report herein a highly selective method for directly determining the trace Co^2+in highly concentrated zinc electrolyte.This novel method is based on a second derivative wave of catalytic adsorptive polarography ge...We report herein a highly selective method for directly determining the trace Co^2+in highly concentrated zinc electrolyte.This novel method is based on a second derivative wave of catalytic adsorptive polarography generated by complexing Co^2+with dimethylglyoxime and nitrite onto a dropping mercury electrode.By employing a medium with NH3-NH4Cl buffer,DMG and NaNO2 during determining the trace Co^2+,any interferences of highly concentrated Zn^2+and other coexisting metal ions in the electrolyte are completely eliminated due to the selective masking effect of EDTA.When the concentration of Co^2+is within 1.0×10^–10–3.2×10^–7 mol/L range,it shows a good linear relationship with the current peak.Detection limit is 1.0×10^–11 mol/L,and RSD≤2.7%for six successive assays.We have compared the efficiency of the current method to that obtained by cobalt nitroso-R-salt spectrophotometry,and the absolute values of relative deviations are≤4.2%.The method developed and described herein has been successfully employed in determining the trace Co2+in actual zinc electrolyte.展开更多
The physical and mathematical model of an operating electrowinning cell was established, and the flow of electrolyte was numerically simulated by the commercial software Fluent. The results indicate that there are two...The physical and mathematical model of an operating electrowinning cell was established, and the flow of electrolyte was numerically simulated by the commercial software Fluent. The results indicate that there are two circulations at the surface flow where part of electrolyte backflows to the inlet from the side of cell, and the rest flows directly to the outlet, and the separation of two circulations with opposite direction occurs at the 20th pair of anode-cathode. This phenomenon was observed in the real operation. The electrolyte flows into the space between anode and cathode from the side portion of the cell. Meanwhile, the interelectrode effective flow rate （IEFR） is put forward to describe quantitively the flow field characteristics and is defined as the ratio of electrolyte flow between the anode and cathode to the total flow area. The influences of structure parameters and operating conditions on IEFR, such as the inlet angle, the volumetric flow rate, the inlet position and the height of steel baffles were simulated. The inlet position has a significant influence on the IEFR and its optimal value is 0.9 m below free surface. The inlet angle should be in the range from -10° to 10°. IEFR is in linear proportion with the volumetric flow rate, and the height of the steel baffle has little influence on the flow field.展开更多
Biocompatible devices are widely employed in modernized lives and medical fields in the forms of wearable and implantable devices,raising higher requirements on the battery biocompatibility,high safety,low cost,and ex...Biocompatible devices are widely employed in modernized lives and medical fields in the forms of wearable and implantable devices,raising higher requirements on the battery biocompatibility,high safety,low cost,and excellent electrochemical performance,which become the evaluation criteria toward developing feasible biocompatible batteries.Herein,through conducting the battery implantation tests and leakage scene simulations on New Zealand rabbits,zinc sulfate electrolyte is proved to exhibit higher biosecurity and turns out to be one of the ideal zinc salts for biocompatible zinc-ion batteries(ZIBs).Furthermore,in order to mitigate the notorious dendrite growth and hydrogen evolution in mildly acidic electrolyte as well as improve their operating stability,Sn hetero nucleus is introduced to stabilize the zinc anode,which not only facilitates the planar zinc deposition,but also contributes to higher hydrogen evolution overpotential.Finally,a long lifetime of 1500 h for the symmetrical cell,the specific capacity of 150 mAh g^(-1)under 0.5 A g^(-1)for the Zn-MnO_(2)battery and 212 mAh g^(-1)under 5 A g^(-1)for the Zn—NH4V4O10 battery are obtained.This work may provide unique perspectives on biocompatible ZIBs toward the biosecurity of their cell components.展开更多
Zinc ion hybrid supercapacitor (ZIHSC) with promising energy and power densities is an excellent answer to the ever-growing demand for energy storage devices.The restricted lifespan due to the dendrite formation on me...Zinc ion hybrid supercapacitor (ZIHSC) with promising energy and power densities is an excellent answer to the ever-growing demand for energy storage devices.The restricted lifespan due to the dendrite formation on metallic zinc (Zn) is one of the main roadblocks.Herein,we investigate the electrochemical capability of oxygen-enriched porous carbon nanofibers (A-CNF) and nitrogen,oxygen-enriched porous carbon nanofibers (N-CNF) cathode materials for structural ZIHSCs.To this end,a series of samples with different chemical compositions (N and O contents) are prepared to present deep insight into the electrochemical mechanism between N/O doping and Zn-ion storage.The as-prepared ZIHSC in the presence of N-CNF cathode and Zn Cl_(2) electrolyte offers a battery-level gravimetric energy density of 143.2 Wh kg^(-1)at a power density of 367.1 W kg^(-1).The free-standing N-CNF electrodes in ZIHSCs enjoy delivering an outstanding areal energy density of 110.4μWh cm^(-2)at 0.24 m W cm^(-2),excellent rate capability,and noticeable cycling stability over 10,000 cycles at 10 A g^(-1)with less than 7%decay.It was also concluded that active pyrrolic N dopants might deliver and facilitate more pseudocapacitance in ZIHSCs than other N configurations,resulting in higher adsorption/desorption and insertion/extraction process of Zn Cl^(+).Taking advantage of the beneficial properties of a free-standing continuous cathode,this novel generation of structural cathode material offers high areal and gravimetric energy densities and mechanical properties in a single zinc-ion-based package.展开更多
The effect of MnO4- and silver content on electrochemical behaviour of five commercial Pb-Ag alloy anodes was studied in acid zinc sulphate electrolyte with and without MnO4- ions at 38 °C during potential decay ...The effect of MnO4- and silver content on electrochemical behaviour of five commercial Pb-Ag alloy anodes was studied in acid zinc sulphate electrolyte with and without MnO4- ions at 38 °C during potential decay periods. When the anodes were immersed into acid zinc sulphate electrolyte without MnO4- ions, the Pb-0.72%Ag anode entered complete passivation state in the shortest time among the five anodes, followed by anodes Pb-0.67%Ag, Pb-0.60%Ag, Pb-0.58%Ag and Pb-0.29%Ag-0.1%Ca by measurement of open circuit potential. During immersion of the anodes, MnO4 ions accelerated the passivation and increased the corrosion current density of the anodes. After immersion in zinc electrolyte with MnO4-, the anode Pb-0.72%Ag had the best corrosion resistance, followed by anodes Pb-0.67%Ag, Pb-0.60%Ag, then the close anodes Pb-0.58%Ag and Pb-0.29%Ag-0.1%Ca by the electrochemical impedance spectroscopy （EIS） analysis.展开更多
基金Projects (61533021,61773403) supported by the National Natural Science Foundation of China
文摘Simultaneous determination of impurity metal ions in high concentration zinc solution is very important for zinc hydrometallurgy,and the purpose is to establish a method for determining the trace Cu^2+,Cd^2+,Ni^2+and Co^2+in zinc electrolytes at the same time using the second derivative waves of single sweep oscillopolarography.Factors affecting the derivative waves of the ions were researched in a medium of dimethylglyoxime(DMG)-sodium citrate-sodium tetraborate.The results indicated that the interferences of a high concentration of Zn^2+and most other coexisting ions on the determination can be eliminated;when the Cu^2+,Cd^2+,Ni^2+and Co^2+are in the ranges of1×10^-7-3×10^-4,6×10^-7-2×10^-4,2×10^-8-1×10^-5and1×10^-8-3×10^-5mol/L,respectively,the relationships between the peak currents of the second derivative waves and the concentrations are linear;the detection limits to determine the Cu^2+,Cd^2+,Ni^2+and Co^2+are8×10^-8,2×10^-7,6×10^-9and4×10^-9mol/L,respectively.Without any sample pretreatment,the method was used to directly determine the trace Cu^2+,Cd^2+,Ni^2+and Co^2+in actual zinc electrolytes with satisfactory results.The method is simple,sensitive and rapid.
基金Projects(61533021,61773403)supported by the National Natural Science Foundation of China
文摘We report herein a highly selective method for directly determining the trace Co^2+in highly concentrated zinc electrolyte.This novel method is based on a second derivative wave of catalytic adsorptive polarography generated by complexing Co^2+with dimethylglyoxime and nitrite onto a dropping mercury electrode.By employing a medium with NH3-NH4Cl buffer,DMG and NaNO2 during determining the trace Co^2+,any interferences of highly concentrated Zn^2+and other coexisting metal ions in the electrolyte are completely eliminated due to the selective masking effect of EDTA.When the concentration of Co^2+is within 1.0×10^–10–3.2×10^–7 mol/L range,it shows a good linear relationship with the current peak.Detection limit is 1.0×10^–11 mol/L,and RSD≤2.7%for six successive assays.We have compared the efficiency of the current method to that obtained by cobalt nitroso-R-salt spectrophotometry,and the absolute values of relative deviations are≤4.2%.The method developed and described herein has been successfully employed in determining the trace Co2+in actual zinc electrolyte.
基金Project(2011AA061003)supported by the National High-Tech Research and Development Program of China
文摘The physical and mathematical model of an operating electrowinning cell was established, and the flow of electrolyte was numerically simulated by the commercial software Fluent. The results indicate that there are two circulations at the surface flow where part of electrolyte backflows to the inlet from the side of cell, and the rest flows directly to the outlet, and the separation of two circulations with opposite direction occurs at the 20th pair of anode-cathode. This phenomenon was observed in the real operation. The electrolyte flows into the space between anode and cathode from the side portion of the cell. Meanwhile, the interelectrode effective flow rate （IEFR） is put forward to describe quantitively the flow field characteristics and is defined as the ratio of electrolyte flow between the anode and cathode to the total flow area. The influences of structure parameters and operating conditions on IEFR, such as the inlet angle, the volumetric flow rate, the inlet position and the height of steel baffles were simulated. The inlet position has a significant influence on the IEFR and its optimal value is 0.9 m below free surface. The inlet angle should be in the range from -10° to 10°. IEFR is in linear proportion with the volumetric flow rate, and the height of the steel baffle has little influence on the flow field.
基金This work was supported by the National Natural Science Foundation of China(Grant Nos.82103472,82202480,and 52372252)the Hunan Natural Science Fund for Distinguished Young Scholar(2021JJ10064)the Program of Youth Talent Support for Hunan Province(2020RC3011).
文摘Biocompatible devices are widely employed in modernized lives and medical fields in the forms of wearable and implantable devices,raising higher requirements on the battery biocompatibility,high safety,low cost,and excellent electrochemical performance,which become the evaluation criteria toward developing feasible biocompatible batteries.Herein,through conducting the battery implantation tests and leakage scene simulations on New Zealand rabbits,zinc sulfate electrolyte is proved to exhibit higher biosecurity and turns out to be one of the ideal zinc salts for biocompatible zinc-ion batteries(ZIBs).Furthermore,in order to mitigate the notorious dendrite growth and hydrogen evolution in mildly acidic electrolyte as well as improve their operating stability,Sn hetero nucleus is introduced to stabilize the zinc anode,which not only facilitates the planar zinc deposition,but also contributes to higher hydrogen evolution overpotential.Finally,a long lifetime of 1500 h for the symmetrical cell,the specific capacity of 150 mAh g^(-1)under 0.5 A g^(-1)for the Zn-MnO_(2)battery and 212 mAh g^(-1)under 5 A g^(-1)for the Zn—NH4V4O10 battery are obtained.This work may provide unique perspectives on biocompatible ZIBs toward the biosecurity of their cell components.
文摘Zinc ion hybrid supercapacitor (ZIHSC) with promising energy and power densities is an excellent answer to the ever-growing demand for energy storage devices.The restricted lifespan due to the dendrite formation on metallic zinc (Zn) is one of the main roadblocks.Herein,we investigate the electrochemical capability of oxygen-enriched porous carbon nanofibers (A-CNF) and nitrogen,oxygen-enriched porous carbon nanofibers (N-CNF) cathode materials for structural ZIHSCs.To this end,a series of samples with different chemical compositions (N and O contents) are prepared to present deep insight into the electrochemical mechanism between N/O doping and Zn-ion storage.The as-prepared ZIHSC in the presence of N-CNF cathode and Zn Cl_(2) electrolyte offers a battery-level gravimetric energy density of 143.2 Wh kg^(-1)at a power density of 367.1 W kg^(-1).The free-standing N-CNF electrodes in ZIHSCs enjoy delivering an outstanding areal energy density of 110.4μWh cm^(-2)at 0.24 m W cm^(-2),excellent rate capability,and noticeable cycling stability over 10,000 cycles at 10 A g^(-1)with less than 7%decay.It was also concluded that active pyrrolic N dopants might deliver and facilitate more pseudocapacitance in ZIHSCs than other N configurations,resulting in higher adsorption/desorption and insertion/extraction process of Zn Cl^(+).Taking advantage of the beneficial properties of a free-standing continuous cathode,this novel generation of structural cathode material offers high areal and gravimetric energy densities and mechanical properties in a single zinc-ion-based package.
基金Project(RDCPJ346365-06)supported by the Natural Sciences and Engineering Research Council of CanadaProject(51208193)supported by the National Natural Science Foundation of ChinaProject(11jj6034)supported by the Hunan Provincial Natural Science Foundation
文摘The effect of MnO4- and silver content on electrochemical behaviour of five commercial Pb-Ag alloy anodes was studied in acid zinc sulphate electrolyte with and without MnO4- ions at 38 °C during potential decay periods. When the anodes were immersed into acid zinc sulphate electrolyte without MnO4- ions, the Pb-0.72%Ag anode entered complete passivation state in the shortest time among the five anodes, followed by anodes Pb-0.67%Ag, Pb-0.60%Ag, Pb-0.58%Ag and Pb-0.29%Ag-0.1%Ca by measurement of open circuit potential. During immersion of the anodes, MnO4 ions accelerated the passivation and increased the corrosion current density of the anodes. After immersion in zinc electrolyte with MnO4-, the anode Pb-0.72%Ag had the best corrosion resistance, followed by anodes Pb-0.67%Ag, Pb-0.60%Ag, then the close anodes Pb-0.58%Ag and Pb-0.29%Ag-0.1%Ca by the electrochemical impedance spectroscopy （EIS） analysis.
