Acid leaching solution was obtained after mixing pyrite cinders with H 2SO 4, then heating the mixture of pyrite cinders and H 2SO 4 at 200300 ℃, leaching the heated mixture with water and filtrating. Polyferric sulf...Acid leaching solution was obtained after mixing pyrite cinders with H 2SO 4, then heating the mixture of pyrite cinders and H 2SO 4 at 200300 ℃, leaching the heated mixture with water and filtrating. Polyferric sulfate (PFS) solution was produced by adding suitable amounts of FeSO 4·7H 2O and NaClO 3 into acid leaching solution. By concentrating and drying PFS solution, solid PFS with alkali degree of 6.40%22.4% was prepared. Fe 4.67 (SO 4) 6(OH) 2·20H 2O in the solid PFS was discovered by XRD analysis. FT IR spectroscopy shows that the absorption peaks at 3 400 cm -1 and 1 635 cm -1 arise from OH and absorption peaks at 998 cm -1 and 669 cm -1 come from Fe-OH in the solid PFS.展开更多
It was found that there lies a linear relationship among the thermodynamic data of complicate inorganic compounds with similar components. A method for estimating the thermodynamic data of complicate compound and a th...It was found that there lies a linear relationship among the thermodynamic data of complicate inorganic compounds with similar components. A method for estimating the thermodynamic data of complicate compound and a thermodynamic database involving alumina production were developed. It was found that the alumina digestion rate of activated diasporic bauxite by means of heat field increased much due to the structure aberration, i.e, from perfect structure to unstable corundum. The results from thermodynamic calculation and experiments showed that it was feasible for desilication at atmospheric pressure, and the effects on equilibrium concentration of SiO 2 included temperature, mole ratio of Na 2O/Al 2O 3 ( α k), caustic and Na + concentration. The technology of desilication of green liquor at atmosphere and separation of alumina and silica in aluminate solution with high concentration were established. The reaction activity of compounds containing silica and the converting law among compounds were studied, and the prototype technology of desilication products by hydrotreatment was also developed.展开更多
Recent development of inert anodes for the primary aluminium industry was reviewed. The preparation method of functionally gradient material was introduced into inert anode research area, and a research flow sheet of ...Recent development of inert anodes for the primary aluminium industry was reviewed. The preparation method of functionally gradient material was introduced into inert anode research area, and a research flow sheet of functionally gradient cermet inert anode was set down. In order to carry out the preparation and optimization of composite oxides as the ceramic matrix of cermet inert anode, the following problems: solid state reaction synthesis of complex oxides, corrosion mechanism of complex oxides in Na 3AlF 6 Al 2O 3 melts, effects of NiO content on the corrosion rate and resistivity at high temperature of NiFe 2O 4 NiO ceramics were studied. The preparation and sintering mechanism of NiFe 2O 4 based cermets were deeply studied to properly control the sintering atmosphere and temperature system. By efficaciously controlling the sintering atmosphere, the oxidization of metallic phase and the decomposition or deoxidization of ceramic phase are avoided effectively during the sintering process of cermets at various temperatures. By optimizing the composition recipe and sintering temperature system, cermets of relatively high density are prepared without the spillage or asymmetric distribution of metallic phase.展开更多
To improve the adsorption properties of chemically modified chitosan, the chelating resin of salicylal chitosan Schiff bases was prepared by the template cross-linking method using Cu（Ⅱ） as template ion and ethylen...To improve the adsorption properties of chemically modified chitosan, the chelating resin of salicylal chitosan Schiff bases was prepared by the template cross-linking method using Cu（Ⅱ） as template ion and ethylene glycol bisglycidyl ether as cross-linking agent in microwave, and was characterized by IR. The adsorption capacity and selectivity coefficient of the chemically modified chitosan for Cu（Ⅱ）, Fe（Ⅲ） and Zn（Ⅱ） were investigated, respectively. The results show that the adsorption capacity of the resin 2.73 mmol/g for Cu（Ⅱ） is bigger than that for other two metal ions, 0.22 mmol/g for Fe（Ⅲ）, and 0.42 mmol/g for Zn（Ⅱ）, and the selectivity coefficients are as follows: KCu（Ⅱ）/Fe（Ⅲ）=12.4, KCu（Ⅱ）/Zn（Ⅱ）=6.5.展开更多
Two kinds of novel chitosan-crown ether resins, Schiff base type chitosan-benzo-15-crown-5 （CTS -B15） and chitosan-benzo-18-crown-6 （CTS -B18）, were synthesized through the reaction between -NH2 in chitosan and -C...Two kinds of novel chitosan-crown ether resins, Schiff base type chitosan-benzo-15-crown-5 （CTS -B15） and chitosan-benzo-18-crown-6 （CTS -B18）, were synthesized through the reaction between -NH2 in chitosan and -CHO in 4′-formyl benzo-crown ethers. Their structures were characterized by elemental analysis and FT-IR spectra analysis. The elemental analysis results show that the mass fractions of nitrogen in CTS -B15 and CTS -B18 are much lower than those of chitosan. The results of FT-IR spectra of CTS -B15 and CTS -B18 reveal that there exist characteristic peak of C=N, N-H and Ar, and characteristic peak of pyr anoside in the chain of chitosan-crown ether resins, showing that the structures of chitosan-crown ethers are as expected. The adsorption properties of CTS -B15 and CTS -B18 for Pd 2+ , Cu 2+ and Hg 2+ were studied and the experimental results show that these adsorbents have both good adsorption characterization and especially high particular adsorption selectivity for Pd 2+ when Cu 2+ and Hg 2+ are in coexistence, and the coefficients of selectivity of CTS -B15 and CTS -B18 for metal ions are K Pd 2+ /Cu 2+ = 7.56, K Pd 2+ /Hg 2+ = 68.00, K Cu 2+ /Hg 2+ = 9.00 and K Pd 2+ /Cu 2+ =6.00, K Pd 2+ /Hg 2+ =19.00, K Cu 2+ /Hg 2+ =3.00, respectively.展开更多
A new pretreatment method has been developed to improve the catalytic activity of the Ni-Fe-Mo-Co alloy electrode for hydrogen evolution reaction （HER）. The procedure involves pre-electrolyzing the Ni-Fe-Mo-Co alloy...A new pretreatment method has been developed to improve the catalytic activity of the Ni-Fe-Mo-Co alloy electrode for hydrogen evolution reaction （HER）. The procedure involves pre-electrolyzing the Ni-Fe-Mo-Co alloy electrode in 30% KOH solution containing 10% potassium sodium tartrate at 70℃ for 2 h, until some of the Mo and Fe elements are leached out. The surface morphology of the Ni-Fe-Mo-Co alloy demonstrates a unique hive-like structure after the pre- treatment, which has the pore size in a nanometer range （about 50 nm）, a very large real surface area, and good stability. The results of the electrochemical studies show that compared to other similar electrode materials and the treated Ni-Fe-Mo-Co electrode by leaching method, the pre-treated Ni-Fe-Mo-Co electrode has a much lower overpotential and much higher exchange current density for HER. In addition, a long-term continuous electrolysis test with a current interruption shows that the Ni-Fe-Mo-Co alloy has excellent catalytic stability.展开更多
LiFePO4/C composites with good rate capability and high energy density were prepared by adding sugar to the synthetic precursor. A significant improvement in electrode performance was achieved. The resulting carbon co...LiFePO4/C composites with good rate capability and high energy density were prepared by adding sugar to the synthetic precursor. A significant improvement in electrode performance was achieved. The resulting carbon contents in the sample 1 and sample 2 are 3.06% and 4.95%（mass fraction）, respectively. It is believed that the synthesis of LiFePO4 with sugar added before heating is a good method because the synthesized particles having uniform small size are covered by carbon. The performance of the cathodes was evaluated using coin cells. The samples were characterized by X-ray diffraction and scanning electron microscope observation. The addition of carbon limits the particles size growth and enables high electron conductivity. The LiFePO4/C composites show very good electrochemical performance delivering about 142 mAh/g specific capacity when being cycled at the C/10 rate. The capacity fade upon cycling is very small.展开更多
Cathode material LiMn2O4 thin films were prepared by solution deposition followed by conventional thermal annealing （CTA） and rapid thermal annealing （RTA） using lithium acetate and manganese acetate as starting m...Cathode material LiMn2O4 thin films were prepared by solution deposition followed by conventional thermal annealing （CTA） and rapid thermal annealing （RTA） using lithium acetate and manganese acetate as starting materials. The phase and surface morphology identification was done by X-ray diffraction and scanning electron microscopy. The electrochemical properties of the thin films were carried out by cyclic voltammetry, chargedischarge experiments, electrochemical impedance spectroscopy and potential step technique. The results show that both thin films are homogeneous and crack-free. Compared with the CTA derived thin films, the RTA derived ones with smaller grain size are more smooth and dense. The CTA and RTA derived LiMn2O4 thin films deliver the capacity of 34.5μAh/（cm^2·μm） and 38μAh/（cm^2·μm） ） and show the capacity loss of 0.050% and 0.037% per cycle after being cycled 100 times, respectively. The diffusion coefficient of lithium ion in the CTA derived LiMn2O4 thin-film electrode is 4.59×10^-11cm^2/s, and that of lithium ion in the RTA derived one is 3.86×10^-11cm^2/s.展开更多
The effects of temperature and the concentration of sulfuric acid on the cell voltage, the anode current efficiency of electrodeposition and the particle size of grainy electrolytic manganese dioxide （EMD） were inve...The effects of temperature and the concentration of sulfuric acid on the cell voltage, the anode current efficiency of electrodeposition and the particle size of grainy electrolytic manganese dioxide （EMD） were investigated. The structure, particle size and appearance of grainy EMD were determined by powder X-ray diffraction, laser particle size analysis and scanning electron micrograph measurements. As the concentration of sulfuric acid increases, both the cell voltage and the average anode current efficiency decrease. With the increase of electrolysis temperature in the range of 30-60℃, the cell voltage, average anode current efficiency and particle size decrease. The optimum temperature of 30℃ and concentration of sulfuric acid of 2.5 mol/L for electrodeposition of the grainy EMD were obtained. XRD patterns show that the grainy EMD electrodeposited under the optimum conditions consists of γ-MnO2 and has an orthorhombic lattice structure. According to the results of SEM, the grainy EMD has a spherical or sphere-like appearance and a narrow particle size distribution with an average size of about 7μm. The grainy EMD is a promising cathode of rechargeable alkaline batteries for high energy density and a prospective precursor for production of the LiMn2O4 cathode of lithium ion batteries.展开更多
The influence of coal desulfurization by fungus was experimentally studied.The results suggest that fungus can effectively remove inorganic and organic sulfur in coal,and main influences of desulfurization by fungus o...The influence of coal desulfurization by fungus was experimentally studied.The results suggest that fungus can effectively remove inorganic and organic sulfur in coal,and main influences of desulfurization by fungus of pH value,temperature,coal slurry concentration and coal granularity were studied by orthodox experiment and the optimal experimental conditions are′as follows:pH value 6,temperature 45℃,coal slurry concentration 10%and coal granularity 100μm.Under above conditions,fungus car remove up to 44.96%total sulfur and 54.87%inorganic sulfur within two days,and their desulfurization rates will increase along with time.Compared with sulfolobas,desulphurization by fungus is steady and more effective,and has advantage of high speed.展开更多
Bioleaching is an environment-friendly and economical technique to remove heavy metals from contaminated soil.The objective of this work is to find out an indigenous strain to remedy soil contaminated by Zn,Pb,Cu and ...Bioleaching is an environment-friendly and economical technique to remove heavy metals from contaminated soil.The objective of this work is to find out an indigenous strain to remedy soil contaminated by Zn,Pb,Cu and Cd.A strain which was selected from the soil of a local smelting industry was found to be able to produce many organic acids and degrade pH value of the liquid medium.The fungus strain is identified as Penicillium Chrysogenum (P.Chrysogenum) by sequencing 18srDNA and ITS.Bioleaching condition using P.Chrysogenum is optimized.Glucose is the best carbon source for P.Chrysogenum and inorganic nitrogen is better than organic nitrogen.In addition,neutral solution and room temperature are fit for P.Chrysogenum to bioleach.In the one-step bioleaching,the bioleaching ratios are 39.95% for Zn,9.4% for Pb,34.89% for Cu and 49.59% for Cd,which are 53.89% for Zn,14.44% for Pb,55.53% for Cu and 62.81% for Cd in the two-step bioleaching.The efficiency of two-step bioleaching is better than the one-step bioleaching.P.Chrysogenum is effective in removing heavy metals from the contaminated soil.展开更多
Si doped composite material was prepared by coating artificial graphite with the mixture of phenol resin and polysilicone and following with heat treatment at 1 050 ℃ in an argon gas atmosphere. The structure and cha...Si doped composite material was prepared by coating artificial graphite with the mixture of phenol resin and polysilicone and following with heat treatment at 1 050 ℃ in an argon gas atmosphere. The structure and characteristics of the composite carbon were determined by means of XRD, SEM, BET surface area and electrochemical measurements. The new carbon material has a disordered carbon/graphite composite structure, with silicon doped in the disordered carbon. Compared with the pristine graphite, the electrochemical performance is improved for the Si doped composite carbon with large reversible capacity of 312.6 mAh/g, high initial charge/discharge efficiency of 88.61%, and excellent cycle stability. The prototype batteries using the composite carbon as anode material have large discharge capacity of 845 mAh and high capacity retention ratio of 95.80% at the 200th cycle.展开更多
The anodic reaction kinetics of zinc electrowinning was investigated on the titanium base RuO2 anode in the system of Zn（Ⅱ）-NH3-NH4Cl-H2O. The effects of stirring speed, ammonium chloride concentration and temperat...The anodic reaction kinetics of zinc electrowinning was investigated on the titanium base RuO2 anode in the system of Zn（Ⅱ）-NH3-NH4Cl-H2O. The effects of stirring speed, ammonium chloride concentration and temperature on anodic reaction rate were studied through the curve measurement of potentiostatic polarization. The results reveal that the electrochemically controlled anodic reaction obeys Tafel equation and the anodic reaction order for ammonium chloride is 1.056, with the apparent activation energy of 40.17 kJ/mol. The general equation of anodic reaction kinetics was obtained.展开更多
The LiMn2O4 thin film as a cathode material was prepared through solution deposition followed by rapid thermal annealing （RTA）. The phase identification and the study of surface morphology were carried out by X-my d...The LiMn2O4 thin film as a cathode material was prepared through solution deposition followed by rapid thermal annealing （RTA）. The phase identification and the study of surface morphology were carried out by X-my diffraction and scanning electron microscopy. Electrochemical properties were examined by cyclic voltammetry, galvanostatic charge-discharge experiments, and electrochemical impedance spectroscopy. The results show that the film prepared by this method is homogeneous, dense, and crack-free. The thin film has a capacity of 38 μtAh/（cm^2·μm） with the capacity loss of 0.037% per cycle after being cycled for 100 times. The average diffusion coefficient for lithium ions in the RTA-derived LiMn2O4 thin film is 1×10 ^-10 cm^2·s^-1.展开更多
Aiming at reducing energy and carbon consumption and enhancing current efficiency of aluminum electrolysis, a batch of property modified prebaked carbon anodes prepared in industrial production were applied to 160 kA ...Aiming at reducing energy and carbon consumption and enhancing current efficiency of aluminum electrolysis, a batch of property modified prebaked carbon anodes prepared in industrial production were applied to 160 kA prebaked anode aluminum electrolysis cells in a domestic aluminum company. The industrial statistical data show that, the property modified anodes can averagely reduce carbon consumption 11.6 kg per ton aluminum and energy consumption 106.1 kW·h, further more, enhance current efficiency 0.72%. The industrial testing results prove that this kind of new type of prebaked anodes has remarkable effect of saving energy, reducing carbon consumption and enhancing current efficiency of aluminum electrolysis.展开更多
The stainless steelmaking dust pellets were reduced in isothermal temperature condition simulating the direct recycling practice in the stainless steel production and the kinetics of the reduction process was investig...The stainless steelmaking dust pellets were reduced in isothermal temperature condition simulating the direct recycling practice in the stainless steel production and the kinetics of the reduction process was investigated. The pellets were formed after mixing the dust with carbon as the reducing agent and dolomite as the binder and smelting flux. An electric furnace was used to heat the pellets and an electrical microbalance was used to check the mass of the pellets in the reduction process. The reduction rate was calculated according to the data of pellet mass change in consideration of the evaporation of moisture, zinc and lead at high temperature. The results of the experiments show that the reduction process is in two consecutive stages. The reduction kinetic models were set up for each stage and the kinetic parameters such as activation energy and frequency factor were determined. The apparent activation energy of the first stage is 21.69 kJ/mol, and this stage is controlled by chemical reaction. The apparent activation energy of the second stage is 17.35 kJ/mol, and this stage is controlled by the diffusion of carbon monoxide through the resultants of reaction.展开更多
The method to calculate internal surface effective factor of cylinder-type vanadium catalyst Ls-9 was given. Based on hypothesis of subjunctive one dimension diffusion and combined shape adjustment factor with three-s...The method to calculate internal surface effective factor of cylinder-type vanadium catalyst Ls-9 was given. Based on hypothesis of subjunctive one dimension diffusion and combined shape adjustment factor with three-step catalytic mechanism model, the macroscopic kinetic model equation about SO2 oxidation on Ls-9 was deduced. With fixed-bed integral reactor and under the conditions of temperature 350410 ℃, space velocity 1 8005 000 h-1, SO2 inlet content 7%12%, the macroscopic kinetic data were detected. Through model parameter estimation, the macroscopic kinetic model equation was obtained.展开更多
Based on the data and methods provided by research literature, dispersing mathematical model of combustion process of asphalt smoke is set by theoretic analysis. Through computer programming, the dynamic combustion pr...Based on the data and methods provided by research literature, dispersing mathematical model of combustion process of asphalt smoke is set by theoretic analysis. Through computer programming, the dynamic combustion process of asphalt smoke is calculated to simulate an experimental model. The computing result shows that the temperature and the concentration of asphalt smoke influence its burning temperature in approximatively linear manner. The consumed quantity of fuel to ignite the asphalt smoke needs to be measured from the two factors.展开更多
The modified PVA CA blend ultrafiltration membranes were prepared by phase inversion from the casting solutions consisting of polyvinyl alcohol(PVA), cellulose acetate(CA), acetic acid, alkali metal chloride and water...The modified PVA CA blend ultrafiltration membranes were prepared by phase inversion from the casting solutions consisting of polyvinyl alcohol(PVA), cellulose acetate(CA), acetic acid, alkali metal chloride and water. The effects of different concentration of alkali metal chloride on the properties of membranes were investigated. The results show that when the mass fraction of the salt in the casting solution is not greater than 1%, the property of rejection of the alkali metal salt modified ultrafiltration PVA CA blend membrane has little change compared with that of the unmodified PVA CA blend membrane, but the permeation flux is much greater than that of the unmodified membrane under the same operation condition. When the mass fraction of the salt is greater than 1.5%, the permeate flux increases much greater than that of the unmodified membrane, but the property of rejection of the modified ultrafiltration membrane decreases greatly. The results also show that the contact angle of the salt modified PVA CA blend UF membrane decreases but the swelling in water increases with the increment of the mass fraction of alkali metal salts. Furthermore, the NaCl modified PVA CA blend membrane has a slightly lower swelling and a little smaller contact angle of water than the KCl modified PVA CA blend membrane does when the mass fraction of salts is the same.展开更多
文摘Acid leaching solution was obtained after mixing pyrite cinders with H 2SO 4, then heating the mixture of pyrite cinders and H 2SO 4 at 200300 ℃, leaching the heated mixture with water and filtrating. Polyferric sulfate (PFS) solution was produced by adding suitable amounts of FeSO 4·7H 2O and NaClO 3 into acid leaching solution. By concentrating and drying PFS solution, solid PFS with alkali degree of 6.40%22.4% was prepared. Fe 4.67 (SO 4) 6(OH) 2·20H 2O in the solid PFS was discovered by XRD analysis. FT IR spectroscopy shows that the absorption peaks at 3 400 cm -1 and 1 635 cm -1 arise from OH and absorption peaks at 998 cm -1 and 669 cm -1 come from Fe-OH in the solid PFS.
文摘It was found that there lies a linear relationship among the thermodynamic data of complicate inorganic compounds with similar components. A method for estimating the thermodynamic data of complicate compound and a thermodynamic database involving alumina production were developed. It was found that the alumina digestion rate of activated diasporic bauxite by means of heat field increased much due to the structure aberration, i.e, from perfect structure to unstable corundum. The results from thermodynamic calculation and experiments showed that it was feasible for desilication at atmospheric pressure, and the effects on equilibrium concentration of SiO 2 included temperature, mole ratio of Na 2O/Al 2O 3 ( α k), caustic and Na + concentration. The technology of desilication of green liquor at atmosphere and separation of alumina and silica in aluminate solution with high concentration were established. The reaction activity of compounds containing silica and the converting law among compounds were studied, and the prototype technology of desilication products by hydrotreatment was also developed.
文摘Recent development of inert anodes for the primary aluminium industry was reviewed. The preparation method of functionally gradient material was introduced into inert anode research area, and a research flow sheet of functionally gradient cermet inert anode was set down. In order to carry out the preparation and optimization of composite oxides as the ceramic matrix of cermet inert anode, the following problems: solid state reaction synthesis of complex oxides, corrosion mechanism of complex oxides in Na 3AlF 6 Al 2O 3 melts, effects of NiO content on the corrosion rate and resistivity at high temperature of NiFe 2O 4 NiO ceramics were studied. The preparation and sintering mechanism of NiFe 2O 4 based cermets were deeply studied to properly control the sintering atmosphere and temperature system. By efficaciously controlling the sintering atmosphere, the oxidization of metallic phase and the decomposition or deoxidization of ceramic phase are avoided effectively during the sintering process of cermets at various temperatures. By optimizing the composition recipe and sintering temperature system, cermets of relatively high density are prepared without the spillage or asymmetric distribution of metallic phase.
文摘To improve the adsorption properties of chemically modified chitosan, the chelating resin of salicylal chitosan Schiff bases was prepared by the template cross-linking method using Cu（Ⅱ） as template ion and ethylene glycol bisglycidyl ether as cross-linking agent in microwave, and was characterized by IR. The adsorption capacity and selectivity coefficient of the chemically modified chitosan for Cu（Ⅱ）, Fe（Ⅲ） and Zn（Ⅱ） were investigated, respectively. The results show that the adsorption capacity of the resin 2.73 mmol/g for Cu（Ⅱ） is bigger than that for other two metal ions, 0.22 mmol/g for Fe（Ⅲ）, and 0.42 mmol/g for Zn（Ⅱ）, and the selectivity coefficients are as follows: KCu（Ⅱ）/Fe（Ⅲ）=12.4, KCu（Ⅱ）/Zn（Ⅱ）=6.5.
文摘Two kinds of novel chitosan-crown ether resins, Schiff base type chitosan-benzo-15-crown-5 （CTS -B15） and chitosan-benzo-18-crown-6 （CTS -B18）, were synthesized through the reaction between -NH2 in chitosan and -CHO in 4′-formyl benzo-crown ethers. Their structures were characterized by elemental analysis and FT-IR spectra analysis. The elemental analysis results show that the mass fractions of nitrogen in CTS -B15 and CTS -B18 are much lower than those of chitosan. The results of FT-IR spectra of CTS -B15 and CTS -B18 reveal that there exist characteristic peak of C=N, N-H and Ar, and characteristic peak of pyr anoside in the chain of chitosan-crown ether resins, showing that the structures of chitosan-crown ethers are as expected. The adsorption properties of CTS -B15 and CTS -B18 for Pd 2+ , Cu 2+ and Hg 2+ were studied and the experimental results show that these adsorbents have both good adsorption characterization and especially high particular adsorption selectivity for Pd 2+ when Cu 2+ and Hg 2+ are in coexistence, and the coefficients of selectivity of CTS -B15 and CTS -B18 for metal ions are K Pd 2+ /Cu 2+ = 7.56, K Pd 2+ /Hg 2+ = 68.00, K Cu 2+ /Hg 2+ = 9.00 and K Pd 2+ /Cu 2+ =6.00, K Pd 2+ /Hg 2+ =19.00, K Cu 2+ /Hg 2+ =3.00, respectively.
文摘A new pretreatment method has been developed to improve the catalytic activity of the Ni-Fe-Mo-Co alloy electrode for hydrogen evolution reaction （HER）. The procedure involves pre-electrolyzing the Ni-Fe-Mo-Co alloy electrode in 30% KOH solution containing 10% potassium sodium tartrate at 70℃ for 2 h, until some of the Mo and Fe elements are leached out. The surface morphology of the Ni-Fe-Mo-Co alloy demonstrates a unique hive-like structure after the pre- treatment, which has the pore size in a nanometer range （about 50 nm）, a very large real surface area, and good stability. The results of the electrochemical studies show that compared to other similar electrode materials and the treated Ni-Fe-Mo-Co electrode by leaching method, the pre-treated Ni-Fe-Mo-Co electrode has a much lower overpotential and much higher exchange current density for HER. In addition, a long-term continuous electrolysis test with a current interruption shows that the Ni-Fe-Mo-Co alloy has excellent catalytic stability.
文摘LiFePO4/C composites with good rate capability and high energy density were prepared by adding sugar to the synthetic precursor. A significant improvement in electrode performance was achieved. The resulting carbon contents in the sample 1 and sample 2 are 3.06% and 4.95%（mass fraction）, respectively. It is believed that the synthesis of LiFePO4 with sugar added before heating is a good method because the synthesized particles having uniform small size are covered by carbon. The performance of the cathodes was evaluated using coin cells. The samples were characterized by X-ray diffraction and scanning electron microscope observation. The addition of carbon limits the particles size growth and enables high electron conductivity. The LiFePO4/C composites show very good electrochemical performance delivering about 142 mAh/g specific capacity when being cycled at the C/10 rate. The capacity fade upon cycling is very small.
基金the Hunan Provincial Natural Science Foundation of China （No. 04JJ40038） the Hunan Provincial Education Department （No. 04C475）.
文摘Cathode material LiMn2O4 thin films were prepared by solution deposition followed by conventional thermal annealing （CTA） and rapid thermal annealing （RTA） using lithium acetate and manganese acetate as starting materials. The phase and surface morphology identification was done by X-ray diffraction and scanning electron microscopy. The electrochemical properties of the thin films were carried out by cyclic voltammetry, chargedischarge experiments, electrochemical impedance spectroscopy and potential step technique. The results show that both thin films are homogeneous and crack-free. Compared with the CTA derived thin films, the RTA derived ones with smaller grain size are more smooth and dense. The CTA and RTA derived LiMn2O4 thin films deliver the capacity of 34.5μAh/（cm^2·μm） and 38μAh/（cm^2·μm） ） and show the capacity loss of 0.050% and 0.037% per cycle after being cycled 100 times, respectively. The diffusion coefficient of lithium ion in the CTA derived LiMn2O4 thin-film electrode is 4.59×10^-11cm^2/s, and that of lithium ion in the RTA derived one is 3.86×10^-11cm^2/s.
基金This work was financially supported by the National Natural Science Foundation of China (No. 50302016) and the PostdoctoralScience Foundation of Central South University.
文摘The effects of temperature and the concentration of sulfuric acid on the cell voltage, the anode current efficiency of electrodeposition and the particle size of grainy electrolytic manganese dioxide （EMD） were investigated. The structure, particle size and appearance of grainy EMD were determined by powder X-ray diffraction, laser particle size analysis and scanning electron micrograph measurements. As the concentration of sulfuric acid increases, both the cell voltage and the average anode current efficiency decrease. With the increase of electrolysis temperature in the range of 30-60℃, the cell voltage, average anode current efficiency and particle size decrease. The optimum temperature of 30℃ and concentration of sulfuric acid of 2.5 mol/L for electrodeposition of the grainy EMD were obtained. XRD patterns show that the grainy EMD electrodeposited under the optimum conditions consists of γ-MnO2 and has an orthorhombic lattice structure. According to the results of SEM, the grainy EMD has a spherical or sphere-like appearance and a narrow particle size distribution with an average size of about 7μm. The grainy EMD is a promising cathode of rechargeable alkaline batteries for high energy density and a prospective precursor for production of the LiMn2O4 cathode of lithium ion batteries.
基金Project(2002AA649220)supported by Hi-tech Research and Development Programeproject(1667)supported by thePostdoctoral Science Foundation of Central South University
文摘The influence of coal desulfurization by fungus was experimentally studied.The results suggest that fungus can effectively remove inorganic and organic sulfur in coal,and main influences of desulfurization by fungus of pH value,temperature,coal slurry concentration and coal granularity were studied by orthodox experiment and the optimal experimental conditions are′as follows:pH value 6,temperature 45℃,coal slurry concentration 10%and coal granularity 100μm.Under above conditions,fungus car remove up to 44.96%total sulfur and 54.87%inorganic sulfur within two days,and their desulfurization rates will increase along with time.Compared with sulfolobas,desulphurization by fungus is steady and more effective,and has advantage of high speed.
基金Project(2009ZX07212-001-01) supported by Major Science and Technology Program for Water Pollution Control and Treatment of ChinaProject(50925417) supported by the National Natural Science Funds for Distinguished Young Scholar in ChinaProjects(50830301,51074191) supported by the National Natural Science Foundation of China
文摘Bioleaching is an environment-friendly and economical technique to remove heavy metals from contaminated soil.The objective of this work is to find out an indigenous strain to remedy soil contaminated by Zn,Pb,Cu and Cd.A strain which was selected from the soil of a local smelting industry was found to be able to produce many organic acids and degrade pH value of the liquid medium.The fungus strain is identified as Penicillium Chrysogenum (P.Chrysogenum) by sequencing 18srDNA and ITS.Bioleaching condition using P.Chrysogenum is optimized.Glucose is the best carbon source for P.Chrysogenum and inorganic nitrogen is better than organic nitrogen.In addition,neutral solution and room temperature are fit for P.Chrysogenum to bioleach.In the one-step bioleaching,the bioleaching ratios are 39.95% for Zn,9.4% for Pb,34.89% for Cu and 49.59% for Cd,which are 53.89% for Zn,14.44% for Pb,55.53% for Cu and 62.81% for Cd in the two-step bioleaching.The efficiency of two-step bioleaching is better than the one-step bioleaching.P.Chrysogenum is effective in removing heavy metals from the contaminated soil.
文摘Si doped composite material was prepared by coating artificial graphite with the mixture of phenol resin and polysilicone and following with heat treatment at 1 050 ℃ in an argon gas atmosphere. The structure and characteristics of the composite carbon were determined by means of XRD, SEM, BET surface area and electrochemical measurements. The new carbon material has a disordered carbon/graphite composite structure, with silicon doped in the disordered carbon. Compared with the pristine graphite, the electrochemical performance is improved for the Si doped composite carbon with large reversible capacity of 312.6 mAh/g, high initial charge/discharge efficiency of 88.61%, and excellent cycle stability. The prototype batteries using the composite carbon as anode material have large discharge capacity of 845 mAh and high capacity retention ratio of 95.80% at the 200th cycle.
文摘The anodic reaction kinetics of zinc electrowinning was investigated on the titanium base RuO2 anode in the system of Zn（Ⅱ）-NH3-NH4Cl-H2O. The effects of stirring speed, ammonium chloride concentration and temperature on anodic reaction rate were studied through the curve measurement of potentiostatic polarization. The results reveal that the electrochemically controlled anodic reaction obeys Tafel equation and the anodic reaction order for ammonium chloride is 1.056, with the apparent activation energy of 40.17 kJ/mol. The general equation of anodic reaction kinetics was obtained.
基金This project was financially supported by the Natural Science Foundation of Hunan Province, China (No. 04JJ40038) and the Education Department of Hunan Province, China (No. 04C 475).
文摘The LiMn2O4 thin film as a cathode material was prepared through solution deposition followed by rapid thermal annealing （RTA）. The phase identification and the study of surface morphology were carried out by X-my diffraction and scanning electron microscopy. Electrochemical properties were examined by cyclic voltammetry, galvanostatic charge-discharge experiments, and electrochemical impedance spectroscopy. The results show that the film prepared by this method is homogeneous, dense, and crack-free. The thin film has a capacity of 38 μtAh/（cm^2·μm） with the capacity loss of 0.037% per cycle after being cycled for 100 times. The average diffusion coefficient for lithium ions in the RTA-derived LiMn2O4 thin film is 1×10 ^-10 cm^2·s^-1.
文摘Aiming at reducing energy and carbon consumption and enhancing current efficiency of aluminum electrolysis, a batch of property modified prebaked carbon anodes prepared in industrial production were applied to 160 kA prebaked anode aluminum electrolysis cells in a domestic aluminum company. The industrial statistical data show that, the property modified anodes can averagely reduce carbon consumption 11.6 kg per ton aluminum and energy consumption 106.1 kW·h, further more, enhance current efficiency 0.72%. The industrial testing results prove that this kind of new type of prebaked anodes has remarkable effect of saving energy, reducing carbon consumption and enhancing current efficiency of aluminum electrolysis.
文摘The stainless steelmaking dust pellets were reduced in isothermal temperature condition simulating the direct recycling practice in the stainless steel production and the kinetics of the reduction process was investigated. The pellets were formed after mixing the dust with carbon as the reducing agent and dolomite as the binder and smelting flux. An electric furnace was used to heat the pellets and an electrical microbalance was used to check the mass of the pellets in the reduction process. The reduction rate was calculated according to the data of pellet mass change in consideration of the evaporation of moisture, zinc and lead at high temperature. The results of the experiments show that the reduction process is in two consecutive stages. The reduction kinetic models were set up for each stage and the kinetic parameters such as activation energy and frequency factor were determined. The apparent activation energy of the first stage is 21.69 kJ/mol, and this stage is controlled by chemical reaction. The apparent activation energy of the second stage is 17.35 kJ/mol, and this stage is controlled by the diffusion of carbon monoxide through the resultants of reaction.
文摘The method to calculate internal surface effective factor of cylinder-type vanadium catalyst Ls-9 was given. Based on hypothesis of subjunctive one dimension diffusion and combined shape adjustment factor with three-step catalytic mechanism model, the macroscopic kinetic model equation about SO2 oxidation on Ls-9 was deduced. With fixed-bed integral reactor and under the conditions of temperature 350410 ℃, space velocity 1 8005 000 h-1, SO2 inlet content 7%12%, the macroscopic kinetic data were detected. Through model parameter estimation, the macroscopic kinetic model equation was obtained.
文摘Based on the data and methods provided by research literature, dispersing mathematical model of combustion process of asphalt smoke is set by theoretic analysis. Through computer programming, the dynamic combustion process of asphalt smoke is calculated to simulate an experimental model. The computing result shows that the temperature and the concentration of asphalt smoke influence its burning temperature in approximatively linear manner. The consumed quantity of fuel to ignite the asphalt smoke needs to be measured from the two factors.
文摘The modified PVA CA blend ultrafiltration membranes were prepared by phase inversion from the casting solutions consisting of polyvinyl alcohol(PVA), cellulose acetate(CA), acetic acid, alkali metal chloride and water. The effects of different concentration of alkali metal chloride on the properties of membranes were investigated. The results show that when the mass fraction of the salt in the casting solution is not greater than 1%, the property of rejection of the alkali metal salt modified ultrafiltration PVA CA blend membrane has little change compared with that of the unmodified PVA CA blend membrane, but the permeation flux is much greater than that of the unmodified membrane under the same operation condition. When the mass fraction of the salt is greater than 1.5%, the permeate flux increases much greater than that of the unmodified membrane, but the property of rejection of the modified ultrafiltration membrane decreases greatly. The results also show that the contact angle of the salt modified PVA CA blend UF membrane decreases but the swelling in water increases with the increment of the mass fraction of alkali metal salts. Furthermore, the NaCl modified PVA CA blend membrane has a slightly lower swelling and a little smaller contact angle of water than the KCl modified PVA CA blend membrane does when the mass fraction of salts is the same.
