Sodium hypochlorite was used to treat the standard molybdenum concentrates; the oxidization conditions for sodium hypochlorite were investigated, and the electro-oxidation process was performed. The results indicate t...Sodium hypochlorite was used to treat the standard molybdenum concentrates; the oxidization conditions for sodium hypochlorite were investigated, and the electro-oxidation process was performed. The results indicate that in the suitable conditions, such as temperature around 25℃, NaCl concentration 4.0mol/L, mass ratio of ore slurry liquid to solid （mL/mS） 20, electric charge per gram Mo 0.522C, pH value of original slurry 8, anodic current density 700A·m-2 （cell potential 2.72.9V）, the Mo leaching rate and the current efficiency reach 98% and 36%, respectively. In order to overcome some shortages of the electro-oxidation process, such as low current efficiency, low Mo concentration in the leaching solution, ultrasonic was adopted to intensify the leaching process. The results show that the Mo leaching rate exceeds 98%, current efficiency increases from 36% to 50% and the Mo concentration in the leaching solution reaches about 60g/L at low mL/mS of 8 and low electric charge of 0.373C.展开更多
MXene materials have got great attention from researchers of environmental treatment for the great electrochemical performance.Monolayer-Ti_(3)C_(2)T_(x)(T_(x) is the surface terminal groups such as-O,-OH and/or-F spe...MXene materials have got great attention from researchers of environmental treatment for the great electrochemical performance.Monolayer-Ti_(3)C_(2)T_(x)(T_(x) is the surface terminal groups such as-O,-OH and/or-F species),as a typical structural MXene,always shows better chemical-physical characteristics than multilayer-Ti_(3)C_(2)T_(x).Thus,we prepared monolayer-Ti_(3)C_(2)T_(x) electrode by HF etching method and absolute ethyl alcohol intercalationdelamination treatment for capacitive deionization(CDI).The prepared monolay-Ti_(3)C_(2)T_(x) shows a higher specific surface area(235.6 m^(2)/g)and a thinner thickness(0.8 nm).Moreover,a series of systematic investigation demonstrated that monolayer-Ti_(3)C_(2)T_(x) has obvious promotional phenomenon on electrochemical properties(e.g.,mass specific capacitance increased from 52.1 F/g to 144.7 F/g).The NaCl adsorption capacity of monolayer-Ti_(3)C_(2)T_(x),is 30.7 mg/g in 1000 mg/L NaCl solution at 1.2 V.We concluded that the electro-sorption mechanism could be expressed as double electric layer and monolayer coverage by a good fitting of Langmuir isotherms and the pseudo-second-order kinetics equation.This work would provide a new strategy for the application of monolayer-Ti_(3)C_(2)T_(x) material in wastewater treatment in the future.展开更多
The dissolution of molybdenite concentrate in NaC1 electrolyte was investigated. The results show that the dissolution rate increases with the increase in liquid-to-solid ratio, stirring speed, NaCl concentration and ...The dissolution of molybdenite concentrate in NaC1 electrolyte was investigated. The results show that the dissolution rate increases with the increase in liquid-to-solid ratio, stirring speed, NaCl concentration and temperature. When the liquid-to-solid ratio is 30：1, stirring speed is 400 r/min, concentration of NaCI is 4 mol/L at pH=9 and room temperature, the leaching efficiency of molybdenite concentrate will reach 99.5% in 240 min. Molybdenite concentrate cannot be electro-oxidized directly on the anode. The kinetic studies show that the dissolution of molybdenite concentrate is represented by shrinking core model with diffusion through a porous product layer of element sulfur, and the apparent activation energy for the dissolution reaction is 8.56 kJ/mol.展开更多
Corrosion test data were measured using non-destructive electrochemical techniques and analysed for studying inhibition effectiveness by different concentrations of NazCr207 on the corrosion of concrete steel-rehar in...Corrosion test data were measured using non-destructive electrochemical techniques and analysed for studying inhibition effectiveness by different concentrations of NazCr207 on the corrosion of concrete steel-rehar in NaC1 and in H2SO4 media. For these, specifications of ASTM G16-95 R04 were combined with the normal and the Gumbel probability density functions as model analytical methods for addressing issues of conflicting reports of inhibitor effectiveness that had generated concerns. Results show that reinforced concrete samples admixed with concentrations having 4 g （0.012 7 tool）, 8 g （0.025 4 mol） and 6 g （0.019 l tool） NaaCr207 exhibited, in that order, high inhibition effectiveness, with respective efficiency, r/, of （90.46±1.30）%, （88.41＋2.24）% and （84.87±4.74）%, in the NaC1 medium. These exhibit good agreements within replicates and statistical methods for the samples. Also, optimal inhibition effectiveness model in the H2SO4 medium was exhibited by 8 g （0.025 4 mol） Na2Cr207 concentration having r/=（78.44±1.10）%. These bear implications for addressing conflicting test data in the study of effective inhibitors for mitigating steel-rebar corrosion in aggressive environments.展开更多
D2EHPA(P204),tri-butyl-phosphate(TBP)and sodium chloride(NaCl)were attractive for selective extraction of scandium from acid leaching solution of red mud.The extraction parameters of P204 concentration(X_(P204)),NaCl ...D2EHPA(P204),tri-butyl-phosphate(TBP)and sodium chloride(NaCl)were attractive for selective extraction of scandium from acid leaching solution of red mud.The extraction parameters of P204 concentration(X_(P204)),NaCl concentration(C_(NaCl)),pH value,reaction time,stirring speed and O/A were investigated to extract scandium and separate iron from the acid leaching solution.The extraction mechanism was analyzed by Fourier transform infrared spectroscopy(FT-IR)and thermodynamic theory.The single-stage extraction efficiency of scandium,iron andβ(Sc/Fe)were 99.1%,9.4%and 1061.2,respectively,with C_(NaCl) of 75 g/L and XP204 of 0.75 at solution pH value of 1.2 and stirring speed of 200 r/min for 6 min,in which a good separation effect of scandium and iron was obtained.The vibration absorption peak Sc─O was contributed to the extraction of scandium with P204.The complex[FeCln]^(3−n) existed in the solution with adding NaCl into the acid leaching solution.The value of n was higher and the valence state of the complex[FeCln]^(3−n) was lower with an increase of chloride concentration,which restricts the extraction efficiency of iron with P204.The extraction of three stages in the counter-current simulation experiments was carried out according to the McCabe-Thiele diagram.Gibbs free energy change(ΔG)of−5.93 kJ/mol,enthalpy change(ΔH)of 23.45 kJ/mol and entropy change(ΔH)of 98.54 J/(mol·K)were obtained in the solvent extraction proces,which indicate that the extraction reaction is easily spontaneous and endothermic and a proper increase of temperature is conducive to the extraction of scandium.展开更多
To investigate the mechanical properties of cement mortar in sodium sulfate and sodium chloride solutions, uniaxial compression test and ultrasonic test were performed. Test results show that the relative dynamic elas...To investigate the mechanical properties of cement mortar in sodium sulfate and sodium chloride solutions, uniaxial compression test and ultrasonic test were performed. Test results show that the relative dynamic elastic modulus, the mass variation,and the compressive strength of cement mortar increase first, and then decrease with increasing erosion time in sodium sulfate and sodium chloride solutions. The relative dynamic elastic moduli and the compressive strengths of cement mortars with water/cement ratios of 0.55 and 0.65 in sodium sulfate solution are lower than those in sodium chloride solution with the same concentration at the420 th day of immersion. The compressive strength of cement mortar with water/cement ratio of 0.65 is more sensitive to strain rate than that with water/cement ratio of 0.55. In addition, the strain-rate sensitivity of compressive strength of cement mortar will increase under attacks of sodium sulfate or sodium chloride solution.展开更多
Anodic films were successfully fabricated on Ti6A14V alloy by anodic oxidation method in an environmental friendly electrolyte with and without sodium hypochlorite. The anodic films were characterized by means of the ...Anodic films were successfully fabricated on Ti6A14V alloy by anodic oxidation method in an environmental friendly electrolyte with and without sodium hypochlorite. The anodic films were characterized by means of the scanning electron microscope （SEM） and energy dispersive spectrometer （EDS）. Results revealed that the addition of sodium hypochlorite leads to the ultrafast growth of oxide films, and results in the significant changes of morphology and thickness. The influence of sodium hypochlorite on formation and crystallization of oxide films as a function of anodizing time was discussed. Meanwhile, potentiodynamic electrochemical tests and dry sliding wear tests were performed to evaluate the corrosion resistance and tribological properties of oxide films. It was found that the oxide film fabricated with the existence of sodium hypochlorite had improved corrosion resistance and tribological properties than the one formed without sodium hypochlorite. Moreover, the effect mechanism of sodium hypochlorite on the growth rate and surface morphologies of oxide films during the anodizing process was discussed. It was found that hypochlorite ions participated in the reaction on anode which causes the rapid growth of oxide films and then affect the whole anodizing process.展开更多
文摘Sodium hypochlorite was used to treat the standard molybdenum concentrates; the oxidization conditions for sodium hypochlorite were investigated, and the electro-oxidation process was performed. The results indicate that in the suitable conditions, such as temperature around 25℃, NaCl concentration 4.0mol/L, mass ratio of ore slurry liquid to solid （mL/mS） 20, electric charge per gram Mo 0.522C, pH value of original slurry 8, anodic current density 700A·m-2 （cell potential 2.72.9V）, the Mo leaching rate and the current efficiency reach 98% and 36%, respectively. In order to overcome some shortages of the electro-oxidation process, such as low current efficiency, low Mo concentration in the leaching solution, ultrasonic was adopted to intensify the leaching process. The results show that the Mo leaching rate exceeds 98%, current efficiency increases from 36% to 50% and the Mo concentration in the leaching solution reaches about 60g/L at low mL/mS of 8 and low electric charge of 0.373C.
基金Project(2018YFC1900300)supported by the National Key R&D Program of ChinaProject(51825403)supported by the National Science Fund for Distinguished Young Scholars,ChinaProject(2018SK2026)supported by the Key R&D Program of Hunan Province,China。
文摘MXene materials have got great attention from researchers of environmental treatment for the great electrochemical performance.Monolayer-Ti_(3)C_(2)T_(x)(T_(x) is the surface terminal groups such as-O,-OH and/or-F species),as a typical structural MXene,always shows better chemical-physical characteristics than multilayer-Ti_(3)C_(2)T_(x).Thus,we prepared monolayer-Ti_(3)C_(2)T_(x) electrode by HF etching method and absolute ethyl alcohol intercalationdelamination treatment for capacitive deionization(CDI).The prepared monolay-Ti_(3)C_(2)T_(x) shows a higher specific surface area(235.6 m^(2)/g)and a thinner thickness(0.8 nm).Moreover,a series of systematic investigation demonstrated that monolayer-Ti_(3)C_(2)T_(x) has obvious promotional phenomenon on electrochemical properties(e.g.,mass specific capacitance increased from 52.1 F/g to 144.7 F/g).The NaCl adsorption capacity of monolayer-Ti_(3)C_(2)T_(x),is 30.7 mg/g in 1000 mg/L NaCl solution at 1.2 V.We concluded that the electro-sorption mechanism could be expressed as double electric layer and monolayer coverage by a good fitting of Langmuir isotherms and the pseudo-second-order kinetics equation.This work would provide a new strategy for the application of monolayer-Ti_(3)C_(2)T_(x) material in wastewater treatment in the future.
基金Project(2007BAB22B01) supported by the 11th Five-Year Plan of National Science and Technology of China Project(50704036) supported by the National Natural Science Foundation of China
文摘The dissolution of molybdenite concentrate in NaC1 electrolyte was investigated. The results show that the dissolution rate increases with the increase in liquid-to-solid ratio, stirring speed, NaCl concentration and temperature. When the liquid-to-solid ratio is 30：1, stirring speed is 400 r/min, concentration of NaCI is 4 mol/L at pH=9 and room temperature, the leaching efficiency of molybdenite concentrate will reach 99.5% in 240 min. Molybdenite concentrate cannot be electro-oxidized directly on the anode. The kinetic studies show that the dissolution of molybdenite concentrate is represented by shrinking core model with diffusion through a porous product layer of element sulfur, and the apparent activation energy for the dissolution reaction is 8.56 kJ/mol.
文摘Corrosion test data were measured using non-destructive electrochemical techniques and analysed for studying inhibition effectiveness by different concentrations of NazCr207 on the corrosion of concrete steel-rehar in NaC1 and in H2SO4 media. For these, specifications of ASTM G16-95 R04 were combined with the normal and the Gumbel probability density functions as model analytical methods for addressing issues of conflicting reports of inhibitor effectiveness that had generated concerns. Results show that reinforced concrete samples admixed with concentrations having 4 g （0.012 7 tool）, 8 g （0.025 4 mol） and 6 g （0.019 l tool） NaaCr207 exhibited, in that order, high inhibition effectiveness, with respective efficiency, r/, of （90.46±1.30）%, （88.41＋2.24）% and （84.87±4.74）%, in the NaC1 medium. These exhibit good agreements within replicates and statistical methods for the samples. Also, optimal inhibition effectiveness model in the H2SO4 medium was exhibited by 8 g （0.025 4 mol） Na2Cr207 concentration having r/=（78.44±1.10）%. These bear implications for addressing conflicting test data in the study of effective inhibitors for mitigating steel-rebar corrosion in aggressive environments.
基金Projects(51904097,51804103)supported by the National Natural Science Foundation of ChinaProject(2019GGJS056)supported by the Training Program for Young Backbone Teachers in Colleges and Universities of Henan Province,China+2 种基金Project(HB201905)supported by Open Foundation of State Environmental Protection Key Laboratory of Mineral Metallurgical Resources Utilization and Pollution Control,ChinaProject(202102310548)supported by Scientific and Technological Project of Henan Province,ChinaProject(21IRTSTHN006)supported by Program for Innovative Research Team in the University of Henan Province,China。
文摘D2EHPA(P204),tri-butyl-phosphate(TBP)and sodium chloride(NaCl)were attractive for selective extraction of scandium from acid leaching solution of red mud.The extraction parameters of P204 concentration(X_(P204)),NaCl concentration(C_(NaCl)),pH value,reaction time,stirring speed and O/A were investigated to extract scandium and separate iron from the acid leaching solution.The extraction mechanism was analyzed by Fourier transform infrared spectroscopy(FT-IR)and thermodynamic theory.The single-stage extraction efficiency of scandium,iron andβ(Sc/Fe)were 99.1%,9.4%and 1061.2,respectively,with C_(NaCl) of 75 g/L and XP204 of 0.75 at solution pH value of 1.2 and stirring speed of 200 r/min for 6 min,in which a good separation effect of scandium and iron was obtained.The vibration absorption peak Sc─O was contributed to the extraction of scandium with P204.The complex[FeCln]^(3−n) existed in the solution with adding NaCl into the acid leaching solution.The value of n was higher and the valence state of the complex[FeCln]^(3−n) was lower with an increase of chloride concentration,which restricts the extraction efficiency of iron with P204.The extraction of three stages in the counter-current simulation experiments was carried out according to the McCabe-Thiele diagram.Gibbs free energy change(ΔG)of−5.93 kJ/mol,enthalpy change(ΔH)of 23.45 kJ/mol and entropy change(ΔH)of 98.54 J/(mol·K)were obtained in the solvent extraction proces,which indicate that the extraction reaction is easily spontaneous and endothermic and a proper increase of temperature is conducive to the extraction of scandium.
基金Project(LY13E080021) supported by the Natural Science Foundation of Zhejiang Province,ChinaProject(2011A610072) supported by the Ningbo Municipal Natural Science Foundation,ChinaProject(XKL14D2063) supported by Subject Program of Ningbo University,China
文摘To investigate the mechanical properties of cement mortar in sodium sulfate and sodium chloride solutions, uniaxial compression test and ultrasonic test were performed. Test results show that the relative dynamic elastic modulus, the mass variation,and the compressive strength of cement mortar increase first, and then decrease with increasing erosion time in sodium sulfate and sodium chloride solutions. The relative dynamic elastic moduli and the compressive strengths of cement mortars with water/cement ratios of 0.55 and 0.65 in sodium sulfate solution are lower than those in sodium chloride solution with the same concentration at the420 th day of immersion. The compressive strength of cement mortar with water/cement ratio of 0.65 is more sensitive to strain rate than that with water/cement ratio of 0.55. In addition, the strain-rate sensitivity of compressive strength of cement mortar will increase under attacks of sodium sulfate or sodium chloride solution.
基金Project(51271012)supported by the National Natural Science Foundation of China
文摘Anodic films were successfully fabricated on Ti6A14V alloy by anodic oxidation method in an environmental friendly electrolyte with and without sodium hypochlorite. The anodic films were characterized by means of the scanning electron microscope （SEM） and energy dispersive spectrometer （EDS）. Results revealed that the addition of sodium hypochlorite leads to the ultrafast growth of oxide films, and results in the significant changes of morphology and thickness. The influence of sodium hypochlorite on formation and crystallization of oxide films as a function of anodizing time was discussed. Meanwhile, potentiodynamic electrochemical tests and dry sliding wear tests were performed to evaluate the corrosion resistance and tribological properties of oxide films. It was found that the oxide film fabricated with the existence of sodium hypochlorite had improved corrosion resistance and tribological properties than the one formed without sodium hypochlorite. Moreover, the effect mechanism of sodium hypochlorite on the growth rate and surface morphologies of oxide films during the anodizing process was discussed. It was found that hypochlorite ions participated in the reaction on anode which causes the rapid growth of oxide films and then affect the whole anodizing process.
