The Experts below are selected from a list of 360 Experts worldwide ranked by ideXlab platform
Xihai Deng - One of the best experts on this subject based on the ideXlab platform.
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effects of redox potential and pH Value on the release of rare earth elements from soil
Chemosphere, 2001Co-Authors: Ying Chen, Xiaorong Wang, Xihai DengAbstract:Abstract Equilibrium release experiments were conducted under three different pH Values of 3.5, 5.5 and 7.5 as well as three redox potentials of 400, 0 and −100 Mv to investigate the influence of redox potential and pH Value on the La, Ce, Gd and Y release of from the simulated-REEs-accumulation (SRA) soil. Oxygen and nitrogen were allowed to flow into soil suspension to adjust redox potential to a preset Value, and 1 mol/l HCl or 1mol/l NaOH solutions were added into the soil suspension to keep pH at a preset Value. Results indicated that La, Ce, Gd and Y release increased gradually with the decrease of pH Value or Eh, and the influence of redox potential on Ce was more remarkable than on La, Gd and Y. At the same time. It was observed that La, Ce, Gd and Y releases were positively correlated with the release of Fe and Mn, indicating that La, Ce, Gd and Y releases might originate from dissolution of Fe–Mn oxyhydroxides under reduction and low pH conditions. Moreover, it was found that alteration of pH Value and redox potential might affect the change of La, Ce, Gd and Y species in the soil. The contents of La, Ce, Gd and Y in exchangeable fraction and Fe–Mn oxide fraction in the solid pHase from soil suspension separation decreased with the decline of pH Value and redox potential. Multiple stepwise regression analysis showed that exchangeable fraction and Fe–Mn oxide fraction predominately contributed to the La, Ce, Gd and Y release. Low pH Value and redox potential were more favorable to La, Ce, Gd and Y releases following the change of their species. The La, Ce, Gd and Y contents in exchangeable fraction and Fe–Mn oxide fraction are the main contributors to their release.
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effects of redox potential and pH Value on the release of rare earth elements from soil
Chemosphere, 2001Co-Authors: Ying Chen, Xiaorong Wang, Xihai DengAbstract:Abstract Equilibrium release experiments were conducted under three different pH Values of 3.5, 5.5 and 7.5 as well as three redox potentials of 400, 0 and −100 Mv to investigate the influence of redox potential and pH Value on the La, Ce, Gd and Y release of from the simulated-REEs-accumulation (SRA) soil. Oxygen and nitrogen were allowed to flow into soil suspension to adjust redox potential to a preset Value, and 1 mol/l HCl or 1mol/l NaOH solutions were added into the soil suspension to keep pH at a preset Value. Results indicated that La, Ce, Gd and Y release increased gradually with the decrease of pH Value or Eh, and the influence of redox potential on Ce was more remarkable than on La, Gd and Y. At the same time. It was observed that La, Ce, Gd and Y releases were positively correlated with the release of Fe and Mn, indicating that La, Ce, Gd and Y releases might originate from dissolution of Fe–Mn oxyhydroxides under reduction and low pH conditions. Moreover, it was found that alteration of pH Value and redox potential might affect the change of La, Ce, Gd and Y species in the soil. The contents of La, Ce, Gd and Y in exchangeable fraction and Fe–Mn oxide fraction in the solid pHase from soil suspension separation decreased with the decline of pH Value and redox potential. Multiple stepwise regression analysis showed that exchangeable fraction and Fe–Mn oxide fraction predominately contributed to the La, Ce, Gd and Y release. Low pH Value and redox potential were more favorable to La, Ce, Gd and Y releases following the change of their species. The La, Ce, Gd and Y contents in exchangeable fraction and Fe–Mn oxide fraction are the main contributors to their release.
A Gebert - One of the best experts on this subject based on the ideXlab platform.
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the effect of a magnetic field on the pH Value in front of the electrode surface during the electrodeposition of co fe and cofe alloys
Journal of Electroanalytical Chemistry, 2008Co-Authors: Jakub Adam Koza, M Uhlemann, A Gebert, L SchultzAbstract:Abstract The effect of an uniform magnetic field applied parallel to the electrode surface, with flux density up to 1 T on the pH Value close to the electrode surface during the electrodeposition of Co, Fe, CoFe alloys as well as for the pure hydrogen evolution reaction (HER) has been investigated. Voltammetric and chronoamperometric experiments have been carried out with the in situ pH measurements at the electrode surface. Results show that the limiting current for all the investigated systems is increased due to the magnetohydrodynamic (MHD) effect. The hydroxides formation in the metal containing electrolytes buffers the cathodic layer and the interfacial pH Value increases to a lesser extent compared to the case of HER electrolyte. The increase of the pH Value at the electrode surface is lower in the applied magnetic field compared to the case without a magnetic field. It was found that the interfacial pH Value is a power function of the magnetic flux density. This effect is attributed to enhanced convection induced by the Lorentz force. The depletion of H + concentration at the electrode surface is compensated by the MHD effect and the hydroxide formation is suppressed, moreover the hydroxyl products are removed faster from the electrode surface in the magnetic field resulting in better quality of the deposited layers. The pH Value close to the electrode surface during CoFe alloys deposition is high enough for the precipitation of the iron hydroxide, what satisfies the model proposed by Dahms and Croll.
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effect of a magnetic field on the local pH Value in front of the electrode surface during electrodeposition of co
Journal of Electroanalytical Chemistry, 2005Co-Authors: M Uhlemann, A Krause, A GebertAbstract:Abstract The change of the pH Value, the hydrogen evolution reaction, and their effect on the electrodeposition of Co were investigated directly at the surface of a gold mesh with and without superimposition of a magnetic field of 1 T by cyclic voltammetry and chronoamperometry in 0.1 M Na 2 SO 4 with and without addition of 0.01 CoSO 4 . The reduction of hydrogen ions is increased by superimposition of a magnetic field oriented parallel to the electrode surface. The increase of the pH Value directly at the surface is lower in an applied magnetic field compared to the case without a magnetic field. This is likely to be due to the enhanced convection generated by the Lorentz force. The discharged hydrogen ions are rapidly compensated. The effect of a magnetic field on the limited current density as well as on the change of pH Value is more significant at lower initial pH Value. For initial pH Values of 3 and 3.5 the deposition of Co under a superimposed magnetic field is improved and the increase of the pH Value is low in front of the electrode. This leads to a suppression of the spontaneous formation of hydroxides.
Ying Chen - One of the best experts on this subject based on the ideXlab platform.
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effects of redox potential and pH Value on the release of rare earth elements from soil
Chemosphere, 2001Co-Authors: Ying Chen, Xiaorong Wang, Xihai DengAbstract:Abstract Equilibrium release experiments were conducted under three different pH Values of 3.5, 5.5 and 7.5 as well as three redox potentials of 400, 0 and −100 Mv to investigate the influence of redox potential and pH Value on the La, Ce, Gd and Y release of from the simulated-REEs-accumulation (SRA) soil. Oxygen and nitrogen were allowed to flow into soil suspension to adjust redox potential to a preset Value, and 1 mol/l HCl or 1mol/l NaOH solutions were added into the soil suspension to keep pH at a preset Value. Results indicated that La, Ce, Gd and Y release increased gradually with the decrease of pH Value or Eh, and the influence of redox potential on Ce was more remarkable than on La, Gd and Y. At the same time. It was observed that La, Ce, Gd and Y releases were positively correlated with the release of Fe and Mn, indicating that La, Ce, Gd and Y releases might originate from dissolution of Fe–Mn oxyhydroxides under reduction and low pH conditions. Moreover, it was found that alteration of pH Value and redox potential might affect the change of La, Ce, Gd and Y species in the soil. The contents of La, Ce, Gd and Y in exchangeable fraction and Fe–Mn oxide fraction in the solid pHase from soil suspension separation decreased with the decline of pH Value and redox potential. Multiple stepwise regression analysis showed that exchangeable fraction and Fe–Mn oxide fraction predominately contributed to the La, Ce, Gd and Y release. Low pH Value and redox potential were more favorable to La, Ce, Gd and Y releases following the change of their species. The La, Ce, Gd and Y contents in exchangeable fraction and Fe–Mn oxide fraction are the main contributors to their release.
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effects of redox potential and pH Value on the release of rare earth elements from soil
Chemosphere, 2001Co-Authors: Ying Chen, Xiaorong Wang, Xihai DengAbstract:Abstract Equilibrium release experiments were conducted under three different pH Values of 3.5, 5.5 and 7.5 as well as three redox potentials of 400, 0 and −100 Mv to investigate the influence of redox potential and pH Value on the La, Ce, Gd and Y release of from the simulated-REEs-accumulation (SRA) soil. Oxygen and nitrogen were allowed to flow into soil suspension to adjust redox potential to a preset Value, and 1 mol/l HCl or 1mol/l NaOH solutions were added into the soil suspension to keep pH at a preset Value. Results indicated that La, Ce, Gd and Y release increased gradually with the decrease of pH Value or Eh, and the influence of redox potential on Ce was more remarkable than on La, Gd and Y. At the same time. It was observed that La, Ce, Gd and Y releases were positively correlated with the release of Fe and Mn, indicating that La, Ce, Gd and Y releases might originate from dissolution of Fe–Mn oxyhydroxides under reduction and low pH conditions. Moreover, it was found that alteration of pH Value and redox potential might affect the change of La, Ce, Gd and Y species in the soil. The contents of La, Ce, Gd and Y in exchangeable fraction and Fe–Mn oxide fraction in the solid pHase from soil suspension separation decreased with the decline of pH Value and redox potential. Multiple stepwise regression analysis showed that exchangeable fraction and Fe–Mn oxide fraction predominately contributed to the La, Ce, Gd and Y release. Low pH Value and redox potential were more favorable to La, Ce, Gd and Y releases following the change of their species. The La, Ce, Gd and Y contents in exchangeable fraction and Fe–Mn oxide fraction are the main contributors to their release.
Zhang Chunyan - One of the best experts on this subject based on the ideXlab platform.
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ratio of total acidity to pH Value of coating bath a new strategy towards pHospHate conversion coatings with optimized corrosion resistance for magnesium alloys
Corrosion Science, 2019Co-Authors: Zhang Chunyan, Liao Shangju, Yu Baoxing, Lu Xiaopeng, Chen Xiaobo, Wang FuhuiAbstract:Abstract In this work, with the aid of thermodynamic equilibrium calculations, a crucial contributor, i.e. total acidity/pH Value (TA/pH), was proposed for the first time to guide the design of the chemical formulation of metal-pHospHate-based conversion coatings having excellent corrosion resistance for Mg alloys. The present study and published works were compared to validate the proposed theory and correlation between the TA/pH and corrosion resistance of the resulting coatings. A significant contribution of this work was the elucidation of the kinetic role of the buffering nature of chemical bath in regulating the formation of corrosion resistant pHospHate conversion coatings.
M Uhlemann - One of the best experts on this subject based on the ideXlab platform.
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the effect of a magnetic field on the pH Value in front of the electrode surface during the electrodeposition of co fe and cofe alloys
Journal of Electroanalytical Chemistry, 2008Co-Authors: Jakub Adam Koza, M Uhlemann, A Gebert, L SchultzAbstract:Abstract The effect of an uniform magnetic field applied parallel to the electrode surface, with flux density up to 1 T on the pH Value close to the electrode surface during the electrodeposition of Co, Fe, CoFe alloys as well as for the pure hydrogen evolution reaction (HER) has been investigated. Voltammetric and chronoamperometric experiments have been carried out with the in situ pH measurements at the electrode surface. Results show that the limiting current for all the investigated systems is increased due to the magnetohydrodynamic (MHD) effect. The hydroxides formation in the metal containing electrolytes buffers the cathodic layer and the interfacial pH Value increases to a lesser extent compared to the case of HER electrolyte. The increase of the pH Value at the electrode surface is lower in the applied magnetic field compared to the case without a magnetic field. It was found that the interfacial pH Value is a power function of the magnetic flux density. This effect is attributed to enhanced convection induced by the Lorentz force. The depletion of H + concentration at the electrode surface is compensated by the MHD effect and the hydroxide formation is suppressed, moreover the hydroxyl products are removed faster from the electrode surface in the magnetic field resulting in better quality of the deposited layers. The pH Value close to the electrode surface during CoFe alloys deposition is high enough for the precipitation of the iron hydroxide, what satisfies the model proposed by Dahms and Croll.
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effect of a magnetic field on the local pH Value in front of the electrode surface during electrodeposition of co
Journal of Electroanalytical Chemistry, 2005Co-Authors: M Uhlemann, A Krause, A GebertAbstract:Abstract The change of the pH Value, the hydrogen evolution reaction, and their effect on the electrodeposition of Co were investigated directly at the surface of a gold mesh with and without superimposition of a magnetic field of 1 T by cyclic voltammetry and chronoamperometry in 0.1 M Na 2 SO 4 with and without addition of 0.01 CoSO 4 . The reduction of hydrogen ions is increased by superimposition of a magnetic field oriented parallel to the electrode surface. The increase of the pH Value directly at the surface is lower in an applied magnetic field compared to the case without a magnetic field. This is likely to be due to the enhanced convection generated by the Lorentz force. The discharged hydrogen ions are rapidly compensated. The effect of a magnetic field on the limited current density as well as on the change of pH Value is more significant at lower initial pH Value. For initial pH Values of 3 and 3.5 the deposition of Co under a superimposed magnetic field is improved and the increase of the pH Value is low in front of the electrode. This leads to a suppression of the spontaneous formation of hydroxides.
