The high oxidation ability of manganese oxides or soils was used to study effects of pH and coatingon Cr(Ⅲ) oxidation. The results indicated that Cr(Ⅲ) oxidation peaked in pH 4.0-6.5. The amount andrate of Cr(Ⅲ) be...The high oxidation ability of manganese oxides or soils was used to study effects of pH and coatingon Cr(Ⅲ) oxidation. The results indicated that Cr(Ⅲ) oxidation peaked in pH 4.0-6.5. The amount andrate of Cr(Ⅲ) being oxidized by uncoated δ-MnO2 were larger than those by Fe oxide- or CaCO3-coatedone. Inorganic Cr(Ⅲ) was more easi1y oxidized by MnO2 than organic complex Cr(Ⅲ) due to differentsurface affinities. Precipitated Cr(Ⅲ) and adsorbed Cr(Ⅲ) might be transferred onto MnO2 surface andthen oxidized to Cr(VI).展开更多
Kinetics parameters of iron oxide reduction by hydrogen were evaluated by the isothermal method in a differential micro-packed bed. Influence of external diffusion, internal diffusion and heat transfer on the intrinsi...Kinetics parameters of iron oxide reduction by hydrogen were evaluated by the isothermal method in a differential micro-packed bed. Influence of external diffusion, internal diffusion and heat transfer on the intrinsic reaction rate was investigated and the conditions free of internal and external diffusion resistance have been determined. In the experiments, in order to correctly evaluate the intrinsic kinetics parameters for reducing Fe203 to Fe3O4, the reaction temperatures were set between 440 ℃ and 490 ℃. However, in order to distinguish the reduction of Fe304 to FeO from that of FeO to Fe, the reaction temperature in the experiment was set to be greater than 570 ℃. Intrinsic kinetics of iron oxide reduction by hydrogen was established and the newly established kinetic models were validated by the experimental data.展开更多
The amounts of chloride ions diffused in four soils of different textures at the same water content under different temperature and at varied time were measured by the diffusion cell method using 36Cl-labelled CaCl2 s...The amounts of chloride ions diffused in four soils of different textures at the same water content under different temperature and at varied time were measured by the diffusion cell method using 36Cl-labelled CaCl2 solution. Five kinetic models were used to fit the dynamic process of the diffusion of chloride ions in the soils. It was found that Elovich equation or power function equation was the best model to describe the process. The pseudothermodynamic parameters, i. e. the net reaction energyl the activation entropy,activation enthalpy and activation free energy of the diffusion, were derived from the absolute reaction-rate theory. The results showed that these parameters decreased in the order of loessal soil > black in soil >lou soil > yellow cinnamon soil, which indicated that the force and the heat-energy barrier to be overcome for diffusion decreased, the diffusion rate increased and the disorder of the soil-solution-ion system due to diffusion decreased successively with the texture becoming heavier in the four soils.展开更多
A mathematical model has been developed to describe the dynamic behaviours of NO+CO reaction on supported Pt MO catalyst. The ignited state kinetics can be fit quantitatively using directly a Langmuir Henshelwood bimo...A mathematical model has been developed to describe the dynamic behaviours of NO+CO reaction on supported Pt MO catalyst. The ignited state kinetics can be fit quantitatively using directly a Langmuir Henshelwood bimolecular rate expression with a heat of adsorption of NO of 32 4 kJ/mol and of CO of 106 7 kJ/mol, respectively.展开更多
Anodic oxidation with different electrolyte was employed to improve the electrochemical properties of carbon paper as negative electrode for vanadium redox battery(VRB).The treated carbon paper exhibits enhanced elect...Anodic oxidation with different electrolyte was employed to improve the electrochemical properties of carbon paper as negative electrode for vanadium redox battery(VRB).The treated carbon paper exhibits enhanced electrochemical activity for V^2+/V^3+redox reaction.The sample(CP-NH3)treated in NH3 solution demonstrates superior performance in comparison with the sample(CP-NaOH)treated in NaOH solution.X-ray photoelectron spectroscopy results show that oxygen-and nitrogen-containing functional groups have been introduced on CP-NH3 surface by the treatment,and Raman spectra confirm the increased surface defect of CP-NH3.Energy storage performance of cell was evaluated by charge/discharge measurement by using CP-NH3.Usage of CP-NH3 can greatly improve the cell performance with energy efficiency increase of 4.8%at 60 mA/cm^2.The excellent performance of CP-NH3 mainly results from introduction of functional groups as active sites and improved wetting properties.This work reveals that anodic oxidation is a clean,simple,and efficient method for boosting the performance of carbon paper as negative electrode for VRB.展开更多
Lactose milk sugar is found only in the milk of mammals. In order to understand the mechanism of oxidation of lactose, a systematic kinetic study of oxidation of lactose with photochemicaUy generated radicals was carr...Lactose milk sugar is found only in the milk of mammals. In order to understand the mechanism of oxidation of lactose, a systematic kinetic study of oxidation of lactose with photochemicaUy generated radicals was carried out. The reaction has a first order dependence on chloramine-T as well as on substrate. The reaction is catalysed by H＋ ions as well. On the basis of kinetic results and product analysis a probable mechanism were suggested.展开更多
The photochemical reaction of sulfur dioxide （802） with tetraphenylporphyrin magnesium （MgTPP） has been investigated in dichloromethane （CH2C12） solution at room temperature with illumination by visible light. C...The photochemical reaction of sulfur dioxide （802） with tetraphenylporphyrin magnesium （MgTPP） has been investigated in dichloromethane （CH2C12） solution at room temperature with illumination by visible light. Conventional fluorescence, UV-vis, and MS spectral analyses showed that under these conditions, SO2 was initially photochemically fixed by MgTPP to form a 1：1 molecular adduct. On continued irradiation and maintaining the flow of SO2, MS and XRD results showed that MgTPP is re- markably effective in the photochemical reduction of SO2 to sulfide （S2 ）. The kinetics of the photochemical reaction of MgTPP with SO2 was studied in a SO2-saturated solution. Under irradiation, the reaction follows pseudo first order kinetics for MgTPP, having a half-life decreasing from 106 to 57 min as the illumination intensity is increased from 350 to 600 Lm. This investigation of the photochemical fixation and reduction of SO2 by MgTPP is of key interest in elucidating fundamental pho- tochemical reaction mechanisms associated with porphyrins in the presence of SO2; furthermore, the analysis of the photo- chemical reaction may offer new opportunities for the fixation and reduction of SO2 to less harmful species.展开更多
文摘The high oxidation ability of manganese oxides or soils was used to study effects of pH and coatingon Cr(Ⅲ) oxidation. The results indicated that Cr(Ⅲ) oxidation peaked in pH 4.0-6.5. The amount andrate of Cr(Ⅲ) being oxidized by uncoated δ-MnO2 were larger than those by Fe oxide- or CaCO3-coatedone. Inorganic Cr(Ⅲ) was more easi1y oxidized by MnO2 than organic complex Cr(Ⅲ) due to differentsurface affinities. Precipitated Cr(Ⅲ) and adsorbed Cr(Ⅲ) might be transferred onto MnO2 surface andthen oxidized to Cr(VI).
基金Supported by the National Natural Science Foundation of China (20736004)the State Key Development Program for Basic Research of China (2007CB613502)
文摘Kinetics parameters of iron oxide reduction by hydrogen were evaluated by the isothermal method in a differential micro-packed bed. Influence of external diffusion, internal diffusion and heat transfer on the intrinsic reaction rate was investigated and the conditions free of internal and external diffusion resistance have been determined. In the experiments, in order to correctly evaluate the intrinsic kinetics parameters for reducing Fe203 to Fe3O4, the reaction temperatures were set between 440 ℃ and 490 ℃. However, in order to distinguish the reduction of Fe304 to FeO from that of FeO to Fe, the reaction temperature in the experiment was set to be greater than 570 ℃. Intrinsic kinetics of iron oxide reduction by hydrogen was established and the newly established kinetic models were validated by the experimental data.
文摘The amounts of chloride ions diffused in four soils of different textures at the same water content under different temperature and at varied time were measured by the diffusion cell method using 36Cl-labelled CaCl2 solution. Five kinetic models were used to fit the dynamic process of the diffusion of chloride ions in the soils. It was found that Elovich equation or power function equation was the best model to describe the process. The pseudothermodynamic parameters, i. e. the net reaction energyl the activation entropy,activation enthalpy and activation free energy of the diffusion, were derived from the absolute reaction-rate theory. The results showed that these parameters decreased in the order of loessal soil > black in soil >lou soil > yellow cinnamon soil, which indicated that the force and the heat-energy barrier to be overcome for diffusion decreased, the diffusion rate increased and the disorder of the soil-solution-ion system due to diffusion decreased successively with the texture becoming heavier in the four soils.
文摘A mathematical model has been developed to describe the dynamic behaviours of NO+CO reaction on supported Pt MO catalyst. The ignited state kinetics can be fit quantitatively using directly a Langmuir Henshelwood bimolecular rate expression with a heat of adsorption of NO of 32 4 kJ/mol and of CO of 106 7 kJ/mol, respectively.
基金Project(NCET-10-0946)supported by Program for New Century Excellent Talents in University of ChinaProject(2017JY0038)supported by Science and Technology Key Project of Sichuan Province,ChinaProject(2013TX8)supported by Titanium and Titanium Alloy Innovation Team of Panzhihua City,China
文摘Anodic oxidation with different electrolyte was employed to improve the electrochemical properties of carbon paper as negative electrode for vanadium redox battery(VRB).The treated carbon paper exhibits enhanced electrochemical activity for V^2+/V^3+redox reaction.The sample(CP-NH3)treated in NH3 solution demonstrates superior performance in comparison with the sample(CP-NaOH)treated in NaOH solution.X-ray photoelectron spectroscopy results show that oxygen-and nitrogen-containing functional groups have been introduced on CP-NH3 surface by the treatment,and Raman spectra confirm the increased surface defect of CP-NH3.Energy storage performance of cell was evaluated by charge/discharge measurement by using CP-NH3.Usage of CP-NH3 can greatly improve the cell performance with energy efficiency increase of 4.8%at 60 mA/cm^2.The excellent performance of CP-NH3 mainly results from introduction of functional groups as active sites and improved wetting properties.This work reveals that anodic oxidation is a clean,simple,and efficient method for boosting the performance of carbon paper as negative electrode for VRB.
文摘Lactose milk sugar is found only in the milk of mammals. In order to understand the mechanism of oxidation of lactose, a systematic kinetic study of oxidation of lactose with photochemicaUy generated radicals was carried out. The reaction has a first order dependence on chloramine-T as well as on substrate. The reaction is catalysed by H＋ ions as well. On the basis of kinetic results and product analysis a probable mechanism were suggested.
基金supported by the Foundation of Inner Mongolia Autonomous Region’s Educational Commission(NJZZ11068)the School Scientific Research Fund (ZD201004,Inner Mongolia University of Technology,China)Yongfeng Boyuan Industry Co.,Ltd. (Jiangxi Province,China)
文摘The photochemical reaction of sulfur dioxide （802） with tetraphenylporphyrin magnesium （MgTPP） has been investigated in dichloromethane （CH2C12） solution at room temperature with illumination by visible light. Conventional fluorescence, UV-vis, and MS spectral analyses showed that under these conditions, SO2 was initially photochemically fixed by MgTPP to form a 1：1 molecular adduct. On continued irradiation and maintaining the flow of SO2, MS and XRD results showed that MgTPP is re- markably effective in the photochemical reduction of SO2 to sulfide （S2 ）. The kinetics of the photochemical reaction of MgTPP with SO2 was studied in a SO2-saturated solution. Under irradiation, the reaction follows pseudo first order kinetics for MgTPP, having a half-life decreasing from 106 to 57 min as the illumination intensity is increased from 350 to 600 Lm. This investigation of the photochemical fixation and reduction of SO2 by MgTPP is of key interest in elucidating fundamental pho- tochemical reaction mechanisms associated with porphyrins in the presence of SO2; furthermore, the analysis of the photo- chemical reaction may offer new opportunities for the fixation and reduction of SO2 to less harmful species.
