The utility of nickel/iron in the remediation of atrazine-contaminated water was investigated. The experimental results showed that nickel/iron had effective catalytic activity in dechlorinating atrazine under acidic ...The utility of nickel/iron in the remediation of atrazine-contaminated water was investigated. The experimental results showed that nickel/iron had effective catalytic activity in dechlorinating atrazine under acidic conditions. The dechlorination reaction approximately followed the first-order kinetics under the experimental conditions(nickel/iron:1.0 g/250 ml;C atrazine=20.0 mg/L), the reaction rate increased with decreasing pH value of the reaction solution and increasing the proportion of Ni:Fe within 2.95%. For condition with 2.95% nickel/iron, the reaction rate constants were 0.07518(R=0.9927), 0.06212(R=0.9846) and 0.00131 min -1(R=0.9565) at pH=2.0, 3.0 and 4.0, respectively. HPLC analysis was used to monitor the decline of atrazine concentration.展开更多
The kinetics of oxygen pressure acid leaching marmatite with high indium content was studied. The effects of particle size, agitation rate, temperature, HSOconcentration, and oxygen partial pressure on leaching rate o...The kinetics of oxygen pressure acid leaching marmatite with high indium content was studied. The effects of particle size, agitation rate, temperature, HSOconcentration, and oxygen partial pressure on leaching rate of indium were investigated. The results show that when the agitation rate is above 600 r-min, its influence on indium leaching rate is insignificant. It is determined that the leaching rates increase with the increase in sulfuric acid concentration, temperature, partial oxygen pressure, and the decrease in particle size. Moreover, the results demonstrate that the process of indium leaching is controlled by interface chemical reaction, with apparent activation energy of 65.7 k J-mol. The apparent reaction orders of sulfuric acid and oxygen partial pressure are determined to be 0.749 and 1.260, respectively. The leaching reaction process follows shrinking unreacted core model. And finally, the kinetics model equation is established for indium.展开更多
Carbonate minerals and water （or geofluids） reactions are important for modeling of geochemical processes and have received considerable attention over the past decades. The calcite dissolution rates from 50℃ to 25...Carbonate minerals and water （or geofluids） reactions are important for modeling of geochemical processes and have received considerable attention over the past decades. The calcite dissolution rates from 50℃ to 250℃ at 10 MPa in deionized water with a flow rate varying from 0.2 to 5 mL/min were experimentally measured in a continuous flow column pressure vessel reactor. The dissolution began near the equilibrium with c/ceq 〉 0.3 and finally reached the equilibrium at 100℃-250℃, so the corresponding solubility was also determined as 1.87, 2.02, 2.02 and 1.88×10^-4.mol/L at 100℃, 150℃, 200℃ and 250℃ respectively, which was first increasing and then switching to decreasing with temperature and the maximum value might occur between 150℃ and 200℃. The experimental dissolution rate not only increased with temperature, but also had a rapid increase between 150℃ and 200℃ at a constant flow rate of 4 mL/min. The measured dissolution rates can be described using rate equations of R = k（1-c/ceq）n or R = kc-n. In these equations the reaction order n changed with temperature, which indicates that n was a variable rather than a constant, and the activation energy was 13.4 kJ/mol calculated with R = k（1-c/ceq）n or 18.0 kJ/mol with R = kc^-n, which is a little lower than the surface controlled values. The varied reaction order and lower activation energy indicates that calcite dissolution in this study is a complex interplay of diffusion controlled and surface controlled processes.展开更多
The calcite dissolution rates at 50-250 ℃ and 20 MPa in deionized water with flow rate varying from 0.2 to 5 mL/min were experimentally measured in a continuous flow column pressure vessel reactor. Equilibrium concen...The calcite dissolution rates at 50-250 ℃ and 20 MPa in deionized water with flow rate varying from 0.2 to 5 mL/min were experimentally measured in a continuous flow column pressure vessel reactor. Equilibrium concentration （Ceq） of calcite dissolution in deionized water at 20 MPa was determined using dissolution data according to the iterative method presented by Jeschke and Dreybrodt. The equilibrium concentrations at 50, 100, 150, 200 and 250 ℃ are 1.84×10^-4, 2.23×10^-4, 2.25×10^-4, 2.31×10^-4 and 2.24×10^-4 mol/L, respectively. The Ceq increases first and then decreases with temperature varying from 50 to 250 ℃ at 20 MPa, and the same variation trend occurs at 10 MPa with lower values. The maximum value （or extremum） of Ceq would increase with temperature at constant pressures. The dissolution reaction of calcite in this experiment is approaching the calcite equilibrium, and the reaction order doesn＇t keep a constant at different temperatures, which could imply that a change of the reac- tion mechanism was occurring. The Arrhenius equation shouldn＇t be used to calculate apparent activation energy using rate constant data at different temperatures when the reaction order or reaction mechanism changed.展开更多
The prepolymerization and curing reaction kinetics of polyurethane/montmorillonite have been studied with end group analysis and FTIR respectively. It was found that the prepolymerization and curing reaction followed ...The prepolymerization and curing reaction kinetics of polyurethane/montmorillonite have been studied with end group analysis and FTIR respectively. It was found that the prepolymerization and curing reaction followed the 2nd-order kinetics. But the activation energy of prepolymerization increased from 42.7 kJ/mol to 56.5 kJ/rnol after the montmorillonite was added in the reaction system, and activation energy of curing reaction decreased from 64.4 kJ/mol to 17.5 kJ/mol. 2007 Bing Liao. Published by Elsevier B.V. on behalf of Chinese Chemical Society. All rights reserved.展开更多
This study examines the behavior of a micropolar nanofluidflowing over a sheet in the presence of a transverse magneticfield and thermal effects.In addition,chemical(first-order homogeneous)reactions are taken into accoun...This study examines the behavior of a micropolar nanofluidflowing over a sheet in the presence of a transverse magneticfield and thermal effects.In addition,chemical(first-order homogeneous)reactions are taken into account.A similarity transformation is used to reduce the system of governing coupled non-linear partial differ-ential equations(PDEs),which account for the transport of mass,momentum,angular momentum,energy and species,to a set of non-linear ordinary differential equations(ODEs).The Runge-Kutta method along with shoot-ing method is used to solve them.The impact of several parameters is evaluated.It is shown that the micro-rota-tional velocity of thefluid rises with the micropolar factor.Moreover,the radiation parameter can have a remarkable influence on theflow and temperature profiles and on the angular momentum distribution.展开更多
Photocatalytic conversion of biomass is considered an effective,clean,and environmentally friendly route to obtain high-valued chemicals and hydrogen.However,the limited conversion efficiency and poor selectivity are ...Photocatalytic conversion of biomass is considered an effective,clean,and environmentally friendly route to obtain high-valued chemicals and hydrogen.However,the limited conversion efficiency and poor selectivity are still the main bottlenecks for photocatalytic biomass conversion.Herein,we report the highly selective photocatalytic conversion of glucose solution on holosymmetrically spherical three-dimensionally ordered macroporous TiO_(2)-CdSe heterojunction photonic crystal structure(s-TCS).The obtained s-TCS photocatalysts show excellent stability and strong light harvesting,uniform mass diffusion and exchange,and efficient photogenerated electrons/holes separation and utilization.The optimized s-TCS-4 photocatalyst displays the highest photocatalytic performance for glucose oxidation and hydrogen production.The glucose conversion,lactic acid selectivity,and yield on s-TCS-4 are about 95.9%,94.3%,and 96.4%,respectively.The photocatalytic production of lactic acid for s-TCS-4(18.5 g/L)is 2.3 times higher than the pure spherical TiO_(2) photonic crystal without CdSe(s-TiO_(2),8.1 g/L),and the hydrogen production rate of s-TCS-4 is 9.4 times that of s-TiO_(2).For the first time,we reveal that the photocatalytic conversion of glucose to lactic acid is a third-order and four-electron-involved reaction.This work could shed some new light on the efficient photocatalysis conversion of biomass to highly value-added products with high selectivity and yield,and simultaneously sustainable hydrogen evolution.展开更多
文摘The utility of nickel/iron in the remediation of atrazine-contaminated water was investigated. The experimental results showed that nickel/iron had effective catalytic activity in dechlorinating atrazine under acidic conditions. The dechlorination reaction approximately followed the first-order kinetics under the experimental conditions(nickel/iron:1.0 g/250 ml;C atrazine=20.0 mg/L), the reaction rate increased with decreasing pH value of the reaction solution and increasing the proportion of Ni:Fe within 2.95%. For condition with 2.95% nickel/iron, the reaction rate constants were 0.07518(R=0.9927), 0.06212(R=0.9846) and 0.00131 min -1(R=0.9565) at pH=2.0, 3.0 and 4.0, respectively. HPLC analysis was used to monitor the decline of atrazine concentration.
基金financially supported by the National High-Tech Research and Development Program of China (No. 2012AA062303)the National Natural Science Foundation of China (Nos. U1402271, 51504059 and 51504058)
文摘The kinetics of oxygen pressure acid leaching marmatite with high indium content was studied. The effects of particle size, agitation rate, temperature, HSOconcentration, and oxygen partial pressure on leaching rate of indium were investigated. The results show that when the agitation rate is above 600 r-min, its influence on indium leaching rate is insignificant. It is determined that the leaching rates increase with the increase in sulfuric acid concentration, temperature, partial oxygen pressure, and the decrease in particle size. Moreover, the results demonstrate that the process of indium leaching is controlled by interface chemical reaction, with apparent activation energy of 65.7 k J-mol. The apparent reaction orders of sulfuric acid and oxygen partial pressure are determined to be 0.749 and 1.260, respectively. The leaching reaction process follows shrinking unreacted core model. And finally, the kinetics model equation is established for indium.
文摘Carbonate minerals and water （or geofluids） reactions are important for modeling of geochemical processes and have received considerable attention over the past decades. The calcite dissolution rates from 50℃ to 250℃ at 10 MPa in deionized water with a flow rate varying from 0.2 to 5 mL/min were experimentally measured in a continuous flow column pressure vessel reactor. The dissolution began near the equilibrium with c/ceq 〉 0.3 and finally reached the equilibrium at 100℃-250℃, so the corresponding solubility was also determined as 1.87, 2.02, 2.02 and 1.88×10^-4.mol/L at 100℃, 150℃, 200℃ and 250℃ respectively, which was first increasing and then switching to decreasing with temperature and the maximum value might occur between 150℃ and 200℃. The experimental dissolution rate not only increased with temperature, but also had a rapid increase between 150℃ and 200℃ at a constant flow rate of 4 mL/min. The measured dissolution rates can be described using rate equations of R = k（1-c/ceq）n or R = kc-n. In these equations the reaction order n changed with temperature, which indicates that n was a variable rather than a constant, and the activation energy was 13.4 kJ/mol calculated with R = k（1-c/ceq）n or 18.0 kJ/mol with R = kc^-n, which is a little lower than the surface controlled values. The varied reaction order and lower activation energy indicates that calcite dissolution in this study is a complex interplay of diffusion controlled and surface controlled processes.
基金supported by the National Basic Research Program of China (973 Program) (No. 2009CB421006)the State Key Laboratory of Geological Processes and Mineral Resources (No. GPMR200843)
文摘The calcite dissolution rates at 50-250 ℃ and 20 MPa in deionized water with flow rate varying from 0.2 to 5 mL/min were experimentally measured in a continuous flow column pressure vessel reactor. Equilibrium concentration （Ceq） of calcite dissolution in deionized water at 20 MPa was determined using dissolution data according to the iterative method presented by Jeschke and Dreybrodt. The equilibrium concentrations at 50, 100, 150, 200 and 250 ℃ are 1.84×10^-4, 2.23×10^-4, 2.25×10^-4, 2.31×10^-4 and 2.24×10^-4 mol/L, respectively. The Ceq increases first and then decreases with temperature varying from 50 to 250 ℃ at 20 MPa, and the same variation trend occurs at 10 MPa with lower values. The maximum value （or extremum） of Ceq would increase with temperature at constant pressures. The dissolution reaction of calcite in this experiment is approaching the calcite equilibrium, and the reaction order doesn＇t keep a constant at different temperatures, which could imply that a change of the reac- tion mechanism was occurring. The Arrhenius equation shouldn＇t be used to calculate apparent activation energy using rate constant data at different temperatures when the reaction order or reaction mechanism changed.
文摘The prepolymerization and curing reaction kinetics of polyurethane/montmorillonite have been studied with end group analysis and FTIR respectively. It was found that the prepolymerization and curing reaction followed the 2nd-order kinetics. But the activation energy of prepolymerization increased from 42.7 kJ/mol to 56.5 kJ/rnol after the montmorillonite was added in the reaction system, and activation energy of curing reaction decreased from 64.4 kJ/mol to 17.5 kJ/mol. 2007 Bing Liao. Published by Elsevier B.V. on behalf of Chinese Chemical Society. All rights reserved.
文摘This study examines the behavior of a micropolar nanofluidflowing over a sheet in the presence of a transverse magneticfield and thermal effects.In addition,chemical(first-order homogeneous)reactions are taken into account.A similarity transformation is used to reduce the system of governing coupled non-linear partial differ-ential equations(PDEs),which account for the transport of mass,momentum,angular momentum,energy and species,to a set of non-linear ordinary differential equations(ODEs).The Runge-Kutta method along with shoot-ing method is used to solve them.The impact of several parameters is evaluated.It is shown that the micro-rota-tional velocity of thefluid rises with the micropolar factor.Moreover,the radiation parameter can have a remarkable influence on theflow and temperature profiles and on the angular momentum distribution.
基金supported by the National Key R&D Program of China(grant nos.2016YFA0202602 and 2021YFE0115800)National Natural Science Foundation of China(grant nos.21805220,U20A20122,and 52103285)+3 种基金Program of Introducing Talents of Discipline to Universities-Plan 111 from the Ministry of Science and Technology and the Ministry of Education of China(grant no.B20002)Natural Science Foundation of Hubei Province(grant nos.2020CFB416,2018CFB242,and 2018CFA054)the Fundamental Research Funds for the Central Universities(WUT:grant no.2021III016GX)Youth Innovation Research Fund project and the Open Fund Project of State Key Laboratory of Advanced Technology for Materials Synthesis and Processing。
文摘Photocatalytic conversion of biomass is considered an effective,clean,and environmentally friendly route to obtain high-valued chemicals and hydrogen.However,the limited conversion efficiency and poor selectivity are still the main bottlenecks for photocatalytic biomass conversion.Herein,we report the highly selective photocatalytic conversion of glucose solution on holosymmetrically spherical three-dimensionally ordered macroporous TiO_(2)-CdSe heterojunction photonic crystal structure(s-TCS).The obtained s-TCS photocatalysts show excellent stability and strong light harvesting,uniform mass diffusion and exchange,and efficient photogenerated electrons/holes separation and utilization.The optimized s-TCS-4 photocatalyst displays the highest photocatalytic performance for glucose oxidation and hydrogen production.The glucose conversion,lactic acid selectivity,and yield on s-TCS-4 are about 95.9%,94.3%,and 96.4%,respectively.The photocatalytic production of lactic acid for s-TCS-4(18.5 g/L)is 2.3 times higher than the pure spherical TiO_(2) photonic crystal without CdSe(s-TiO_(2),8.1 g/L),and the hydrogen production rate of s-TCS-4 is 9.4 times that of s-TiO_(2).For the first time,we reveal that the photocatalytic conversion of glucose to lactic acid is a third-order and four-electron-involved reaction.This work could shed some new light on the efficient photocatalysis conversion of biomass to highly value-added products with high selectivity and yield,and simultaneously sustainable hydrogen evolution.
