Derivation of the Freundlich and Temkin isotherm models from the kinetic adsorption/desorpt ion equations was carried out to calculate their thermodynamic equilibrium constants. The calculation formulae ofthree thermo...Derivation of the Freundlich and Temkin isotherm models from the kinetic adsorption/desorpt ion equations was carried out to calculate their thermodynamic equilibrium constants. The calculation formulae ofthree thermodynamic parameters, the standard molar Gibbs free energy change, the standard molar enthalpy change and the standard molar entropy change, of isothermal adsorption processes for Freundlich andTemkin isotherm models were deduced according to the relationship between the thermodynamic equilibriumconstats and the temperature.展开更多
The inhibition ability of 2-amino-5-nitrothiazole （Nitramine） against the corrosion of AISI steel 4130 in 1 mol/L HCI solution was evaluated by polarization, electrochemical impedance spectroscopy （EIS） and chrono...The inhibition ability of 2-amino-5-nitrothiazole （Nitramine） against the corrosion of AISI steel 4130 in 1 mol/L HCI solution was evaluated by polarization, electrochemical impedance spectroscopy （EIS） and chronoamperometry. Polarization studies indicated that nitramine retards both the cathodic and anodic reactions through chemical adsorption and blocks the active corrosion sites. The adsorption of this compound obeyed the Temkin＇s adsorption isotherm. The inhibition efficiency was increased with inhibitor concentration as well as temperature. EIS data were analysed by equivalent circuit model shows that as the inhibitor concentration increased the charge transfer resistance of steel increased whilst double layer capacitance decreased. Kinetic and thermodynamic parameters such as activation energy, enthalpy, entropy and free energy of activation and adsorption were calculated. Atomic force microscopy and optical microscopy were used to study the steel surface with and without inhibitor.展开更多
Herein, the present paper were attempted to identify ions in LiF-DyF_3 melts according to the law of decreasing primary crystallization temperature and model analysis. Specifically.the primary crystallization temperat...Herein, the present paper were attempted to identify ions in LiF-DyF_3 melts according to the law of decreasing primary crystallization temperature and model analysis. Specifically.the primary crystallization temperatures of LiF-DyF_3 and LiF-DyF_3-Dy_2O_3 melts with various DyF_3 and Dy_2O_3 contents were determined by differential scanning calorimetry(DSC), and reactions occurring in the above melts were investigated using ideal dilute solution(Temkin and Flood) models. Moreover, crystal phases produced by rapid solidification of LiF-DyF_3, LiF-Dy_2O_3, DyF_3-Dy_2O_3, and LiF-DyF_3-Dy_2O_3 melts were identified by X-ray diffraction(XRD) analysis. The primary crystallization temperature of LiF-DyF_3 melts exhibits an approximately linear decrease with increasing molar fraction of DyF_3, and the general formula of complex ions in these melts is expressed as DyF_x^((3-x)),e.g., DyF_4^-. Finally, we investigated the dissolution of Dy_2O_3 in LiF-DyF_3 melts, showing that it was chemical in nature and afforded Dy_(1+x)O_(3x)F_(3-3x) and DyOF.展开更多
Bispyribac-sodium is a weakly acidic herbicide with high water solubility and is thus a potential source of groundwater contamination.Considering the risk inherent to the use of this herbicide,this study assessed the ...Bispyribac-sodium is a weakly acidic herbicide with high water solubility and is thus a potential source of groundwater contamination.Considering the risk inherent to the use of this herbicide,this study assessed the impacts of rice straw(RS)and biochar amendments on the adsorption and leaching behavior of bispyribac-sodium in soil.Biochars were produced from RS at different pyrolysis temperatures and characterized using various spectral techniques.Rice straw had a surface area of 3.996×10^(4)m^(2)kg^(-1),which increased under pyrolysis;biochars prepared at 350 and 550℃(RS350 and RS550)in a closed furnace with limited oxygen supply had a surface area of 5.763×10^(4)and 6.890×10^(4)m^(2)kg^(-1),respectively,and biochar prepared by purging the pyroformer with N2(RSC)had the highest surface area of 12.173×10^(4)m^(2)kg^(-1).After amendment with RS and biochar,soil Freundlich adsorption capacity(KF ads)increased to varying extents in the order RSC>RS350>RS550,from 2.89×10^(3)to 29.57×10^(3)mg^(1-1)/nkg^(-1)L1/n,compared to1.55×10^(3)mg^(1-1)/nkg^(-1)L1/nin unamended soil.The variability in KF ads of bispyribac-sodium amongst the RS-and biochar-amended soils was dependent on the surface area of the amendments.The desorption of bispyribac-sodium decreased in the RS-and biochar-amended soils and varied from90.45%to 95.20%in unamended soils and from 60.95%to 89.50%in amended soils.The adsorption and desorption of bispyribac-sodium varied significantly depending on its concentration and the type and application rate of soil amendment.Different leaching risk evaluation indices,viz.,modified leach index(M.LEACH),leach index(LEACH),groundwater ubiquity score(GUS),Hornsby index(HI),leaching index(LIN),and pesticide leaching potential(PLP)index,were used to assess the susceptibility of groundwater to herbicide leaching.To reduce the repetitive effects of common parameters in each index,a new index was developed by employing principal component analysis(PCA)to condense their information into a single ranking.The results of the PCA indicated that RS and biochar amendments could be an effective management practice for controlling the leaching potential of bispyribac-sodium in soil.展开更多
A biocarbon after activation process showed the removal percentage of 92% of methylene blue in solution, the equilibrium parameter—RL value was in the interval from 0 to 1, with 46% of surface coverage degree. The Fr...A biocarbon after activation process showed the removal percentage of 92% of methylene blue in solution, the equilibrium parameter—RL value was in the interval from 0 to 1, with 46% of surface coverage degree. The Freundlich constant (n) was higher than 1 as an indication of the physical adsorption process. The Radlich-Peterson calculations obtained the higher R2 value which g constant near 1, a high similarity with Langmuir model. Temkin constant B1 was a positive indication of endothermic process. All calculations provided favorable results for the use of activated biocarbon for dye removing and possible for other organic substances.展开更多
Ammonia synthesis reactors operate in conditions of high pressure and high temperature. Consequently, the flow inside these reactors always presents interaction between components in the feed mixture. A modeling accou...Ammonia synthesis reactors operate in conditions of high pressure and high temperature. Consequently, the flow inside these reactors always presents interaction between components in the feed mixture. A modeling accounts these interactions with pressure, temperature and the molar fraction is essential to converter simulation more realistic. The compositional approach based on cubic equations of state provides the influences of the component of a gas mixture using mixing rules and binary interaction parameters. This multicomponent description makes the model more robust and reliable for properties mixture prediction. In this work, two models of ammonia synthesis reactors were simulated: adiabatic and autothermal. The fitted expression of Singh and Saraf was used. The adiabatic reactor model presented a maximum relative error of 1.6% in temperature and 11.4% in conversion while the autothermal reactor model presents a maximum error of 2.7% in temperature, when compared to plant data. Furthermore, a sensitivity analysis in input variables of both converter models was performed to predict operational limits and performance of the Models for Ammonia Reactor Simulation (MARS).展开更多
The paper deals with the application of multiwall carbon nanotubes(CNTs) to the adsorption of dyes from wastewater. Textile dyes are dangerous and diffused pollutant in wastewater, and the paper results confirmed the ...The paper deals with the application of multiwall carbon nanotubes(CNTs) to the adsorption of dyes from wastewater. Textile dyes are dangerous and diffused pollutant in wastewater, and the paper results confirmed the good adsorption ability of CNTs, with respect to classic active carbon, even for different dye types. The effect of surface treatments of CNTs was primarily investigated, revealing that neither the presence of residual catalyst nor common surface treatment(oxidation) affects the CNT's performances. Therefore less expensive nonpurified CNTs were assessed as good and economically convenient alternative for the process. In order to gain in generality in adsorption kinetic modelling, the parameters of the "best fitting" pseudo-second order model have been correlated to the main process variables(the dye initial concentration and the specific mass of CNTs.) setting-up a predictive kinetic model useful design new application of these materials in currently operating industrial operations for adsorption. In addition, isothermal data were used to screen all the relevant adsorption isotherms models and the Temkin model was confirmed as the more effective to accurately fit equilibrium data for any of the considered different dye types.展开更多
文摘Derivation of the Freundlich and Temkin isotherm models from the kinetic adsorption/desorpt ion equations was carried out to calculate their thermodynamic equilibrium constants. The calculation formulae ofthree thermodynamic parameters, the standard molar Gibbs free energy change, the standard molar enthalpy change and the standard molar entropy change, of isothermal adsorption processes for Freundlich andTemkin isotherm models were deduced according to the relationship between the thermodynamic equilibriumconstats and the temperature.
文摘The inhibition ability of 2-amino-5-nitrothiazole （Nitramine） against the corrosion of AISI steel 4130 in 1 mol/L HCI solution was evaluated by polarization, electrochemical impedance spectroscopy （EIS） and chronoamperometry. Polarization studies indicated that nitramine retards both the cathodic and anodic reactions through chemical adsorption and blocks the active corrosion sites. The adsorption of this compound obeyed the Temkin＇s adsorption isotherm. The inhibition efficiency was increased with inhibitor concentration as well as temperature. EIS data were analysed by equivalent circuit model shows that as the inhibitor concentration increased the charge transfer resistance of steel increased whilst double layer capacitance decreased. Kinetic and thermodynamic parameters such as activation energy, enthalpy, entropy and free energy of activation and adsorption were calculated. Atomic force microscopy and optical microscopy were used to study the steel surface with and without inhibitor.
基金Project supported by the National Natural Science Foundation of China(5167041092,51564015)Natural Science Foundation of Jiangxi Province(20161BAB206142)Outstanding Doctoral Dissertation Project Fund of JXUST(YB2017007)
文摘Herein, the present paper were attempted to identify ions in LiF-DyF_3 melts according to the law of decreasing primary crystallization temperature and model analysis. Specifically.the primary crystallization temperatures of LiF-DyF_3 and LiF-DyF_3-Dy_2O_3 melts with various DyF_3 and Dy_2O_3 contents were determined by differential scanning calorimetry(DSC), and reactions occurring in the above melts were investigated using ideal dilute solution(Temkin and Flood) models. Moreover, crystal phases produced by rapid solidification of LiF-DyF_3, LiF-Dy_2O_3, DyF_3-Dy_2O_3, and LiF-DyF_3-Dy_2O_3 melts were identified by X-ray diffraction(XRD) analysis. The primary crystallization temperature of LiF-DyF_3 melts exhibits an approximately linear decrease with increasing molar fraction of DyF_3, and the general formula of complex ions in these melts is expressed as DyF_x^((3-x)),e.g., DyF_4^-. Finally, we investigated the dissolution of Dy_2O_3 in LiF-DyF_3 melts, showing that it was chemical in nature and afforded Dy_(1+x)O_(3x)F_(3-3x) and DyOF.
文摘Bispyribac-sodium is a weakly acidic herbicide with high water solubility and is thus a potential source of groundwater contamination.Considering the risk inherent to the use of this herbicide,this study assessed the impacts of rice straw(RS)and biochar amendments on the adsorption and leaching behavior of bispyribac-sodium in soil.Biochars were produced from RS at different pyrolysis temperatures and characterized using various spectral techniques.Rice straw had a surface area of 3.996×10^(4)m^(2)kg^(-1),which increased under pyrolysis;biochars prepared at 350 and 550℃(RS350 and RS550)in a closed furnace with limited oxygen supply had a surface area of 5.763×10^(4)and 6.890×10^(4)m^(2)kg^(-1),respectively,and biochar prepared by purging the pyroformer with N2(RSC)had the highest surface area of 12.173×10^(4)m^(2)kg^(-1).After amendment with RS and biochar,soil Freundlich adsorption capacity(KF ads)increased to varying extents in the order RSC>RS350>RS550,from 2.89×10^(3)to 29.57×10^(3)mg^(1-1)/nkg^(-1)L1/n,compared to1.55×10^(3)mg^(1-1)/nkg^(-1)L1/nin unamended soil.The variability in KF ads of bispyribac-sodium amongst the RS-and biochar-amended soils was dependent on the surface area of the amendments.The desorption of bispyribac-sodium decreased in the RS-and biochar-amended soils and varied from90.45%to 95.20%in unamended soils and from 60.95%to 89.50%in amended soils.The adsorption and desorption of bispyribac-sodium varied significantly depending on its concentration and the type and application rate of soil amendment.Different leaching risk evaluation indices,viz.,modified leach index(M.LEACH),leach index(LEACH),groundwater ubiquity score(GUS),Hornsby index(HI),leaching index(LIN),and pesticide leaching potential(PLP)index,were used to assess the susceptibility of groundwater to herbicide leaching.To reduce the repetitive effects of common parameters in each index,a new index was developed by employing principal component analysis(PCA)to condense their information into a single ranking.The results of the PCA indicated that RS and biochar amendments could be an effective management practice for controlling the leaching potential of bispyribac-sodium in soil.
文摘A biocarbon after activation process showed the removal percentage of 92% of methylene blue in solution, the equilibrium parameter—RL value was in the interval from 0 to 1, with 46% of surface coverage degree. The Freundlich constant (n) was higher than 1 as an indication of the physical adsorption process. The Radlich-Peterson calculations obtained the higher R2 value which g constant near 1, a high similarity with Langmuir model. Temkin constant B1 was a positive indication of endothermic process. All calculations provided favorable results for the use of activated biocarbon for dye removing and possible for other organic substances.
文摘Ammonia synthesis reactors operate in conditions of high pressure and high temperature. Consequently, the flow inside these reactors always presents interaction between components in the feed mixture. A modeling accounts these interactions with pressure, temperature and the molar fraction is essential to converter simulation more realistic. The compositional approach based on cubic equations of state provides the influences of the component of a gas mixture using mixing rules and binary interaction parameters. This multicomponent description makes the model more robust and reliable for properties mixture prediction. In this work, two models of ammonia synthesis reactors were simulated: adiabatic and autothermal. The fitted expression of Singh and Saraf was used. The adiabatic reactor model presented a maximum relative error of 1.6% in temperature and 11.4% in conversion while the autothermal reactor model presents a maximum error of 2.7% in temperature, when compared to plant data. Furthermore, a sensitivity analysis in input variables of both converter models was performed to predict operational limits and performance of the Models for Ammonia Reactor Simulation (MARS).
文摘The paper deals with the application of multiwall carbon nanotubes(CNTs) to the adsorption of dyes from wastewater. Textile dyes are dangerous and diffused pollutant in wastewater, and the paper results confirmed the good adsorption ability of CNTs, with respect to classic active carbon, even for different dye types. The effect of surface treatments of CNTs was primarily investigated, revealing that neither the presence of residual catalyst nor common surface treatment(oxidation) affects the CNT's performances. Therefore less expensive nonpurified CNTs were assessed as good and economically convenient alternative for the process. In order to gain in generality in adsorption kinetic modelling, the parameters of the "best fitting" pseudo-second order model have been correlated to the main process variables(the dye initial concentration and the specific mass of CNTs.) setting-up a predictive kinetic model useful design new application of these materials in currently operating industrial operations for adsorption. In addition, isothermal data were used to screen all the relevant adsorption isotherms models and the Temkin model was confirmed as the more effective to accurately fit equilibrium data for any of the considered different dye types.
