The adsorption equilibrium isotherms of three aromatic sulfonic acid compounds, 2-naphthalenesulfonic acid, p-toluenesulfonic acid and p-chlorobenzenesulfonic acid, from aqueous solutions by macroporous weak base anio...The adsorption equilibrium isotherms of three aromatic sulfonic acid compounds, 2-naphthalenesulfonic acid, p-toluenesulfonic acid and p-chlorobenzenesulfonic acid, from aqueous solutions by macroporous weak base anion exchanger within the temperature range of 293 K-313 K were obtained. Several isotherm equations were correlated with the equilibrium data, and the experimental data was found to fit the three-parameter Redlich-Peterson equation best within the entire range of concentrations. The study showed that the hydrophobicity of solute has distinct influence on adsorption capacity of the anion exchanger for the aromatic sulfonic acid. Moreover, estimations of the isosteric enthalpy, free energy, and entropy change of adsorption were also reported. The positive isosteric enthalpy and entropy change for adsorption indicate an endothermic and entropy driven process in the present study.展开更多
This paper reports a new method of titration for very weak acids and bases using the appearance of incisions on oscillopolarogram to indicate the end-point.This method has the advantages of rapidity,simplicity,no indi...This paper reports a new method of titration for very weak acids and bases using the appearance of incisions on oscillopolarogram to indicate the end-point.This method has the advantages of rapidity,simplicity,no indicator needed as well as good precision.展开更多
pH-fixed titration method for the determination of weak acids and bases has been studied in this paper.It is not necessary to know the ionization constant of weak acid or base and the concentration of titrant. This me...pH-fixed titration method for the determination of weak acids and bases has been studied in this paper.It is not necessary to know the ionization constant of weak acid or base and the concentration of titrant. This method had been applied to determine phenol,4-aminoantipyrine and glycine,whose ionization constants range from 10^(-10)to 10^(-12).The results were satisfactory.展开更多
Objective: The traditional approach for acid base interpretation is based on Handerson-Hasselbalch formula and includes Base Excess (BE), bicarbonate (HCO3), albumin corrected anion gap. The Physicochemical approach i...Objective: The traditional approach for acid base interpretation is based on Handerson-Hasselbalch formula and includes Base Excess (BE), bicarbonate (HCO3), albumin corrected anion gap. The Physicochemical approach is centered on the Carbon Dioxide tension (PCO2), the strong ion difference (SID), strong ion gap (SIG) = SID apparent-SID effective and totally weak acids (Atot). The study aims to compare between the traditional approach and the physicochemical approach in acid base disorder interpretation. Design: Prospective observational study in an adult Intensive Care Unit (ICU) recruiting six hundred and sixty one patients. Methods: Arterial blood samples were analyzed to measure pH, PaCO2 sodium, potassium, chloride and lactate. Venous blood samples were analyzed to measure ionized calcium, magnesium, phosphorous and albumin. These samples were interpreted by both techniques. Results: Normal HCO3 and BE were detected by traditional approach in 49 cases of which SIG acidosis was detected in 22 cases (46%) and Hyperchloremic acidosis was detected in 29 cases (60%) by physicochemical method. SIG was elevated in 72 cases (58%) of 124 cases with high anion gap acidosis. SIDeff and BE were strongly correlated, r = 0.8, p 0.0001, while SIG and Albumin corrected Anion Gap (ALAG) were moderately correlated r = 0.56, p Conclusion: Both approaches are important for interpretation of the acid base status. Traditional approach identifies the diagnostic description without many calculations and detects body compensatory response to acid base disorders. Physicochemical approach is essential to identify the exact causation and the severity of the acid base disorders.展开更多
A naturally occurring nitrogen heterocycle-based Schiff base sensor 8-methyl-2-oxo-1,2-dihydroquinoline-3-carboxaldehyde-4N-phenylsemicarbazone(8MPS)was synthesized;a highly sensitive and selective“on-off-on”chemose...A naturally occurring nitrogen heterocycle-based Schiff base sensor 8-methyl-2-oxo-1,2-dihydroquinoline-3-carboxaldehyde-4N-phenylsemicarbazone(8MPS)was synthesized;a highly sensitive and selective“on-off-on”chemosensor for aspartic acid in aqueous solution was established.展开更多
Cobalt oxides are economical and environmentally friendly electrocatalysts and they may be possible alternatives to noble metals for the oxygen evolution reaction.However,the most studied intrinsic cobalt oxides still...Cobalt oxides are economical and environmentally friendly electrocatalysts and they may be possible alternatives to noble metals for the oxygen evolution reaction.However,the most studied intrinsic cobalt oxides still need a high overpotential to overcome the current density threshold of oxygen evolution and are unstable for continuous reactions.Herein,we found that the catalytic activity of cobalt oxides improved significantly on soaking them in a weakly acidic iron–ion solution.The structure of the catalyst could be modified by the abovementioned treatment to reduce the overpotential,thus achieving improved catalytic efficiency for the oxygen evolution reaction.The formation of Fe-Co_(3)O_(4) delivered a much lower overpotential of 280 mV at 10 mA cm^(-2) (with a small Tafel slope of 55 mV dec^(-1)) compared with normal Co_(3)O_(4) (409 mV) for the OER;additionally,Fe-CoO also exhibited a lower overpotential of 296 mV compared with normal CoO (361 mV).The activity of the Fe ion-treated cobalt oxides was promoted by a thousand CV scans,which might form an amorphous phase layer.Density functional theory (DFT) calculations also indicated that the theoretical overpotentials of Fe-Co_(3)O_(4) and Fe-CoO were obviously lower than that of the untreated material.The treated cobalt oxides replaced cobalt atoms with a certain number of iron atoms,which dramatically changed the electronic structure and charge transfer rate.展开更多
文摘The adsorption equilibrium isotherms of three aromatic sulfonic acid compounds, 2-naphthalenesulfonic acid, p-toluenesulfonic acid and p-chlorobenzenesulfonic acid, from aqueous solutions by macroporous weak base anion exchanger within the temperature range of 293 K-313 K were obtained. Several isotherm equations were correlated with the equilibrium data, and the experimental data was found to fit the three-parameter Redlich-Peterson equation best within the entire range of concentrations. The study showed that the hydrophobicity of solute has distinct influence on adsorption capacity of the anion exchanger for the aromatic sulfonic acid. Moreover, estimations of the isosteric enthalpy, free energy, and entropy change of adsorption were also reported. The positive isosteric enthalpy and entropy change for adsorption indicate an endothermic and entropy driven process in the present study.
文摘This paper reports a new method of titration for very weak acids and bases using the appearance of incisions on oscillopolarogram to indicate the end-point.This method has the advantages of rapidity,simplicity,no indicator needed as well as good precision.
文摘pH-fixed titration method for the determination of weak acids and bases has been studied in this paper.It is not necessary to know the ionization constant of weak acid or base and the concentration of titrant. This method had been applied to determine phenol,4-aminoantipyrine and glycine,whose ionization constants range from 10^(-10)to 10^(-12).The results were satisfactory.
文摘Objective: The traditional approach for acid base interpretation is based on Handerson-Hasselbalch formula and includes Base Excess (BE), bicarbonate (HCO3), albumin corrected anion gap. The Physicochemical approach is centered on the Carbon Dioxide tension (PCO2), the strong ion difference (SID), strong ion gap (SIG) = SID apparent-SID effective and totally weak acids (Atot). The study aims to compare between the traditional approach and the physicochemical approach in acid base disorder interpretation. Design: Prospective observational study in an adult Intensive Care Unit (ICU) recruiting six hundred and sixty one patients. Methods: Arterial blood samples were analyzed to measure pH, PaCO2 sodium, potassium, chloride and lactate. Venous blood samples were analyzed to measure ionized calcium, magnesium, phosphorous and albumin. These samples were interpreted by both techniques. Results: Normal HCO3 and BE were detected by traditional approach in 49 cases of which SIG acidosis was detected in 22 cases (46%) and Hyperchloremic acidosis was detected in 29 cases (60%) by physicochemical method. SIG was elevated in 72 cases (58%) of 124 cases with high anion gap acidosis. SIDeff and BE were strongly correlated, r = 0.8, p 0.0001, while SIG and Albumin corrected Anion Gap (ALAG) were moderately correlated r = 0.56, p Conclusion: Both approaches are important for interpretation of the acid base status. Traditional approach identifies the diagnostic description without many calculations and detects body compensatory response to acid base disorders. Physicochemical approach is essential to identify the exact causation and the severity of the acid base disorders.
基金the Department of Science and Technology and Ministry of Science and Technology,Government of India,New Delhi,India,for the INSPIRE Fellowship.Grant number for the INSPIRE Fellowship is IF150603,dated 10.04.2015.
文摘A naturally occurring nitrogen heterocycle-based Schiff base sensor 8-methyl-2-oxo-1,2-dihydroquinoline-3-carboxaldehyde-4N-phenylsemicarbazone(8MPS)was synthesized;a highly sensitive and selective“on-off-on”chemosensor for aspartic acid in aqueous solution was established.
基金supported by the Talent Support Program of Anhui Province(Grant No.gxgwfx2018083)the National Natural Science Foundation of China(Grant No.11504120)the Natural Science Foundation of Anhui Province(Grant No.1608085QE90).
文摘Cobalt oxides are economical and environmentally friendly electrocatalysts and they may be possible alternatives to noble metals for the oxygen evolution reaction.However,the most studied intrinsic cobalt oxides still need a high overpotential to overcome the current density threshold of oxygen evolution and are unstable for continuous reactions.Herein,we found that the catalytic activity of cobalt oxides improved significantly on soaking them in a weakly acidic iron–ion solution.The structure of the catalyst could be modified by the abovementioned treatment to reduce the overpotential,thus achieving improved catalytic efficiency for the oxygen evolution reaction.The formation of Fe-Co_(3)O_(4) delivered a much lower overpotential of 280 mV at 10 mA cm^(-2) (with a small Tafel slope of 55 mV dec^(-1)) compared with normal Co_(3)O_(4) (409 mV) for the OER;additionally,Fe-CoO also exhibited a lower overpotential of 296 mV compared with normal CoO (361 mV).The activity of the Fe ion-treated cobalt oxides was promoted by a thousand CV scans,which might form an amorphous phase layer.Density functional theory (DFT) calculations also indicated that the theoretical overpotentials of Fe-Co_(3)O_(4) and Fe-CoO were obviously lower than that of the untreated material.The treated cobalt oxides replaced cobalt atoms with a certain number of iron atoms,which dramatically changed the electronic structure and charge transfer rate.
