The study examined the adsorption of Pb（II） ions from aqueous solution onto chitosan, chitosan-GLA and chitosan-alginate beads. Several important parameters influencing the adsorption of Pb（II） ions such as initia...The study examined the adsorption of Pb（II） ions from aqueous solution onto chitosan, chitosan-GLA and chitosan-alginate beads. Several important parameters influencing the adsorption of Pb（II） ions such as initial pH, adsorbent dosage and different initial concentration of Pb（II） ions were evaluated. The mechanism involved during the adsorption process was explored based on ion exchange study and using spectroscopic techniques. The adsorption capacities obtained based on non–linear Langmuir isotherm for chitosan, chitosan-GLA and chitosan-alginate beads in single metal system were 34.98, 14.24 and 60.27 mg/g, respectively. However, the adsorption capacity of Pb（II） ions were reduced in the binary metal system due to the competitive adsorption between Pb（II） and Cu（II） ions. Based on the ion exchange study, the release of Ca2＋, Mg2＋, K＋ and Na＋ ions played an important role in the adsorption of Pb（II） ions by all three adsorbents but only at lower concentrations of Pb（II） ions. Infrared spectra showed that the binding between Pb（II） ions and the adsorbents involved mostly the nitrogen and oxygen atoms. All three adsorbents showed satisfactory adsorption capacities and can be considered as an efficient adsorbent for the removal of Pb（II） ions from aqueous solutions.展开更多
The rates of electron exchange between oxidized and reduced forms of sev- eral derivatives of ferrocene(1-3)have been measured in acetonitrile by the NMR line h(?)oadening method at 25℃。It was found that the r(?)tes...The rates of electron exchange between oxidized and reduced forms of sev- eral derivatives of ferrocene(1-3)have been measured in acetonitrile by the NMR line h(?)oadening method at 25℃。It was found that the r(?)tes vary with the lengtn of the substitutent chain and the potential of E_(Fe(Ⅲ)/Fe(Ⅱ))in the ferrocene derivatives.展开更多
In October 2012,the Chinese Association for International Understanding(CAFIU) with which I am working organized a seminar in Beijing with the aim of exploring the status quo and prospects of exchanges between NGOs in...In October 2012,the Chinese Association for International Understanding(CAFIU) with which I am working organized a seminar in Beijing with the aim of exploring the status quo and prospects of exchanges between NGOs in Asia.People present at the seminar were heads of NGOs and think展开更多
A series of novel derivatives of ligustrazine linked with substituted benzoyl guanidine were synthesized. These compounds have not been reported in literature, and their chemical structures were confirmed by IR, ^1H N...A series of novel derivatives of ligustrazine linked with substituted benzoyl guanidine were synthesized. These compounds have not been reported in literature, and their chemical structures were confirmed by IR, ^1H NMR and MS. The results of NHE1 inhibitory activity test showed that compounds I2, I3, I4, I6, and I7 possess more potent NHE1 inhibitory activity than cariporide.展开更多
As pointed out in the paper preceding this one, in the case of functionals whose independent variable must obey conditions of integral normalization, conventional functional differentiation, defined in terms of an arb...As pointed out in the paper preceding this one, in the case of functionals whose independent variable must obey conditions of integral normalization, conventional functional differentiation, defined in terms of an arbitrary test function, is generally inapplicable and functional derivatives with respect to the density must be evaluated through the alternative and widely used limiting procedure based on the Dirac delta function. This leads to the determination of the rate of change of the dependent variable with respect to its independent variable at each isolated pair, , that may not be part of a functional (a set of ordered pairs). This extends the concept of functional derivative to expectation values of operators with respect to wave functions leading to a density even if the wave functions (and expectation values) do not form functionals. This new formulation of functional differentiation forms the basis for the study of the mathematical integrity of a number of concepts in density functional theory (DFT) such as the existence of a universal functional of the density, of orbital-free density functional theory, the derivative discontinuity of the exchange and correlation functional and the extension of DFT to open systems characterized by densities with fractional normalization. It is shown that no universal functional exists but, rather, a universal process based only on the density and independent of the possible existence of a potential, leads to unique functionals of the density determined through the minimization procedure of the constrained search. The mathematical integrity of two methodologies proposed for the treatment of the Coulomb interaction, the self-interaction free method and the optimized effective potential method is examined and the methodologies are compared in terms of numerical calculations. As emerges from this analysis, the optimized effective potential method is found to be numerically approximate but formally invalid, contrary to the rigorously exact results of the self-interaction-free method.展开更多
Novel composite magnetic microspheres containing chitosan and quaternary ammonium chitosan derivative(CHMMs) were prepared by inverse suspension method,and used for the methyl orange(MO) removal from aqueous solutions...Novel composite magnetic microspheres containing chitosan and quaternary ammonium chitosan derivative(CHMMs) were prepared by inverse suspension method,and used for the methyl orange(MO) removal from aqueous solutions.The CHMMs were characterized by a scanning electron microscope,a transmission electron microscope,and Fourier transform infrared spectroscopy,respectively.Compared with the chitosan beads,the incorporation of quaternary ammonium chitosan derivative significantly reduced the particle size.The MO adsorption by CHMMs was investigated by batch adsorption experiments.The adsorption kinetics was conformed to the pseudo second-order kinetics equation.The adsorption isotherm followed the Langmuir model better than the Freundlich model and the calculated maximum MO adsorption capacity was 266.6 mg·g^-1 at 293 K.Thermodynamic studies indicated that the MO adsorption was endothermic in nature with the enthalpy change(△H°) of 99.44 kJ·mol^-1.The CHMMs had a stable performance for MO adsorption in the pH range of 4-10,but high ionic strength deteriorated the MO removal due to the shielding of the ion exchange interaction.A 1 mol·L^-1 NaCl solution could be used to regenerate the exhausted CHMMs.The proposed CHMMs can be used as an effective adsorbent for dye removal or recovery from the dye wastewater.展开更多
A novel chiral bonded stationary phase(CBSP) for ligand exchange chromatography was prepared by bonding ( S ) 1,2,3,4 tetrahydro 3 isoquinoline carboxylic acid prepared from L Phe to YWG 80 silica gel via 3 glycidylox...A novel chiral bonded stationary phase(CBSP) for ligand exchange chromatography was prepared by bonding ( S ) 1,2,3,4 tetrahydro 3 isoquinoline carboxylic acid prepared from L Phe to YWG 80 silica gel via 3 glycidyloxypropyltrimethoxysilane as a coupling agent. Chromatographic resolutions of some DL amino acids were achieved on the CBSP by using an aqueous solution of 2 mmol/L N(C 2H 5) 3, 2 mmol/L HAc and 0 2 mmol/L Cu(Ac) 2 as the mobile phase with a flow rate 1 0 mL/min, column temperature 50 ℃ and detection at 254 nm. The enantioselectivity α of the DL amino acids on the CBSP was found to be between 1 11 and 1 51. The elution order of D isomer before L isomer on the CBSP was observed for all the DL amino acids resolved except DL Val. For DL Pro, DL Val and DL Leu the elution order through the CBSP was different from that through the chiral ligand exchange phases prepared from L Pro or L hydroxyl proline with a five\|membered ring structure. [WT5HZ]展开更多
基金the financial support under the Short Term Grant (No.304/PKIMIA/636065)
文摘The study examined the adsorption of Pb（II） ions from aqueous solution onto chitosan, chitosan-GLA and chitosan-alginate beads. Several important parameters influencing the adsorption of Pb（II） ions such as initial pH, adsorbent dosage and different initial concentration of Pb（II） ions were evaluated. The mechanism involved during the adsorption process was explored based on ion exchange study and using spectroscopic techniques. The adsorption capacities obtained based on non–linear Langmuir isotherm for chitosan, chitosan-GLA and chitosan-alginate beads in single metal system were 34.98, 14.24 and 60.27 mg/g, respectively. However, the adsorption capacity of Pb（II） ions were reduced in the binary metal system due to the competitive adsorption between Pb（II） and Cu（II） ions. Based on the ion exchange study, the release of Ca2＋, Mg2＋, K＋ and Na＋ ions played an important role in the adsorption of Pb（II） ions by all three adsorbents but only at lower concentrations of Pb（II） ions. Infrared spectra showed that the binding between Pb（II） ions and the adsorbents involved mostly the nitrogen and oxygen atoms. All three adsorbents showed satisfactory adsorption capacities and can be considered as an efficient adsorbent for the removal of Pb（II） ions from aqueous solutions.
文摘The rates of electron exchange between oxidized and reduced forms of sev- eral derivatives of ferrocene(1-3)have been measured in acetonitrile by the NMR line h(?)oadening method at 25℃。It was found that the r(?)tes vary with the lengtn of the substitutent chain and the potential of E_(Fe(Ⅲ)/Fe(Ⅱ))in the ferrocene derivatives.
文摘In October 2012,the Chinese Association for International Understanding(CAFIU) with which I am working organized a seminar in Beijing with the aim of exploring the status quo and prospects of exchanges between NGOs in Asia.People present at the seminar were heads of NGOs and think
文摘A series of novel derivatives of ligustrazine linked with substituted benzoyl guanidine were synthesized. These compounds have not been reported in literature, and their chemical structures were confirmed by IR, ^1H NMR and MS. The results of NHE1 inhibitory activity test showed that compounds I2, I3, I4, I6, and I7 possess more potent NHE1 inhibitory activity than cariporide.
文摘As pointed out in the paper preceding this one, in the case of functionals whose independent variable must obey conditions of integral normalization, conventional functional differentiation, defined in terms of an arbitrary test function, is generally inapplicable and functional derivatives with respect to the density must be evaluated through the alternative and widely used limiting procedure based on the Dirac delta function. This leads to the determination of the rate of change of the dependent variable with respect to its independent variable at each isolated pair, , that may not be part of a functional (a set of ordered pairs). This extends the concept of functional derivative to expectation values of operators with respect to wave functions leading to a density even if the wave functions (and expectation values) do not form functionals. This new formulation of functional differentiation forms the basis for the study of the mathematical integrity of a number of concepts in density functional theory (DFT) such as the existence of a universal functional of the density, of orbital-free density functional theory, the derivative discontinuity of the exchange and correlation functional and the extension of DFT to open systems characterized by densities with fractional normalization. It is shown that no universal functional exists but, rather, a universal process based only on the density and independent of the possible existence of a potential, leads to unique functionals of the density determined through the minimization procedure of the constrained search. The mathematical integrity of two methodologies proposed for the treatment of the Coulomb interaction, the self-interaction free method and the optimized effective potential method is examined and the methodologies are compared in terms of numerical calculations. As emerges from this analysis, the optimized effective potential method is found to be numerically approximate but formally invalid, contrary to the rigorously exact results of the self-interaction-free method.
基金Supported by the National Key Project for Research and Development(2016YFC0400503)the National Natural Science Foundation of China(51478314,51678408,51508385)the Science and Technology Plans of Tianjin(17PTSYJC00050,17ZYPTJC00060)
文摘Novel composite magnetic microspheres containing chitosan and quaternary ammonium chitosan derivative(CHMMs) were prepared by inverse suspension method,and used for the methyl orange(MO) removal from aqueous solutions.The CHMMs were characterized by a scanning electron microscope,a transmission electron microscope,and Fourier transform infrared spectroscopy,respectively.Compared with the chitosan beads,the incorporation of quaternary ammonium chitosan derivative significantly reduced the particle size.The MO adsorption by CHMMs was investigated by batch adsorption experiments.The adsorption kinetics was conformed to the pseudo second-order kinetics equation.The adsorption isotherm followed the Langmuir model better than the Freundlich model and the calculated maximum MO adsorption capacity was 266.6 mg·g^-1 at 293 K.Thermodynamic studies indicated that the MO adsorption was endothermic in nature with the enthalpy change(△H°) of 99.44 kJ·mol^-1.The CHMMs had a stable performance for MO adsorption in the pH range of 4-10,but high ionic strength deteriorated the MO removal due to the shielding of the ion exchange interaction.A 1 mol·L^-1 NaCl solution could be used to regenerate the exhausted CHMMs.The proposed CHMMs can be used as an effective adsorbent for dye removal or recovery from the dye wastewater.
文摘A novel chiral bonded stationary phase(CBSP) for ligand exchange chromatography was prepared by bonding ( S ) 1,2,3,4 tetrahydro 3 isoquinoline carboxylic acid prepared from L Phe to YWG 80 silica gel via 3 glycidyloxypropyltrimethoxysilane as a coupling agent. Chromatographic resolutions of some DL amino acids were achieved on the CBSP by using an aqueous solution of 2 mmol/L N(C 2H 5) 3, 2 mmol/L HAc and 0 2 mmol/L Cu(Ac) 2 as the mobile phase with a flow rate 1 0 mL/min, column temperature 50 ℃ and detection at 254 nm. The enantioselectivity α of the DL amino acids on the CBSP was found to be between 1 11 and 1 51. The elution order of D isomer before L isomer on the CBSP was observed for all the DL amino acids resolved except DL Val. For DL Pro, DL Val and DL Leu the elution order through the CBSP was different from that through the chiral ligand exchange phases prepared from L Pro or L hydroxyl proline with a five\|membered ring structure. [WT5HZ]
