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2013 Volume 30 Issue 10
2013, 30(10): 1099-1106
doi: 10.3724/SP.J.1095.2013.30333
Abstract:
This comprehensive review summarized the characteristics of high performance polyurethane,including high tensile strength,low creep resistance,stable modules in wide range of temperature,and tunable damping properties. The potentials of this kind of material in real applications,for example,in ship industries,were also presented,with emphasis on polyurethane vibration isolator,anechoic tile,water lubricated bearings,and anti-fouling coatings.
This comprehensive review summarized the characteristics of high performance polyurethane,including high tensile strength,low creep resistance,stable modules in wide range of temperature,and tunable damping properties. The potentials of this kind of material in real applications,for example,in ship industries,were also presented,with emphasis on polyurethane vibration isolator,anechoic tile,water lubricated bearings,and anti-fouling coatings.
2013, 30(10): 1107-1113
doi: 10.3724/SP.J.1095.2013.30038
Abstract:
Wood flour was modified in sequence by toluene-2,4-diisocyanate(TDI) and stearic acid(SA),and then the modified wood flour were mixed with polypropylene(PP) in a twin screw extruder to produce PP/wood flour composites. The influences of the molar ratios of SA and TDI on the surface properties of wood flour,mechanical and processing properties of the composites were studied.The results show that the surface tension of the modified wood flour decreases step by step generally,and the interfacial tension between the wood flour and PP decreases at first and then increases with the raise of molar ratio of SA and TDI.Mechanical tests reveal that,compared with the unmodified composites,SA and TDI have no obvious influence on the tensile,flexural and notched impact strength,but the unnotched impact strength of all modified composites is improved.When the molar ratio of SA and TDI is 1.07,the unnotched impact strength and melt-mass flow rate of composites reach 9.74 kJ/m2 and 13.12 g/10 min,respectively,improving by 77% and 22% compared with unmodified composites.
Wood flour was modified in sequence by toluene-2,4-diisocyanate(TDI) and stearic acid(SA),and then the modified wood flour were mixed with polypropylene(PP) in a twin screw extruder to produce PP/wood flour composites. The influences of the molar ratios of SA and TDI on the surface properties of wood flour,mechanical and processing properties of the composites were studied.The results show that the surface tension of the modified wood flour decreases step by step generally,and the interfacial tension between the wood flour and PP decreases at first and then increases with the raise of molar ratio of SA and TDI.Mechanical tests reveal that,compared with the unmodified composites,SA and TDI have no obvious influence on the tensile,flexural and notched impact strength,but the unnotched impact strength of all modified composites is improved.When the molar ratio of SA and TDI is 1.07,the unnotched impact strength and melt-mass flow rate of composites reach 9.74 kJ/m2 and 13.12 g/10 min,respectively,improving by 77% and 22% compared with unmodified composites.
2013, 30(10): 1114-1119
doi: 10.3724/SP.J.1095.2013.20600
Abstract:
It was found that boron trifluoride etherate was an effective catalyst for the reactions between carbamoylsilane and imines. The influences of various substitution groups(ethyl,isopropyl,trifluoromethyl,styryl,phenyl,furyl,thienyl,pyridyl) on the C-terminus of the parent iminium to the reaction have been studied and some α-aminoamides were synthesized. The stereoselectivety of the reaction was found by connecting chiral alkyl(S-1-phenylethyl) on the N-terminus of the iminium and the highly stereoselective product was obtained (diastereomer ratio of 14:1) by connecting chiral alkyl both on the N-terminus of the iminium structure(S-1-phenylethyl) and on the N-terminus of carbamoylsilane(R-1-phenylethyl). So this is a new method for stereoselectivly synthesizing α-aminoamides.
It was found that boron trifluoride etherate was an effective catalyst for the reactions between carbamoylsilane and imines. The influences of various substitution groups(ethyl,isopropyl,trifluoromethyl,styryl,phenyl,furyl,thienyl,pyridyl) on the C-terminus of the parent iminium to the reaction have been studied and some α-aminoamides were synthesized. The stereoselectivety of the reaction was found by connecting chiral alkyl(S-1-phenylethyl) on the N-terminus of the iminium and the highly stereoselective product was obtained (diastereomer ratio of 14:1) by connecting chiral alkyl both on the N-terminus of the iminium structure(S-1-phenylethyl) and on the N-terminus of carbamoylsilane(R-1-phenylethyl). So this is a new method for stereoselectivly synthesizing α-aminoamides.
2013, 30(10): 1120-1126
doi: 10.3724/SP.J.1095.2013.20592
Abstract:
Using D-glucose as precursor,eleven alkyl β-D-glucopyranosides with different carbon chain length were synthesized, via five consecutive steps including acetylation,selective deacetylation at the C1 position,conversion to trichloroacetimidate, coupling with acceptors alcohols and deprotection. Their structures and properties were characterized by NMR, polarization microscope(POM) and thermogravimetry(TG). The results show that alkyl β-D-glucopyranosides possess foaming and emulsifying capacities for those with chain length of hydrophobic aglycon n=6~10. Remarkably,n-nonyl β-D-glucopyranoside(n=9) shows even superior foaming and emulsifying capacities. Meanwhile,when the chain length of hydrophobic aglycon (n) is greater than 7,all alkyl β-D-glucopyranosides exhibit thermotropic liquid crystalline behavior. Among them,n-dodecyl β-D-glucopyranoside with n=12 and n-tetradecyl β-D-glucopyranoside with n=14 can form more stable liquid crystal state.
Using D-glucose as precursor,eleven alkyl β-D-glucopyranosides with different carbon chain length were synthesized, via five consecutive steps including acetylation,selective deacetylation at the C1 position,conversion to trichloroacetimidate, coupling with acceptors alcohols and deprotection. Their structures and properties were characterized by NMR, polarization microscope(POM) and thermogravimetry(TG). The results show that alkyl β-D-glucopyranosides possess foaming and emulsifying capacities for those with chain length of hydrophobic aglycon n=6~10. Remarkably,n-nonyl β-D-glucopyranoside(n=9) shows even superior foaming and emulsifying capacities. Meanwhile,when the chain length of hydrophobic aglycon (n) is greater than 7,all alkyl β-D-glucopyranosides exhibit thermotropic liquid crystalline behavior. Among them,n-dodecyl β-D-glucopyranoside with n=12 and n-tetradecyl β-D-glucopyranoside with n=14 can form more stable liquid crystal state.
2013, 30(10): 1127-1132
doi: 10.3724/SP.J.1095.2013.20593
Abstract:
6-Hydroxytropinone was chosen as the primary precursor and subjected to a series of reactions including acetylation or benzoylation of its hydroxyl group,reduction and ammoniation of its keto group to yield two compounds containing tropane with primary amine core structure. A series of N-acyl compounds has been prepared by the reactions of the core structures with a variety of acyl chlorides. These compounds were screened in peroxisome proliferateive activeated recaptor-γ(PPARγ) and dipeptidylpeptidase-Ⅳ(DPP-Ⅳ) in-vitro models. Most of these compounds displayed inhibitory effect against DPP-Ⅳ and two of them showed inhibitory rates higher than 30% at 3 μmol/L in DMSO. But no activation toward PPARγ of all compounds could be observed.
6-Hydroxytropinone was chosen as the primary precursor and subjected to a series of reactions including acetylation or benzoylation of its hydroxyl group,reduction and ammoniation of its keto group to yield two compounds containing tropane with primary amine core structure. A series of N-acyl compounds has been prepared by the reactions of the core structures with a variety of acyl chlorides. These compounds were screened in peroxisome proliferateive activeated recaptor-γ(PPARγ) and dipeptidylpeptidase-Ⅳ(DPP-Ⅳ) in-vitro models. Most of these compounds displayed inhibitory effect against DPP-Ⅳ and two of them showed inhibitory rates higher than 30% at 3 μmol/L in DMSO. But no activation toward PPARγ of all compounds could be observed.
2013, 30(10): 1133-1138
doi: 10.3724/SP.J.1095.2013.20561
Abstract:
Using ursolic acid as the precursor,2β-hydroxyursolic acid was synthesized by 6-step successive reactions including oxidation,benzylation,acetylation,hydrolysis,reduction,and group deprotection reactions. The overall yield is 60.1%. Its structure was determined by IR,1H NMR,13C NMR and MS. The antitumor activity of the target compound was evaluated against the proliferation of human leukemia cell K562 and human lung carcinoma cell A549 by the MTT assay. The results indicate that the target compound has inhibitive activity toward cell growth for the two tumor cells.
Using ursolic acid as the precursor,2β-hydroxyursolic acid was synthesized by 6-step successive reactions including oxidation,benzylation,acetylation,hydrolysis,reduction,and group deprotection reactions. The overall yield is 60.1%. Its structure was determined by IR,1H NMR,13C NMR and MS. The antitumor activity of the target compound was evaluated against the proliferation of human leukemia cell K562 and human lung carcinoma cell A549 by the MTT assay. The results indicate that the target compound has inhibitive activity toward cell growth for the two tumor cells.
2013, 30(10): 1139-1143
doi: 10.3724/SP.J.1095.2013.20571
Abstract:
A novel compound,containing a strong electron donor and a strong electron acceptor,3-((2-(2,4-dinitrophenyl) hydrazono) methyl)-9-ethyl-9H-carbazole,was synthesized. Its spectral property and photophysical behavior were studied. Intermolecular charge transfer occurred from N-ethylcarbazole to NO2-with the increase of the solvent polarity. Double fluorescence emission was observed in strong polarity solvent. Change of dipole moment between the ground state and the excitation state was 4.53 D. Dimmer or polymer was formed at high concentration and the emission wavelength was red shifted.
A novel compound,containing a strong electron donor and a strong electron acceptor,3-((2-(2,4-dinitrophenyl) hydrazono) methyl)-9-ethyl-9H-carbazole,was synthesized. Its spectral property and photophysical behavior were studied. Intermolecular charge transfer occurred from N-ethylcarbazole to NO2-with the increase of the solvent polarity. Double fluorescence emission was observed in strong polarity solvent. Change of dipole moment between the ground state and the excitation state was 4.53 D. Dimmer or polymer was formed at high concentration and the emission wavelength was red shifted.
2013, 30(10): 1144-1148
doi: 10.3724/SP.J.1095.2013.20557
Abstract:
The interaction between aluminium(Ⅲ) cation (Al3+) and hydroxyl functionalized carbon dots (CDs) was studied through the fluorescence spectra. Upon the addition of increasing amounts of Al3+ in the range of 0.2~8 μmol/L,the fluorescence of CDs quenched gradually. Further increasing the concentration of Al3+,the quenched fluorescence could be recovered. By employing the dynamic light scattering (DLS) and Zeta potential,we proposed a plausible mechanism for the observed phenomena. At lower concentration of Al3+,Al3+ can easily coordinate with hydroxyl groups on the surface of CDs,the distance among neighboring CDs was then shortened,which causes the aggregation of CDs and quenching of fluorescent CDs. Further increasing the concentration of Al3+,the hydroxyl groups of CDs were completely coordinated with Al3+. In such case,the charges of CDs changed from negative to positive. Owing to the repulsion of the positive charges,the aggregated CDs tend to dissolve and the fluorescence of CDs can be recovered. Although Cr3+ and Fe3+ can also coordinate with hydroxyl groups,our experimental results show that they just have strong fluorescence quenching effects on CDs but no fluorescence recovery phenomena. This is probably ascribed to the fact that Al3+ can form amphoteric hydroxide easily.
The interaction between aluminium(Ⅲ) cation (Al3+) and hydroxyl functionalized carbon dots (CDs) was studied through the fluorescence spectra. Upon the addition of increasing amounts of Al3+ in the range of 0.2~8 μmol/L,the fluorescence of CDs quenched gradually. Further increasing the concentration of Al3+,the quenched fluorescence could be recovered. By employing the dynamic light scattering (DLS) and Zeta potential,we proposed a plausible mechanism for the observed phenomena. At lower concentration of Al3+,Al3+ can easily coordinate with hydroxyl groups on the surface of CDs,the distance among neighboring CDs was then shortened,which causes the aggregation of CDs and quenching of fluorescent CDs. Further increasing the concentration of Al3+,the hydroxyl groups of CDs were completely coordinated with Al3+. In such case,the charges of CDs changed from negative to positive. Owing to the repulsion of the positive charges,the aggregated CDs tend to dissolve and the fluorescence of CDs can be recovered. Although Cr3+ and Fe3+ can also coordinate with hydroxyl groups,our experimental results show that they just have strong fluorescence quenching effects on CDs but no fluorescence recovery phenomena. This is probably ascribed to the fact that Al3+ can form amphoteric hydroxide easily.
2013, 30(10): 1149-1155
doi: 10.3724/SP.J.1095.2013.20559
Abstract:
Electrophoretic deposition (EPD) has been exploited for the preparation of hydroxyapatite/chitosan/ferric oxide (HA/CS/Fe2O3) composite coating,which was then sintered at 700℃ for 2 h to yield HA/Fe2O3 composite coating. The surface morphology,phase composition,corrosion resistance and adhesion between the composite coating and substrate were characterized by SEM,EDS and XRD,FT-IR,electrochemical instrument and Lloyd LR5K Plus Testing Instrument,respectively. The bioactivity for inducing bone growth of the HA/Fe2O3 composite coating was evaluated in 1.5 times of ionic concentration of simulated body fluid (1.5SBF). When the mass ratio of HA:CS:Fe2O3 in the suspension was 100:100:1,the resultant HA/Fe2O3 composite coating had rough surface and strong adhesion up to 27.5 MPa with substrate and showed high corrosion resistance in 1.5SBF and excellent bioactivity for inducing bone growth in 1.5SBF.
Electrophoretic deposition (EPD) has been exploited for the preparation of hydroxyapatite/chitosan/ferric oxide (HA/CS/Fe2O3) composite coating,which was then sintered at 700℃ for 2 h to yield HA/Fe2O3 composite coating. The surface morphology,phase composition,corrosion resistance and adhesion between the composite coating and substrate were characterized by SEM,EDS and XRD,FT-IR,electrochemical instrument and Lloyd LR5K Plus Testing Instrument,respectively. The bioactivity for inducing bone growth of the HA/Fe2O3 composite coating was evaluated in 1.5 times of ionic concentration of simulated body fluid (1.5SBF). When the mass ratio of HA:CS:Fe2O3 in the suspension was 100:100:1,the resultant HA/Fe2O3 composite coating had rough surface and strong adhesion up to 27.5 MPa with substrate and showed high corrosion resistance in 1.5SBF and excellent bioactivity for inducing bone growth in 1.5SBF.
2013, 30(10): 1156-1162
doi: 10.3724/SP.J.1095.2013.30045
Abstract:
3-Methylindole was synthesized by vapor-phase method from aniline and biomass-derived glycerol over Fe promoted Cu/SiO2-Al2O3 catalyst. The catalysts were characterized by X-ray photoelectron spectroscopy(XPS),H2 temperature-programmed-reduction (H2-TPR),X ray diffraction (XRD),transmission electron microscopy (TEM),inductively coupled plasma (ICP) emission spectroscopy,temperature-programmeddesorption of ammonia (NH3-TPD) and thermogravimetric (TG) analysis techniques. The results indicated that the addition of Fe to Cu/SiO2-Al2O3 could not only increase the activity and selectivity clearly,but also improve the stability of the catalyst remarkably. Over Cu-Fe/SiO2-Al2O3,the yield of 3-methylindole reached 48% after three hours reaction and the catalyst could be reused by regeneration without obvious loss of the yield even after 43 h reaction. The characterizations revealed that the addition of Fe to Cu/SiO2-Al2O3 could reinforce the interaction between copper and the support,which greatly improved the dispersion of Cu particles on the surface of the support and efficiently decreased the loss of copper component during the reaction. Furthermore,Fe promoter could decrease the amount of middle-strong acid sites remarkably and increase the amount of the weak acid sites of the catalyst,which was propitious to the high selectivity of 3-methylindole and inhibited the formation of the coke.
3-Methylindole was synthesized by vapor-phase method from aniline and biomass-derived glycerol over Fe promoted Cu/SiO2-Al2O3 catalyst. The catalysts were characterized by X-ray photoelectron spectroscopy(XPS),H2 temperature-programmed-reduction (H2-TPR),X ray diffraction (XRD),transmission electron microscopy (TEM),inductively coupled plasma (ICP) emission spectroscopy,temperature-programmeddesorption of ammonia (NH3-TPD) and thermogravimetric (TG) analysis techniques. The results indicated that the addition of Fe to Cu/SiO2-Al2O3 could not only increase the activity and selectivity clearly,but also improve the stability of the catalyst remarkably. Over Cu-Fe/SiO2-Al2O3,the yield of 3-methylindole reached 48% after three hours reaction and the catalyst could be reused by regeneration without obvious loss of the yield even after 43 h reaction. The characterizations revealed that the addition of Fe to Cu/SiO2-Al2O3 could reinforce the interaction between copper and the support,which greatly improved the dispersion of Cu particles on the surface of the support and efficiently decreased the loss of copper component during the reaction. Furthermore,Fe promoter could decrease the amount of middle-strong acid sites remarkably and increase the amount of the weak acid sites of the catalyst,which was propitious to the high selectivity of 3-methylindole and inhibited the formation of the coke.
2013, 30(10): 1163-1168
doi: 10.3724/SP.J.1095.2013.20595
Abstract:
With copolymeric modification by Schiff base monomer,NiO nanoparticles supported on SBA-15 mesoporous molecular sieves were prepared and characterized by powder X-ray diffraction (XRD),UV-Vis spectrometer,high resolution transmission electron microscopy(HRTEM) and N2 adsorption-desorption isotherms. The results show that the as-prepared samples possess a bi-dimensional P6mm hexagonal symmetry of the pores and the formed NiO nanoparticles are mainly dispersed into channels of SBA-15. When the loadings of Schiff base monomer are less than 10%,the pore diameter is in the range of 6~8 nm. Increasing the loading of Schiff base monomer up to 15%,the channels of SBA-15 are severely blocked by encapsulated NiO nanoparticles and the pore diameter is reduced to 3.8 nm. In addition,NiO nanoparticle size increases with increasing Schiff base monomer loading.
With copolymeric modification by Schiff base monomer,NiO nanoparticles supported on SBA-15 mesoporous molecular sieves were prepared and characterized by powder X-ray diffraction (XRD),UV-Vis spectrometer,high resolution transmission electron microscopy(HRTEM) and N2 adsorption-desorption isotherms. The results show that the as-prepared samples possess a bi-dimensional P6mm hexagonal symmetry of the pores and the formed NiO nanoparticles are mainly dispersed into channels of SBA-15. When the loadings of Schiff base monomer are less than 10%,the pore diameter is in the range of 6~8 nm. Increasing the loading of Schiff base monomer up to 15%,the channels of SBA-15 are severely blocked by encapsulated NiO nanoparticles and the pore diameter is reduced to 3.8 nm. In addition,NiO nanoparticle size increases with increasing Schiff base monomer loading.
2013, 30(10): 1169-1175
doi: 10.3724/SP.J.1095.2013.20606
Abstract:
Six transition metal (Cu,Fe,Zn,Ni,Mn,Ce) compounds were loaded on activated carbon (AC) by impregnation method to yield six catalysts (AC/M(M=Cu,Fe,Zn,Ni,Mn,Ce)) that were assessed as ozonation catalysts for the removal of aqueous phenol solution and textile dyeing sludge at room temperature. The resultant products were characterized by Boehm titrations,XRD and BET analyses. The presence of AC/M catalysts considerably improved their degradation in the ozonation of phenol and textile dyeing sludge. The phenol decomposition were evaluated using three catalytic systems:a) ozone(O3),b) AC/M catalysts,and c) a mixture of AC/M catalysts and O3. It was found that catalytic activity toward the degradation of phenol decreased in the order of c b a.Among the six catalysts for phenol decomposition,the order of AC/Fe AC/Zn AC/Ni AC/Ce AC/Cu AC/Mn was followed. For all the catalysts,their catalytic activities toward phenol degradation increase with the increase of pH value of phenol solution. For practical textile dyeing sludge,the similar order for the decomposition of phenol could be maintained except the catalytic activities of AC/Ce and AC/Ni are comparable. Using AC/Fe catalyst,together with ozone,the organic matter of textile dyeing sludge could be reduced by 8.17%.
Six transition metal (Cu,Fe,Zn,Ni,Mn,Ce) compounds were loaded on activated carbon (AC) by impregnation method to yield six catalysts (AC/M(M=Cu,Fe,Zn,Ni,Mn,Ce)) that were assessed as ozonation catalysts for the removal of aqueous phenol solution and textile dyeing sludge at room temperature. The resultant products were characterized by Boehm titrations,XRD and BET analyses. The presence of AC/M catalysts considerably improved their degradation in the ozonation of phenol and textile dyeing sludge. The phenol decomposition were evaluated using three catalytic systems:a) ozone(O3),b) AC/M catalysts,and c) a mixture of AC/M catalysts and O3. It was found that catalytic activity toward the degradation of phenol decreased in the order of c b a.Among the six catalysts for phenol decomposition,the order of AC/Fe AC/Zn AC/Ni AC/Ce AC/Cu AC/Mn was followed. For all the catalysts,their catalytic activities toward phenol degradation increase with the increase of pH value of phenol solution. For practical textile dyeing sludge,the similar order for the decomposition of phenol could be maintained except the catalytic activities of AC/Ce and AC/Ni are comparable. Using AC/Fe catalyst,together with ozone,the organic matter of textile dyeing sludge could be reduced by 8.17%.
2013, 30(10): 1176-1181
doi: 10.3724/SP.J.1095.2013.20566
Abstract:
Carbon-loaded Ag or Ag-Sn bimetallic nanoparticles were prepared by the hydrothermal process,in which Ag+ or Ag+ + Sn2+ dissolved in ethanol were reduced to Ag or binary Ag-Sn nanoparticles by ethanol as the reduction agent. The morphological features of the catalysts show a typical nanoporous structure. Cyclic voltammetry and steady state polarization measurements were used to investigate the electroactivity of the samples for oxygen reduction reaction (ORR). The results show that both Ag/C and Ag-Sn/C exhibits a high electrocatalysis activity,with the onset potential of ca.0.05 V(vs.Ag/AgCl) and a high current density for the ORR. Levich analysis shows that the binary Ag-Sn/C possesses a much greater electron number for ORR than Ag/C. Among the prepared samples,the Ag97Sn3/C catalyst displays the highest current density for oxygen reduction reaction. In addition,the Ag/C and Ag-Sn/C catalysts exhibit strong tolerance towards methanol.
Carbon-loaded Ag or Ag-Sn bimetallic nanoparticles were prepared by the hydrothermal process,in which Ag+ or Ag+ + Sn2+ dissolved in ethanol were reduced to Ag or binary Ag-Sn nanoparticles by ethanol as the reduction agent. The morphological features of the catalysts show a typical nanoporous structure. Cyclic voltammetry and steady state polarization measurements were used to investigate the electroactivity of the samples for oxygen reduction reaction (ORR). The results show that both Ag/C and Ag-Sn/C exhibits a high electrocatalysis activity,with the onset potential of ca.0.05 V(vs.Ag/AgCl) and a high current density for the ORR. Levich analysis shows that the binary Ag-Sn/C possesses a much greater electron number for ORR than Ag/C. Among the prepared samples,the Ag97Sn3/C catalyst displays the highest current density for oxygen reduction reaction. In addition,the Ag/C and Ag-Sn/C catalysts exhibit strong tolerance towards methanol.
2013, 30(10): 1182-1188
doi: 10.3724/SP.J.1095.2013.20612
Abstract:
The sponge powder bismuth replaced by powder iron is low grade. In order to overcome such problem,new approach for producing sponge powder bismuth is developed with the use of iron plates under micro-current. The grade of the obtained sponge powder bismuth is over 90%,which is replaced by iron plates with the use of iron plates as the anode,graphite as the cathode,and the current density is 5 × 10-3 A/cm2at a temperature of 40℃. Studies on the replacement process have shown that the replacement process meets the first-order reaction rate law,with the activation energy Ea=13.72 kJ/mol,and the reaction is diffusion-controlled. The reaction rate equation is v=3.2470 × c(Bi3+) exp(-(13720)/(RT)). Electrochemical analysis shows that the micro-current promotes the replacement process,and the obtained sponge powder bismuth is high grade with fewer impurities,in particular,the lead content is significantly reduced.
The sponge powder bismuth replaced by powder iron is low grade. In order to overcome such problem,new approach for producing sponge powder bismuth is developed with the use of iron plates under micro-current. The grade of the obtained sponge powder bismuth is over 90%,which is replaced by iron plates with the use of iron plates as the anode,graphite as the cathode,and the current density is 5 × 10-3 A/cm2at a temperature of 40℃. Studies on the replacement process have shown that the replacement process meets the first-order reaction rate law,with the activation energy Ea=13.72 kJ/mol,and the reaction is diffusion-controlled. The reaction rate equation is v=3.2470 × c(Bi3+) exp(-(13720)/(RT)). Electrochemical analysis shows that the micro-current promotes the replacement process,and the obtained sponge powder bismuth is high grade with fewer impurities,in particular,the lead content is significantly reduced.
2013, 30(10): 1189-1193
doi: 10.3724/SP.J.1095.2013.20562
Abstract:
Hybrid electrochemical capacitors composed with molybdenum trioxide as negative materials and activated carbon as positive materials were studied in 1 mol/L NaPF6-propylene carbonate(PC). The voltage window of the electrochemical capacitors is in the range of 0~3 V,the energy density and power density is 33.0 W·h/kg and 595.6 W/kg respectively,the capacity is reduced to 93.8% after 1000 cycles compared with the 20th cycle,and the coulombic efficiency reaches 95.1% of the value of the 20th cycle.
Hybrid electrochemical capacitors composed with molybdenum trioxide as negative materials and activated carbon as positive materials were studied in 1 mol/L NaPF6-propylene carbonate(PC). The voltage window of the electrochemical capacitors is in the range of 0~3 V,the energy density and power density is 33.0 W·h/kg and 595.6 W/kg respectively,the capacity is reduced to 93.8% after 1000 cycles compared with the 20th cycle,and the coulombic efficiency reaches 95.1% of the value of the 20th cycle.
2013, 30(10): 1194-1201
doi: 10.3724/SP.J.1095.2013.20554
Abstract:
This article adopted the composite made up of chitosan and meso-porous carbon doped with nitrogen material which was secured by mechanical mixing as carrier for laccase immobilization.Entrapped laccase based biocathode was prepared by complex with enzyme dripping and coating on the surface of bare glassy carbon electrode and drying process in air consecutively.The direct electrochemical behavior of this asprepared electrode in the electrolyte without any substrate was investigated,furthermore its catalytic function for oxygen reduction reactioN(ORR),its long-term usability,reproducibility and mechanical stability were systematically estimated.On the basis of previous results,performance of this laccase based electrode as oxygen electrochemical sensor was examined.Results from research indicate that the composite composed of meso-porous carbon doped with nitrogen and chitosan with entrapped enzyme modified electrode displays the direct electron transfer between T1 active centre in laccase and the electrode in the absence of any extra electron relay and can catalyze oxygen electrochemical reductioN(ORR) under higher potentials.The onset potential for ORR is~860 mV and the mid-wave current density for ORR is 78 × 10-12 A/cm2. This laccase based electrode shows excellent reproducibility and desirable long-term stability,but its mechanical stability is inferior. This laccase base electrode was proved to be a suitable sensor for oxygen molecules with the detection limit low to 0.4 μmol/L,the high sensitivity of 67.9 × 10-6 A·L/mmol and the preferable affinity KM=764.0 μmol/L for oxygen.
This article adopted the composite made up of chitosan and meso-porous carbon doped with nitrogen material which was secured by mechanical mixing as carrier for laccase immobilization.Entrapped laccase based biocathode was prepared by complex with enzyme dripping and coating on the surface of bare glassy carbon electrode and drying process in air consecutively.The direct electrochemical behavior of this asprepared electrode in the electrolyte without any substrate was investigated,furthermore its catalytic function for oxygen reduction reactioN(ORR),its long-term usability,reproducibility and mechanical stability were systematically estimated.On the basis of previous results,performance of this laccase based electrode as oxygen electrochemical sensor was examined.Results from research indicate that the composite composed of meso-porous carbon doped with nitrogen and chitosan with entrapped enzyme modified electrode displays the direct electron transfer between T1 active centre in laccase and the electrode in the absence of any extra electron relay and can catalyze oxygen electrochemical reductioN(ORR) under higher potentials.The onset potential for ORR is~860 mV and the mid-wave current density for ORR is 78 × 10-12 A/cm2. This laccase based electrode shows excellent reproducibility and desirable long-term stability,but its mechanical stability is inferior. This laccase base electrode was proved to be a suitable sensor for oxygen molecules with the detection limit low to 0.4 μmol/L,the high sensitivity of 67.9 × 10-6 A·L/mmol and the preferable affinity KM=764.0 μmol/L for oxygen.
2013, 30(10): 1202-1207
doi: 10.3724/SP.J.1095.2013.20560
Abstract:
Hydrophobic dodecyl sulfonate-layered double hydroxides (DSO-LDHs) were prepared with Mg-AlLDHs as the precursors,and its structure was characterized by XRD,optical microscope and FTIR. The results indicate that DSO anions are intercalated into LDHs interlayer successfully. In this paper,DSO-LDHs were applied as thixotropic materials in 4% nicosulfuron oil flowable suspension.The rheological results indicate that pesticide particles are attached to DSO-LDHs through electrostatic interaction since DSO-LDHs has a special structure of hydrotalcite laminated layers.As the concentration of DSO-LDHs increases,the oil suspension shows a positive thixotropy,and the yield value is also increased,whereas the oil separation ratio is decreased.
Hydrophobic dodecyl sulfonate-layered double hydroxides (DSO-LDHs) were prepared with Mg-AlLDHs as the precursors,and its structure was characterized by XRD,optical microscope and FTIR. The results indicate that DSO anions are intercalated into LDHs interlayer successfully. In this paper,DSO-LDHs were applied as thixotropic materials in 4% nicosulfuron oil flowable suspension.The rheological results indicate that pesticide particles are attached to DSO-LDHs through electrostatic interaction since DSO-LDHs has a special structure of hydrotalcite laminated layers.As the concentration of DSO-LDHs increases,the oil suspension shows a positive thixotropy,and the yield value is also increased,whereas the oil separation ratio is decreased.
2013, 30(10): 1208-1214
doi: 10.3724/SP.J.1095.2013.20553
Abstract:
In order to unveil the rheological properties of suspensions of montmorillonite (MT) and its mixture with sodium carboxymethyl cellulose (CMC)/MT,the effects of the mass fraction w of MT,mass ratio R of CMC to MT,electrolyte,pH and experimental temperature on such properties have been systematically studied. When w(MT) was increased from 1.0% to 3.0%,pure MT suspension changed from Newtonianlike fluid to plastic one,and the thixotropic type changed from non-thixotropy to positive thixotropy and then a complex one. For CMC/MT plastic suspension,the increase of R(fixing w(MT)=2.0% in all the systems)would cause the yield value(τ0) and consistency coefficient (K) to increase as well. The hysteresis loop area(S) increased initially and then decreased,which was accompanied with a synchronous variation of the absolute zeta potential value(|ζ|). The plastic and thixotropic characters of CMC/MT suspension could not be altered by either the electrolytes or experimental temperature investigated. But the yield value τ0 and consistency coefficient K would increase with the increase of electrolyte (NaCl,MgCl2 and AlCl3) concentrations or the decrease of experimental temperature. With the increase of pH value of CMC/MT suspension,its thixotropic type was transformed from negative into positive and the|ζ|incresesd,meanwhile the S firstly increased and then decreased and its maximum value was reached at pH=8.46.
In order to unveil the rheological properties of suspensions of montmorillonite (MT) and its mixture with sodium carboxymethyl cellulose (CMC)/MT,the effects of the mass fraction w of MT,mass ratio R of CMC to MT,electrolyte,pH and experimental temperature on such properties have been systematically studied. When w(MT) was increased from 1.0% to 3.0%,pure MT suspension changed from Newtonianlike fluid to plastic one,and the thixotropic type changed from non-thixotropy to positive thixotropy and then a complex one. For CMC/MT plastic suspension,the increase of R(fixing w(MT)=2.0% in all the systems)would cause the yield value(τ0) and consistency coefficient (K) to increase as well. The hysteresis loop area(S) increased initially and then decreased,which was accompanied with a synchronous variation of the absolute zeta potential value(|ζ|). The plastic and thixotropic characters of CMC/MT suspension could not be altered by either the electrolytes or experimental temperature investigated. But the yield value τ0 and consistency coefficient K would increase with the increase of electrolyte (NaCl,MgCl2 and AlCl3) concentrations or the decrease of experimental temperature. With the increase of pH value of CMC/MT suspension,its thixotropic type was transformed from negative into positive and the|ζ|incresesd,meanwhile the S firstly increased and then decreased and its maximum value was reached at pH=8.46.
2013, 30(10): 1215-1221
doi: 10.3724/SP.J.1095.2013.30021
Abstract:
The structure and characteristics of synthetic G-COOH were studied using the FTIR technique. The adsorption of four ionic dyes,methyl violet,neutral red,brilliant yellow and alizarin red,onto G-COOH in aqueous solution was studied in a batch system with respect to adsorbent dose,contact time,initial dye concentration and solution pH.Also,the desorption properties of methyl violet dye was investigated.The desorption data show that the removal percent of dye methyl violet from G-COOH is 88.2% by using NaOH/EtOH eluting reagent,and the desorbed G-COOH can be reused to adsorb the dye.The Langmuir and Freundlich adsorption models have been applied to describe the equilibrium isotherms and the isotherm constants are determined.The Langmuir model agrees very well with the experimental data of cation dyes (methyl violet and neutral red),while the adsorption behavior of anion dyes (brilliant yellow and alizarin red) are fitted to Freundlich isotherms.The calculated absorption parameters indicate that absorption process of dyes on G-COOH is easy to take place.Batch kinetic data from experimental investigations on the removal of four ionic dyes from aqueous solutions fit well with the pseudo-second-order kinetic model.The results in this study indicate that G-COOH is an attractive candidate for removing dyes from dye wastewater.
The structure and characteristics of synthetic G-COOH were studied using the FTIR technique. The adsorption of four ionic dyes,methyl violet,neutral red,brilliant yellow and alizarin red,onto G-COOH in aqueous solution was studied in a batch system with respect to adsorbent dose,contact time,initial dye concentration and solution pH.Also,the desorption properties of methyl violet dye was investigated.The desorption data show that the removal percent of dye methyl violet from G-COOH is 88.2% by using NaOH/EtOH eluting reagent,and the desorbed G-COOH can be reused to adsorb the dye.The Langmuir and Freundlich adsorption models have been applied to describe the equilibrium isotherms and the isotherm constants are determined.The Langmuir model agrees very well with the experimental data of cation dyes (methyl violet and neutral red),while the adsorption behavior of anion dyes (brilliant yellow and alizarin red) are fitted to Freundlich isotherms.The calculated absorption parameters indicate that absorption process of dyes on G-COOH is easy to take place.Batch kinetic data from experimental investigations on the removal of four ionic dyes from aqueous solutions fit well with the pseudo-second-order kinetic model.The results in this study indicate that G-COOH is an attractive candidate for removing dyes from dye wastewater.
2013, 30(10): 1222-1230
doi: 10.3724/SP.J.1095.2013.30018
Abstract:
A novel melamine magnetic molecularly imprinted polymer(Fe3O4-GO@SiO2@MIP) was prepared based on graphene oxide(GO) using melamine(MEL) as the template molecule,methacrylic acid(MAA) as the functional monomer and ethylene glycol dimethacrylate(EGDMA) as the cross-linker. The Fe3O4-GO@SiO2@MIP was characterized by scanning electron microscope(SEM),transmission electron microscope(TEM),thermogravimetric analysis(TGA) and vibrating sample magnetometer(VSM).The results showed that MEL imprinted layer was grafted on magnetic GO surface successfully.The adsorption properties were investigated by high performance liquid chromatography,and the results demonstrated that the Fe3O4-GO@SiO2@MIP exhibited specific selectivity towards MEL.The maximum adsorption capacity of Fe3O4-GO@SiO2@MIP is 33.11 mg/g,and the selectivity factor of MEL towards CYR and CYA is 2.43 and 2.84,respectively.Combined with magnetic solid phase extraction(M-SPE) and high-performance liquid chromatography with the imprinted material as stationary phase,melamine from the sample solution of milk was successfully separated,enriched and detected.
A novel melamine magnetic molecularly imprinted polymer(Fe3O4-GO@SiO2@MIP) was prepared based on graphene oxide(GO) using melamine(MEL) as the template molecule,methacrylic acid(MAA) as the functional monomer and ethylene glycol dimethacrylate(EGDMA) as the cross-linker. The Fe3O4-GO@SiO2@MIP was characterized by scanning electron microscope(SEM),transmission electron microscope(TEM),thermogravimetric analysis(TGA) and vibrating sample magnetometer(VSM).The results showed that MEL imprinted layer was grafted on magnetic GO surface successfully.The adsorption properties were investigated by high performance liquid chromatography,and the results demonstrated that the Fe3O4-GO@SiO2@MIP exhibited specific selectivity towards MEL.The maximum adsorption capacity of Fe3O4-GO@SiO2@MIP is 33.11 mg/g,and the selectivity factor of MEL towards CYR and CYA is 2.43 and 2.84,respectively.Combined with magnetic solid phase extraction(M-SPE) and high-performance liquid chromatography with the imprinted material as stationary phase,melamine from the sample solution of milk was successfully separated,enriched and detected.
2013, 30(10): 1231-1236
doi: 10.3724/SP.J.1095.2013.30067
Abstract:
Cellulose tris(3,5-dimethylphenylcarbamate)(CDMPC) was prepared from cellulose and 3,5-dimethylphenyl isocyanate.Then the product was coated onto three supports,i.e.small-pore silica gel(SG),aminopropylsilylated silica gel(APS-SG),and mesoporous silica SBA-15.The obtained chiral stationary phases(CSPs) were denoted as SG@CDMPC(CSP1),APS-SG@CDMPC(CSP2),and SBA-15@CDMPC(CSP3).Twelve neutral or acidic compounds were enantioseparated with these three homemade CSPs in the normal phase mode.The results were compared with enantioseparation using the commercial CSP,Chiralcel OD-H.Six compounds are obtained with a better column efficiency on CSP1 than that on Chiralcel OD-H,and two of them are obtained with a better enantioseparation.The enantioseparation ability is poorer on CSP2 and CSP3 than those on CSP1 and the commercial column in general.Enantioseparation and quantitative determination of warfarin were performed on the homemade CSPs.The limit of detection(LOD) is 10 μg/L for warfarin on CSP1.The linear calibration curve is obtained in the concentration range of 0.05~5.0 g/L.
Cellulose tris(3,5-dimethylphenylcarbamate)(CDMPC) was prepared from cellulose and 3,5-dimethylphenyl isocyanate.Then the product was coated onto three supports,i.e.small-pore silica gel(SG),aminopropylsilylated silica gel(APS-SG),and mesoporous silica SBA-15.The obtained chiral stationary phases(CSPs) were denoted as SG@CDMPC(CSP1),APS-SG@CDMPC(CSP2),and SBA-15@CDMPC(CSP3).Twelve neutral or acidic compounds were enantioseparated with these three homemade CSPs in the normal phase mode.The results were compared with enantioseparation using the commercial CSP,Chiralcel OD-H.Six compounds are obtained with a better column efficiency on CSP1 than that on Chiralcel OD-H,and two of them are obtained with a better enantioseparation.The enantioseparation ability is poorer on CSP2 and CSP3 than those on CSP1 and the commercial column in general.Enantioseparation and quantitative determination of warfarin were performed on the homemade CSPs.The limit of detection(LOD) is 10 μg/L for warfarin on CSP1.The linear calibration curve is obtained in the concentration range of 0.05~5.0 g/L.
