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2011 Volume 28 Issue 12
2011, 28(12): 1343-1353
doi: 10.3724/SP.J.1095.2011.00004
Abstract:
Reactions of C60 with amines(C60 amination reaction) are important methods for the derivatization of C60.In this review,basic principles and characteristics of C60 hydroaminaton are introduced.Recent development on hydroamination of C60 and its application in preparing C60-containing functional polymers,C60-containing self-assembled monolayers,C60-containing organic/inorganic nanoparticles,and C60-based biological materials are also summarized.
Reactions of C60 with amines(C60 amination reaction) are important methods for the derivatization of C60.In this review,basic principles and characteristics of C60 hydroaminaton are introduced.Recent development on hydroamination of C60 and its application in preparing C60-containing functional polymers,C60-containing self-assembled monolayers,C60-containing organic/inorganic nanoparticles,and C60-based biological materials are also summarized.
2011, 28(12): 1354-1359
doi: 10.3724/SP.J.1095.2011.00027
Abstract:
The kinetics of polymerization of acrylamide(AM) and dimethyldiallylammonium chloride(DMDAAC) initiated by ammonium persulfate-sodium bisulfate redox complex in aqueous solution was studied.The polymerization rate equation was obtained,and the apparent activation energy and reactivity ratio were measured.The results show that when the polymerization temperature is 45℃,n(AM):n(DMDAAC) is 5:5,6:4 and 7:3,the polymerization rate equations are Rp1=kc(M)2.84c(IO)0.51 c(IR)0.61,Rp2=kc(M)2.77c(IO)0.51c(IR)0.59 and Rp3=kc(M)2.73c(IO)0.50c(IR)0.56.The apparent activation energies are Ea1=90.61 kJ/mol,Ea2=88.88 kJ/mol and Ea3=85.15 kJ/mol,respectively,while the reactivity ratios of AM and DMDAAC are rAM=6.11,rDMDAAC=0.14.The kinetics results could explain the difference of copolymerization rate and intrinsic viscosity of poly(DMDAAC-co-AM)(PDA) with different cationicities.
The kinetics of polymerization of acrylamide(AM) and dimethyldiallylammonium chloride(DMDAAC) initiated by ammonium persulfate-sodium bisulfate redox complex in aqueous solution was studied.The polymerization rate equation was obtained,and the apparent activation energy and reactivity ratio were measured.The results show that when the polymerization temperature is 45℃,n(AM):n(DMDAAC) is 5:5,6:4 and 7:3,the polymerization rate equations are Rp1=kc(M)2.84c(IO)0.51 c(IR)0.61,Rp2=kc(M)2.77c(IO)0.51c(IR)0.59 and Rp3=kc(M)2.73c(IO)0.50c(IR)0.56.The apparent activation energies are Ea1=90.61 kJ/mol,Ea2=88.88 kJ/mol and Ea3=85.15 kJ/mol,respectively,while the reactivity ratios of AM and DMDAAC are rAM=6.11,rDMDAAC=0.14.The kinetics results could explain the difference of copolymerization rate and intrinsic viscosity of poly(DMDAAC-co-AM)(PDA) with different cationicities.
2011, 28(12): 1360-1363
doi: 10.3724/SP.J.1095.2011.00035
Abstract:
Chloromethylation of phenophthalein polyether sulfone(PES-C) was performed in a homogeneous system using 1,4-bis(chloromethoxyl) butane(BCMB) as the chloromethylation reagent.Chloromethylation of PES-C(CMPES-C) with an appropriate chloromethylation degree and complete linearity was obtained under the optimum reaction conditions.The chemical structures and compositions of the products were characterized by IR and 1H NMR.The chloromethylation degree and properties of CMPES-C,such as solubility in common organic solvents and thermal stability compared with phenophthalein polyether ketone(PEK-C) were also discussed.The chloromethylation degree was determined by 1H NMR integration.
Chloromethylation of phenophthalein polyether sulfone(PES-C) was performed in a homogeneous system using 1,4-bis(chloromethoxyl) butane(BCMB) as the chloromethylation reagent.Chloromethylation of PES-C(CMPES-C) with an appropriate chloromethylation degree and complete linearity was obtained under the optimum reaction conditions.The chemical structures and compositions of the products were characterized by IR and 1H NMR.The chloromethylation degree and properties of CMPES-C,such as solubility in common organic solvents and thermal stability compared with phenophthalein polyether ketone(PEK-C) were also discussed.The chloromethylation degree was determined by 1H NMR integration.
2011, 28(12): 1364-1369
doi: 10.3724/SP.J.1095.2011.00011
Abstract:
Fluorine groups were integrated into polyurethane main chains using monocarboxyl fluorocarbon chain as fluorinated modifier.Fluorinated waterborne polyurethane(WPU) containing ionic in soft segment(FSPU) was obtained via molecular designing process.The properties such as synthetic method,water assistance,thermal stability and crystallinity of conventional WPU,fluorinated WPU containing ionic in hard segment(FHPU) and FSPU were compared.Among of them,FSPU shows the best performance.The structure of fluorinated WPU was determined and the influence of fluorine groups on hydrogen bond between soft and hard segments was characterized by IR spectra.The water contact angle was increased from 73° to 107° with the increase of fluorine groups.Water absorption was reduced by 66% and water resistance of polyurethane was increased.The themogravimetric analysis results indicated that the max mass loss temperature of polyurethane glue film was increased by 30℃ therefore the thermal stability was improved.Wide X-ray diffraction and scanning electron microscope results showed that multiphase structure existed in the fluorinated polyurethane,the crystallinity of fluorinated polyurethane glue film was increased and the crystalline form was slightly changed.
Fluorine groups were integrated into polyurethane main chains using monocarboxyl fluorocarbon chain as fluorinated modifier.Fluorinated waterborne polyurethane(WPU) containing ionic in soft segment(FSPU) was obtained via molecular designing process.The properties such as synthetic method,water assistance,thermal stability and crystallinity of conventional WPU,fluorinated WPU containing ionic in hard segment(FHPU) and FSPU were compared.Among of them,FSPU shows the best performance.The structure of fluorinated WPU was determined and the influence of fluorine groups on hydrogen bond between soft and hard segments was characterized by IR spectra.The water contact angle was increased from 73° to 107° with the increase of fluorine groups.Water absorption was reduced by 66% and water resistance of polyurethane was increased.The themogravimetric analysis results indicated that the max mass loss temperature of polyurethane glue film was increased by 30℃ therefore the thermal stability was improved.Wide X-ray diffraction and scanning electron microscope results showed that multiphase structure existed in the fluorinated polyurethane,the crystallinity of fluorinated polyurethane glue film was increased and the crystalline form was slightly changed.
2011, 28(12): 1370-1374
doi: 10.3724/SP.J.1095.2011.00754
Abstract:
A novel bisphenol F-type dianhydride(BPFDA) monomer was synthesized using 4-chlorophthalimide through hydration,acidification,and dehydration.Its structure was determined with 1H NMR and IR.Two types of polyimide films were prepared with the dianhydride and 4,4'-diaminodiphenyl ether(ODA) or 4,4'-methylene dianiline(MDA) via conventional one-step method in N,N'-dimethylacetamide.The obtained polyamic acid was then further imidized into polyimide films and characterized.Results show that the glasstransition temperatures of the polyimide films were 200 and 204℃;the temperatures of 5% mass loss were 506.50 and 459.10℃;and the tensile strength of the films were 110 and 100 MPa,respectively.
A novel bisphenol F-type dianhydride(BPFDA) monomer was synthesized using 4-chlorophthalimide through hydration,acidification,and dehydration.Its structure was determined with 1H NMR and IR.Two types of polyimide films were prepared with the dianhydride and 4,4'-diaminodiphenyl ether(ODA) or 4,4'-methylene dianiline(MDA) via conventional one-step method in N,N'-dimethylacetamide.The obtained polyamic acid was then further imidized into polyimide films and characterized.Results show that the glasstransition temperatures of the polyimide films were 200 and 204℃;the temperatures of 5% mass loss were 506.50 and 459.10℃;and the tensile strength of the films were 110 and 100 MPa,respectively.
2011, 28(12): 1375-1378
doi: 10.3724/SP.J.1095.2011.00006
Abstract:
1-(4-Chloroaniline)-4-(4-pyridylmethyl)-2,3-benzodiazine succinate(4) was synthesized by addition,rearrangement,substitution and halogenesis steps with phthalide and 4-pyridinecarbaldehydes as starting reagents.The intermediate and target compound 4 were characterized by 1H NMR,MS and HPLC.After purification by recrystallization,the compound 4(98.1% purity estimated by HPLC) was experimentally used to treat colorectal cancer nude mice.The result shows that this compound obviously restrains the growth of tumors.
1-(4-Chloroaniline)-4-(4-pyridylmethyl)-2,3-benzodiazine succinate(4) was synthesized by addition,rearrangement,substitution and halogenesis steps with phthalide and 4-pyridinecarbaldehydes as starting reagents.The intermediate and target compound 4 were characterized by 1H NMR,MS and HPLC.After purification by recrystallization,the compound 4(98.1% purity estimated by HPLC) was experimentally used to treat colorectal cancer nude mice.The result shows that this compound obviously restrains the growth of tumors.
2011, 28(12): 1379-1386
doi: 10.3724/SP.J.1095.2011.00022
Abstract:
The Fe-doped TiO2 films were prepared by sol-gel method and characterized by X-ray photoelectron spectroscopy(XPS),X-ray diffraction(XRD),confocal microscope Raman spectrometer(Raman),UV-Vis absorption spectroscopy(UV-Vis) and atomic force microscopy(AFM).The photocatalytic activities of the films were evaluated by using the degradation of the methyl orange.The results showed that TiO2 in Fe/TiO2 films took an anatase structure when calcinated between 300℃ and 600℃.Increasing the calcination temperature up to 700℃,TiO2 transformed to rutile phase.The roughness and the grain size of Fe/TiO2 films grew gradually with the increases of the doping amount of Fe content and the calcination temperature.The photon excited wavelength of the Fe/TiO2 films moved to the visible light gradually with the increase of number of coating layer.Low levels of Fe-doping improved the photocatalytic activities of the TiO2 thin films,while higher doping decreased the photocatalytic activities of TiO2 thin films.The optimal Fe-doping was found to be 0.1% for the maximum degradation of methyl orange.
The Fe-doped TiO2 films were prepared by sol-gel method and characterized by X-ray photoelectron spectroscopy(XPS),X-ray diffraction(XRD),confocal microscope Raman spectrometer(Raman),UV-Vis absorption spectroscopy(UV-Vis) and atomic force microscopy(AFM).The photocatalytic activities of the films were evaluated by using the degradation of the methyl orange.The results showed that TiO2 in Fe/TiO2 films took an anatase structure when calcinated between 300℃ and 600℃.Increasing the calcination temperature up to 700℃,TiO2 transformed to rutile phase.The roughness and the grain size of Fe/TiO2 films grew gradually with the increases of the doping amount of Fe content and the calcination temperature.The photon excited wavelength of the Fe/TiO2 films moved to the visible light gradually with the increase of number of coating layer.Low levels of Fe-doping improved the photocatalytic activities of the TiO2 thin films,while higher doping decreased the photocatalytic activities of TiO2 thin films.The optimal Fe-doping was found to be 0.1% for the maximum degradation of methyl orange.
2011, 28(12): 1387-1392
doi: 10.3724/SP.J.1095.2011.00753
Abstract:
The synthesis,characterization,and photovoltaic performance of two new organic dyes,hexapropyltruxeneamino-rhodanine-3-acetic acid(MXD8) and hexapropyltruxeneamino-3,4-ethylenedioxythiophenerhodanine-3-acetic acid(MXD9),were reported.The two dyes contain truxene-based triarylamine as electron donor and a rhodanine-3-acetic acid as electron acceptor.It is found that the two dyes exhibit broad absorption and high molar absorption coefficients.The ground and the excited state levels of the two dyes were determined by using the cyclic voltammetry and the optical absorption spectroscopy.The results show the HOMO and LUMO levels of two dyes are suitable for dye-sensitized solar cells.The dyes were applied into nanocrystalline TiO2 dye-sensitized solar cells through standard operations.Under simulated AM 1.5 irradiation(100×10-3 W/cm2),MXD8 sensitized cell afforded a short-circuit photocurrent density(JSC) of 5.76×10-3 A/cm2,an open-circuit voltage(VOC) of 614 mV,and a fill factor(FF) of 0.66,corresponding to an overall conversion efficiency(η) of 2.33%.In contrast,though 3,4-ethylenedioxythiophene(EDOT) unit was introduced as the π-bridge,MXD9 sensitized cell gave a lower efficiency of 1.72%.A significantly larger extent of charge recombination between the injection electron and I2 and/or I3- acceptor species was found for MXD9 dyes than MXD8 dyes based on the electrochemical impedance spectroscopy measurements,consequently,leading to a lower efficiency.These results suggest that the charge recombination may be correlated to the increased polarizability of the larger truxene-based triarylamine dyes.From our findings,we propose that the functionalized-truxene is a promising donor unit for the future development of organic sensitizers.
The synthesis,characterization,and photovoltaic performance of two new organic dyes,hexapropyltruxeneamino-rhodanine-3-acetic acid(MXD8) and hexapropyltruxeneamino-3,4-ethylenedioxythiophenerhodanine-3-acetic acid(MXD9),were reported.The two dyes contain truxene-based triarylamine as electron donor and a rhodanine-3-acetic acid as electron acceptor.It is found that the two dyes exhibit broad absorption and high molar absorption coefficients.The ground and the excited state levels of the two dyes were determined by using the cyclic voltammetry and the optical absorption spectroscopy.The results show the HOMO and LUMO levels of two dyes are suitable for dye-sensitized solar cells.The dyes were applied into nanocrystalline TiO2 dye-sensitized solar cells through standard operations.Under simulated AM 1.5 irradiation(100×10-3 W/cm2),MXD8 sensitized cell afforded a short-circuit photocurrent density(JSC) of 5.76×10-3 A/cm2,an open-circuit voltage(VOC) of 614 mV,and a fill factor(FF) of 0.66,corresponding to an overall conversion efficiency(η) of 2.33%.In contrast,though 3,4-ethylenedioxythiophene(EDOT) unit was introduced as the π-bridge,MXD9 sensitized cell gave a lower efficiency of 1.72%.A significantly larger extent of charge recombination between the injection electron and I2 and/or I3- acceptor species was found for MXD9 dyes than MXD8 dyes based on the electrochemical impedance spectroscopy measurements,consequently,leading to a lower efficiency.These results suggest that the charge recombination may be correlated to the increased polarizability of the larger truxene-based triarylamine dyes.From our findings,we propose that the functionalized-truxene is a promising donor unit for the future development of organic sensitizers.
2011, 28(12): 1393-1396
doi: 10.3724/SP.J.1095.2011.00721
Abstract:
Red phosphors Sr(1-1.5x)Mo0.8Si0.2O3.8:Eux3+(x=0.1,0.2,0.3,0.4,0.5) used for LED were synthesized by high temperature solid state method.XRD,fluorescence excitation and emission spectra were used for analysis the phase composition and luminescent properties of the materials.The XRD result of sample x=0.1 is consistent with JCPDS-Card No.08-0482(SrMoO4).As luminescence center,Eu3+ takes the position of Sr2+.With the increase of Eu3+ concentration,which represents the concentration of Eu3+,the emission intensities of 5D0-7F1 magnetic dipole transition at 593 nm and 5D0-7F2 transition at 614 nm were converted.When x ≤0.4,the magnetic dipole transition 5D0-7F1 dominates emitting with an orange light.For x=0.5,the electric dipole transition 5D0-7F2 dominates emitting with red light.The excessive doped Eu3+ ion in the lattice could not enter into SrMoO4 site,but only exist in lattice vacancy formed defect,which made Eu3+ in unsymmetrical lattice site.It is lead to promote the electric dipole 5D0-7F2 transitions and reduce the magnetic dipole 5D0-7F1 transitions.Therefore,phosphors with different emitting color can be obtained by adjusting the content of activator.In Eu3+ doped strontium silicon molybdate system,under excitation at 614 nm,the wide bands at 368 nm and the absorption band at 467 nm corresponded to absorption of the host matrix and the 7F0-5D2 transitions,respectively.The extra activator Eu3+ at lattice gap(x=0.5) promote the absorption bands 3 times more than that for x=0.4.The material can produce tunable orange-red color,and its excitation wavelength can match with UV LED chips very well.
Red phosphors Sr(1-1.5x)Mo0.8Si0.2O3.8:Eux3+(x=0.1,0.2,0.3,0.4,0.5) used for LED were synthesized by high temperature solid state method.XRD,fluorescence excitation and emission spectra were used for analysis the phase composition and luminescent properties of the materials.The XRD result of sample x=0.1 is consistent with JCPDS-Card No.08-0482(SrMoO4).As luminescence center,Eu3+ takes the position of Sr2+.With the increase of Eu3+ concentration,which represents the concentration of Eu3+,the emission intensities of 5D0-7F1 magnetic dipole transition at 593 nm and 5D0-7F2 transition at 614 nm were converted.When x ≤0.4,the magnetic dipole transition 5D0-7F1 dominates emitting with an orange light.For x=0.5,the electric dipole transition 5D0-7F2 dominates emitting with red light.The excessive doped Eu3+ ion in the lattice could not enter into SrMoO4 site,but only exist in lattice vacancy formed defect,which made Eu3+ in unsymmetrical lattice site.It is lead to promote the electric dipole 5D0-7F2 transitions and reduce the magnetic dipole 5D0-7F1 transitions.Therefore,phosphors with different emitting color can be obtained by adjusting the content of activator.In Eu3+ doped strontium silicon molybdate system,under excitation at 614 nm,the wide bands at 368 nm and the absorption band at 467 nm corresponded to absorption of the host matrix and the 7F0-5D2 transitions,respectively.The extra activator Eu3+ at lattice gap(x=0.5) promote the absorption bands 3 times more than that for x=0.4.The material can produce tunable orange-red color,and its excitation wavelength can match with UV LED chips very well.
2011, 28(12): 1397-1401
doi: 10.3724/SP.J.1095.2011.00638
Abstract:
The catalyst support SiO2 was firstly pretreated with different amounts of sodium nitrate solution followed by impregnation in copper and zinc nitrates solution.The effects of the preparation method and contents of sodium on the structures and performances of Cu-ZnO/Na-SiO2 catalysts were investigated.The catalytic activities of these catalysts were evaluated using the dehydrogenation of 2-butanol and the selectivity for methyl ethyl ketone as probes.These catalysts were characterized by means of XRD and TPR.The results indicated that sodium-pretreatment can improve the dispersion of metallic copper and the interaction between the copper species and the support.
The catalyst support SiO2 was firstly pretreated with different amounts of sodium nitrate solution followed by impregnation in copper and zinc nitrates solution.The effects of the preparation method and contents of sodium on the structures and performances of Cu-ZnO/Na-SiO2 catalysts were investigated.The catalytic activities of these catalysts were evaluated using the dehydrogenation of 2-butanol and the selectivity for methyl ethyl ketone as probes.These catalysts were characterized by means of XRD and TPR.The results indicated that sodium-pretreatment can improve the dispersion of metallic copper and the interaction between the copper species and the support.
2011, 28(12): 1402-1407
doi: 10.3724/SP.J.1095.2011.00246
Abstract:
The Ti1.4V0.6Ni and V5Ti9Zr26.2Ni38Cr3.5Co1.5Mn15.6Al0.4Sn0.8(VTZN) alloys were prepared via an arc-melting method followed by the melt-spinning technique.We systematically investigated the structures and electrochemical hydrogen storage performances of Ti1.4V0.6Ni+20%(mass fraction) ball-milled VTZN composite materials.It was found that the icosahedral quasicrystal,FCC(Ti2Ni) and BCC structural solid solution coexisted in the resultant composite material.When using such composite materials as Ni-MH battery anodes,the discharge current densities were about 30 mA/g at 303 K,the maximal electrochemical discharge capacity reaches 310 mA·h/g.In addition,the electrode of Ti1.4V0.6Ni and VTZN composite showed high-rate discharge ability compared with that of Ti1.4V0.6Ni.
The Ti1.4V0.6Ni and V5Ti9Zr26.2Ni38Cr3.5Co1.5Mn15.6Al0.4Sn0.8(VTZN) alloys were prepared via an arc-melting method followed by the melt-spinning technique.We systematically investigated the structures and electrochemical hydrogen storage performances of Ti1.4V0.6Ni+20%(mass fraction) ball-milled VTZN composite materials.It was found that the icosahedral quasicrystal,FCC(Ti2Ni) and BCC structural solid solution coexisted in the resultant composite material.When using such composite materials as Ni-MH battery anodes,the discharge current densities were about 30 mA/g at 303 K,the maximal electrochemical discharge capacity reaches 310 mA·h/g.In addition,the electrode of Ti1.4V0.6Ni and VTZN composite showed high-rate discharge ability compared with that of Ti1.4V0.6Ni.
2011, 28(12): 1408-1414
doi: 10.3724/SP.J.1095.2011.00758
Abstract:
Anodes of proton exchange membrane fuel cell with the platinum-hydrogen tungsten bronze(HxWO3) as the composite catalysts were prepared by electrochemical reduction on carbon cloth.The catalysts were characterized by XRD,SEM,EIS and single-cell polarization tests.The results showed that the order of electrochemical reduction had a major impact on the morphology and dispersion of the catalysts.The composite catalyst of HxWO3/Pt exhibited synergistic catalytic effect and increased the catalytic activity for hydrogen oxidation.The HxWO3/Pt catalyst showed the highest catalytic activity for hydrogen oxidation,while the Pt-HxWO3 catalyst showed the lowest catalytic activity.Because of the coexistence of two electrolytes,less hydrogen tungsten bronze catalyst was deposited on the electrode and platinum agglomerated obviously on the Pt-HxWO3 electrodes,leading to a decrease of the catalytic activity.
Anodes of proton exchange membrane fuel cell with the platinum-hydrogen tungsten bronze(HxWO3) as the composite catalysts were prepared by electrochemical reduction on carbon cloth.The catalysts were characterized by XRD,SEM,EIS and single-cell polarization tests.The results showed that the order of electrochemical reduction had a major impact on the morphology and dispersion of the catalysts.The composite catalyst of HxWO3/Pt exhibited synergistic catalytic effect and increased the catalytic activity for hydrogen oxidation.The HxWO3/Pt catalyst showed the highest catalytic activity for hydrogen oxidation,while the Pt-HxWO3 catalyst showed the lowest catalytic activity.Because of the coexistence of two electrolytes,less hydrogen tungsten bronze catalyst was deposited on the electrode and platinum agglomerated obviously on the Pt-HxWO3 electrodes,leading to a decrease of the catalytic activity.
2011, 28(12): 1415-1420
doi: 10.3724/SP.J.1095.2011.00697
Abstract:
Tungsten oxide-based nano-materials with two different crystal structures were prepared by hydrothermal method and characterized by X-ray diffraction(XRD) and electron probe micro analyzer(EPMA),respectively.The electrocatalytic activity for methanol oxidation on Pt-WO3/C electrode was studied by cyclic voltammetry.The results indicate that the electrocatalytic activity of Pt-WO3/C is much higher than that of Pt/C catalyst.For various amount of WO3,the catalyst with 20% mass fraction of WO3 has the best electrocatalytic activity.The electrocatalytic activity of the pyrochlore type tungsten oxide doped Pt/C electrode is higher than that of the tungsten bronze doped electrode,which is likely due to the strong attractions of OHads on the surface of pyrochlore type tungsten oxide.The current density of the pyrochlore type tungsten oxide doped Pt/C electrode for electro-oxidation of methanol is 87.2×10-3 A/cm2 in 0.5 mol/L CH3OH+1 mol/L H2SO4 solution.
Tungsten oxide-based nano-materials with two different crystal structures were prepared by hydrothermal method and characterized by X-ray diffraction(XRD) and electron probe micro analyzer(EPMA),respectively.The electrocatalytic activity for methanol oxidation on Pt-WO3/C electrode was studied by cyclic voltammetry.The results indicate that the electrocatalytic activity of Pt-WO3/C is much higher than that of Pt/C catalyst.For various amount of WO3,the catalyst with 20% mass fraction of WO3 has the best electrocatalytic activity.The electrocatalytic activity of the pyrochlore type tungsten oxide doped Pt/C electrode is higher than that of the tungsten bronze doped electrode,which is likely due to the strong attractions of OHads on the surface of pyrochlore type tungsten oxide.The current density of the pyrochlore type tungsten oxide doped Pt/C electrode for electro-oxidation of methanol is 87.2×10-3 A/cm2 in 0.5 mol/L CH3OH+1 mol/L H2SO4 solution.
2011, 28(12): 1421-1428
doi: 10.3724/SP.J.1095.2011.00020
Abstract:
L-Cysteine functionalized nanogold particles were synthesized with hydrogen tetrachloroaurate tetrahydrate and L-cysteine as raw materials.The functionalized nanogold particles were attached to the surface of gold disk electrode and then were covalently coupled with laccase.Electrochemical behavior of this laccasebased electrode in deaerated phosphate buffer solution and its electrocatalytic effect for oxygen reduction were investigated by cyclic voltammetry.Furthermore,the performance of this laccase based cathode as oxygen sensor was evaluated:oxygen detection limit of this sensor and its affinity towards oxygen(characterized with Michaelis-Menten constant K M) were measured with chronoamperometry.The long-term usability,thermal stability of O2 sensor together with the relationship between pH value and catalytic current were also studied.The results indicate that a direct electron transfer between the redox active centre T2 of laccase and the conductive functionalized nanogold particle occurs without any additional electron relay(formal potential of redox peaks:192.5 mV vs AgCl/Ag),and oxygen reduction occurs at a potential similar to that of T3 redox centre in laccase(780 mV vs NHE).The affinity of the laccase based sensor towards O2 was relatively high(KM=216.4 μmol/L) and the detection limit of oxygen was 0.22 μmol/L.Catalytic current for oxygen reduction can still retain approximately 78% of the initial value after storage at 4℃ refrigerator for 60 days.However,this laccase based O2 sensor displayed inferior thermal stability,and its catalytic current corresponding to O2 reduction was strongly influenced by pH value in buffer solution:when pH value of the buffer solution comes close to physiological condition,near all catalytic activity towards O2 was lost.
L-Cysteine functionalized nanogold particles were synthesized with hydrogen tetrachloroaurate tetrahydrate and L-cysteine as raw materials.The functionalized nanogold particles were attached to the surface of gold disk electrode and then were covalently coupled with laccase.Electrochemical behavior of this laccasebased electrode in deaerated phosphate buffer solution and its electrocatalytic effect for oxygen reduction were investigated by cyclic voltammetry.Furthermore,the performance of this laccase based cathode as oxygen sensor was evaluated:oxygen detection limit of this sensor and its affinity towards oxygen(characterized with Michaelis-Menten constant K M) were measured with chronoamperometry.The long-term usability,thermal stability of O2 sensor together with the relationship between pH value and catalytic current were also studied.The results indicate that a direct electron transfer between the redox active centre T2 of laccase and the conductive functionalized nanogold particle occurs without any additional electron relay(formal potential of redox peaks:192.5 mV vs AgCl/Ag),and oxygen reduction occurs at a potential similar to that of T3 redox centre in laccase(780 mV vs NHE).The affinity of the laccase based sensor towards O2 was relatively high(KM=216.4 μmol/L) and the detection limit of oxygen was 0.22 μmol/L.Catalytic current for oxygen reduction can still retain approximately 78% of the initial value after storage at 4℃ refrigerator for 60 days.However,this laccase based O2 sensor displayed inferior thermal stability,and its catalytic current corresponding to O2 reduction was strongly influenced by pH value in buffer solution:when pH value of the buffer solution comes close to physiological condition,near all catalytic activity towards O2 was lost.
2011, 28(12): 1429-1435
doi: 10.3724/SP.J.1095.2011.00766
Abstract:
This paper reports the preparation of an acetylcholinesterase(AChE)/Nafion/Prussian blue(PB)/glass carbon electrode(GCE) and the electrochemical detection of pesticides such as carbaryl and trichlorfon.Atomic force microscopy and electrochemical technique were used to investigate the construction of the modified electrode and its effects on pesticide detection.Those results indicated that AChE dispersed uniformly in Nafion/PB/GCE.The AChE/Nafion/PB/GCE constructed under optimal conditions showed a good linear relationship between the peak current and the concentration of pesticide in the range of 0.01~0.5 μmol/L & 2.0~10.0 μmol/L for carbaryl and 0.02~1.0 μmol/L & 2.0~8.0 μmol/L for trichlorfon,respectively.The limit of detection is 5.0 nmol/L for carbaryl and 10.0 nmol/L for trichlorfon,respectively.Furthermore the modified electrode was applied in the detection of analogous practical samples.It was found that the asprepared sensor had high detection sensitivity,good reproducibility and anti-interference.
This paper reports the preparation of an acetylcholinesterase(AChE)/Nafion/Prussian blue(PB)/glass carbon electrode(GCE) and the electrochemical detection of pesticides such as carbaryl and trichlorfon.Atomic force microscopy and electrochemical technique were used to investigate the construction of the modified electrode and its effects on pesticide detection.Those results indicated that AChE dispersed uniformly in Nafion/PB/GCE.The AChE/Nafion/PB/GCE constructed under optimal conditions showed a good linear relationship between the peak current and the concentration of pesticide in the range of 0.01~0.5 μmol/L & 2.0~10.0 μmol/L for carbaryl and 0.02~1.0 μmol/L & 2.0~8.0 μmol/L for trichlorfon,respectively.The limit of detection is 5.0 nmol/L for carbaryl and 10.0 nmol/L for trichlorfon,respectively.Furthermore the modified electrode was applied in the detection of analogous practical samples.It was found that the asprepared sensor had high detection sensitivity,good reproducibility and anti-interference.
2011, 28(12): 1436-1440
doi: 10.3724/SP.J.1095.2011.00009
Abstract:
A novel type of fluorescent ionic liquid,1-butyl-2-phenyl thiourea pyridinium bromide,was synthesized and a new method for determining Hg2+ in aqueous medium was developed.The results show that the method has an excellent selectivity,good linear relationship(r2=0.999 1),recovery 95.2%~102.2%,and low detection limit(0.011 mg/L) in the mass concentration range of 0.02~4 mg/L in BR buffer solution at pH=7.The method is successfully used for Hg2+ determination in natural water.
A novel type of fluorescent ionic liquid,1-butyl-2-phenyl thiourea pyridinium bromide,was synthesized and a new method for determining Hg2+ in aqueous medium was developed.The results show that the method has an excellent selectivity,good linear relationship(r2=0.999 1),recovery 95.2%~102.2%,and low detection limit(0.011 mg/L) in the mass concentration range of 0.02~4 mg/L in BR buffer solution at pH=7.The method is successfully used for Hg2+ determination in natural water.
2011, 28(12): 1441-1447
doi: 10.3724/SP.J.1095.2011.00722
Abstract:
Sorption activities of Pb2+ on montmorillonite and kaolinite were studied and a sorption mechanism was proposed.The sorption kinetics and the sorption isotherms of Pb2+ on montmorillonite and kaolinite can be described by the pseudo-second-order kinetics and Langmuir isotherm respectively.The sorption mechanism of Pb2+ on the montmorillonite and kaolinite is the surface complex mechanism,simultaneously forming innersphere surface complexes and outer-sphere surface complexes.The relative content of inner(or outer)-sphere surface complexes is pH dependent and is dominant beyond(or within) the pH range of 4~8,respectively.The sorption amount in mg/g of Pb2+ on montmorillonite is obviously higher than that on kaolinite.The affinity of montmorillonite for Pb2+ is higher than that of kaolinite for Pb2+.
Sorption activities of Pb2+ on montmorillonite and kaolinite were studied and a sorption mechanism was proposed.The sorption kinetics and the sorption isotherms of Pb2+ on montmorillonite and kaolinite can be described by the pseudo-second-order kinetics and Langmuir isotherm respectively.The sorption mechanism of Pb2+ on the montmorillonite and kaolinite is the surface complex mechanism,simultaneously forming innersphere surface complexes and outer-sphere surface complexes.The relative content of inner(or outer)-sphere surface complexes is pH dependent and is dominant beyond(or within) the pH range of 4~8,respectively.The sorption amount in mg/g of Pb2+ on montmorillonite is obviously higher than that on kaolinite.The affinity of montmorillonite for Pb2+ is higher than that of kaolinite for Pb2+.
2011, 28(12): 1448-1452
doi: 10.3724/SP.J.1095.2011.00761
Abstract:
The effect of pH on the particle distribution and zeta potential of the fumed silica(SiO2) suspended in H2SO4 or NaOH aqueous solution and their relationship were investigated with laser dynamic light scattering(DSL).The experiment showed that the isoelectric point(IEP) and titration end(TE) of silanol were at pH(IEP)=2.09 and pH(TE)=7.47,respectively,and a simple method was given for the determination of Si-OH concentration on SiO2 particle surface based on pH(TE).The dispersed phase particle size measurement showed that between IEP and TE,the hydration radius of SiO2 was stabilized near 230 nm;in H2SO4 medium,when pH< pH(IEP),the apparent hydration radius of SiO2 increased with the increased H2SO4 concentration due to the coalescence of dispersed SiO2 aggregates;in NaOH medium,when pH >pH(TE),the SiO2 aggregates decomposed and the apparent size of the dispersed phase decreased with increasing the NaOH concentration,which showed that NaOH can promote the dispersion stability of fumed silica in aqueous.
The effect of pH on the particle distribution and zeta potential of the fumed silica(SiO2) suspended in H2SO4 or NaOH aqueous solution and their relationship were investigated with laser dynamic light scattering(DSL).The experiment showed that the isoelectric point(IEP) and titration end(TE) of silanol were at pH(IEP)=2.09 and pH(TE)=7.47,respectively,and a simple method was given for the determination of Si-OH concentration on SiO2 particle surface based on pH(TE).The dispersed phase particle size measurement showed that between IEP and TE,the hydration radius of SiO2 was stabilized near 230 nm;in H2SO4 medium,when pH< pH(IEP),the apparent hydration radius of SiO2 increased with the increased H2SO4 concentration due to the coalescence of dispersed SiO2 aggregates;in NaOH medium,when pH >pH(TE),the SiO2 aggregates decomposed and the apparent size of the dispersed phase decreased with increasing the NaOH concentration,which showed that NaOH can promote the dispersion stability of fumed silica in aqueous.
2011, 28(12): 1453-1455
doi: 10.3724/SP.J.1095.2011.00107
Abstract:
Dibenzo-18-crown-6 was synthesized from catechol and disubstituted diethylene glycol in one pot under microwave irradiation in the presence of potassium hydroxide as base and template reagent.The effects of the materials,solvent,microwave power,reaction time and temperature on the yield of the reaction were examined through single factor and orthogonal experiments.The optimal conditions were obtained as follows:catechol and 2,2'-dichloroethyl ether as raw materials,dimethyl sulfoxide as solvent,reaction temperature was 70℃,reaction time was 60 min,microwave power was 500 W,and the yield of dibenzo-18-crown-6 was 46.3%.
Dibenzo-18-crown-6 was synthesized from catechol and disubstituted diethylene glycol in one pot under microwave irradiation in the presence of potassium hydroxide as base and template reagent.The effects of the materials,solvent,microwave power,reaction time and temperature on the yield of the reaction were examined through single factor and orthogonal experiments.The optimal conditions were obtained as follows:catechol and 2,2'-dichloroethyl ether as raw materials,dimethyl sulfoxide as solvent,reaction temperature was 70℃,reaction time was 60 min,microwave power was 500 W,and the yield of dibenzo-18-crown-6 was 46.3%.
2011, 28(12): 1456-1458
doi: 10.3724/SP.J.1095.2011.00046
Abstract:
Nanosized SiO2 microspheres with an average diameter of 226 nm were synthesized by sol-gel methods.After being modified by silane coupling agent KH-570 and using sodium dodecylsulphate(SDS) as emulsifier,nanosized SiO2 microspheres were fabricated on melamine formaldehyde with ultrasonication,which aimed at weakening the disadvantages of nanosized materials as well as remaining the merits of high specific surface area.Fourier transform infrared spectroscopy,scanning electron microscopy and the laser light scattering were used to characterize the appearance and chemical composition of the product.The mechanism of the synthesis was also analyzed.The particles have an average size of 30 μm and distributed uniformly.The product has potential applications in reinforcing materials and other fields and it may be used as a kind of substitute material of nanosized materials to reduce their toxity in some extent.
Nanosized SiO2 microspheres with an average diameter of 226 nm were synthesized by sol-gel methods.After being modified by silane coupling agent KH-570 and using sodium dodecylsulphate(SDS) as emulsifier,nanosized SiO2 microspheres were fabricated on melamine formaldehyde with ultrasonication,which aimed at weakening the disadvantages of nanosized materials as well as remaining the merits of high specific surface area.Fourier transform infrared spectroscopy,scanning electron microscopy and the laser light scattering were used to characterize the appearance and chemical composition of the product.The mechanism of the synthesis was also analyzed.The particles have an average size of 30 μm and distributed uniformly.The product has potential applications in reinforcing materials and other fields and it may be used as a kind of substitute material of nanosized materials to reduce their toxity in some extent.
2011, 28(12): 1459-1461
doi: 10.3724/SP.J.1095.2011.00384
Abstract:
Ag2S/Al2O3 nanocomposite was successfully prepared by hydrothermal method and calcination process.The structure and morphology of Ag2S/Al2O3 nanocomposite were characterized and confirmed by scanning electron microscopy(SEM),energy-dispersive X-ray analysis(EDX),and X-ray diffraction(XRD) patterns.The morphology and distribution of the product prepared with nonporous Al2O3 and porous Al2O3 as templates are different.
Ag2S/Al2O3 nanocomposite was successfully prepared by hydrothermal method and calcination process.The structure and morphology of Ag2S/Al2O3 nanocomposite were characterized and confirmed by scanning electron microscopy(SEM),energy-dispersive X-ray analysis(EDX),and X-ray diffraction(XRD) patterns.The morphology and distribution of the product prepared with nonporous Al2O3 and porous Al2O3 as templates are different.
2011, 28(12): 1462-1464
doi: 10.3724/SP.J.1095.2011.00085
Abstract:
Zinc powders were firstly modified by mechanic-chemistry method using titanate coupling agent,silane coupling agents and sodium dodecylbenzenesulfonate.Their dispersion stabilities were investigated via measuring the height with the sedimentation method.The results showed that different species and concentrations of surface modifier have dramatic effects on the dispersion stability.The dispersion stability of the zinc powder modified by 1.0% titanate coupling agent was significantly improved and close to that of imported zinc powder.
Zinc powders were firstly modified by mechanic-chemistry method using titanate coupling agent,silane coupling agents and sodium dodecylbenzenesulfonate.Their dispersion stabilities were investigated via measuring the height with the sedimentation method.The results showed that different species and concentrations of surface modifier have dramatic effects on the dispersion stability.The dispersion stability of the zinc powder modified by 1.0% titanate coupling agent was significantly improved and close to that of imported zinc powder.
