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2017 Volume 34 Issue 8
2017, 34(8): 855-867
doi: 10.11944/j.issn.1000-0518.2017.08.170103
Abstract:
Biological nanopore sensing has been developed as an attractive single-molecule tool with advantages of being rapid, low-cost, and label-free. Nanopores are not only being widely developed for DNA sequencing, but they also have been utilized to analyze a wide range of analytes at the single-molecule level. This review summarizes and prospects the principle of the nanopore analysis and nanpore category, with an emphasis on the progress in nanopore-based DNA sequencing and single-molecule analysis.
Biological nanopore sensing has been developed as an attractive single-molecule tool with advantages of being rapid, low-cost, and label-free. Nanopores are not only being widely developed for DNA sequencing, but they also have been utilized to analyze a wide range of analytes at the single-molecule level. This review summarizes and prospects the principle of the nanopore analysis and nanpore category, with an emphasis on the progress in nanopore-based DNA sequencing and single-molecule analysis.
2017, 34(8): 868-876
doi: 10.11944/j.issn.1000-0518.2017.08.170090
Abstract:
Hollow nanostructures possess the properties of high loading, low density and large specific surface area, therefore they find a lot of applications in many fields. The synthesis of hollow nanostructure by soft template method has the advantages of simplicity and structure controllability. At present, the most commonly used templates include microemulsion templates, micelle/vesicle templates and bubble templates. The hollow nanostructure is obtained by nanoparticle assembly on these soft templates via electrostatic adsorption, hydrogen bonding and interfacial reaction. The progresses on synthesis of hollow nanostructures by soft template are summarized and perspected.
Hollow nanostructures possess the properties of high loading, low density and large specific surface area, therefore they find a lot of applications in many fields. The synthesis of hollow nanostructure by soft template method has the advantages of simplicity and structure controllability. At present, the most commonly used templates include microemulsion templates, micelle/vesicle templates and bubble templates. The hollow nanostructure is obtained by nanoparticle assembly on these soft templates via electrostatic adsorption, hydrogen bonding and interfacial reaction. The progresses on synthesis of hollow nanostructures by soft template are summarized and perspected.
2017, 34(8): 877-884
doi: 10.11944/j.issn.1000-0518.2017.08.160398
Abstract:
Cationic polymerizable imdazolium ionic liquid-acrylamide copolymers as the corrosion inhibitors were successfully prepared by copolymerization of hydrophilic polymerizable ionic liquid, 1-methyl-3-[2-[(1-oxo-2-propenyl)oxy]ethyl]imdazoliumtetrafluoroborate(ACIMBF4), with acrylamide via inverse microemulsion polymerization. Various impact factors on the inhibition of carbon steel corrosion by hydrochloric acid including the cationic degree, the relative molecular mass of the copolymer, the concentration of copolymer solution and the absorption time were investigated simultaneously, and the corrosion mitigation mechanism was also discussed preliminary. The corrosion inhibition efficiency of cationic ionic liquid-acrylamide copolymers can reach higher than 90% by forming a protective adsorption film on the carbon steel. The corrosion inhibition ability of cationic copolymer depends on not only its cationic degree but also its relative molecular mass. Moreover, the corrosion inhibition efficiency increases with the increase of the concentration of cationic poly(ionic liquid) copolymer, and then decreases when the concentration of copolymer solution is too high. Furthermore, with the extension of the adsorption time, the corrosion rate of carbon steel is reduced gradually, and remains constant after approximately 40 h, namely the absorbing capacity of inhibitor on the carbon steel reaches the maximum.
Cationic polymerizable imdazolium ionic liquid-acrylamide copolymers as the corrosion inhibitors were successfully prepared by copolymerization of hydrophilic polymerizable ionic liquid, 1-methyl-3-[2-[(1-oxo-2-propenyl)oxy]ethyl]imdazoliumtetrafluoroborate(ACIMBF4), with acrylamide via inverse microemulsion polymerization. Various impact factors on the inhibition of carbon steel corrosion by hydrochloric acid including the cationic degree, the relative molecular mass of the copolymer, the concentration of copolymer solution and the absorption time were investigated simultaneously, and the corrosion mitigation mechanism was also discussed preliminary. The corrosion inhibition efficiency of cationic ionic liquid-acrylamide copolymers can reach higher than 90% by forming a protective adsorption film on the carbon steel. The corrosion inhibition ability of cationic copolymer depends on not only its cationic degree but also its relative molecular mass. Moreover, the corrosion inhibition efficiency increases with the increase of the concentration of cationic poly(ionic liquid) copolymer, and then decreases when the concentration of copolymer solution is too high. Furthermore, with the extension of the adsorption time, the corrosion rate of carbon steel is reduced gradually, and remains constant after approximately 40 h, namely the absorbing capacity of inhibitor on the carbon steel reaches the maximum.
2017, 34(8): 885-890
doi: 10.11944/j.issn.1000-0518.2017.08.170128
Abstract:
Poly(propylene carbonate)(PPC)/starch blends with different blend morphologies were prepared by normal melt blending and water-assisted processing method. The effect of blend morphology on glass transition temperature(Tg), rheological and mechanical properties of PPC/starch blends was studied in details. The obtained results show that the starch remains its original granule structure when a normal melt blending is used. Interestingly, fine dispersed starch fibers are formed during extrusion of PPC/starch blends with the assistance of water. The formation of starch fibers in PPC matrix will increase the contact area between them leading to an enhanced interfacial interaction. Therefore, Tg, storage modulus and complex viscosity increase apparently. Additionally, when mass fraction of starch is 30%, there is a 67.7% increase in tensile modulus of PPC/starch blend.
Poly(propylene carbonate)(PPC)/starch blends with different blend morphologies were prepared by normal melt blending and water-assisted processing method. The effect of blend morphology on glass transition temperature(Tg), rheological and mechanical properties of PPC/starch blends was studied in details. The obtained results show that the starch remains its original granule structure when a normal melt blending is used. Interestingly, fine dispersed starch fibers are formed during extrusion of PPC/starch blends with the assistance of water. The formation of starch fibers in PPC matrix will increase the contact area between them leading to an enhanced interfacial interaction. Therefore, Tg, storage modulus and complex viscosity increase apparently. Additionally, when mass fraction of starch is 30%, there is a 67.7% increase in tensile modulus of PPC/starch blend.
2017, 34(8): 891-898
doi: 10.11944/j.issn.1000-0518.2017.08.160299
Abstract:
Triacetate cellulose(TCA) porous nanofiber membranes(Cell) with diameter of (110±28) nm were successfully prepared by thermally induced phase separation. Succinic acid anhydride grafted cellulose(Cell-g-SAA) nanofiber membranes were obtained through hydrolyzation and grafting of TCA nanofibers. The Cell and Cell-g-SAA membranes were used for the adsorption of Cu2+ and Pb2+. The adsorption kinetics and thermodynamics were studied and found to fit pseudo-second-order and Langmuir model. Compared with cellulose membranes, the max adsorption capacity of Cell-g-SAA membranes for Cu2+ and Pb2+ increases from 51.73 and 34.29 mg/g to 116.41 and 51.73 mg/g, respectively. The adsorptions of Cu2+ and Pb2+ on the Cell and Cell-g-SAA membranes are more agreeable with monolayer adsorption mode via mainly chemical interactions.
Triacetate cellulose(TCA) porous nanofiber membranes(Cell) with diameter of (110±28) nm were successfully prepared by thermally induced phase separation. Succinic acid anhydride grafted cellulose(Cell-g-SAA) nanofiber membranes were obtained through hydrolyzation and grafting of TCA nanofibers. The Cell and Cell-g-SAA membranes were used for the adsorption of Cu2+ and Pb2+. The adsorption kinetics and thermodynamics were studied and found to fit pseudo-second-order and Langmuir model. Compared with cellulose membranes, the max adsorption capacity of Cell-g-SAA membranes for Cu2+ and Pb2+ increases from 51.73 and 34.29 mg/g to 116.41 and 51.73 mg/g, respectively. The adsorptions of Cu2+ and Pb2+ on the Cell and Cell-g-SAA membranes are more agreeable with monolayer adsorption mode via mainly chemical interactions.
2017, 34(8): 899-904
doi: 10.11944/j.issn.1000-0518.2017.08.170022
Abstract:
In this work, a variety of new thiosemicarbazone derivatives were prepared by combining ionoe with chalcone and thiosemicarbazide according to the structure-activity combination principle. The ionone-based dichalcones were firstly synthesized through the condensation of ionone and substituted benzaldehydes, followed by thiosemicarbazide to obtain the target products. Their structures were confirmed by fourier transform infrared spectroscopy(FT-IR), nuclear magnetic resonance spectroscopy(1H NMR and 13C NMR), elemental analysis, and mass spectrometry(MS). The in vitro antitumor activities against MCF-7(human breast cancer), HepG2(human liver cancer) and A549(human lung cancer) cells were tested using a 3-(4, 5-dimethyl-2-thiazolyl)-2, 5-diphenyl-2-H-tetrazolium bromide(MTT) method. The bioassay results demonstrate that compounds 3a and 3b display highly effective antiproliferative effects against MCF-7 cells with half maximal inhibitory concentration(IC50) values of 10.83 and 7.62 μmol/L, respectively. Compound 3e exhibits preferable antiproliferative activities against A549 cells with an IC50 value of 13.36 μmol/L, while compound 3f shows the best inhibitory effect against HepG2 cells with an IC50 value of 8.55 μmol/L. Antitumor experiments show that the activities of these compounds are mainly affected by ionone and substituted groups in aromatic rings of chalcone.
In this work, a variety of new thiosemicarbazone derivatives were prepared by combining ionoe with chalcone and thiosemicarbazide according to the structure-activity combination principle. The ionone-based dichalcones were firstly synthesized through the condensation of ionone and substituted benzaldehydes, followed by thiosemicarbazide to obtain the target products. Their structures were confirmed by fourier transform infrared spectroscopy(FT-IR), nuclear magnetic resonance spectroscopy(1H NMR and 13C NMR), elemental analysis, and mass spectrometry(MS). The in vitro antitumor activities against MCF-7(human breast cancer), HepG2(human liver cancer) and A549(human lung cancer) cells were tested using a 3-(4, 5-dimethyl-2-thiazolyl)-2, 5-diphenyl-2-H-tetrazolium bromide(MTT) method. The bioassay results demonstrate that compounds 3a and 3b display highly effective antiproliferative effects against MCF-7 cells with half maximal inhibitory concentration(IC50) values of 10.83 and 7.62 μmol/L, respectively. Compound 3e exhibits preferable antiproliferative activities against A549 cells with an IC50 value of 13.36 μmol/L, while compound 3f shows the best inhibitory effect against HepG2 cells with an IC50 value of 8.55 μmol/L. Antitumor experiments show that the activities of these compounds are mainly affected by ionone and substituted groups in aromatic rings of chalcone.
2017, 34(8): 905-911
doi: 10.11944/j.issn.1000-0518.2017.08.160420
Abstract:
A series of novel 5, 6, 7, 8-tetrahydroimidazo[2', 1':2, 3]thiazolo[5, 4-c]piperidines was synthesized through sequential amino protection, condensation, cyclization, and deprotection reactions using piperidone as the raw material. The structures of these compounds were confirmed by proton or carbon nuclear magnetic resonance(1H NMR, 13C NMR), mass spectrometry(MS) and elemental analysis. The antitumor activities of these compounds were evaluated in vitro, and the results indicated that these compounds had certain inhibitory activities against MCF-7 human breast cancer cells, and the inhibitory activity of compound 5a reached the level of strong potency with the half maximal inhibitory concentration(IC50) value of 8.6 μmol/L. It provides a reference for the antitumor activity of such compounds.
A series of novel 5, 6, 7, 8-tetrahydroimidazo[2', 1':2, 3]thiazolo[5, 4-c]piperidines was synthesized through sequential amino protection, condensation, cyclization, and deprotection reactions using piperidone as the raw material. The structures of these compounds were confirmed by proton or carbon nuclear magnetic resonance(1H NMR, 13C NMR), mass spectrometry(MS) and elemental analysis. The antitumor activities of these compounds were evaluated in vitro, and the results indicated that these compounds had certain inhibitory activities against MCF-7 human breast cancer cells, and the inhibitory activity of compound 5a reached the level of strong potency with the half maximal inhibitory concentration(IC50) value of 8.6 μmol/L. It provides a reference for the antitumor activity of such compounds.
2017, 34(8): 912-917
doi: 10.11944/j.issn.1000-0518.2017.08.160462
Abstract:
A new complex[Zn(dna)(phen)(H2O)] based on 5, 5'-dithiobis(2-nitrobenzoic acid)(H2dna) and 1, 10-phenanthroline(phen), has been hydrothermally synthesized and structurally characterized by elemental analysis, Fourier transform infrared spectrometer, X-ray single crystal diffraction and powder X-ray diffraction. Crystal structural analysis reveals that it crystallizes in monoclinic, space group P21/n, a=1.5312(3) nm, b=1.16054(18) nm, c=1.5609(3) nm, β=110.451(2)°, V=2.5990(7) nm3, Z=4. There is a binuclear ring structure in the complex, and the neighboring binuclear rings are linked into 1D supramolecular chain through hydrogen bonding interaction. The adjacent supramolecular chains are further interconnected by S‥‥O and C-H‥‥π weak interactions resulting a 3D supramolecular structure. The complex after dehydration remains relatively stable until 245~450℃. Then ligands begin to decompose, which shows good thermal stability. The complex displays a strong fluorescence emission maximum at ca. 440 nm upon excitation at 280 nm. The emission peaks of H2dna ligand and the complex are similar. Compared with H2dna ligand, the fluorescence intensity of complex is significantly enhanced.
A new complex[Zn(dna)(phen)(H2O)] based on 5, 5'-dithiobis(2-nitrobenzoic acid)(H2dna) and 1, 10-phenanthroline(phen), has been hydrothermally synthesized and structurally characterized by elemental analysis, Fourier transform infrared spectrometer, X-ray single crystal diffraction and powder X-ray diffraction. Crystal structural analysis reveals that it crystallizes in monoclinic, space group P21/n, a=1.5312(3) nm, b=1.16054(18) nm, c=1.5609(3) nm, β=110.451(2)°, V=2.5990(7) nm3, Z=4. There is a binuclear ring structure in the complex, and the neighboring binuclear rings are linked into 1D supramolecular chain through hydrogen bonding interaction. The adjacent supramolecular chains are further interconnected by S‥‥O and C-H‥‥π weak interactions resulting a 3D supramolecular structure. The complex after dehydration remains relatively stable until 245~450℃. Then ligands begin to decompose, which shows good thermal stability. The complex displays a strong fluorescence emission maximum at ca. 440 nm upon excitation at 280 nm. The emission peaks of H2dna ligand and the complex are similar. Compared with H2dna ligand, the fluorescence intensity of complex is significantly enhanced.
2017, 34(8): 918-927
doi: 10.11944/j.issn.1000-0518.2017.08.160464
Abstract:
2D platelet like nickel nanomaterials have high anisotropy with the morphology, and have the significant application on the catalysis, magnetic recording, energy source and biological detection field. It is important to search a simple, low cost method to prepare platelet like nickel nanomaterials without any surfactant. Without any organic surfactant and other morphology control agent, thin nickel nanoplatelets were successfully prepared on the fluorine-doped tin oxide(FTO) under the hydrothermal condition. The influence of synthetic conditions on the morphology of the nanoplatelets was investigated. It is found that the concentration of nickel salt, sodium hydroxide, and ammonia and the reaction temperature have apparent influences on the morphology of the nickel nanoplatelets. The ideal nickel nanoplatelets with large lateral size and small thickness can be obtained only under optimal concentrations of both sodium hydroxide and ammonia together. Approximate two-dimensional(2D) hexgonal thin nickel nanoplatlets with a characteristic thickness of about 10 nm and the lateral feature width of about 1 μm were obtained under optimal synthetic conditions. The pH value and the reaction temperature affect the reaction speed, and finally the morphology of the nanoplatelets. At pH 10, the complexation of ammonia to the nickel ion can facilitate the 2D growth of nickel nanoplatelets.
2D platelet like nickel nanomaterials have high anisotropy with the morphology, and have the significant application on the catalysis, magnetic recording, energy source and biological detection field. It is important to search a simple, low cost method to prepare platelet like nickel nanomaterials without any surfactant. Without any organic surfactant and other morphology control agent, thin nickel nanoplatelets were successfully prepared on the fluorine-doped tin oxide(FTO) under the hydrothermal condition. The influence of synthetic conditions on the morphology of the nanoplatelets was investigated. It is found that the concentration of nickel salt, sodium hydroxide, and ammonia and the reaction temperature have apparent influences on the morphology of the nickel nanoplatelets. The ideal nickel nanoplatelets with large lateral size and small thickness can be obtained only under optimal concentrations of both sodium hydroxide and ammonia together. Approximate two-dimensional(2D) hexgonal thin nickel nanoplatlets with a characteristic thickness of about 10 nm and the lateral feature width of about 1 μm were obtained under optimal synthetic conditions. The pH value and the reaction temperature affect the reaction speed, and finally the morphology of the nanoplatelets. At pH 10, the complexation of ammonia to the nickel ion can facilitate the 2D growth of nickel nanoplatelets.
2017, 34(8): 928-935
doi: 10.11944/j.issn.1000-0518.2017.08.160466
Abstract:
Tetrazine compounds have great applications in energetic materials field, which is attributed to its high energy, insensitivity, high burning rate, low pressure and good thermal stability properties. However, they have disadvantages of low density and thermal stability. To enhance the low properties of tetrazine compounds, a series of the tetrazine derivatives have attracted considerable attention. 3, 6-Bis(1-H-1, 2, 3, 4-tetrazole-5-amino)-1, 2, 4, 5-tetrazine(BTATz), as a high-nitrogen energetic material, has good catalytic performance and application prospect. Therefore, we synthesized 1, 2, 4, 5-tetrazine (s-tetrazine) cobalt salt with potassium salt of BTATz and cobalt nitrate in an aqueous solution. Its structure was characterized with elemental analysis, Fourier transform infrared spectrometer(FTIR) and inductively coupled plasma mass spectrometry(ICP-MS). Its chemical formula is Co(C4H2N14)·4H2O. The thermal behavior and thermal decomposition reaction kinetics were also investigated with differential scanning calorimetric(DSC) and thermal gravimetric-differential thermal gravimetric(TG-DTG) methods. The self-accelerating decomposition temperature(TSADT), thermal ignition temperature(TTIT), critical temperature of thermal explosion(Tb) and the adiabatic time-to-explosion(tTIAD) were calculated as the important parameters to estimate the thermal safety, and the value were 509.69 K, 556.31 K, 524.93 K and 88.40 s, respectively. The adiabatic time-to-explosion is longer than those of Ca salt, Mg salt and Sr salt and the exothermic capacity is higher than that of its ligand BTATz. Therefore, it is expected to be a good combustion catalyst.
Tetrazine compounds have great applications in energetic materials field, which is attributed to its high energy, insensitivity, high burning rate, low pressure and good thermal stability properties. However, they have disadvantages of low density and thermal stability. To enhance the low properties of tetrazine compounds, a series of the tetrazine derivatives have attracted considerable attention. 3, 6-Bis(1-H-1, 2, 3, 4-tetrazole-5-amino)-1, 2, 4, 5-tetrazine(BTATz), as a high-nitrogen energetic material, has good catalytic performance and application prospect. Therefore, we synthesized 1, 2, 4, 5-tetrazine (s-tetrazine) cobalt salt with potassium salt of BTATz and cobalt nitrate in an aqueous solution. Its structure was characterized with elemental analysis, Fourier transform infrared spectrometer(FTIR) and inductively coupled plasma mass spectrometry(ICP-MS). Its chemical formula is Co(C4H2N14)·4H2O. The thermal behavior and thermal decomposition reaction kinetics were also investigated with differential scanning calorimetric(DSC) and thermal gravimetric-differential thermal gravimetric(TG-DTG) methods. The self-accelerating decomposition temperature(TSADT), thermal ignition temperature(TTIT), critical temperature of thermal explosion(Tb) and the adiabatic time-to-explosion(tTIAD) were calculated as the important parameters to estimate the thermal safety, and the value were 509.69 K, 556.31 K, 524.93 K and 88.40 s, respectively. The adiabatic time-to-explosion is longer than those of Ca salt, Mg salt and Sr salt and the exothermic capacity is higher than that of its ligand BTATz. Therefore, it is expected to be a good combustion catalyst.
2017, 34(8): 936-945
doi: 10.11944/j.issn.1000-0518.2017.08.170019
Abstract:
The C/Fe-Bi2WO6 photocatalyst was prepared by a two-step method, involving resin carbonization and hydrothermal reaction process. Comparative research on photoactivities of different catalysts was carried out. Influence of condition factors on photocatalytic oxidation degradation of norfloxacin(NOR) solution under simulated sunlight irradiation was investigated. The degrading reaction fits the first-order kinetics well under experimental conditions. After irradiation under a 500 W Xenon lamp for 60 min, NOR completely decomposed with the first order reaction rate constant(Kapp) of 0.0751 min-1 under the conditions that the initial concentration of NOR is 10 mg/L, the C/Fe-Bi2WO6 loading is 0.75 g/L, and the concentration of H2O2 is 200 mg/L at pH 7.0. The OH formation in C/Fe-Bi2WO6 photocatalytic oxidation was studied via molecular fluorescence spectrum, and the possible photocatalytic oxidation mechnasim and the degradation paths and intermediate products of NOR were proposed.
The C/Fe-Bi2WO6 photocatalyst was prepared by a two-step method, involving resin carbonization and hydrothermal reaction process. Comparative research on photoactivities of different catalysts was carried out. Influence of condition factors on photocatalytic oxidation degradation of norfloxacin(NOR) solution under simulated sunlight irradiation was investigated. The degrading reaction fits the first-order kinetics well under experimental conditions. After irradiation under a 500 W Xenon lamp for 60 min, NOR completely decomposed with the first order reaction rate constant(Kapp) of 0.0751 min-1 under the conditions that the initial concentration of NOR is 10 mg/L, the C/Fe-Bi2WO6 loading is 0.75 g/L, and the concentration of H2O2 is 200 mg/L at pH 7.0. The OH formation in C/Fe-Bi2WO6 photocatalytic oxidation was studied via molecular fluorescence spectrum, and the possible photocatalytic oxidation mechnasim and the degradation paths and intermediate products of NOR were proposed.
2017, 34(8): 946-954
doi: 10.11944/j.issn.1000-0518.2017.08.160474
Abstract:
Photocatalytic degradation of ammonia-nitrogen in simulated wastewater was investigated by the TiO2/pumice photocatalyst under solar light. TiO2 prepared by the sol-gel method was used as the photocatalyst and immobilized on porous pumice granules. To optimize the photocatalytic reaction, the effect of the initial concentration of ammonia-nitrogen, pH, reaction time and catalyst loading on the ammonia-nitrogen degradation rate were investigated in an aerated reactor. Also, the morphology and chemical structure properties of the prepared catalysts were characterized by scanning electron microscopy(SEM), X-ray fluorescence spectrometer(XRF) and Fourier transform infrared spectroscopy(FT-IR) analyses. The experimental results indicate that the coating ratio of TiO2 on pumice is 3.71%; the ammonia-nitrogen degradation rate is increased by increasing the pH value, time of solar light irradiation and dose of TiO2/pumice. After solar light irradiation for 180 min, a high degradation rate of 82.0% and a removal rate of 86.8% are achieved under 500 mg/L ammonia-nitrogen, pH 11 and 30 g/L TiO2/pumice. Moreover, the NO2- and NO3- pollutes are not found in degradation products. The photocatalyst can be reused at least three consecutive times with about 10.0% decrease on the ammonia-nitrogen degradation rate. The results suggest that the photocatalytic purification by photocatalysis is a rapid, low consumed and effective method for the degradation of ammonia-nitrogen in wastewater.
Photocatalytic degradation of ammonia-nitrogen in simulated wastewater was investigated by the TiO2/pumice photocatalyst under solar light. TiO2 prepared by the sol-gel method was used as the photocatalyst and immobilized on porous pumice granules. To optimize the photocatalytic reaction, the effect of the initial concentration of ammonia-nitrogen, pH, reaction time and catalyst loading on the ammonia-nitrogen degradation rate were investigated in an aerated reactor. Also, the morphology and chemical structure properties of the prepared catalysts were characterized by scanning electron microscopy(SEM), X-ray fluorescence spectrometer(XRF) and Fourier transform infrared spectroscopy(FT-IR) analyses. The experimental results indicate that the coating ratio of TiO2 on pumice is 3.71%; the ammonia-nitrogen degradation rate is increased by increasing the pH value, time of solar light irradiation and dose of TiO2/pumice. After solar light irradiation for 180 min, a high degradation rate of 82.0% and a removal rate of 86.8% are achieved under 500 mg/L ammonia-nitrogen, pH 11 and 30 g/L TiO2/pumice. Moreover, the NO2- and NO3- pollutes are not found in degradation products. The photocatalyst can be reused at least three consecutive times with about 10.0% decrease on the ammonia-nitrogen degradation rate. The results suggest that the photocatalytic purification by photocatalysis is a rapid, low consumed and effective method for the degradation of ammonia-nitrogen in wastewater.
2017, 34(8): 955-964
doi: 10.11944/j.issn.1000-0518.2017.08.170039
Abstract:
In order to develop new environment-friendly corrosion inhibitors, the corrosion inhibition of Q235 steel by moxifloxacin in 1 mol/L HCl solution and its mechanism were investigated using electrochemical measurements, mass loss method and quantum chemistry calculation. The results reveal that moxifloxacin is an effective mixed-type inhibitor with a predominantly cathodic action for the corrosion of Q235 steel in HCl solution. The inhibition efficiency increases with increased concentration of the inhibitor, but decreases with incremental temperature. The adsorption of moxifloxacin on steel surface is a spontaneous process, and obeys the Langmuir isotherm as well as the El-Awady thermodynamic-kinetic model. Accordingly, the thermodynamic and kinetic parameters were calculated and discussed. Moreover, quantum chemistry calculation was employed to give further insight into the inhibition mechanism of moxifloxacin, and the results showed that the corrosion inhibition of moxifloxacin was caused by physical adsorption and chemical adsorption.
In order to develop new environment-friendly corrosion inhibitors, the corrosion inhibition of Q235 steel by moxifloxacin in 1 mol/L HCl solution and its mechanism were investigated using electrochemical measurements, mass loss method and quantum chemistry calculation. The results reveal that moxifloxacin is an effective mixed-type inhibitor with a predominantly cathodic action for the corrosion of Q235 steel in HCl solution. The inhibition efficiency increases with increased concentration of the inhibitor, but decreases with incremental temperature. The adsorption of moxifloxacin on steel surface is a spontaneous process, and obeys the Langmuir isotherm as well as the El-Awady thermodynamic-kinetic model. Accordingly, the thermodynamic and kinetic parameters were calculated and discussed. Moreover, quantum chemistry calculation was employed to give further insight into the inhibition mechanism of moxifloxacin, and the results showed that the corrosion inhibition of moxifloxacin was caused by physical adsorption and chemical adsorption.
2017, 34(8): 965-970
doi: 10.11944/j.issn.1000-0518.2017.08.160481
Abstract:
The research of chemical changes in ginseng processing has been focusing on saponins and sugars. In this paper, volatile components in ginseng were studied for the first time, which provide a substance basis for different processed ginseng. The volatile components and their derivative paths of fresh ginseng, sun-dry ginseng and red ginseng were studied by gas chromatography-mass spectrometry(GC-MS/MS). The volatile components were detected and analyzed using TG-5SILMS nonpolar GC column, with He as the carrier gas through the NIST MS Spectral Database. Thirty, thirty-three and thirty-four species of volatile compounds in fresh ginseng, sun-dry ginseng and red ginseng were detected, respectively. The content of (-)-spartak alcohol in sun-dry ginseng is 31.98 times higher than that in the fresh ginseng, while the levels of eight volatile components such as octanal in sun-dry ginseng is three times higher than those in the fresh ginseng. The contents of ten volatile components such as cyclodecanone in red ginseng are 3 times higher than those in the fresh ginseng. Four volatile compounds in sun-dry ginseng and in red ginseng are not detected in fresh ginseng.
The research of chemical changes in ginseng processing has been focusing on saponins and sugars. In this paper, volatile components in ginseng were studied for the first time, which provide a substance basis for different processed ginseng. The volatile components and their derivative paths of fresh ginseng, sun-dry ginseng and red ginseng were studied by gas chromatography-mass spectrometry(GC-MS/MS). The volatile components were detected and analyzed using TG-5SILMS nonpolar GC column, with He as the carrier gas through the NIST MS Spectral Database. Thirty, thirty-three and thirty-four species of volatile compounds in fresh ginseng, sun-dry ginseng and red ginseng were detected, respectively. The content of (-)-spartak alcohol in sun-dry ginseng is 31.98 times higher than that in the fresh ginseng, while the levels of eight volatile components such as octanal in sun-dry ginseng is three times higher than those in the fresh ginseng. The contents of ten volatile components such as cyclodecanone in red ginseng are 3 times higher than those in the fresh ginseng. Four volatile compounds in sun-dry ginseng and in red ginseng are not detected in fresh ginseng.
2017, 34(8): 971-976
doi: 10.11944/j.issn.1000-0518.2017.08.160489
Abstract:
The hollow fiber dispersion liquid membrane technique was applied for the enrichment of rare earth using 2-ethylhexylphosphonic acid mono-(2-ethylhexyl) ester(HEHEHP) as the extractant and HCl as the stripping agent. All experiments were conducted in the hollow fiber modules that were self-assembled with 20 microporous hydrophobic hollow fiber of polyvinylidene fluoride membrane(PVDF) lumens. The experiment parameters, e.g., HCl concentration, extractant concentration, initial pH in feed phase and rare earth ions concentration, and the volume ratio of the stripping dispersion phase to the feed solution, etc., were investigated. The stripping dispersion phase and the feed phase(50 mL each) were agitated continuously to provide a uniform concentration of metal ions and circulated by means of precise constant flow pumps through the shell side and lumen side of the module, respectively. A membrane pressure was applied in the lumen side to prevent the dispersion of the organic phase into the feed phase. The flow rates of both phases were maintained constant with the help of the constant-flow pump equipped with a precise flow controller. After the stable flows are achieved on both the shell side and the lumen side, aqueous samples are taken from the reservoir every ten minutes for analysis of concentrations of rare earth ions. The optimum extraction conditions of Yb3+ were obtained:the HCl concentration is 4.00 mol/L in the stripping dispersion phase, the concentration of HEHEHP is 0.25 mol/L, the volume ratio of the stripping dispersion phase to the feed solution is 10:40, the pH value in the feed phase is 2.80, and the initial concentration of Yb3+ is 0.025 mol/L. The optimum conditions obtained may contribute to the development of new methods for the extraction of heavy rare earth ions.
The hollow fiber dispersion liquid membrane technique was applied for the enrichment of rare earth using 2-ethylhexylphosphonic acid mono-(2-ethylhexyl) ester(HEHEHP) as the extractant and HCl as the stripping agent. All experiments were conducted in the hollow fiber modules that were self-assembled with 20 microporous hydrophobic hollow fiber of polyvinylidene fluoride membrane(PVDF) lumens. The experiment parameters, e.g., HCl concentration, extractant concentration, initial pH in feed phase and rare earth ions concentration, and the volume ratio of the stripping dispersion phase to the feed solution, etc., were investigated. The stripping dispersion phase and the feed phase(50 mL each) were agitated continuously to provide a uniform concentration of metal ions and circulated by means of precise constant flow pumps through the shell side and lumen side of the module, respectively. A membrane pressure was applied in the lumen side to prevent the dispersion of the organic phase into the feed phase. The flow rates of both phases were maintained constant with the help of the constant-flow pump equipped with a precise flow controller. After the stable flows are achieved on both the shell side and the lumen side, aqueous samples are taken from the reservoir every ten minutes for analysis of concentrations of rare earth ions. The optimum extraction conditions of Yb3+ were obtained:the HCl concentration is 4.00 mol/L in the stripping dispersion phase, the concentration of HEHEHP is 0.25 mol/L, the volume ratio of the stripping dispersion phase to the feed solution is 10:40, the pH value in the feed phase is 2.80, and the initial concentration of Yb3+ is 0.025 mol/L. The optimum conditions obtained may contribute to the development of new methods for the extraction of heavy rare earth ions.
