Ordered mesoporous TiO2 (OMPT) was prepared by an evaporation induced self-assembly technique using liquid crystal as template. The key factors affecting the methylene blue (MB) oxidation efficiency were investiga...Ordered mesoporous TiO2 (OMPT) was prepared by an evaporation induced self-assembly technique using liquid crystal as template. The key factors affecting the methylene blue (MB) oxidation efficiency were investigated, including the initial concentration of MB, pH value and catalyst concentration. The results show that the obtained OMPT has high thermal stability and shows a 2D hexagonal mesostructure with the small particle size and high surface area, which lead to higher degradation efficiency than commercial P25 or nanoparticle TiO2 (NPT) fabricated by sol-gel process. The optimal conditions are 5 mg/L MB, pH 6 and 1.5 g/L OMPT for the fastest rate of MB degradation. Total organic carbon (TOC) analysis indicates complete mineralization of MB in 240 min by OMPT, with rate constant higher than NPT or P25.展开更多
[Objective] The aim was to study the cloning and sequence analysis of rbcS gene of wild barley under salt stress. [Method] The tender leaf blade of wild barley under salt stress was taken as the experimental material....[Objective] The aim was to study the cloning and sequence analysis of rbcS gene of wild barley under salt stress. [Method] The tender leaf blade of wild barley under salt stress was taken as the experimental material. The primers were designed according to the homology of rbcS gene sequences of wheat and barely in Genbank; then PCR amplification,recovery,ligation,transformation and sequencing of rbcS gene were carried out. [Result] Two rbcS genes including rbcS1 and rbcS2 with the length of 1 252 and 908 bp respectively were cloned from the barely genome. rbcS1 and rbcS2 were both composed by two exons and one intron. The exons length of the two genes was the same of 525 bp,encoding 174 amino acids,and the homology between them was 96%; however,the intron length of rbcS1 and rbcS2 was 448 and 107 bp respectively.展开更多
The photocatalytic ability of ZnO is improved through the addition of flower‐like Bi2WO6 to prepare a Bi2WO6/ZnO composite with visible light activity.The composite is characterized by X‐ray diffraction,transmission...The photocatalytic ability of ZnO is improved through the addition of flower‐like Bi2WO6 to prepare a Bi2WO6/ZnO composite with visible light activity.The composite is characterized by X‐ray diffraction,transmission electron microscopy,scanning electron microscopy with UV–vis diffuse reflectance spectroscopy,X‐ray photoelectron spectroscopy and N2 adsorption‐desorption isotherms.After modification,the band gap energy of Bi2WO6/ZnO is reduced from 3.2 eV for ZnO to 2.6 eV.Under visible light irradiation,the Bi2WO6/ZnO composite shows an excellent photocatalytic activity for degrading methylene blue(MB)and tetracycline.The photo‐degradation efficiencies of(0.3:1)Bi2WO6/ZnO for MB and tetracycline are approximately 246 and 4500 times higher than those of bare ZnO,respectively,and correspondingly,the photo‐degradation rates for the two pollutants are approximately 120 and 200 times higher than those with bare ZnO,respectively.Moreover,the photocatalyst of(0.3:1)Bi2WO6/ZnO exhibits a higher transient photocurrent density of approximately 4.5μA compared with those of bare Bi2WO6 and ZnO nanoparticles.The successful recombination of Bi2WO6 and ZnO enhances the photocatalytic activity and reduces the band gap energy of ZnO,which can be attributed to the effective separation of electron–hole pairs.Active species trapping experiments display that[O2]-is the major species involved during photocatalysis rather than·OH and h+.This study provides insight into designing a meaningful visible‐light‐driven photocatalyst for environmental remediation.展开更多
The bombycid moth, Triuncina daii Xing Wang & Zolotuhin, 2015, plays an important role for analyzing the phylogenetic relationships of the family Bombycidae (Lepidoptera: Bombycoidea). Here we first describe the c...The bombycid moth, Triuncina daii Xing Wang & Zolotuhin, 2015, plays an important role for analyzing the phylogenetic relationships of the family Bombycidae (Lepidoptera: Bombycoidea). Here we first describe the complete mitochondrial genome (mitogenome) of T. daii, which includes thirteen protein-coding genes (PCGs), twenty-two transfer RNA genes, two ribosomal RNA genes and an A+T-rich region, and we find the mitogenome is 15,482 bp in length (GenBank no. KY091643). The genes order and orientation in the T. daii mitogenome are similar to other sequenced lepidopteran species. Except for cox1, all of the PCGs started with ATN. Twelve PCGs stopped at TAA except for cox1 which stops at a single T. Thirteen PCGs of available species are used to demonstrate the inner phylogenetic relationships of Bombycoidea. The bombycid species form a monophyletic clade with a bootstrap value of 100% and a posterior probability of 1.00.展开更多
The magnetic field effects (MFEs) are studied on photocatalytic degradation of methylene blue (MB) solution using ZnO and TiO2 particles. The UV-VIS-NIR spectrometer is used to monitor the MB concentrations, and t...The magnetic field effects (MFEs) are studied on photocatalytic degradation of methylene blue (MB) solution using ZnO and TiO2 particles. The UV-VIS-NIR spectrometer is used to monitor the MB concentrations, and the dependence of the reaction rate on the initial dye concentration and settling duration is studied under UV light irradiation. It is found that the MFEs exist on the heterogeneous reaction systems for both ZnO and TiO2 powders and that the extraordinary phenomenon is reproducible. For ZnO powder, the results are in good agreement with the second-order reaction kinetics following the Langmuir-Hinshelwood (L-H) model, while the reaction for TiO2 follows first-order kinetics. It enhances the photodegradation for ZnO, while it reduces or enhances the reaction for TiO2 depending on the initial dye concentrations. The MFEs become small or negligible when the same photodecomposition experiment is carried out after settling the MB solution for more than three hours for both ZnO and TiO2. It is suggested that the key factors of MFEs on photocatalytic degradation is the condition of the MB solution as well as the characteristics of photocatalysts. The alteration of the MFEs ascribed to the solution condition caused by variation of the settling time.展开更多
In this study,porous silica with high surface area was prepared through selective leaching of thermally activated chlorite in HCl solution.In the process,chlorite was activated by pre-calcining treatment,then activate...In this study,porous silica with high surface area was prepared through selective leaching of thermally activated chlorite in HCl solution.In the process,chlorite was activated by pre-calcining treatment,then activated components(MgO,Al_(2)O_(3),and Fe_(2)O_(3))were selectively leached by acid solution,resulting in the formation of nanopores in situ.The morphology,structure,surface area and pore-size distribution of the material were characterized by XRD,TG/DSC,^(27)Al MAS NMR,SEM,TEM and N2 adsorption−desorption isotherms.The highest specific surface area(SBET=333 m^(2)/g)was obtained by selectively leaching the 600℃ calcined chlorite from 3 mol/L HCl at 90℃ for 2 h.The pore sizes and specific surface areas can be controlled by calcination and leaching conditions.The ^(27)Al MAS NMR spectra of the samples revealed the relationship between structural transformation and the selective acid leaching properties of thermal-activated chlorite,demonstrating that AlVI transfers into AlV when chlorite changes into activated chlorite during thermal activation,and the coordinations of Al has a significant effect on acid solubility of chlorite.The as-prepared porous silica showed favorable adsorption abilities with capacity of 148.79 mg/g for methylene blue at pH of about 7 and temperature of 25℃,indicating its promising potential in adsorption application.展开更多
A Cu2O/SiC heterogeneous catalyst was prepared via a two‐step liquid‐phase method using diethyleneglycol as both the solvent and the reducing agent.The catalyst was characterized using X‐raydiffraction,X‐ray photo...A Cu2O/SiC heterogeneous catalyst was prepared via a two‐step liquid‐phase method using diethyleneglycol as both the solvent and the reducing agent.The catalyst was characterized using X‐raydiffraction,X‐ray photoelectron spectroscopy,scanning electron microscopy(SEM),transmissionelectron microscopy(TEM),and H2temperature‐programmed reduction.All the results indicatethat Cu is present on the SiC support primarily as Cu2O.The SEM and TEM results show that cubicCu2O nanoparticles are uniformly dispersed on theβ‐SiC surface.The reaction conditions,namelythe temperature,reaction time,and amounts of base and catalyst used,for the Ullmann‐type C–Ocross‐coupling reaction were optimized.A model reaction was performed using iodobenzene(14.0mmol)and phenol(14.0mmol)with Cu2O/SiC(5wt%Cu)as the catalyst,Cs2CO3(1.0equiv.)as thebase,and tetrahydrofuran as the solvent at150°C for3h;a yield of97%was obtained and theturnover frequency(TOF)was1136h?1.The Cu2O/SiC catalyst has a broad substrate scope and canbe used in Ullmann‐type C–O cross‐coupling reactions of aryl halides and phenols bearing a varietyof different substituents.The catalyst also showed high activity in the Ullmann‐type C–Scross‐coupling of thiophenol with iodobenzene and substituted iodobenzenes;a TOF of1186h?1was achieved.The recyclability of the Cu2O/SiC catalyst in the O‐arylation of phenol with iodobenzenewas investigated under the optimum conditions.The yield decreased from97%to64%afterfive cycles.The main reason for the decrease in the catalyst activity is loss of the active component,i.e.,Cu2O.展开更多
Selective oxidation with molecular oxygen as the sole oxidant under mild conditions is of crucialimportance for the long‐term sustainable exploitation of available feedstocks and the formation ofrequired intermediate...Selective oxidation with molecular oxygen as the sole oxidant under mild conditions is of crucialimportance for the long‐term sustainable exploitation of available feedstocks and the formation ofrequired intermediates for organic synthesis and industrial processes.Among the developed oxidationprotocols,innovative strategies using hydroxyimide organocatalysts in combination with metallicor metal‐free cocatalysts have attracted much attention because of the good activities andselectivities of such catalysts in the oxo functionalization of hydrocarbons.This method is based onthe reaction using N‐hydroxyphthalimide,which was first reported by Ishii’s group in the1990s.Although the important and wide‐ranging applications of such catalysts have been summarizedrecently,there are no reviews that focus solely on oxidation strategies using multi‐nitroxy organocatalysts,which have interesting properties and high reactivities.This review covers the concisesynthetic methods and mechanistic profiles of known multi‐nitroxy organocatalysts and summarizessignificant advances in their use in efficient aerobic oxidation.Based on a combination of experimentaland theoretical results,guidelines for the future rational design of multi‐nitroxy organocatalystsare proposed,and the properties of various model multi‐nitroxy organocatalysts are predicted.The present overview of the advantages,limitations,and potential applications of multi‐nitroxyorganocatalysts can provide useful tools for researchers in the field of selective oxidation.展开更多
Solubility data of carbon dioxide (CO2) (1) in methanol (2), 1-octyl-3-methylimidazolium bis(trifluoro- methylsulfonyl)imide ([omim]+[TfzN]-) (3), and their mixtures (w3 = 0.2, 0.5, and 0.8) at temperat...Solubility data of carbon dioxide (CO2) (1) in methanol (2), 1-octyl-3-methylimidazolium bis(trifluoro- methylsulfonyl)imide ([omim]+[TfzN]-) (3), and their mixtures (w3 = 0.2, 0.5, and 0.8) at temperatures 313.2 and 333.2 K and pressures up to 7.0 MPa were measured by a high-pressure view-cell technique. The solubility of CO2 in methanol (w3 = 0), [omim]+[Tf2N]- (w3 = 1.0) and their mixtures follows the order of (w3 = 0)〈(w3 = 0.2)〈 (w3 = 0.5)〈(w3 = 0.8)〈(w3 = 1.0) at the same temperature and pressure, while the magnitude of Henry's constants follows the reverse order at a given temperature, which is consistent with the COSMO-RS (conductor-like screen- ing for real solvents) calculation. The solubility data of CO2 in methanol and [omim]~[Tf2N]- are correlated with the Peng-Robinson equation of state, and the solubility of CO2 in the mixtures of methanol and [omim]+[TfzN] can be well predicted based on the mole fraction average of methanol and [omim]+[Tf2N] over the solubility of CO2 in pure methanol and [omim]+[Tf2N] . The mixtures of methanol and [omim]+[Tf2N]- may be used as physical solvents for capturing CO2 with high partial pressures since they combine the advantages of organic solvents and ionic liquids.展开更多
Carboxyl graphene modified CuxO/Cu electrode was fabricated. The bare copper electrode was firstly anodic polarized in 1.0 mol/L NaOH solution in order to get CuxO nanoparticles, then the carboxyl graphene (CG) was ...Carboxyl graphene modified CuxO/Cu electrode was fabricated. The bare copper electrode was firstly anodic polarized in 1.0 mol/L NaOH solution in order to get CuxO nanoparticles, then the carboxyl graphene (CG) was electrodeposited on the CuxO/Cu electrode by cyclic potential sweeping. The electrocatalytic oxidation behaviors of calcium folinate (CF) at the graphene modified CuxO/Cu electrode were investigated by cyclic voltammetry. A positive scan polarization reverse catalytic voltammetry was used to obtain the pure catalytic oxidation current. The graphene modified CuxO/Cu electrode was served as the electrochemical sensor of CF, a highly sensitivity of 22.0μA.(μmol/μL)^-1cm^-2 was achieved, and the current response was linear with increasing CF concentration in the range of 2.0×10^-7 mol/L to 2.0×10^-5 mol/L, which crossed three orders of magnitude, and the detection limit was found 7.6×10^-5 mol/L (S/N=3). In addition, the proposed sensor was successfully applied in determination of CF in drug sample.展开更多
Methylene-bis[benzobicyclo(diaza-diphenyl) stannoxide,C_(41)H_(34)N_4O_4Sn_2·1/2C_6H_6],Mr=923.19,m.p.126-127℃,triclinic,P1,a=9.780(4),b=14.485(2),c=15.122(6),α=74. 95(3),β=72.21(3),γ=82.68(2)°,V=1967(1)...Methylene-bis[benzobicyclo(diaza-diphenyl) stannoxide,C_(41)H_(34)N_4O_4Sn_2·1/2C_6H_6],Mr=923.19,m.p.126-127℃,triclinic,P1,a=9.780(4),b=14.485(2),c=15.122(6),α=74. 95(3),β=72.21(3),γ=82.68(2)°,V=1967(1) Z=2,Dx=1.56 g/cm ̄3, MoKα(λ=0.71073),μ=13.20 cm-1,F(000)=922;final R=0.045, Rw=0.046 for 3637 observed reflections(I≥3σ(I)).The title compound is a bimetallo-heterocyclic complex prepared by condensation.Each tin atom has a trigonal bipyramidal coordination with two oxygen atoms occupying the axial positions.展开更多
Reverse-transcription qualitative PCR(RT-qPCR)was used to analyze the changes in transcription levels of the sulfur metabolism-related periplasmic protein genes of Acidithiobacillus ferrooxidans ATCC 23270 grown on su...Reverse-transcription qualitative PCR(RT-qPCR)was used to analyze the changes in transcription levels of the sulfur metabolism-related periplasmic protein genes of Acidithiobacillus ferrooxidans ATCC 23270 grown on sulfur or ferrous.Seven periplasmic proteins with apparently higher abundance grown on elemental sulfur than on ferrous sulfate were identified by matrix-assisted laser desorption ionization time-of-flight mass spectrometry(MALDI-TOF-MS).Expression analysis of the corresponding genes by RT-qPCR shows that the constitutive expression of all those genes are more up-regulated grown on sulfur than those grown on ferrous(>10 folder).Study on the corresponding genes of the identified periplasmic proteins by RT-qPCR confirmed the results of two-dimensioned gel electrophoresis,indicating they may be related with sulfur metabolism in A.ferrooxidans.展开更多
Two artificial intelligence techniques, artificial neural network and genetic algorithm, were applied to optimize the fermentation medium for improving the nitrite oxidization rate of nitrite oxidizing bacteria. Exper...Two artificial intelligence techniques, artificial neural network and genetic algorithm, were applied to optimize the fermentation medium for improving the nitrite oxidization rate of nitrite oxidizing bacteria. Experiments were conducted with the composition of medium components obtained by genetic algorithm, and the experimental data were used to build a BP (back propagation) neural network model. The concentrations of six medium components were used as input vectors, and the nitrite oxidization rate was used as output vector of the model. The BP neural network model was used as the objective function of genetic algorithm to find the optimum medium composition for the maximum nitrite oxidization rate. The maximum nitrite oxidization rate was 0.952 g 2 NO-2-N·(g MLSS)-1·d-1 , obtained at the genetic algorithm optimized concentration of medium components (g·L-1 ): NaCl 0.58, MgSO 4 ·7H 2 O 0.14, FeSO 4 ·7H 2 O 0.141, KH 2 PO 4 0.8485, NaNO 2 2.52, and NaHCO 3 3.613. Validation experiments suggest that the experimental results are consistent with the best result predicted by the model. A scale-up experiment shows that the nitrite degraded completely after 34 h when cultured in the optimum medium, which is 10 h less than that cultured in the initial medium.展开更多
The side-glowing optical fibers (SOFs) were chosen as the conducting medium of endogenous light; and 20 mg·L-1 methylene blue was chosen as the target to be degraded. The SOF is made up of quartz core with a sili...The side-glowing optical fibers (SOFs) were chosen as the conducting medium of endogenous light; and 20 mg·L-1 methylene blue was chosen as the target to be degraded. The SOF is made up of quartz core with a silicon cladding, which can emit light through side surface more uniformly and transmit light for longer distance to avoid attenuation of light by liquid medium. The filament lamp was chosen as visible light source. Different reaction conditions, such as the presence of optical fiber or not, the quantity of SOF, light irradiation intensity were tested by measuring the methylene blue degradation of methylene blue. The results show that suitable reaction conditions were 1.167 g·L-1 Ag + /TiO 2 with 7% (by mass) of Ag + doped in TiO 2 , and 500 roots of SOF (30 cm length in solution). The photocatalytic degradation efficiency under 300W lamp irradiation for 8h was about 97%. And the photocatalytic degradation efficiency of methylene blue degradation was proportional to SOF quantity, light irradiation intensity and catalytic dosage within a certain range. Compared with general UV and visible light SOFs could save a huge amount of energy and cost, in the potential applications in dealing with organic pollutants on a large scale.展开更多
Into the photooxidation process, several factors such as pH, time of irradiation, dose of UV light, lamp power, contaminant concentration, turbidity of the solution and the presence of salts can interfere with the pho...Into the photooxidation process, several factors such as pH, time of irradiation, dose of UV light, lamp power, contaminant concentration, turbidity of the solution and the presence of salts can interfere with the photodegradation of pollutants. This research aims to evaluate the influence of salts: NaCl, MgCl2, CaCI2, BaC12, CuCl2, Na2SO4, MgSO4, MnSO4, FeSO4, CuSO4, Na3PO4, K2CrO4 and K2Cr207 in concentrations of 0.0005 M, 0.005 M and 0.05 M during photodegradation of aqueous solution of 59.5 mg/L of nitrobenzene at a pH of 2.5. It was observed that the presence of salts such as CuCI2, CuSO4, FeSO4, K2CrO4 and K2Cr207 interfere negatively in the system UV/H202 applied for degradation of nitrobenzene; possibly by oxidation of Fe2+ to Fe3+ and Cu+ to Cu2+ in the Cr case, due to the difficulty of transforming the Cr6+ to Cr3+ or because these solutions have color and act as radiation absorbing filter.展开更多
基金Project (51172092) supported by the National Natural Science Foundation of ChinaProject (11A093) supported the Education Department of Hunan Province,China+1 种基金Project (13JJ1023) supported by the Natural Science Fund for Distinguished Youth of Hunan Province,ChinaProject (NECT-12-0720) supported the Program for New Century Excellent Talents in Universities of China
文摘Ordered mesoporous TiO2 (OMPT) was prepared by an evaporation induced self-assembly technique using liquid crystal as template. The key factors affecting the methylene blue (MB) oxidation efficiency were investigated, including the initial concentration of MB, pH value and catalyst concentration. The results show that the obtained OMPT has high thermal stability and shows a 2D hexagonal mesostructure with the small particle size and high surface area, which lead to higher degradation efficiency than commercial P25 or nanoparticle TiO2 (NPT) fabricated by sol-gel process. The optimal conditions are 5 mg/L MB, pH 6 and 1.5 g/L OMPT for the fastest rate of MB degradation. Total organic carbon (TOC) analysis indicates complete mineralization of MB in 240 min by OMPT, with rate constant higher than NPT or P25.
基金Supported by National Natural Science Foundation of China(30471229 )National High Technology Research and Development Program "863" Project(2008AA10Z224)Students Innovative Experimental Projects in Jilin University (2009C81147)~~
文摘[Objective] The aim was to study the cloning and sequence analysis of rbcS gene of wild barley under salt stress. [Method] The tender leaf blade of wild barley under salt stress was taken as the experimental material. The primers were designed according to the homology of rbcS gene sequences of wheat and barely in Genbank; then PCR amplification,recovery,ligation,transformation and sequencing of rbcS gene were carried out. [Result] Two rbcS genes including rbcS1 and rbcS2 with the length of 1 252 and 908 bp respectively were cloned from the barely genome. rbcS1 and rbcS2 were both composed by two exons and one intron. The exons length of the two genes was the same of 525 bp,encoding 174 amino acids,and the homology between them was 96%; however,the intron length of rbcS1 and rbcS2 was 448 and 107 bp respectively.
基金supported by the National Natural Science Foundation of China(51578354)Six Talent Peaks Program(2016-JNHB-067)+1 种基金Suzhou Science and Technology Bureau(SS201667)Qing Lan Project and Research Innovation Project for College Graduates of Jiangsu Province(KYCX17_2067)~~
文摘The photocatalytic ability of ZnO is improved through the addition of flower‐like Bi2WO6 to prepare a Bi2WO6/ZnO composite with visible light activity.The composite is characterized by X‐ray diffraction,transmission electron microscopy,scanning electron microscopy with UV–vis diffuse reflectance spectroscopy,X‐ray photoelectron spectroscopy and N2 adsorption‐desorption isotherms.After modification,the band gap energy of Bi2WO6/ZnO is reduced from 3.2 eV for ZnO to 2.6 eV.Under visible light irradiation,the Bi2WO6/ZnO composite shows an excellent photocatalytic activity for degrading methylene blue(MB)and tetracycline.The photo‐degradation efficiencies of(0.3:1)Bi2WO6/ZnO for MB and tetracycline are approximately 246 and 4500 times higher than those of bare ZnO,respectively,and correspondingly,the photo‐degradation rates for the two pollutants are approximately 120 and 200 times higher than those with bare ZnO,respectively.Moreover,the photocatalyst of(0.3:1)Bi2WO6/ZnO exhibits a higher transient photocurrent density of approximately 4.5μA compared with those of bare Bi2WO6 and ZnO nanoparticles.The successful recombination of Bi2WO6 and ZnO enhances the photocatalytic activity and reduces the band gap energy of ZnO,which can be attributed to the effective separation of electron–hole pairs.Active species trapping experiments display that[O2]-is the major species involved during photocatalysis rather than·OH and h+.This study provides insight into designing a meaningful visible‐light‐driven photocatalyst for environmental remediation.
基金supported by the National Natural Science Foundation of China(31100482,31411140034)the Scientific Research Fund of Hunan Provincial Education Department(16B119)
文摘The bombycid moth, Triuncina daii Xing Wang & Zolotuhin, 2015, plays an important role for analyzing the phylogenetic relationships of the family Bombycidae (Lepidoptera: Bombycoidea). Here we first describe the complete mitochondrial genome (mitogenome) of T. daii, which includes thirteen protein-coding genes (PCGs), twenty-two transfer RNA genes, two ribosomal RNA genes and an A+T-rich region, and we find the mitogenome is 15,482 bp in length (GenBank no. KY091643). The genes order and orientation in the T. daii mitogenome are similar to other sequenced lepidopteran species. Except for cox1, all of the PCGs started with ATN. Twelve PCGs stopped at TAA except for cox1 which stops at a single T. Thirteen PCGs of available species are used to demonstrate the inner phylogenetic relationships of Bombycoidea. The bombycid species form a monophyletic clade with a bootstrap value of 100% and a posterior probability of 1.00.
文摘The magnetic field effects (MFEs) are studied on photocatalytic degradation of methylene blue (MB) solution using ZnO and TiO2 particles. The UV-VIS-NIR spectrometer is used to monitor the MB concentrations, and the dependence of the reaction rate on the initial dye concentration and settling duration is studied under UV light irradiation. It is found that the MFEs exist on the heterogeneous reaction systems for both ZnO and TiO2 powders and that the extraordinary phenomenon is reproducible. For ZnO powder, the results are in good agreement with the second-order reaction kinetics following the Langmuir-Hinshelwood (L-H) model, while the reaction for TiO2 follows first-order kinetics. It enhances the photodegradation for ZnO, while it reduces or enhances the reaction for TiO2 depending on the initial dye concentrations. The MFEs become small or negligible when the same photodecomposition experiment is carried out after settling the MB solution for more than three hours for both ZnO and TiO2. It is suggested that the key factors of MFEs on photocatalytic degradation is the condition of the MB solution as well as the characteristics of photocatalysts. The alteration of the MFEs ascribed to the solution condition caused by variation of the settling time.
基金Project(51772153)supported by the National Natural Science Foundation of China。
文摘In this study,porous silica with high surface area was prepared through selective leaching of thermally activated chlorite in HCl solution.In the process,chlorite was activated by pre-calcining treatment,then activated components(MgO,Al_(2)O_(3),and Fe_(2)O_(3))were selectively leached by acid solution,resulting in the formation of nanopores in situ.The morphology,structure,surface area and pore-size distribution of the material were characterized by XRD,TG/DSC,^(27)Al MAS NMR,SEM,TEM and N2 adsorption−desorption isotherms.The highest specific surface area(SBET=333 m^(2)/g)was obtained by selectively leaching the 600℃ calcined chlorite from 3 mol/L HCl at 90℃ for 2 h.The pore sizes and specific surface areas can be controlled by calcination and leaching conditions.The ^(27)Al MAS NMR spectra of the samples revealed the relationship between structural transformation and the selective acid leaching properties of thermal-activated chlorite,demonstrating that AlVI transfers into AlV when chlorite changes into activated chlorite during thermal activation,and the coordinations of Al has a significant effect on acid solubility of chlorite.The as-prepared porous silica showed favorable adsorption abilities with capacity of 148.79 mg/g for methylene blue at pH of about 7 and temperature of 25℃,indicating its promising potential in adsorption application.
基金supported by the National Natural Science Foundation of China (21203233,21473232,21403270)Youth Innovation Promotion Association,CAS (2013115)~~
文摘A Cu2O/SiC heterogeneous catalyst was prepared via a two‐step liquid‐phase method using diethyleneglycol as both the solvent and the reducing agent.The catalyst was characterized using X‐raydiffraction,X‐ray photoelectron spectroscopy,scanning electron microscopy(SEM),transmissionelectron microscopy(TEM),and H2temperature‐programmed reduction.All the results indicatethat Cu is present on the SiC support primarily as Cu2O.The SEM and TEM results show that cubicCu2O nanoparticles are uniformly dispersed on theβ‐SiC surface.The reaction conditions,namelythe temperature,reaction time,and amounts of base and catalyst used,for the Ullmann‐type C–Ocross‐coupling reaction were optimized.A model reaction was performed using iodobenzene(14.0mmol)and phenol(14.0mmol)with Cu2O/SiC(5wt%Cu)as the catalyst,Cs2CO3(1.0equiv.)as thebase,and tetrahydrofuran as the solvent at150°C for3h;a yield of97%was obtained and theturnover frequency(TOF)was1136h?1.The Cu2O/SiC catalyst has a broad substrate scope and canbe used in Ullmann‐type C–O cross‐coupling reactions of aryl halides and phenols bearing a varietyof different substituents.The catalyst also showed high activity in the Ullmann‐type C–Scross‐coupling of thiophenol with iodobenzene and substituted iodobenzenes;a TOF of1186h?1was achieved.The recyclability of the Cu2O/SiC catalyst in the O‐arylation of phenol with iodobenzenewas investigated under the optimum conditions.The yield decreased from97%to64%afterfive cycles.The main reason for the decrease in the catalyst activity is loss of the active component,i.e.,Cu2O.
基金supported by the China Postdoctoral Science Foundation (2014M551746)~~
文摘Selective oxidation with molecular oxygen as the sole oxidant under mild conditions is of crucialimportance for the long‐term sustainable exploitation of available feedstocks and the formation ofrequired intermediates for organic synthesis and industrial processes.Among the developed oxidationprotocols,innovative strategies using hydroxyimide organocatalysts in combination with metallicor metal‐free cocatalysts have attracted much attention because of the good activities andselectivities of such catalysts in the oxo functionalization of hydrocarbons.This method is based onthe reaction using N‐hydroxyphthalimide,which was first reported by Ishii’s group in the1990s.Although the important and wide‐ranging applications of such catalysts have been summarizedrecently,there are no reviews that focus solely on oxidation strategies using multi‐nitroxy organocatalysts,which have interesting properties and high reactivities.This review covers the concisesynthetic methods and mechanistic profiles of known multi‐nitroxy organocatalysts and summarizessignificant advances in their use in efficient aerobic oxidation.Based on a combination of experimentaland theoretical results,guidelines for the future rational design of multi‐nitroxy organocatalystsare proposed,and the properties of various model multi‐nitroxy organocatalysts are predicted.The present overview of the advantages,limitations,and potential applications of multi‐nitroxyorganocatalysts can provide useful tools for researchers in the field of selective oxidation.
基金Supported by the National Natural Science Foundation of China (21121064, 21076008), and the Projects in the National Sci ence & Technology Pillar Program During the Twelfth Five-Year Plan Period (2011BAC06B04).
文摘Solubility data of carbon dioxide (CO2) (1) in methanol (2), 1-octyl-3-methylimidazolium bis(trifluoro- methylsulfonyl)imide ([omim]+[TfzN]-) (3), and their mixtures (w3 = 0.2, 0.5, and 0.8) at temperatures 313.2 and 333.2 K and pressures up to 7.0 MPa were measured by a high-pressure view-cell technique. The solubility of CO2 in methanol (w3 = 0), [omim]+[Tf2N]- (w3 = 1.0) and their mixtures follows the order of (w3 = 0)〈(w3 = 0.2)〈 (w3 = 0.5)〈(w3 = 0.8)〈(w3 = 1.0) at the same temperature and pressure, while the magnitude of Henry's constants follows the reverse order at a given temperature, which is consistent with the COSMO-RS (conductor-like screen- ing for real solvents) calculation. The solubility data of CO2 in methanol and [omim]~[Tf2N]- are correlated with the Peng-Robinson equation of state, and the solubility of CO2 in the mixtures of methanol and [omim]+[TfzN] can be well predicted based on the mole fraction average of methanol and [omim]+[Tf2N] over the solubility of CO2 in pure methanol and [omim]+[Tf2N] . The mixtures of methanol and [omim]+[Tf2N]- may be used as physical solvents for capturing CO2 with high partial pressures since they combine the advantages of organic solvents and ionic liquids.
文摘Carboxyl graphene modified CuxO/Cu electrode was fabricated. The bare copper electrode was firstly anodic polarized in 1.0 mol/L NaOH solution in order to get CuxO nanoparticles, then the carboxyl graphene (CG) was electrodeposited on the CuxO/Cu electrode by cyclic potential sweeping. The electrocatalytic oxidation behaviors of calcium folinate (CF) at the graphene modified CuxO/Cu electrode were investigated by cyclic voltammetry. A positive scan polarization reverse catalytic voltammetry was used to obtain the pure catalytic oxidation current. The graphene modified CuxO/Cu electrode was served as the electrochemical sensor of CF, a highly sensitivity of 22.0μA.(μmol/μL)^-1cm^-2 was achieved, and the current response was linear with increasing CF concentration in the range of 2.0×10^-7 mol/L to 2.0×10^-5 mol/L, which crossed three orders of magnitude, and the detection limit was found 7.6×10^-5 mol/L (S/N=3). In addition, the proposed sensor was successfully applied in determination of CF in drug sample.
文摘Methylene-bis[benzobicyclo(diaza-diphenyl) stannoxide,C_(41)H_(34)N_4O_4Sn_2·1/2C_6H_6],Mr=923.19,m.p.126-127℃,triclinic,P1,a=9.780(4),b=14.485(2),c=15.122(6),α=74. 95(3),β=72.21(3),γ=82.68(2)°,V=1967(1) Z=2,Dx=1.56 g/cm ̄3, MoKα(λ=0.71073),μ=13.20 cm-1,F(000)=922;final R=0.045, Rw=0.046 for 3637 observed reflections(I≥3σ(I)).The title compound is a bimetallo-heterocyclic complex prepared by condensation.Each tin atom has a trigonal bipyramidal coordination with two oxygen atoms occupying the axial positions.
基金Projects(50674101,50974140)supported by the National Natural Science Foundation of ChinaProject(2010CB630902)supported by the National Basic Research Program of China
文摘Reverse-transcription qualitative PCR(RT-qPCR)was used to analyze the changes in transcription levels of the sulfur metabolism-related periplasmic protein genes of Acidithiobacillus ferrooxidans ATCC 23270 grown on sulfur or ferrous.Seven periplasmic proteins with apparently higher abundance grown on elemental sulfur than on ferrous sulfate were identified by matrix-assisted laser desorption ionization time-of-flight mass spectrometry(MALDI-TOF-MS).Expression analysis of the corresponding genes by RT-qPCR shows that the constitutive expression of all those genes are more up-regulated grown on sulfur than those grown on ferrous(>10 folder).Study on the corresponding genes of the identified periplasmic proteins by RT-qPCR confirmed the results of two-dimensioned gel electrophoresis,indicating they may be related with sulfur metabolism in A.ferrooxidans.
基金Supported by the National Natural Science Foundation of China (21076090)
文摘Two artificial intelligence techniques, artificial neural network and genetic algorithm, were applied to optimize the fermentation medium for improving the nitrite oxidization rate of nitrite oxidizing bacteria. Experiments were conducted with the composition of medium components obtained by genetic algorithm, and the experimental data were used to build a BP (back propagation) neural network model. The concentrations of six medium components were used as input vectors, and the nitrite oxidization rate was used as output vector of the model. The BP neural network model was used as the objective function of genetic algorithm to find the optimum medium composition for the maximum nitrite oxidization rate. The maximum nitrite oxidization rate was 0.952 g 2 NO-2-N·(g MLSS)-1·d-1 , obtained at the genetic algorithm optimized concentration of medium components (g·L-1 ): NaCl 0.58, MgSO 4 ·7H 2 O 0.14, FeSO 4 ·7H 2 O 0.141, KH 2 PO 4 0.8485, NaNO 2 2.52, and NaHCO 3 3.613. Validation experiments suggest that the experimental results are consistent with the best result predicted by the model. A scale-up experiment shows that the nitrite degraded completely after 34 h when cultured in the optimum medium, which is 10 h less than that cultured in the initial medium.
文摘The side-glowing optical fibers (SOFs) were chosen as the conducting medium of endogenous light; and 20 mg·L-1 methylene blue was chosen as the target to be degraded. The SOF is made up of quartz core with a silicon cladding, which can emit light through side surface more uniformly and transmit light for longer distance to avoid attenuation of light by liquid medium. The filament lamp was chosen as visible light source. Different reaction conditions, such as the presence of optical fiber or not, the quantity of SOF, light irradiation intensity were tested by measuring the methylene blue degradation of methylene blue. The results show that suitable reaction conditions were 1.167 g·L-1 Ag + /TiO 2 with 7% (by mass) of Ag + doped in TiO 2 , and 500 roots of SOF (30 cm length in solution). The photocatalytic degradation efficiency under 300W lamp irradiation for 8h was about 97%. And the photocatalytic degradation efficiency of methylene blue degradation was proportional to SOF quantity, light irradiation intensity and catalytic dosage within a certain range. Compared with general UV and visible light SOFs could save a huge amount of energy and cost, in the potential applications in dealing with organic pollutants on a large scale.
文摘Into the photooxidation process, several factors such as pH, time of irradiation, dose of UV light, lamp power, contaminant concentration, turbidity of the solution and the presence of salts can interfere with the photodegradation of pollutants. This research aims to evaluate the influence of salts: NaCl, MgCl2, CaCI2, BaC12, CuCl2, Na2SO4, MgSO4, MnSO4, FeSO4, CuSO4, Na3PO4, K2CrO4 and K2Cr207 in concentrations of 0.0005 M, 0.005 M and 0.05 M during photodegradation of aqueous solution of 59.5 mg/L of nitrobenzene at a pH of 2.5. It was observed that the presence of salts such as CuCI2, CuSO4, FeSO4, K2CrO4 and K2Cr207 interfere negatively in the system UV/H202 applied for degradation of nitrobenzene; possibly by oxidation of Fe2+ to Fe3+ and Cu+ to Cu2+ in the Cr case, due to the difficulty of transforming the Cr6+ to Cr3+ or because these solutions have color and act as radiation absorbing filter.