The attractive utilization route for one-step catalytic oxidation of dimethyl ether to dimethoxymethane was successfully carried out over the H3PW12O40（40%）/SiO2 catalyst, modified by Cs, K, Ni, and V. The Cs modifi...The attractive utilization route for one-step catalytic oxidation of dimethyl ether to dimethoxymethane was successfully carried out over the H3PW12O40（40%）/SiO2 catalyst, modified by Cs, K, Ni, and V. The Cs modification of H3PW12O40（40%）/SiO2 gave the most promising result of 20% dimethyl ether conversion and 34.8% dimethoxymethane selectivity. Dimethoxymethane could be synthe- sized via methoxy groups decomposed from dimethyl ether through the synergistic effect between the acid sites and the redox sites of Cs modified H3PW12O40（40%）/SiO2.展开更多
DBUH-Br_3 catalyzed selective conversion of sulfides to sulfoxides in the presence of H_2O_2 as oxidizing agent is described.The reaction was performed selectively at room temperature and relatively short reaction times.
The effect of Na-excess content in the precursor on the structural and electrochemical performances of sodium nickel manganese oxide(NNMO)prepared by sol-gel and electrospinning methods is investigated in this paper.X...The effect of Na-excess content in the precursor on the structural and electrochemical performances of sodium nickel manganese oxide(NNMO)prepared by sol-gel and electrospinning methods is investigated in this paper.X-ray diffraction results of the prepared NNMO without adding Na-excess content indicate sodium loss,while the mixed phase of P2/O′3-type layered NNMO presented after adding Na-excess content.Compared with the sol-gel method,the secondary phase of NiO is more suppressed by using the electrospinning method,which is further confirmed by field emission scanning electron microscope images.N_(2) adsorption-desorption isotherms show no remarkably difference in specific surface areas between different preparation methods and Na-excess contents.The analysis of X-ray absorption near edge structure indicates that the oxidation states of Ni and Mn are+2 and+4,respectively.For the electrochemical properties,superior electrochemical performance is observed in the NNMO electrode with a low Na-excess content of 5wt%.The highest specific capacitance is 36.07 F·g^(-1)at0.1 A·g^(-1)in the NNMO electrode prepared by using the sol-gel method.By contrast,the NNMO electrode prepared using the electrospinning method with decreased Na-excess content shows excellent cycling stability of 100%after charge-discharge measurements for 300 cycles.Therefore,controlling the Na excess in the precursor together with the preparation method is important for improving the electrochemical performance of Na-based electrode materials in supercapacitors.展开更多
V（HSO4）3 has been found to be an efficient reagent for the promotion of the oxidation of alcohols and trimethylsilyl, tetrahydropyranyl and methoxymethyl ethers to their corresponding carbonyl compounds with Cu（NO3...V（HSO4）3 has been found to be an efficient reagent for the promotion of the oxidation of alcohols and trimethylsilyl, tetrahydropyranyl and methoxymethyl ethers to their corresponding carbonyl compounds with Cu（NO3）2-3H2O in the absence of solvent.展开更多
The comparison of degradation of Acid Yellow 61 as a model dye compound in both oxidation processes of H 2O 2/UV and O 3 has been studied. When the decolorization rate of Acid Yellow 61 in both reactions presented ...The comparison of degradation of Acid Yellow 61 as a model dye compound in both oxidation processes of H 2O 2/UV and O 3 has been studied. When the decolorization rate of Acid Yellow 61 in both reactions presented similar, it was found there are some differences from the results of AOX removal and production of inorganic ions and organic acids. The results reveal that the H 2O 2/UV has beneficial effect on mineralization than O 3 only for degradation of Acid Yellow 61 solution and it is possible for enhancement of method efficiency by taking longer reaction time and addition of high concentration of oxidants.展开更多
The characteristics of water quality had significant effects on the oxidative degradation of O_3/H_2O_2 system.In this study,iron supported on activated carbon catalyst was prepared firstly,and then the treatment of l...The characteristics of water quality had significant effects on the oxidative degradation of O_3/H_2O_2 system.In this study,iron supported on activated carbon catalyst was prepared firstly,and then the treatment of landfill leachate by O_3/H_2O_2/catalyst system was analyzed,especially the roles of H_2O_2 in the oxidation of landfill leachate by O_3/H_2O_2 system.The results showed that at room temperature,when the dosage of the catalyst was 1.0g,the removal rate of COD from the landfill leachate reached 79.8% after 50 ml of the landfill leachate(pH=3)was oxidized by O_3(its flow rate was 5g/h)for 50 min.If 0.3ml of H_2O_2 was added to the landfill leachate,the removal rate of COD increased from 79.8%to 88.7%.It showed that the landfill leachate with the characteristics of complex composition and difficult biodegradation could be effectively degraded by the O_3/H_2O_2 system.展开更多
Selective oxidation of sulfides to sulfoxides was successfully performed by employing readily available Fe（NO3）3-9H2O as the active catalyst with oxygen as the oxidant in 2,2,2-trifluoroethanol （TFE） without the f...Selective oxidation of sulfides to sulfoxides was successfully performed by employing readily available Fe（NO3）3-9H2O as the active catalyst with oxygen as the oxidant in 2,2,2-trifluoroethanol （TFE） without the formation of sulfones. Nitrate anion could play a crucial role in promoting the reaction due to the oxidation capacity under acidic media. High yields of sulfoxides were exclusively obtained from the corresponding sulfides. Furthermore, both aromatic and aliphatic sulfides gave moderate to high yields of sulfoxides with this protocol.展开更多
A series of heteropoly acid (HPA) based Al2O3 catalysts with three-dimensional ordered (3DOM) structure were synthesized by colloidal crystal template method.Interconnected macropores (250 nm) could be clearly observe...A series of heteropoly acid (HPA) based Al2O3 catalysts with three-dimensional ordered (3DOM) structure were synthesized by colloidal crystal template method.Interconnected macropores (250 nm) could be clearly observed by scanning electron microscope (SEM) and transmission electron microscope (TEM).Mesopores could be detected by N2 adsorption-desorption isotherms which further confirmed the 3DOM structural characteristics of catalyst.Moreover,Keggin-type HPW was highly dispersed in the Al2O3 framework,which suggested by powder X-ray diffraction (XRD) and Fourier transform infrared spectra (FT-IR) results.The oxidation desulfurization (ODS) performance of 3DOM H3PW12O40/Al2O3 of refractory sulphur compounds was evaluated in the presence of hydrogen peroxide.It oxidized 98.5% of dibenzothiophene (DBT) into corresponding sulfone within 3 h,which exhibited superior ODS performance than corresponding mesoporous and microporous H3PW12O40/Al2O3 catalyst.The enhancement of ODS efficiency is related to the improvement of mass transfer of DBT in the pore channel resulting from the interconnected 3DOM structure.Furthermore,the as-prepared catalyst still demonstrates outstanding cycle performance after 6 runs,which could be easily recovered from the model fuel.展开更多
The degradations of hexazinone and aldicarb by direct ozonation combined an advanced oxidation process( AOP) of O3/H2O2 were investigated in this study focusing on the oxidation mechanism by identifying the hydrogen p...The degradations of hexazinone and aldicarb by direct ozonation combined an advanced oxidation process( AOP) of O3/H2O2 were investigated in this study focusing on the oxidation mechanism by identifying the hydrogen peroxide consumption during the oxidation process of the two chemicals. The results showed that H2O2 could enhance the removal rate of the triazine herbicide hexazinone,and it was consumed along with the variation of removal rate in the light of different pH levels. The addition of H2O2 contributed little to the removal of the thiocarbamate herbicide aldicarb and H2O2 content kept constantly throughout the degradation process. Tert-butyl alcohol( TBA) effectively scavenged the ·OH radical for hexazinone,but had no effect on the removal rate of aldicarb. Aldicarb removal was mainly attributed to direct ozonation molecule in both O3( 97.00%) and O3/H2O2( 96.76%)systems. Moreover,sole O3 could hardly oxidize hexazinone whereas·OH radicals contribute respective 74.70% and 97.50% of removal in O3 system and O3/H2O2 AOP. All of these findings suggest that the mechanism of ·OH radical generation and the chain reaction in O3/H2O2 AOP should be further discussed.展开更多
The oxysulfide La3NbS2O5 was synthesized by sulfurization using H2S and characterized by X-ray diffraction （XRD）, UV-Vis diffuse reflectance spectroscopy （DRS） and field emission scanning electron microscopy （FE-...The oxysulfide La3NbS2O5 was synthesized by sulfurization using H2S and characterized by X-ray diffraction （XRD）, UV-Vis diffuse reflectance spectroscopy （DRS） and field emission scanning electron microscopy （FE-SEM）. The relationship between the sulfurization conditions and the photocatalytic activities for H2 evolution was investigated. Sulfurization method allowed for synthesis of La3NbS2O5 at much lower temperatures and significantly shortened reaction time of 1 h compared with conventional solid-state techniques. The particle morphologies were regular platelike with sizes of 0.1-0.6μm and smooth surfaces. The highest activity for H2 evolution was obtained at 1073 K for 1 h, which was about 1.83 times that of La3NbS2O5 prepared by solid-state method.展开更多
Eucommia ulmoides Oliv.(EuO),also known as Duzhong,native to China,has been reported to have antioxidative function,but its cellular mechanism is not fully examined yet.We investigated inhibitory effects of EuO leaf e...Eucommia ulmoides Oliv.(EuO),also known as Duzhong,native to China,has been reported to have antioxidative function,but its cellular mechanism is not fully examined yet.We investigated inhibitory effects of EuO leaf ethanol extracts on H2O2-induced apoptosis in rat osteoblastic MC3T3-E1 cells and underlying mechanisms.Locally-grown Duzhong leaves were extracted with ethanol.MC3T3-E1 cells were treated with EuO (6.25,12.5,25,50,and 100 μg/ml) for 24 h,and then H2O2 (800 μmol/L) for an additional 24 h.Cell survival rate,percentage of apoptosis,and expressions of caspases 3,6,7,and 9 were examined using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay,microscopic analysis,Western blotting,and reverse transcription polymerase chain reaction (RT-PCR).The final EuO leaf ethanol extract powder was detected to contain caffeotannic acid at 58 mg/g and geniposide at 3.45 mg/g by high performance liquid chromatography (HPLC).EuO remarkably restrained cell oxidative damage and increased cell survival rate in a dose-dependent manner: 0 μg/ml,0.21;6.25 μg/ml,0.28;12.5 μg/ml,0.31;25 μg/ml,0.48;50 μg/ml,0.54;and 100 μg/ml,0.66 (P<0.05),with the half-effective concentration being around 25 μg/ml.MTT results were confirmed by microscopic analysis.Western blotting and RT-PCR analyses showed that the expressions of caspases 3,6,7,and 9 were significantly decreased in the EuO-treated cells compared with the control (EuOand H2O2-free) (P<0.05),with the half-effective concentration of EuO ranging from 12.5 to 25 μg/ml.We conclude that the ethanol-extracted EuO leaf extracts promoted the growth of MC3T3-E1 cells,and suppressed the H2O2-induced apoptosis in a rat MC3T3-E1 osteogenic cell model,likely due to the inhibition of caspases’ activities.The results indicate that EuO is a potent antioxidant,which may contribute to its many cellular protective functions,including the promotion of bone growth.展开更多
A series of Ce, H3PW12O40 co-doped TiO2 hollow fibers photocatalysts have been prepared by sol-gel method using ammonium ceric nitrate, H3PW12O40 and tetrabutyltitanate as precursors and cotton fibers as template, fol...A series of Ce, H3PW12O40 co-doped TiO2 hollow fibers photocatalysts have been prepared by sol-gel method using ammonium ceric nitrate, H3PW12O40 and tetrabutyltitanate as precursors and cotton fibers as template, followed by calcination at 500 ℃ in N2 atmosphere for 2 h. Scanning electron microscopy, X-ray diffraction, nitrogen adsorption-desorption mea- surements, and UV-Vis spectroscopy are employed to characterize the morphology, crystal structure, surface structure, and optical absorption properties of the samples. The photo- catalytic performance of the samples has been studied by photodegradation phenol in water under UV and visible light irradiation. The results show that the TiO2 fiber materials have hollow structures, and the co-doped TiO2 hollow fibers exhibit higher photocatalytic activities for the degradation of phenol than un-doped, single-doped TiO2 hollow fibers under UV and visible light. In addition, the recyclability of co-doped TiO2 fibers is also confirmed that the TiO2 fiber retains ca. 90% of its activity after being used four times. It is shown that the co-doped TiO2 fibers can be activated by visible light and may be potentially applied to the treatment of water contaminated by organic pollutants. The synergistic effect of Ce and H3PW12O40 co-doping plays an important role in improving the photocatalytic activity.展开更多
The La2O3/Fe2O3-CeO2 composite oxide catalysts were prepared by coprecipitation method, sol-gel method and hydrothermal method. The effect of preparation methods on structure morphology and photocatalytic properties o...The La2O3/Fe2O3-CeO2 composite oxide catalysts were prepared by coprecipitation method, sol-gel method and hydrothermal method. The effect of preparation methods on structure morphology and photocatalytic properties of La2O3/Fe2O3-CeO2 samples was investigated. The results show that the cubic CeO2 structure can be obtained at 600℃. The rod-shaped sample prepared by coprecipitation method, displays the highest crystalline and the strongest diffraction peak intensity. The spherical sample is acquired from sol-gel method, while the small granular sample prepared by hydrothermal method tends to aggregate. The maximum specific surface area of the sample prepared by coprecipitation method is 76.21 m2/g, the minimum specific area of the sample from sol-gel method is 32.66 m2/g and the maximum pore size is 13.84 nm, while the minimum pore volume and pore size of the sample by hydrothermal method are 0.038 cm3/g and 3.95 nm respectively. The band gap energy of catalyst samples is in the following order: sample-CP < sample-SG < sample-HT. The sample obtained by coprecipitation method has the best catalytic degradation performance for methylene blue. Under the excitation of visible light, the degradation rate was 99.58% at 50 minutes, which was higher than those of sol-gel method and hydrothermal method by 5.58% and 9.54% respectively. The catalytic degradation reaction is a first-order kinetic model: ln (c0/ct) = kt + qe. The maximum k-value of the sample degradation process obtained by coprecipitation method is 0.074 min-1.展开更多
The performance of UV/H 2O 2, UV/O 3 and UV/H 2O 2/O 3 oxidation systems for treating spent caustic from an ethylene plant was investigated. In UV/H 2O 2 system, with the increase of H 2O 2 dosage, removal e...The performance of UV/H 2O 2, UV/O 3 and UV/H 2O 2/O 3 oxidation systems for treating spent caustic from an ethylene plant was investigated. In UV/H 2O 2 system, with the increase of H 2O 2 dosage, removal efficiencies of COD and the ratio of biochemical oxygen demand(BOD) to chemical oxygen demand(COD) of the effluent were increased and a better performance was obtained than the H 2O 2 system alone. In UV/H 2O 2 system, removal efficiency of COD reach 68% under the optimum condition, and BOD/COD ratio was significantly increased from 0 22 to 0 52. In UV/O 3 system, with the increase of O 3 dosage, removal efficiency of COD and BOD/COD ratio were increased, and a better performance was obtained than the O 3 system alone. Under the optimum condition, removal efficiency of COD was 54%, and BOD/COD ratio was significantly increased from 0 22 to 0 48. In UV/H 2O 2/O 3 system, COD removal efficiency was found to be 22.0% higher than UV/O 3 system.展开更多
Cobalt oxide catalysts supported on mesoporous silica （Co3O4/MPS） were prepared, characterized and applied for catalytic oxidation of NO. Effects of catalyst supports, calcination temperatures, H2O and SO2 on NO con...Cobalt oxide catalysts supported on mesoporous silica （Co3O4/MPS） were prepared, characterized and applied for catalytic oxidation of NO. Effects of catalyst supports, calcination temperatures, H2O and SO2 on NO conversion were investigated. The samples were also characterized by BET, XRD, FTIR and TG/DTG. The results suggested that Co3O4/MPS catalyst calcined at 573 K had the smallest crystal particles and the best surface dispersion. This catalyst had the highest activity and yielded 82% NO conversion at 573 K, at a space velocity of 12000 h^-1. Although the conversion of NO decreased with the introduction of H2O, it could be restored completely after removing residual H2O from Co3O4/MPS catalyst by heating at 573 K. In the presence of SO2, the oxidation activity decreased and COSO4 was detected on the catalyst. The NO conversion decreased to 30.2% in the presence of SO2 and H2O. It could not be restored completely after cutting off H2O and SO2. The deactivation of the catalyst in the presence of SO2 and H2O was attributed to the formation of cobalt sulfate species.展开更多
A mild and efficient method for the oxidative deprotection of 1,3-oxathiolanes with Fe（NO3）3·9H2O and Cu（NO3）2·3H2O in the absence of solvent is reported.
Methylprednisolone markedly reduces autophagy and apoptosis after secondary spinal cord injury. Here, we investigated whether pretreatment of cells with methylprednisolone would protect neuron-like cells from subseque...Methylprednisolone markedly reduces autophagy and apoptosis after secondary spinal cord injury. Here, we investigated whether pretreatment of cells with methylprednisolone would protect neuron-like cells from subsequent oxidative damage via suppression of autophagy and apoptosis. Cultured N2 a cells were pretreated with 10 μM methylprednisolone for 30 minutes, then exposed to 100 μM H2O2 for 24 hours. Inverted phase contrast microscope images, MTT assay, flow cytometry and western blot results showed that, compared to cells exposed to 100 μM H2O2 alone, cells pretreated with methylprednisolone had a significantly lower percentage of apoptotic cells, maintained a healthy morphology, and showed downregulation of autophagic protein light chain 3B and Beclin-1 protein expression. These findings indicate that methylprednisolone exerted neuroprotective effects against oxidative damage by suppressing autophagy and apoptosis.展开更多
基金Foundation items:the National Natural Science Foundation of China(No.20373085)the Natural Science Foundation of Shanxi Province(No.20051023)
文摘The attractive utilization route for one-step catalytic oxidation of dimethyl ether to dimethoxymethane was successfully carried out over the H3PW12O40（40%）/SiO2 catalyst, modified by Cs, K, Ni, and V. The Cs modification of H3PW12O40（40%）/SiO2 gave the most promising result of 20% dimethyl ether conversion and 34.8% dimethoxymethane selectivity. Dimethoxymethane could be synthe- sized via methoxy groups decomposed from dimethyl ether through the synergistic effect between the acid sites and the redox sites of Cs modified H3PW12O40（40%）/SiO2.
文摘DBUH-Br_3 catalyzed selective conversion of sulfides to sulfoxides in the presence of H_2O_2 as oxidizing agent is described.The reaction was performed selectively at room temperature and relatively short reaction times.
基金financially supported by (i) Suranaree University of Technology,(ii) Thailand Science Research and Innovation,and (iii) National Science,Research and Innovation Fund(project codes 90464 and 160363)。
文摘The effect of Na-excess content in the precursor on the structural and electrochemical performances of sodium nickel manganese oxide(NNMO)prepared by sol-gel and electrospinning methods is investigated in this paper.X-ray diffraction results of the prepared NNMO without adding Na-excess content indicate sodium loss,while the mixed phase of P2/O′3-type layered NNMO presented after adding Na-excess content.Compared with the sol-gel method,the secondary phase of NiO is more suppressed by using the electrospinning method,which is further confirmed by field emission scanning electron microscope images.N_(2) adsorption-desorption isotherms show no remarkably difference in specific surface areas between different preparation methods and Na-excess contents.The analysis of X-ray absorption near edge structure indicates that the oxidation states of Ni and Mn are+2 and+4,respectively.For the electrochemical properties,superior electrochemical performance is observed in the NNMO electrode with a low Na-excess content of 5wt%.The highest specific capacitance is 36.07 F·g^(-1)at0.1 A·g^(-1)in the NNMO electrode prepared by using the sol-gel method.By contrast,the NNMO electrode prepared using the electrospinning method with decreased Na-excess content shows excellent cycling stability of 100%after charge-discharge measurements for 300 cycles.Therefore,controlling the Na excess in the precursor together with the preparation method is important for improving the electrochemical performance of Na-based electrode materials in supercapacitors.
基金the University of Guilan Research Council for the partial support of this work
文摘V（HSO4）3 has been found to be an efficient reagent for the promotion of the oxidation of alcohols and trimethylsilyl, tetrahydropyranyl and methoxymethyl ethers to their corresponding carbonyl compounds with Cu（NO3）2-3H2O in the absence of solvent.
文摘The comparison of degradation of Acid Yellow 61 as a model dye compound in both oxidation processes of H 2O 2/UV and O 3 has been studied. When the decolorization rate of Acid Yellow 61 in both reactions presented similar, it was found there are some differences from the results of AOX removal and production of inorganic ions and organic acids. The results reveal that the H 2O 2/UV has beneficial effect on mineralization than O 3 only for degradation of Acid Yellow 61 solution and it is possible for enhancement of method efficiency by taking longer reaction time and addition of high concentration of oxidants.
基金Supported by the Natural Science Foundation of Ningbo City,Zhejiang Province(2013A610188)the Self-designed Subject of "Modern Microorganism Technology and Application",the Priority Discipline of Zhejiang Province,China(ZS2013011)
文摘The characteristics of water quality had significant effects on the oxidative degradation of O_3/H_2O_2 system.In this study,iron supported on activated carbon catalyst was prepared firstly,and then the treatment of landfill leachate by O_3/H_2O_2/catalyst system was analyzed,especially the roles of H_2O_2 in the oxidation of landfill leachate by O_3/H_2O_2 system.The results showed that at room temperature,when the dosage of the catalyst was 1.0g,the removal rate of COD from the landfill leachate reached 79.8% after 50 ml of the landfill leachate(pH=3)was oxidized by O_3(its flow rate was 5g/h)for 50 min.If 0.3ml of H_2O_2 was added to the landfill leachate,the removal rate of COD increased from 79.8%to 88.7%.It showed that the landfill leachate with the characteristics of complex composition and difficult biodegradation could be effectively degraded by the O_3/H_2O_2 system.
基金the National Natural Science Foundation of ChinaSpecialized Research Fund for the Doctoral Program of Higher Education(No.20130031110013)MOE Innovation Team (No.IRT13022) of China for financial support
文摘Selective oxidation of sulfides to sulfoxides was successfully performed by employing readily available Fe（NO3）3-9H2O as the active catalyst with oxygen as the oxidant in 2,2,2-trifluoroethanol （TFE） without the formation of sulfones. Nitrate anion could play a crucial role in promoting the reaction due to the oxidation capacity under acidic media. High yields of sulfoxides were exclusively obtained from the corresponding sulfides. Furthermore, both aromatic and aliphatic sulfides gave moderate to high yields of sulfoxides with this protocol.
基金Funded by the National Natural Science Foundation of China(No.21476177)。
文摘A series of heteropoly acid (HPA) based Al2O3 catalysts with three-dimensional ordered (3DOM) structure were synthesized by colloidal crystal template method.Interconnected macropores (250 nm) could be clearly observed by scanning electron microscope (SEM) and transmission electron microscope (TEM).Mesopores could be detected by N2 adsorption-desorption isotherms which further confirmed the 3DOM structural characteristics of catalyst.Moreover,Keggin-type HPW was highly dispersed in the Al2O3 framework,which suggested by powder X-ray diffraction (XRD) and Fourier transform infrared spectra (FT-IR) results.The oxidation desulfurization (ODS) performance of 3DOM H3PW12O40/Al2O3 of refractory sulphur compounds was evaluated in the presence of hydrogen peroxide.It oxidized 98.5% of dibenzothiophene (DBT) into corresponding sulfone within 3 h,which exhibited superior ODS performance than corresponding mesoporous and microporous H3PW12O40/Al2O3 catalyst.The enhancement of ODS efficiency is related to the improvement of mass transfer of DBT in the pore channel resulting from the interconnected 3DOM structure.Furthermore,the as-prepared catalyst still demonstrates outstanding cycle performance after 6 runs,which could be easily recovered from the model fuel.
基金Science and Technology Project of Shenzhen,China(No.JCYJ20120617141700417)Natural Science Foundation of Guangdong Province,China(No.2012040007855)
文摘The degradations of hexazinone and aldicarb by direct ozonation combined an advanced oxidation process( AOP) of O3/H2O2 were investigated in this study focusing on the oxidation mechanism by identifying the hydrogen peroxide consumption during the oxidation process of the two chemicals. The results showed that H2O2 could enhance the removal rate of the triazine herbicide hexazinone,and it was consumed along with the variation of removal rate in the light of different pH levels. The addition of H2O2 contributed little to the removal of the thiocarbamate herbicide aldicarb and H2O2 content kept constantly throughout the degradation process. Tert-butyl alcohol( TBA) effectively scavenged the ·OH radical for hexazinone,but had no effect on the removal rate of aldicarb. Aldicarb removal was mainly attributed to direct ozonation molecule in both O3( 97.00%) and O3/H2O2( 96.76%)systems. Moreover,sole O3 could hardly oxidize hexazinone whereas·OH radicals contribute respective 74.70% and 97.50% of removal in O3 system and O3/H2O2 AOP. All of these findings suggest that the mechanism of ·OH radical generation and the chain reaction in O3/H2O2 AOP should be further discussed.
基金Projects(11JJ3020,10JJ9015)supported by Hunan Provincial Natural Science Foundation of ChinaProject supported by the Construct Program of the Key Discipline in Hunan Province,China
文摘The oxysulfide La3NbS2O5 was synthesized by sulfurization using H2S and characterized by X-ray diffraction （XRD）, UV-Vis diffuse reflectance spectroscopy （DRS） and field emission scanning electron microscopy （FE-SEM）. The relationship between the sulfurization conditions and the photocatalytic activities for H2 evolution was investigated. Sulfurization method allowed for synthesis of La3NbS2O5 at much lower temperatures and significantly shortened reaction time of 1 h compared with conventional solid-state techniques. The particle morphologies were regular platelike with sizes of 0.1-0.6μm and smooth surfaces. The highest activity for H2 evolution was obtained at 1073 K for 1 h, which was about 1.83 times that of La3NbS2O5 prepared by solid-state method.
基金Project (No.2007C33030) supported by the Science and Technology Program of Zhejiang Province,China
文摘Eucommia ulmoides Oliv.(EuO),also known as Duzhong,native to China,has been reported to have antioxidative function,but its cellular mechanism is not fully examined yet.We investigated inhibitory effects of EuO leaf ethanol extracts on H2O2-induced apoptosis in rat osteoblastic MC3T3-E1 cells and underlying mechanisms.Locally-grown Duzhong leaves were extracted with ethanol.MC3T3-E1 cells were treated with EuO (6.25,12.5,25,50,and 100 μg/ml) for 24 h,and then H2O2 (800 μmol/L) for an additional 24 h.Cell survival rate,percentage of apoptosis,and expressions of caspases 3,6,7,and 9 were examined using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay,microscopic analysis,Western blotting,and reverse transcription polymerase chain reaction (RT-PCR).The final EuO leaf ethanol extract powder was detected to contain caffeotannic acid at 58 mg/g and geniposide at 3.45 mg/g by high performance liquid chromatography (HPLC).EuO remarkably restrained cell oxidative damage and increased cell survival rate in a dose-dependent manner: 0 μg/ml,0.21;6.25 μg/ml,0.28;12.5 μg/ml,0.31;25 μg/ml,0.48;50 μg/ml,0.54;and 100 μg/ml,0.66 (P<0.05),with the half-effective concentration being around 25 μg/ml.MTT results were confirmed by microscopic analysis.Western blotting and RT-PCR analyses showed that the expressions of caspases 3,6,7,and 9 were significantly decreased in the EuO-treated cells compared with the control (EuOand H2O2-free) (P<0.05),with the half-effective concentration of EuO ranging from 12.5 to 25 μg/ml.We conclude that the ethanol-extracted EuO leaf extracts promoted the growth of MC3T3-E1 cells,and suppressed the H2O2-induced apoptosis in a rat MC3T3-E1 osteogenic cell model,likely due to the inhibition of caspases’ activities.The results indicate that EuO is a potent antioxidant,which may contribute to its many cellular protective functions,including the promotion of bone growth.
基金ACKNOWLEDGMENTS This work was supported by the National Natural Science Foundation of China （No.41373127） and Liaon- ing Provincial Natural Science Foundation of China （No.2013020121）.
文摘A series of Ce, H3PW12O40 co-doped TiO2 hollow fibers photocatalysts have been prepared by sol-gel method using ammonium ceric nitrate, H3PW12O40 and tetrabutyltitanate as precursors and cotton fibers as template, followed by calcination at 500 ℃ in N2 atmosphere for 2 h. Scanning electron microscopy, X-ray diffraction, nitrogen adsorption-desorption mea- surements, and UV-Vis spectroscopy are employed to characterize the morphology, crystal structure, surface structure, and optical absorption properties of the samples. The photo- catalytic performance of the samples has been studied by photodegradation phenol in water under UV and visible light irradiation. The results show that the TiO2 fiber materials have hollow structures, and the co-doped TiO2 hollow fibers exhibit higher photocatalytic activities for the degradation of phenol than un-doped, single-doped TiO2 hollow fibers under UV and visible light. In addition, the recyclability of co-doped TiO2 fibers is also confirmed that the TiO2 fiber retains ca. 90% of its activity after being used four times. It is shown that the co-doped TiO2 fibers can be activated by visible light and may be potentially applied to the treatment of water contaminated by organic pollutants. The synergistic effect of Ce and H3PW12O40 co-doping plays an important role in improving the photocatalytic activity.
文摘The La2O3/Fe2O3-CeO2 composite oxide catalysts were prepared by coprecipitation method, sol-gel method and hydrothermal method. The effect of preparation methods on structure morphology and photocatalytic properties of La2O3/Fe2O3-CeO2 samples was investigated. The results show that the cubic CeO2 structure can be obtained at 600℃. The rod-shaped sample prepared by coprecipitation method, displays the highest crystalline and the strongest diffraction peak intensity. The spherical sample is acquired from sol-gel method, while the small granular sample prepared by hydrothermal method tends to aggregate. The maximum specific surface area of the sample prepared by coprecipitation method is 76.21 m2/g, the minimum specific area of the sample from sol-gel method is 32.66 m2/g and the maximum pore size is 13.84 nm, while the minimum pore volume and pore size of the sample by hydrothermal method are 0.038 cm3/g and 3.95 nm respectively. The band gap energy of catalyst samples is in the following order: sample-CP < sample-SG < sample-HT. The sample obtained by coprecipitation method has the best catalytic degradation performance for methylene blue. Under the excitation of visible light, the degradation rate was 99.58% at 50 minutes, which was higher than those of sol-gel method and hydrothermal method by 5.58% and 9.54% respectively. The catalytic degradation reaction is a first-order kinetic model: ln (c0/ct) = kt + qe. The maximum k-value of the sample degradation process obtained by coprecipitation method is 0.074 min-1.
文摘The performance of UV/H 2O 2, UV/O 3 and UV/H 2O 2/O 3 oxidation systems for treating spent caustic from an ethylene plant was investigated. In UV/H 2O 2 system, with the increase of H 2O 2 dosage, removal efficiencies of COD and the ratio of biochemical oxygen demand(BOD) to chemical oxygen demand(COD) of the effluent were increased and a better performance was obtained than the H 2O 2 system alone. In UV/H 2O 2 system, removal efficiency of COD reach 68% under the optimum condition, and BOD/COD ratio was significantly increased from 0 22 to 0 52. In UV/O 3 system, with the increase of O 3 dosage, removal efficiency of COD and BOD/COD ratio were increased, and a better performance was obtained than the O 3 system alone. Under the optimum condition, removal efficiency of COD was 54%, and BOD/COD ratio was significantly increased from 0 22 to 0 48. In UV/H 2O 2/O 3 system, COD removal efficiency was found to be 22.0% higher than UV/O 3 system.
文摘Cobalt oxide catalysts supported on mesoporous silica （Co3O4/MPS） were prepared, characterized and applied for catalytic oxidation of NO. Effects of catalyst supports, calcination temperatures, H2O and SO2 on NO conversion were investigated. The samples were also characterized by BET, XRD, FTIR and TG/DTG. The results suggested that Co3O4/MPS catalyst calcined at 573 K had the smallest crystal particles and the best surface dispersion. This catalyst had the highest activity and yielded 82% NO conversion at 573 K, at a space velocity of 12000 h^-1. Although the conversion of NO decreased with the introduction of H2O, it could be restored completely after removing residual H2O from Co3O4/MPS catalyst by heating at 573 K. In the presence of SO2, the oxidation activity decreased and COSO4 was detected on the catalyst. The NO conversion decreased to 30.2% in the presence of SO2 and H2O. It could not be restored completely after cutting off H2O and SO2. The deactivation of the catalyst in the presence of SO2 and H2O was attributed to the formation of cobalt sulfate species.
文摘A mild and efficient method for the oxidative deprotection of 1,3-oxathiolanes with Fe（NO3）3·9H2O and Cu（NO3）2·3H2O in the absence of solvent is reported.
基金supported by the National Natural Science Foundation of China,No.81171799,81471854the Science and Technology Research Project of Education Department of Liaoning Province of China,No.L2013333+1 种基金the"College Students’Science and Technology Innovation Project"of Liaoning Medical University Principal Fund-Aohong Boze Fund of China,No.2014D08the Liaoning Medical University Principal Fund-Aohong Boze Graduate Student Science Research Innovation Fund,No.AH2014017
文摘Methylprednisolone markedly reduces autophagy and apoptosis after secondary spinal cord injury. Here, we investigated whether pretreatment of cells with methylprednisolone would protect neuron-like cells from subsequent oxidative damage via suppression of autophagy and apoptosis. Cultured N2 a cells were pretreated with 10 μM methylprednisolone for 30 minutes, then exposed to 100 μM H2O2 for 24 hours. Inverted phase contrast microscope images, MTT assay, flow cytometry and western blot results showed that, compared to cells exposed to 100 μM H2O2 alone, cells pretreated with methylprednisolone had a significantly lower percentage of apoptotic cells, maintained a healthy morphology, and showed downregulation of autophagic protein light chain 3B and Beclin-1 protein expression. These findings indicate that methylprednisolone exerted neuroprotective effects against oxidative damage by suppressing autophagy and apoptosis.
