To improve separation efficiency of the photogenerated electron-hole pairs,constructing a heterojunction is considered to be a promising strategy.However,the fabrication of heterojunction via a facile route to achieve...To improve separation efficiency of the photogenerated electron-hole pairs,constructing a heterojunction is considered to be a promising strategy.However,the fabrication of heterojunction via a facile route to achieve a substantial improvement in photocatalytic performance is still challenging.In this work,a well-designed nanosheet-based rodlike step-scheme(S-scheme)heterojunction Bi_(4)O_(5)I_(2)/Bi_(4)O_(5)Br_(2) with rich oxygen vacancies(OVs)(Bi_(4)O_(5)I_(2)/Bi_(4)O_(5)Br_(2)-OV)was easily synthesized by calcining BiOAc0.6Br0.2I0.2(Ac-=CH3 COO-)precursor.The as-prepared Bi4O5I2/Bi4O5Br2-OV exhibited excellent visible light photocatalytic performance towards antibiotic tetracycline(TC)and dye rhodamine B(Rh B)degradation and removal rate reached 90.2% and 97.0%within 120 min,respectively,which was higher than those of Bi4O5I2-OV(56.8% and 71.8%),Bi4O5Br2-OV(47.4%and 68.4%),solid solution BiOAc0.6Br0.2I0.2(67.0% and 84.0%)and Bi_(4)O_(5)I_(2)/Bi_(4)O_(5)Br_(2) with poor oxygen vacancies(Bi4O5I2/Bi4O5Br2-P)(30.6%and 40.4%).Owing to the release of heat and generation of reducing carbon during calcining the precursor with Ac-,it could not only reduce the generation temperature of Bi-rich bismuth oxyhalides,which thus decreased particle size and increased surface areas,but also introduce surface OVs,which could trap photoelectrons and inhibit the recombination of carriers.In addition,the calcination of single solid solution precursor benefited to the formation of well-alloyed interfaces with larger contact areas between 2D/2D nanosheet-like materials,which facilitates charge carriers transfer at the interfaces.The Bi4O5I2/Bi4O5Br2-OV also shows the desirable removal rate for TC and Rh B in actual wastewater or in the presence of some electrolytes.This study provides an effective and simple strategy for designing OVs modified Bi-rich oxyhalides heterojunctions.展开更多
The production of environmental friendly emulsion paint is of great significance. Vacuum steam stripping of methyl isobutyl ketone （MIBK） and methyl ethyl ketone （MEK） from cathodic electrophoretic emulsion was st...The production of environmental friendly emulsion paint is of great significance. Vacuum steam stripping of methyl isobutyl ketone （MIBK） and methyl ethyl ketone （MEK） from cathodic electrophoretic emulsion was studied. The effects of mass ratio of vapor to feed （V/F）, vacuum degree and feed temperature on removal rate of MIBK and MEK, emulsion size and solid volume fraction of the emulsion were investigated, and the removal of MIBK and MEK from cathodic electrophoretic emulsion by vacuum desorption was also studied. The results show that removal rates of both MIBK and MEK increase with the increase of V/F, vacuum degree and feed temperature. Removal rates of MIBK and MEK are 98.3% and 93.6%, respectively, at the operating condition V/F of 0.7, feed temperature of 27℃ and vacuum degree of 90 kPa. The emulsion size of cathodic electrophoretic emulsion increases slightly with feed temperature when temperature is below 42 ℃, and increases rapidly with feed temperature when temperature is above 42℃. Solid volume fraction increases by 10% as vacuum degree increases from 0 to 90 kPa at V/F of 0.7 and feed temperature of 27 ℃. Compared with vacuum desorption, vacuum steam stripping can get a higher removal rate of MIBK and MEK under the same feed flow, vacuum degree and feed temperature.展开更多
The estrogenic activity of influents and effluents of five municipal sewage treatment works （STWs） in Nanjing was investigated. The water samples were enriched by solid phase extraction, then eluted with different p...The estrogenic activity of influents and effluents of five municipal sewage treatment works （STWs） in Nanjing was investigated. The water samples were enriched by solid phase extraction, then eluted with different polar solvents, and f＇mally three fractionated extracts were obtained. Estrogen receptor recombinant yeast screen was used to evaluate the estrogenic activity of individual fractionated extracts and their mixture. The results show that the influents and effluents of the two STWs mainly receiving industrial wastewater have no obvious estrogenic activity, and the water samples from the other three STWs mainly receiving domestic wastewater show different degrees of estrogenic activity. The total estrogenic concentration ranged from 171. 52 ng/L EEQ （E2 - equivalent concentration） to 1 008.37 ng/L EEQ in the influents, and from ND （not detected） to 36.3 ng/L EEQ in the effluents. By comparing the results of different fractionated extracts, the methanol and dichloromethane extracts of the water samples show higher estrogenic activity, while the hexane extracts very low. The （xeno）estrogens from domestic wastewater could be removed obviously by activated sludge treatment units. However, the effluents of STWs in Nanjing still have chemical contaminants capable of binding to estrogen receptors.展开更多
Six newly synthesized racemic 1-（substituted phenyl）-4-[3-（indole-4-yl-oxy）-2-hydroxypropyl]-piperazine 1-6 were successfully resolved by carbon dioxide supercritical fluid chromatography （SFC） on an analytical ...Six newly synthesized racemic 1-（substituted phenyl）-4-[3-（indole-4-yl-oxy）-2-hydroxypropyl]-piperazine 1-6 were successfully resolved by carbon dioxide supercritical fluid chromatography （SFC） on an analytical scale column packed with immobilized polysaccharide-based chiral stationary phases （CSPs）. We found that separation on the Chiralpak IA CSP was superior to the other two immobilized CSPs （Chiralpak IB and Chiralpak IC）, and isopropanol （IPA） was a superior modifier compared to the other five solvents including ethanol, methanol, tetrahydrofuran, acetonitrile and dichloromethane. The effects of organic modifier composition, back pressure, and column temperature for enantioseparation of all six compounds were studied. Of the physical parameters studied, modifier composition had the greatest impact on retention. Changing temperature generally had less impact on retention but produced the greatest selectivity changes. The optimum condition was found as follows： Chiralpak IA column, column temperature 35 ~C, back pressure 120 bar, 35% IPA containing 0.1% diethylamine （v/v） in mobile phase, flow rate of mobile phase 3.0 mL/min, UV detection 283 nm. Separation of all six racemic compounds was completed within 10 rain and excellent resolution was obtained. Thus, SFC was found to be the methodology of choice for resolving the enantiomers of this class of compounds.展开更多
文摘To improve separation efficiency of the photogenerated electron-hole pairs,constructing a heterojunction is considered to be a promising strategy.However,the fabrication of heterojunction via a facile route to achieve a substantial improvement in photocatalytic performance is still challenging.In this work,a well-designed nanosheet-based rodlike step-scheme(S-scheme)heterojunction Bi_(4)O_(5)I_(2)/Bi_(4)O_(5)Br_(2) with rich oxygen vacancies(OVs)(Bi_(4)O_(5)I_(2)/Bi_(4)O_(5)Br_(2)-OV)was easily synthesized by calcining BiOAc0.6Br0.2I0.2(Ac-=CH3 COO-)precursor.The as-prepared Bi4O5I2/Bi4O5Br2-OV exhibited excellent visible light photocatalytic performance towards antibiotic tetracycline(TC)and dye rhodamine B(Rh B)degradation and removal rate reached 90.2% and 97.0%within 120 min,respectively,which was higher than those of Bi4O5I2-OV(56.8% and 71.8%),Bi4O5Br2-OV(47.4%and 68.4%),solid solution BiOAc0.6Br0.2I0.2(67.0% and 84.0%)and Bi_(4)O_(5)I_(2)/Bi_(4)O_(5)Br_(2) with poor oxygen vacancies(Bi4O5I2/Bi4O5Br2-P)(30.6%and 40.4%).Owing to the release of heat and generation of reducing carbon during calcining the precursor with Ac-,it could not only reduce the generation temperature of Bi-rich bismuth oxyhalides,which thus decreased particle size and increased surface areas,but also introduce surface OVs,which could trap photoelectrons and inhibit the recombination of carriers.In addition,the calcination of single solid solution precursor benefited to the formation of well-alloyed interfaces with larger contact areas between 2D/2D nanosheet-like materials,which facilitates charge carriers transfer at the interfaces.The Bi4O5I2/Bi4O5Br2-OV also shows the desirable removal rate for TC and Rh B in actual wastewater or in the presence of some electrolytes.This study provides an effective and simple strategy for designing OVs modified Bi-rich oxyhalides heterojunctions.
基金Project(21176264)supported by the National Natural Science Foundation of ChinaProject(ZL110414)supported by the Undergraduate Free Exploration Innovation Foundation of Central South University,China
文摘The production of environmental friendly emulsion paint is of great significance. Vacuum steam stripping of methyl isobutyl ketone （MIBK） and methyl ethyl ketone （MEK） from cathodic electrophoretic emulsion was studied. The effects of mass ratio of vapor to feed （V/F）, vacuum degree and feed temperature on removal rate of MIBK and MEK, emulsion size and solid volume fraction of the emulsion were investigated, and the removal of MIBK and MEK from cathodic electrophoretic emulsion by vacuum desorption was also studied. The results show that removal rates of both MIBK and MEK increase with the increase of V/F, vacuum degree and feed temperature. Removal rates of MIBK and MEK are 98.3% and 93.6%, respectively, at the operating condition V/F of 0.7, feed temperature of 27℃ and vacuum degree of 90 kPa. The emulsion size of cathodic electrophoretic emulsion increases slightly with feed temperature when temperature is below 42 ℃, and increases rapidly with feed temperature when temperature is above 42℃. Solid volume fraction increases by 10% as vacuum degree increases from 0 to 90 kPa at V/F of 0.7 and feed temperature of 27 ℃. Compared with vacuum desorption, vacuum steam stripping can get a higher removal rate of MIBK and MEK under the same feed flow, vacuum degree and feed temperature.
基金Program for New Century Excellent Talents in University of China(No.05-0481)
文摘The estrogenic activity of influents and effluents of five municipal sewage treatment works （STWs） in Nanjing was investigated. The water samples were enriched by solid phase extraction, then eluted with different polar solvents, and f＇mally three fractionated extracts were obtained. Estrogen receptor recombinant yeast screen was used to evaluate the estrogenic activity of individual fractionated extracts and their mixture. The results show that the influents and effluents of the two STWs mainly receiving industrial wastewater have no obvious estrogenic activity, and the water samples from the other three STWs mainly receiving domestic wastewater show different degrees of estrogenic activity. The total estrogenic concentration ranged from 171. 52 ng/L EEQ （E2 - equivalent concentration） to 1 008.37 ng/L EEQ in the influents, and from ND （not detected） to 36.3 ng/L EEQ in the effluents. By comparing the results of different fractionated extracts, the methanol and dichloromethane extracts of the water samples show higher estrogenic activity, while the hexane extracts very low. The （xeno）estrogens from domestic wastewater could be removed obviously by activated sludge treatment units. However, the effluents of STWs in Nanjing still have chemical contaminants capable of binding to estrogen receptors.
基金Science and Technology Program of Guangzhou City(Grant No.2010U1-E0531-2)
文摘Six newly synthesized racemic 1-（substituted phenyl）-4-[3-（indole-4-yl-oxy）-2-hydroxypropyl]-piperazine 1-6 were successfully resolved by carbon dioxide supercritical fluid chromatography （SFC） on an analytical scale column packed with immobilized polysaccharide-based chiral stationary phases （CSPs）. We found that separation on the Chiralpak IA CSP was superior to the other two immobilized CSPs （Chiralpak IB and Chiralpak IC）, and isopropanol （IPA） was a superior modifier compared to the other five solvents including ethanol, methanol, tetrahydrofuran, acetonitrile and dichloromethane. The effects of organic modifier composition, back pressure, and column temperature for enantioseparation of all six compounds were studied. Of the physical parameters studied, modifier composition had the greatest impact on retention. Changing temperature generally had less impact on retention but produced the greatest selectivity changes. The optimum condition was found as follows： Chiralpak IA column, column temperature 35 ~C, back pressure 120 bar, 35% IPA containing 0.1% diethylamine （v/v） in mobile phase, flow rate of mobile phase 3.0 mL/min, UV detection 283 nm. Separation of all six racemic compounds was completed within 10 rain and excellent resolution was obtained. Thus, SFC was found to be the methodology of choice for resolving the enantiomers of this class of compounds.
