The watermiscible room temperature ionic liquid 1butyl3methylimidazolium tetrafluorob orate （[bmim] [BF4]） is a model system for studying the interactions between ionic liquid and water molecules. In this work the o...The watermiscible room temperature ionic liquid 1butyl3methylimidazolium tetrafluorob orate （[bmim] [BF4]） is a model system for studying the interactions between ionic liquid and water molecules. In this work the orientational structure of the low concentrated aqueous solution of [bmim] [BF4] at the air/liquid interface was investigated by sum frequency gener ation vibrational spectroscopy. It has been found that at very low concentrations, the butyl chain exhibited a significant gauche defect, indicating a disordered conformation; and the cation ring oriented with a fairly small tilting angle at the surface. When the concentration increased, the cation ring tended to lie flat at the surface, and the gauche defects of the butyl chain decreased due to the intermolecular chainchain interactions and the consequent more ordered interfacial molecular arrangement. Additionally, the antisymmetric stretching mode in the PPP and SPS spectra exhibited a peak shift, showing that there exists more than one kind of orientation or chemical environment for the butyl CH3 group. These results may shed new light on understanding the surface behavior of watermiscible ionic liquids as well as the imidazolium based surfactants.展开更多
Lead has caused serious environmental pollution due to its toxicity, accumulation in food chains and persistence in nature. In this paper, removal of lead from aqueous solutions is investigated using a novel gel adsor...Lead has caused serious environmental pollution due to its toxicity, accumulation in food chains and persistence in nature. In this paper, removal of lead from aqueous solutions is investigated using a novel gel adsorbent synthesized from natural condensed tannin. The novel adsorbent performs in aqueous solutions as a weak base with valid basic groups of 1.2mmol·g-1 tannin gel particles and therefore results in the elevation of pH value of aqueous solutions. Even when initial pH is 3.6, final pH at equilibrium can climb up to 6.5 that is above the pH value for Pb(OH)2 precipitation formation and then lead can be removed from wastewater by this so-called surface precipitation. The adsorption isotherm can be expressed by the Langmuir equation and the maximum capacity for adsorption of Pb is up to 92 mg·g-1 (based on dry adsorbent) when initial pH value is 3.6. Hence, the adsorbent does offer favorable properties in lead removal with respect to its high adsorption capacity at low initial pH value, which is advantageous to lead removal from acidic wastewater. A model is put forward to describe the individual adsorption phenomenon of the tannin gel adsorbent.展开更多
TiO2 nanosheets mainly exposed （001） facet were prepared through a hydrothermal process with HF as the morphology-directing agent. Ru and RuO2 species were loaded by photo-deposition methods to prepare the photocata...TiO2 nanosheets mainly exposed （001） facet were prepared through a hydrothermal process with HF as the morphology-directing agent. Ru and RuO2 species were loaded by photo-deposition methods to prepare the photocatalysts. The structural features of the catalysts were characterized by X-ray di raction, transmission electron microscopy, inductively cou-pled plasma atomic emission spectrum, and H2 Temperature-programmed reduction. The photocatalytic property was studied by the O2 evolution from water oxidation, which was examined with respect to the in uences of Ru contents as well as the oxidation and reduction treatments, suggesting the charge separation effect of the Ru species co-catalysts on di erent facets of TiO2 nanosheets. In contrast to Ru/TiO2 and RuO2/TiO2 with the single deposited co-catalyst, the optimized catalyst 0.5%Ru-1.0%RuO2/TiO2 with dual co-catalysts achieved a much improved catalytic performance, in terms of the synergetic effect of dual co-catalysts and the enhanced charge separation effect.展开更多
Through a simulation test carried out with soil columns (61.8 cm in diameter), the changes of ioniccomposition in soil profile during the processes of water evaporation and infiltration were studied. Underevaporation ...Through a simulation test carried out with soil columns (61.8 cm in diameter), the changes of ioniccomposition in soil profile during the processes of water evaporation and infiltration were studied. Underevaporation conditions, ions moving upward with fresh groundwater were mainly Cl￣-, SO, Ca￣(2+), andNa￣+. When the mineralized groundwater took part in the salt accumulation, the ionic composition in soilswas close to that in ground water supplemented. Under rainfall infiltration conditions, the salt-leaching roleoccurred mainly in the top soil. With the decrease of total salt content, NO and Cl￣- reduced rapidly, SOdecreased slowly, but HCO had a little change only. Among cations, Na￣+ and Ca￣(2+) contents lowered atthe same speed, and Mg￣(2+) decreased slowly.展开更多
A comparative study on the foaming properties and behavior at the air-water interface of soy and whey protein isolates were made, Foams were obtained by the method of gas bubbling. The initial rate of passage of liqui...A comparative study on the foaming properties and behavior at the air-water interface of soy and whey protein isolates were made, Foams were obtained by the method of gas bubbling. The initial rate of passage of liquid to the foam （vi） and the maximum volume of liquid incorporated to the foam （VLEmax） were determined. The destabilization process of the formed foams was analyzed by a biphasic second order equation. Measurements of equilibrium surface tension （water/air） and surface rheological properties were carried out in a dynamic drop tensiometer. The foaming capacity （vi and VLEmax） and the stability of foams prepared with the whey protein isolates （WPI） were better than those formulated with the soy protein isolates （SPI）. WPI foams were more stable showing the lower values of rate constants of gravity drainage and disproportion. There were significant differences （P 〈 0.05） in the dilatational modulus in the surface rheology measurements, which were higher at the interface with WPI, implying greater resistance of the film formed to collapse and disproportion. In conclusion, WPI formed better and more stable foams than the SPI.展开更多
Photoelectorchemical（PEC） water splitting is an attractive approach for producing sustainable and environment-friendly hydrogen. An efficient PEC process is rooted in appropriate semiconductor materials, which shoul...Photoelectorchemical（PEC） water splitting is an attractive approach for producing sustainable and environment-friendly hydrogen. An efficient PEC process is rooted in appropriate semiconductor materials, which should possess small bandgap to ensure wide light harvest, facile charge separation to allow the generated photocharges migrating to the reactive sites and highly catalytic capability to fully utilize the separated photocharges. Proper electrode fabrication method is of equal importance for promoting charge transfer and accelerating surface reactions in the electrodes. Moreover,powerful characterization method can shed light on the complex PEC process and provide deep understanding of the rate-determining step for us to improve the PEC systems further. Targeting on high solar conversion efficiency, here we provide a review on the development of PEC water splitting in the aspect of materials exploring, fabrication method and characterization. It is expected to provide some fundamental insight of PEC and inspire the design of more effective PEC systems.展开更多
Vegetation information is seldom considered in lumped conceptual rainfall-runoff models.This paper uses two modified rainfall-runoff models,the Xinanjiang-ET and SIMHYD-ET models in which vegetation leaf area index is...Vegetation information is seldom considered in lumped conceptual rainfall-runoff models.This paper uses two modified rainfall-runoff models,the Xinanjiang-ET and SIMHYD-ET models in which vegetation leaf area index is incorporated,to investigate impacts of vegetation change and climate variability on streamflow in a Southern Australian catchment,the Crawford River experimental catchment,where Tasmanian blue gum plantations were introduced gradually from 1998 till 2005.The Xinanjiang-ET and SIMHYD-ET models incorporate remotely-sensed leaf area index(LAI) data obtained from the Advanced Very High Resolution Radiometer(AVHRR) on board NOAA polar orbiting satellites.Compared to the original versions,the Xinanjiang-ET and SIMHYD-ET models show marginal improvements in runoff simulations in the pre-plantation period(1882-1997).The calibrated Xinanjaing-ET and SIMHYD-ET models are then used to simulate plantation impact on streamflow in the post-plantation period.The total change in streamflow between the pre-plantation and post-plantation periods is 32.4 mm/a.The modelling results from the two models show that plantation reduces streamflow by 20.5 mm/a,and climate variability reduces streamflow by 11.9 mm/a.These results suggest that increase in plantations can reduce streamflow substantially,even more than climate variability.展开更多
Two hydrocarbon-biodegrading bacterial strains, B1 and B2, were isolated from petroleum-contaminated soil collected from Tianjin, China. The strains were identified as Pseudomonas aeruginosa （B 1） and Acinetobacter ...Two hydrocarbon-biodegrading bacterial strains, B1 and B2, were isolated from petroleum-contaminated soil collected from Tianjin, China. The strains were identified as Pseudomonas aeruginosa （B 1） and Acinetobacter junii （B2）. The degradation rate of n-hexadecane by BI and B2 reached 96% and 78% respectively after 7 days, though the strains employed different mechanisms of degradation. The results showed that B2 was not able to use glucose as carbon source. B 1 could produce glyco- lipid surfactants using glucose as the carbon source, according to the results of blue agar plate analysis and thin layer chroma- tography （TLC）, and the bacterial culture of B 1 had a high oil discharge and emulsification activity. Both B I and B2 could produce biosurfactants with hexadecane as the sole carbon source, but their modes of action were different. The carbon source was found to affect the cell surface hydrophobicity. Cell surface hydrophobicity was poor with glucose as the carbon source, but enhanced when hexadecane was used as the carbon source.展开更多
文摘The watermiscible room temperature ionic liquid 1butyl3methylimidazolium tetrafluorob orate （[bmim] [BF4]） is a model system for studying the interactions between ionic liquid and water molecules. In this work the orientational structure of the low concentrated aqueous solution of [bmim] [BF4] at the air/liquid interface was investigated by sum frequency gener ation vibrational spectroscopy. It has been found that at very low concentrations, the butyl chain exhibited a significant gauche defect, indicating a disordered conformation; and the cation ring oriented with a fairly small tilting angle at the surface. When the concentration increased, the cation ring tended to lie flat at the surface, and the gauche defects of the butyl chain decreased due to the intermolecular chainchain interactions and the consequent more ordered interfacial molecular arrangement. Additionally, the antisymmetric stretching mode in the PPP and SPS spectra exhibited a peak shift, showing that there exists more than one kind of orientation or chemical environment for the butyl CH3 group. These results may shed new light on understanding the surface behavior of watermiscible ionic liquids as well as the imidazolium based surfactants.
文摘Lead has caused serious environmental pollution due to its toxicity, accumulation in food chains and persistence in nature. In this paper, removal of lead from aqueous solutions is investigated using a novel gel adsorbent synthesized from natural condensed tannin. The novel adsorbent performs in aqueous solutions as a weak base with valid basic groups of 1.2mmol·g-1 tannin gel particles and therefore results in the elevation of pH value of aqueous solutions. Even when initial pH is 3.6, final pH at equilibrium can climb up to 6.5 that is above the pH value for Pb(OH)2 precipitation formation and then lead can be removed from wastewater by this so-called surface precipitation. The adsorption isotherm can be expressed by the Langmuir equation and the maximum capacity for adsorption of Pb is up to 92 mg·g-1 (based on dry adsorbent) when initial pH value is 3.6. Hence, the adsorbent does offer favorable properties in lead removal with respect to its high adsorption capacity at low initial pH value, which is advantageous to lead removal from acidic wastewater. A model is put forward to describe the individual adsorption phenomenon of the tannin gel adsorbent.
文摘TiO2 nanosheets mainly exposed （001） facet were prepared through a hydrothermal process with HF as the morphology-directing agent. Ru and RuO2 species were loaded by photo-deposition methods to prepare the photocatalysts. The structural features of the catalysts were characterized by X-ray di raction, transmission electron microscopy, inductively cou-pled plasma atomic emission spectrum, and H2 Temperature-programmed reduction. The photocatalytic property was studied by the O2 evolution from water oxidation, which was examined with respect to the in uences of Ru contents as well as the oxidation and reduction treatments, suggesting the charge separation effect of the Ru species co-catalysts on di erent facets of TiO2 nanosheets. In contrast to Ru/TiO2 and RuO2/TiO2 with the single deposited co-catalyst, the optimized catalyst 0.5%Ru-1.0%RuO2/TiO2 with dual co-catalysts achieved a much improved catalytic performance, in terms of the synergetic effect of dual co-catalysts and the enhanced charge separation effect.
文摘Through a simulation test carried out with soil columns (61.8 cm in diameter), the changes of ioniccomposition in soil profile during the processes of water evaporation and infiltration were studied. Underevaporation conditions, ions moving upward with fresh groundwater were mainly Cl￣-, SO, Ca￣(2+), andNa￣+. When the mineralized groundwater took part in the salt accumulation, the ionic composition in soilswas close to that in ground water supplemented. Under rainfall infiltration conditions, the salt-leaching roleoccurred mainly in the top soil. With the decrease of total salt content, NO and Cl￣- reduced rapidly, SOdecreased slowly, but HCO had a little change only. Among cations, Na￣+ and Ca￣(2+) contents lowered atthe same speed, and Mg￣(2+) decreased slowly.
文摘A comparative study on the foaming properties and behavior at the air-water interface of soy and whey protein isolates were made, Foams were obtained by the method of gas bubbling. The initial rate of passage of liquid to the foam （vi） and the maximum volume of liquid incorporated to the foam （VLEmax） were determined. The destabilization process of the formed foams was analyzed by a biphasic second order equation. Measurements of equilibrium surface tension （water/air） and surface rheological properties were carried out in a dynamic drop tensiometer. The foaming capacity （vi and VLEmax） and the stability of foams prepared with the whey protein isolates （WPI） were better than those formulated with the soy protein isolates （SPI）. WPI foams were more stable showing the lower values of rate constants of gravity drainage and disproportion. There were significant differences （P 〈 0.05） in the dilatational modulus in the surface rheology measurements, which were higher at the interface with WPI, implying greater resistance of the film formed to collapse and disproportion. In conclusion, WPI formed better and more stable foams than the SPI.
基金supported by the Australian Research Council through its Discovery Project (DP)Federation Fellowship (FF) Program
文摘Photoelectorchemical（PEC） water splitting is an attractive approach for producing sustainable and environment-friendly hydrogen. An efficient PEC process is rooted in appropriate semiconductor materials, which should possess small bandgap to ensure wide light harvest, facile charge separation to allow the generated photocharges migrating to the reactive sites and highly catalytic capability to fully utilize the separated photocharges. Proper electrode fabrication method is of equal importance for promoting charge transfer and accelerating surface reactions in the electrodes. Moreover,powerful characterization method can shed light on the complex PEC process and provide deep understanding of the rate-determining step for us to improve the PEC systems further. Targeting on high solar conversion efficiency, here we provide a review on the development of PEC water splitting in the aspect of materials exploring, fabrication method and characterization. It is expected to provide some fundamental insight of PEC and inspire the design of more effective PEC systems.
文摘Vegetation information is seldom considered in lumped conceptual rainfall-runoff models.This paper uses two modified rainfall-runoff models,the Xinanjiang-ET and SIMHYD-ET models in which vegetation leaf area index is incorporated,to investigate impacts of vegetation change and climate variability on streamflow in a Southern Australian catchment,the Crawford River experimental catchment,where Tasmanian blue gum plantations were introduced gradually from 1998 till 2005.The Xinanjiang-ET and SIMHYD-ET models incorporate remotely-sensed leaf area index(LAI) data obtained from the Advanced Very High Resolution Radiometer(AVHRR) on board NOAA polar orbiting satellites.Compared to the original versions,the Xinanjiang-ET and SIMHYD-ET models show marginal improvements in runoff simulations in the pre-plantation period(1882-1997).The calibrated Xinanjaing-ET and SIMHYD-ET models are then used to simulate plantation impact on streamflow in the post-plantation period.The total change in streamflow between the pre-plantation and post-plantation periods is 32.4 mm/a.The modelling results from the two models show that plantation reduces streamflow by 20.5 mm/a,and climate variability reduces streamflow by 11.9 mm/a.These results suggest that increase in plantations can reduce streamflow substantially,even more than climate variability.
基金supported by the National Natural Science Foundation of China (40901149,81072989)the Foundation of the State Key Laboratory of Pollution Control and Resource Reuse Tongji University),Chinathe Chinese Universities Scientific Fund (ZD0904)
文摘Two hydrocarbon-biodegrading bacterial strains, B1 and B2, were isolated from petroleum-contaminated soil collected from Tianjin, China. The strains were identified as Pseudomonas aeruginosa （B 1） and Acinetobacter junii （B2）. The degradation rate of n-hexadecane by BI and B2 reached 96% and 78% respectively after 7 days, though the strains employed different mechanisms of degradation. The results showed that B2 was not able to use glucose as carbon source. B 1 could produce glyco- lipid surfactants using glucose as the carbon source, according to the results of blue agar plate analysis and thin layer chroma- tography （TLC）, and the bacterial culture of B 1 had a high oil discharge and emulsification activity. Both B I and B2 could produce biosurfactants with hexadecane as the sole carbon source, but their modes of action were different. The carbon source was found to affect the cell surface hydrophobicity. Cell surface hydrophobicity was poor with glucose as the carbon source, but enhanced when hexadecane was used as the carbon source.
