It is important to develop efficient technologies on removal of perfluorooctanoic acid(PFOA)and perfluorooctane sulfonate(PFOS)from water due to their wide distribution and potential threat to human health.In this wor...It is important to develop efficient technologies on removal of perfluorooctanoic acid(PFOA)and perfluorooctane sulfonate(PFOS)from water due to their wide distribution and potential threat to human health.In this work,a durable and convenient electrosorption device was designed in continuous flow mode to investigate the adsorption of PFOX(X=A and S)on multiwalled carbon nanotubes(MWNTs)from water under electrochemical assistance.The electrosorption experiments were conducted under different influent and electrolyte concentrations,hydraulic retention time(HRT)and electrode distance to optimize the operation.The results showed that the highest removal efficiencies toward both PFOA and PFOS could come up to 90%at 1 V.Compared with open circuit(OC)adsorption under the same conditions,the removal efficiencies were improved by 4.9 times(PFOA)and 4.2 times(PFOS)respectively.In addition,the MWNTs electrode was found to be reusable.These findings provide an efficient method to remove PFOX from water by electrosorption in continuous flow mode.展开更多
To study the effect of electrolytic concentration,bioactive ceramic films containing Ca and P on the surface of the Ti6Al4V alloy were prepared by micro-arc oxidation(MAO) in aqueous solutions of different concentrati...To study the effect of electrolytic concentration,bioactive ceramic films containing Ca and P on the surface of the Ti6Al4V alloy were prepared by micro-arc oxidation(MAO) in aqueous solutions of different concentrations.Composition,micro-morphology,wettability of the films and their corrosion behavior in a Hank's SBF were studied.Our experimental results show that the film is mainly composed of anatase,rutile and amorphous phases.With an increase in electrolytic concentration,the ratio of rutile in films enlarge and small amounts of calcium phosphate(Ca3(PO4)2) and hydroxyapatite(HA) appear.The number of micropores in films increases but their dimensions decrease and their porosities increase slightly.As the surface roughness of MAO film increases with concentration,the wettablility of the oxide film improves continually,while micro-hardness increases at first and then decreases.MAO treatment clearly improves the corrosion resistance of substrates in a Hank's SBF.展开更多
The reduction of soil and water losses under furrow irrigation with saline water is important to environmental protection and agricultural production. The objective of this study was to determine the effect of polyacr...The reduction of soil and water losses under furrow irrigation with saline water is important to environmental protection and agricultural production. The objective of this study was to determine the effect of polyacrylamide (PAM) application on soil infiltration and erosion under simulated furrow irrigation with saline water. Polyacrylamide was applied by dissolving it in irrigation water at the rates of 1.5, 7.5, and 15.0 mg L-1 or spreading it as a powder on soil surface at the rates of 0.3, 1.5, 3.0, and 6.0 g m-2, respectively. The electrolyte concentration of tested irrigation water was 10 and 30 mmolc L-1 and its sodium adsorption ratio (SAR) was 0.5, 10.0, and 20.0 (mmolc L-1)0.5. Distilled water was used as a control for irrigation water quality. Results indicated that the electrolyte concentration and SAR generally did not significantly affect soil and water losses after PAM application. Infiltration rate and total infiltration volume decreased with the increase of PAM application rate. Polyacrylamide application in both methods significantly reduced soil erosion, but PAM application rate did not significantly affect it. The solution PAM application was more effective in controlling soil erosion than the powdered PAM application, but the former exerted a greater adverse influence on soil infiltration than the latter. Under the same total amounts, the powdered PAM application resulted in a 38.2%-139.6% greater infiltration volume but a soil mass loss of 1.3-3.4 times greater than the solution PAM application.展开更多
As a potential solution to the crises of energy and resources, forward osmosis(FO) has been limited by the development of draw agents. An ideal draw agent should be able to generate high osmotic pressure and can be ea...As a potential solution to the crises of energy and resources, forward osmosis(FO) has been limited by the development of draw agents. An ideal draw agent should be able to generate high osmotic pressure and can be easily recovered. In this study, a thermo-sensitive polyelectrolyte of poly(N-isopropylacrylamide-co-acrylic acid)(PNA)is developed as an efficient draw agent, and two easy and simple methods are proposed to effectively recover the polyelectrolytes. After adjusting the pH value of polyelectrolyte solutions to around 6.0, the polyelectrolyte can generate relatively high osmotic pressure, and induce average water fluxes of 2.09 and 2.95 L·m^(-2)·h^(-1) during12 h FO processes when the polyelectrolyte concentrations are 0.20 and 0.38 g·ml^(-1) respectively. After acidifying and heating to 70 °C, the PNA-10 polyelectrolyte can aggregate together because of hydrophobic association and separate from water, so it can be easily recovered by either simple centrifugation or gravitational sedimentation. The recovery ratios of PNA-10 polyelectrolyte in both methods are as high as 89%, and the recovered polyelectrolytes can be reused with almost the same FO performance as fresh ones. The results in this study provide valuable guidance for designing efficient and easily recoverable draw agents for FO processes.展开更多
基金supported by the National Crucial Research Project for Water Pollution Control of China (2012ZX07202006)the Fundamental Research Funds for the Central Universities of China (DUT14QY01 and DUT13LK19)
文摘It is important to develop efficient technologies on removal of perfluorooctanoic acid(PFOA)and perfluorooctane sulfonate(PFOS)from water due to their wide distribution and potential threat to human health.In this work,a durable and convenient electrosorption device was designed in continuous flow mode to investigate the adsorption of PFOX(X=A and S)on multiwalled carbon nanotubes(MWNTs)from water under electrochemical assistance.The electrosorption experiments were conducted under different influent and electrolyte concentrations,hydraulic retention time(HRT)and electrode distance to optimize the operation.The results showed that the highest removal efficiencies toward both PFOA and PFOS could come up to 90%at 1 V.Compared with open circuit(OC)adsorption under the same conditions,the removal efficiencies were improved by 4.9 times(PFOA)and 4.2 times(PFOS)respectively.In addition,the MWNTs electrode was found to be reusable.These findings provide an efficient method to remove PFOX from water by electrosorption in continuous flow mode.
基金Projects 50535050 supported by the National Natural Science Foundation of ChinaNCET-06-0479 by the Program for New Century Excellent Talents in University of China
文摘To study the effect of electrolytic concentration,bioactive ceramic films containing Ca and P on the surface of the Ti6Al4V alloy were prepared by micro-arc oxidation(MAO) in aqueous solutions of different concentrations.Composition,micro-morphology,wettability of the films and their corrosion behavior in a Hank's SBF were studied.Our experimental results show that the film is mainly composed of anatase,rutile and amorphous phases.With an increase in electrolytic concentration,the ratio of rutile in films enlarge and small amounts of calcium phosphate(Ca3(PO4)2) and hydroxyapatite(HA) appear.The number of micropores in films increases but their dimensions decrease and their porosities increase slightly.As the surface roughness of MAO film increases with concentration,the wettablility of the oxide film improves continually,while micro-hardness increases at first and then decreases.MAO treatment clearly improves the corrosion resistance of substrates in a Hank's SBF.
基金the National Natural Science Foundation of China (No.40635027)the State Key Laboratory of Soil Erosion and Dryland Farming on Loess Plateau of China (No.10501-169)
文摘The reduction of soil and water losses under furrow irrigation with saline water is important to environmental protection and agricultural production. The objective of this study was to determine the effect of polyacrylamide (PAM) application on soil infiltration and erosion under simulated furrow irrigation with saline water. Polyacrylamide was applied by dissolving it in irrigation water at the rates of 1.5, 7.5, and 15.0 mg L-1 or spreading it as a powder on soil surface at the rates of 0.3, 1.5, 3.0, and 6.0 g m-2, respectively. The electrolyte concentration of tested irrigation water was 10 and 30 mmolc L-1 and its sodium adsorption ratio (SAR) was 0.5, 10.0, and 20.0 (mmolc L-1)0.5. Distilled water was used as a control for irrigation water quality. Results indicated that the electrolyte concentration and SAR generally did not significantly affect soil and water losses after PAM application. Infiltration rate and total infiltration volume decreased with the increase of PAM application rate. Polyacrylamide application in both methods significantly reduced soil erosion, but PAM application rate did not significantly affect it. The solution PAM application was more effective in controlling soil erosion than the powdered PAM application, but the former exerted a greater adverse influence on soil infiltration than the latter. Under the same total amounts, the powdered PAM application resulted in a 38.2%-139.6% greater infiltration volume but a soil mass loss of 1.3-3.4 times greater than the solution PAM application.
基金Supported by the National Natural Science Foundation of China(21276162)the Program for Yangtse River Scholars and Innovative Research Team in Universities(IRT1163)
文摘As a potential solution to the crises of energy and resources, forward osmosis(FO) has been limited by the development of draw agents. An ideal draw agent should be able to generate high osmotic pressure and can be easily recovered. In this study, a thermo-sensitive polyelectrolyte of poly(N-isopropylacrylamide-co-acrylic acid)(PNA)is developed as an efficient draw agent, and two easy and simple methods are proposed to effectively recover the polyelectrolytes. After adjusting the pH value of polyelectrolyte solutions to around 6.0, the polyelectrolyte can generate relatively high osmotic pressure, and induce average water fluxes of 2.09 and 2.95 L·m^(-2)·h^(-1) during12 h FO processes when the polyelectrolyte concentrations are 0.20 and 0.38 g·ml^(-1) respectively. After acidifying and heating to 70 °C, the PNA-10 polyelectrolyte can aggregate together because of hydrophobic association and separate from water, so it can be easily recovered by either simple centrifugation or gravitational sedimentation. The recovery ratios of PNA-10 polyelectrolyte in both methods are as high as 89%, and the recovered polyelectrolytes can be reused with almost the same FO performance as fresh ones. The results in this study provide valuable guidance for designing efficient and easily recoverable draw agents for FO processes.
