Carbon dioxide(CO_2) is greenhouse gas which originates primarily as a main combustion product of biogas and landfill gas. To separate this gas, an inside coated thin film composite(TFC) hollow fiber membrane was deve...Carbon dioxide(CO_2) is greenhouse gas which originates primarily as a main combustion product of biogas and landfill gas. To separate this gas, an inside coated thin film composite(TFC) hollow fiber membrane was developed by interfacial polymerization between 1,3–cyclohexanebis–methylamine(CHMA) and trimesoyl chloride(TMC). ATR-FTIR, SEM and AFM were used to characterize the active thin layer formed inside the PSf hollow fiber. The separation behavior of the CHMA-TMC/PSf membrane was scrutinized by studying various effects like feed gas pressure and temperature. Furthermore, the influence of CHMA concentration and TMC concentration on membrane morphology and performance were investigated. As a result, it was found that mutually the CHMA concentration and TMC concentration play key roles in determining membrane morphology and performance. Moreover, the CHMA-TMC/PSf composite membrane showed good CO_2/CH_4 separation performance. For CO_2/CH_4 mixture gas(30/70 by volume) test, the membrane(PD1 prepared by CHMA 1.0% and TMC 0.5%) showed a CO_2 permeance of 25 GPU and the best CO_2/CH_4 selectivity of 28 at stage cut of 0.1. The high CO_2/CH_4 separation performance of CHMA-TMC/PSf thin film composite membrane was mostly accredited to the thin film thickness and the properties of binary amino groups.展开更多
Poly(4-methyl-1-pentene) (PMP) hollow fiber membranes were prepared by the melt-spun and cold-stretch(MSCS) method. Scanning electronic microscopy (SEM) was used to characterize the section and surface structures of t...Poly(4-methyl-1-pentene) (PMP) hollow fiber membranes were prepared by the melt-spun and cold-stretch(MSCS) method. Scanning electronic microscopy (SEM) was used to characterize the section and surface structures of themembranes with special asymmetric structure. The preliminary results of gas permeation measurements indicated that the resultant hollow fiber membranes have the potential ability for oxygen/nitrogen separation.展开更多
Mixed matrix hollow fiber membranes（MMHFMs）filled with metal-organic frameworks（MOFs）have great potential for energy-efficient gas separation processes,but the major hurdle is polymer/MOFs interfacial defects and ...Mixed matrix hollow fiber membranes（MMHFMs）filled with metal-organic frameworks（MOFs）have great potential for energy-efficient gas separation processes,but the major hurdle is polymer/MOFs interfacial defects and membrane plasticization.Herein,lab-synthesized MIL-53 was post-functionalized by aminosilane grafting and subsequently incorporated into Ultem-1000 polymer matrix to fabricate high performance MMHFMs.SEM,DLS,XRD and TGA were performed to characterize silane-modified MIL-53（S-MIL-53）and prepared MMHFMs.Moreover,the effect of MOFs loading was systematically investigated first;then gas separation performance of MMHFMs for pure and mixed gas was evaluated under different pressures.MMHFMs containing post-functionalized S-MIL-53 achieved remarkable gas permeation properties which was better than model predictions.Compared to pure HFMs,CO2permeance of MMHFM loaded with 15%S-MIL-53 increased by 157%accompanying with 40%increase for CO2/N2selectivity,which outperformed the MMHFM filled with naked MIL-53.The pure and mixed gas permeation measurements with elevated feed pressure indicated that incorporation of S-MIL-53 also increased the resistance against CO2plasticization.This work reveals that post-modified MOFs embedded in MMHFMs facilitate the improvement of gas separation performance and suppression of membrane plasticization.展开更多
Carbon dioxide(CO_(2))capture by gas-separation membranes has become increasingly attractive due to its high energy efficiency,relatively low cost,and environmental impact.Polyvinylamine(PVAm)-based facilitated transp...Carbon dioxide(CO_(2))capture by gas-separation membranes has become increasingly attractive due to its high energy efficiency,relatively low cost,and environmental impact.Polyvinylamine(PVAm)-based facilitated transport(FT)membranes were developed in the last decade for CO_(2) capture.This work discusses the challenges of applying PVAm-based FT membranes from materials to processes for postcombustion CO_(2) capture in power plants and cement factories.Experiences learned from a pilot demonstration system can be used to guide the design of other membranes for CO_(2) capture.The importance of module and process design is emphasized in the achievement of a high-performance membrane system.Moreover,the results from process simulation and cost estimation indicate that a three-stage membrane system is feasible for achieving a high CO_(2) purity of 95 vol%.The specific CO_(2) capture cost was found to significantly depend on the required CO_(2) capture ratio,and a moderate CO_(2) capture ratio of 50%presented a cost of 63.7USD per tonne CO_(2) captured.Thus,FT membrane systems were found to be more competitive for partial CO_(2) capture.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 transport of Cu(II)from aqueous solutions containing buffer media through hollow fiber supported liquid membrane(HFSLM)using di(2-ethylhexyl)phosphoric acid(D2EHPA)dissolved in kerosene as membrane phase and hydro...The transport of Cu(II)from aqueous solutions containing buffer media through hollow fiber supported liquid membrane(HFSLM)using di(2-ethylhexyl)phosphoric acid(D2EHPA)dissolved in kerosene as membrane phase and hydrochloric acid as striping phase was investigated.A set of factors were studied,including tube side velocity,shell side velocity,pH of the feed phase,Cu(II)concentration in the feed phase,buffer media concentration and D2EHPA concentration in the membrane phase.Experimental results indicate that the mass transfer coefficient increases with increasing both carrier concentration in the organic phase and flow rates on the tube side and shell side,and decreases with increasing initial Cu(II)concentration in the feed phase.With increasing pH value and acetate concentration in the feed phase,the mass transfer coefficient reaches a maximum value then decreases.The optimal operating conditions are obtained at pH value of 4.44 and 0.1 mol·L -1 acetic ion concentration in feed phase,and carrier volume fraction of around 10%in kerosene as organic phase.A mathematical model of the transport mechanism through HFSLM is developed.The modeled results agree well with the experimental ones.展开更多
CO2 capture from post combustion does not need significant alteration of the current power generation facilities and is therefore of more interests to the research and industrial circles. Polymeric membrane separation...CO2 capture from post combustion does not need significant alteration of the current power generation facilities and is therefore of more interests to the research and industrial circles. Polymeric membrane separations, which are based mainly on physical phenomena, are easy for operation and to scale up. The details and future research trends are covered in this most updated review, which serve as an excellent technique reference for the research circle and technology evaluation for the related industrial circle.展开更多
Poly （N,N-dimethylaminoethyl methacrylate）-poly （ethylene glycol methyl ether methacrylate） （PDMAEMA-PEGMEMA） and cesium fluoride （CsF） were blended and used as the separation material of composite membranes.H...Poly （N,N-dimethylaminoethyl methacrylate）-poly （ethylene glycol methyl ether methacrylate） （PDMAEMA-PEGMEMA） and cesium fluoride （CsF） were blended and used as the separation material of composite membranes.Hollow fiber composite membranes were fabricated by coating the blend on polysulfone （PSf） hollow fiber substrate.Introduction of fluorine ion improved the separation performance of the membrane.The concentration of coating solution was adjusted to obtain a membrane with high permeance.The composite membrane showed good performance with the CO2 permeance of 30.4 GPU （1 GPU=10-6 cm3 （STP）/（cm 2 s cmHg））,and selectivities to CO2/N2,CO2/CH4,CO2/H2 and O2/N2 of 47.2,37.6,1.75 and 4.70,respectively.Potassium fluoride （KF）,due to its low cost,was also used as a substitute of CsF to prepare composite membrane and the permeation data showed that CsF can be replaced by KF.The effect of operating temperature on the permeation properties of the composite membrane was also investigated.展开更多
The separation of Sm（III） through stripping dispersion hollow fiber liquid membrane system （SDHFLM） containing feed phase adding acetate buffer solution and dispersion solution with HC1 solution as the stripping s...The separation of Sm（III） through stripping dispersion hollow fiber liquid membrane system （SDHFLM） containing feed phase adding acetate buffer solution and dispersion solution with HC1 solution as the stripping solution and membrane solution of di（2-ethylhexyl） phosphoric acid （p204） dissolved in kerosene, has been studied. A set of factors were studied, including pH value, initial concentration of Sm（III） and different ionic strength of feed phase, volume ratio of membrane solution and stripping solution （O/W）, HC1 concentration, carrier concentration, different stripping agents of dispersion phase on Sm（III） separation. Experimental results indicate that the optimum separa- tion conditions of Sm（III） were obtained as that HC1 concentration was 4.00 tool/L, p204 concentration was 0.150 mol/L, and volume ratio of membrane solution and stripping solution （O/W） was 1.00 in the dispersion phase, and pH value was 4.60 in the feed phase. Ionic strength had no obvious effect on separation of Sm（III）. When initial Sm（III） concentration was 1.00 × 10^-4 mol/L, the separation rate of Sm（III） was up to 93.5% in 85 min. The kinetic equation was developed in terms of the law of mass diffusion and the theory of interface chemistry. The modeled results were in good agreement with the experiment data.展开更多
Perfluorosulfonic acid/Polysulfone(PFSA/PSf) hollow fiber composite membranes have been prepared by dip-coating method using PSf ultrafiltration(UF) membrane as substrate with recovered PFSA.The composite membranes we...Perfluorosulfonic acid/Polysulfone(PFSA/PSf) hollow fiber composite membranes have been prepared by dip-coating method using PSf ultrafiltration(UF) membrane as substrate with recovered PFSA.The composite membranes were applied to the pervaporation separation of 95% ethanol(EtOH)/H2O mixture.SEM images show that the thickness of the PFSA skin layer of the composite membranes is about 2 μm,much thinner than those of other PFSA composite membranes revealed in the literatures.Effects of annealing temperature,coating solution concentration and counter-ions of PFSA on the pervaporation performances of the composite membranes were investigated.The total flux decreases and separation factor increases with the increase of annealing temperature.The highest permeation flux of 3230 g m-2 h-1 and a separation factor of 5.4 is obtained for the composite membrane annealed at 80°C.The lowest permeation flux of 396 g m-2 h-1 and a separation factor of 27.7 is obtained for the composite membrane annealed at 160°C.The permeation performances of the PFSA/PSf composite membrane are evidently influenced by the counter-ions of PFSA.The flux sequence of the PFSA/PSf composite membranes with different counter-ions is H+】Li+】Ca2+】Mg2+】Na+】K+】Ba2+】Fe3+】Al3+,and the separation factor sequence is H+【Li+【Al3+【Na+【Mg2+【Ca2+【K+ 【Ba2+【Fe3+.The apparent activation energy △Eapp values of the composite membranes with different counter-ions were calculated by Arrhenius law.The sequence of △Eapp values for the membranes with monovalent counter-ions is Li+】Na+】K+.There are very little variations of △Eapp values between the composite membranes with three divalent counterions(Mg2+,Ca2+ and Ba2+),and the △Eapp values of the composite membranes with two trivalent counterions(Fe3+ and Al3+) are relatively high.展开更多
In this work, ultra-high molecular weight polyethylene (UHMWPE) microfiltration hollow fiber membranes prepared via the thermally induced phase separation (TIPS) method were modified by chemically bounding hydrophilic...In this work, ultra-high molecular weight polyethylene (UHMWPE) microfiltration hollow fiber membranes prepared via the thermally induced phase separation (TIPS) method were modified by chemically bounding hydrophilic silica (SiO2) nanoparticles onto the surface to improve anti-fouling performance. A range of testing techniques including attenuated total reflection Flourier transformed infrared spectroscopy(ATR-FTIR), X-ray photoelectron spectroscopy (XPS), field emission scanning electron microscopy (FE-SEM), water contact angle, mechanical test,filtration and anti-fouling performance were carried out to discuss the influence of different modification conditions on the properties of the membranes. The prepared hollow fiber membranes display the significantly excellent performance when the vinyl trimethoxy silane (VTMS) concentration was 13%, the pH value of the hydrolyzate was 4 and the hydrolysis reaction time was 6 h. In particular, the hydrophilicity of modified membranes was improved effectively, resulting in the enhancement of membrane anti-fouling properties. The results of this work can be consulted for improving the anti-fouling performance of the UHMWPE microfiltration hollow fiber membrane applied in the field of water purification.展开更多
With the rapid development of membrane technology in water treatment,there is a growing demand for membrane products with high performance.The inorganic hollow fiber membranes are of great interest due to their high r...With the rapid development of membrane technology in water treatment,there is a growing demand for membrane products with high performance.The inorganic hollow fiber membranes are of great interest due to their high resistance to abrasion,chemical/thermal degradation,and higher surface area/volume ratio therefore they can be utilized in the fields of water treatment.In this study,the alumina(Al_(2)O_(3))hollow fiber membranes were prepared by a combined phase-inversion and sintering method.The organic binder solution(dope)containing suspended Al_(2)O_(3) powders was spun to a hollow fiber precursor,which was then sintered at elevated tempera-tures in order to obtain the Al_(2)O_(3) hollow fiber membrane.The dope solution consisted of polyethersulfone(PES),N-methyl-2-pyrrolidone(NMP)and polyvinylpyrrolidone(PVP),which were used as polymer binder,solvent and additive,respectively.The prepared Al_(2)O_(3) hollow fiber membranes were characterized by a scanning electron microscope(SEM)and thermal gravimetric analysis(TG).The effects of the sintering temperature and Al_(2)O_(3)/PES ratios on the morphological structure,pure water flux,pore size and porosity of the membranes were also investigated extensively.The results showed that the pure water flux,maximum pore size and porosity of the prepared membranes decreased with the increase in Al_(2)O_(3)/PES ratios and sintering temperature.When the Al_(2)O_(3)/PES ratio reached 9,the pure water flux and maximum pore size were at 2547L/m 2$h and 1.4μm,respectively.Under 1600℃ of sintering temperature,the pure water flux and maximum pore size reached 2398L/(m^(2)@h)and 2.3μm,respectively.The results showed that the alumina hollow fiber membranes we prepared were suitable for the microfiltration process.The morphology investigation also revealed that the prepared Al_(2)O_(3) hollow fiber membrane retained its’asymmetric structure even after the sintering process.展开更多
Stripping dispersion hollow fiber liquid membrane system（SDHFLM） containing feed phase adding acetate buffer solution and dispersion solution with HNO_3 solution as the stripping solution and membrane solution of 2-...Stripping dispersion hollow fiber liquid membrane system（SDHFLM） containing feed phase adding acetate buffer solution and dispersion solution with HNO_3 solution as the stripping solution and membrane solution of 2-ethyl hexyl phosphoric acid-mono-2-ethylhexyl ester（PC-88A） dissolved in kerosene,has been studied for the extraction of Sm^（3＋）.Many factors including pH value, volume ratio of membrane solution to stripping solution（OAV） and carrier concentration on Sm^（3＋） extraction were investigated. Experimental results indicate that the optimum extraction conditions of Sm^（3＋） were obtained as that PC-88A concentration was 0.120 mol/L,and OAV was 1.00 in the dispersion phase,and pH value was 4.80 in the feed phase.When initial Sm^（3＋） concentration was 1.20×10^（-4） mol/L,the extraction percentage of Sm^（3＋） was up to 92.8%in 160 min.展开更多
基金Supported by the National Research Council of Science&Technology(NST)grant by the Korea government(MSIP)(No.CRC-15-07-KIER)
文摘Carbon dioxide(CO_2) is greenhouse gas which originates primarily as a main combustion product of biogas and landfill gas. To separate this gas, an inside coated thin film composite(TFC) hollow fiber membrane was developed by interfacial polymerization between 1,3–cyclohexanebis–methylamine(CHMA) and trimesoyl chloride(TMC). ATR-FTIR, SEM and AFM were used to characterize the active thin layer formed inside the PSf hollow fiber. The separation behavior of the CHMA-TMC/PSf membrane was scrutinized by studying various effects like feed gas pressure and temperature. Furthermore, the influence of CHMA concentration and TMC concentration on membrane morphology and performance were investigated. As a result, it was found that mutually the CHMA concentration and TMC concentration play key roles in determining membrane morphology and performance. Moreover, the CHMA-TMC/PSf composite membrane showed good CO_2/CH_4 separation performance. For CO_2/CH_4 mixture gas(30/70 by volume) test, the membrane(PD1 prepared by CHMA 1.0% and TMC 0.5%) showed a CO_2 permeance of 25 GPU and the best CO_2/CH_4 selectivity of 28 at stage cut of 0.1. The high CO_2/CH_4 separation performance of CHMA-TMC/PSf thin film composite membrane was mostly accredited to the thin film thickness and the properties of binary amino groups.
基金This work was supported by the National Natural Science Foundation of China (Grant No. 59833120).
文摘Poly(4-methyl-1-pentene) (PMP) hollow fiber membranes were prepared by the melt-spun and cold-stretch(MSCS) method. Scanning electronic microscopy (SEM) was used to characterize the section and surface structures of themembranes with special asymmetric structure. The preliminary results of gas permeation measurements indicated that the resultant hollow fiber membranes have the potential ability for oxygen/nitrogen separation.
基金the financial support from the National Natural Science Foundation of China(No.21436009)
文摘Mixed matrix hollow fiber membranes（MMHFMs）filled with metal-organic frameworks（MOFs）have great potential for energy-efficient gas separation processes,but the major hurdle is polymer/MOFs interfacial defects and membrane plasticization.Herein,lab-synthesized MIL-53 was post-functionalized by aminosilane grafting and subsequently incorporated into Ultem-1000 polymer matrix to fabricate high performance MMHFMs.SEM,DLS,XRD and TGA were performed to characterize silane-modified MIL-53（S-MIL-53）and prepared MMHFMs.Moreover,the effect of MOFs loading was systematically investigated first;then gas separation performance of MMHFMs for pure and mixed gas was evaluated under different pressures.MMHFMs containing post-functionalized S-MIL-53 achieved remarkable gas permeation properties which was better than model predictions.Compared to pure HFMs,CO2permeance of MMHFM loaded with 15%S-MIL-53 increased by 157%accompanying with 40%increase for CO2/N2selectivity,which outperformed the MMHFM filled with naked MIL-53.The pure and mixed gas permeation measurements with elevated feed pressure indicated that incorporation of S-MIL-53 also increased the resistance against CO2plasticization.This work reveals that post-modified MOFs embedded in MMHFMs facilitate the improvement of gas separation performance and suppression of membrane plasticization.
文摘Carbon dioxide(CO_(2))capture by gas-separation membranes has become increasingly attractive due to its high energy efficiency,relatively low cost,and environmental impact.Polyvinylamine(PVAm)-based facilitated transport(FT)membranes were developed in the last decade for CO_(2) capture.This work discusses the challenges of applying PVAm-based FT membranes from materials to processes for postcombustion CO_(2) capture in power plants and cement factories.Experiences learned from a pilot demonstration system can be used to guide the design of other membranes for CO_(2) capture.The importance of module and process design is emphasized in the achievement of a high-performance membrane system.Moreover,the results from process simulation and cost estimation indicate that a three-stage membrane system is feasible for achieving a high CO_(2) purity of 95 vol%.The specific CO_(2) capture cost was found to significantly depend on the required CO_(2) capture ratio,and a moderate CO_(2) capture ratio of 50%presented a cost of 63.7USD per tonne CO_(2) captured.Thus,FT membrane systems were found to be more competitive for partial CO_(2) capture.
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.
基金Supported by the Program for New Century Excellent Talents in University （NCET-05-0122） the National Natural Science Foundation of China（20576008 20706003） the Ph.D.Programs Foundation of Ministry of Education of China（200800100001） The authors are grateful to Prof. Xiaolong Lii of Tianjin Polytechnic University for supplying PVDF hollow fibers.
文摘The transport of Cu(II)from aqueous solutions containing buffer media through hollow fiber supported liquid membrane(HFSLM)using di(2-ethylhexyl)phosphoric acid(D2EHPA)dissolved in kerosene as membrane phase and hydrochloric acid as striping phase was investigated.A set of factors were studied,including tube side velocity,shell side velocity,pH of the feed phase,Cu(II)concentration in the feed phase,buffer media concentration and D2EHPA concentration in the membrane phase.Experimental results indicate that the mass transfer coefficient increases with increasing both carrier concentration in the organic phase and flow rates on the tube side and shell side,and decreases with increasing initial Cu(II)concentration in the feed phase.With increasing pH value and acetate concentration in the feed phase,the mass transfer coefficient reaches a maximum value then decreases.The optimal operating conditions are obtained at pH value of 4.44 and 0.1 mol·L -1 acetic ion concentration in feed phase,and carrier volume fraction of around 10%in kerosene as organic phase.A mathematical model of the transport mechanism through HFSLM is developed.The modeled results agree well with the experimental ones.
文摘CO2 capture from post combustion does not need significant alteration of the current power generation facilities and is therefore of more interests to the research and industrial circles. Polymeric membrane separations, which are based mainly on physical phenomena, are easy for operation and to scale up. The details and future research trends are covered in this most updated review, which serve as an excellent technique reference for the research circle and technology evaluation for the related industrial circle.
基金supported by the Chinese Ministry of Science and Technology(973 Program,No. 2009CB623405)the National Natural Science Foundation of China(NSFC program,20706051 and 20836006)
文摘Poly （N,N-dimethylaminoethyl methacrylate）-poly （ethylene glycol methyl ether methacrylate） （PDMAEMA-PEGMEMA） and cesium fluoride （CsF） were blended and used as the separation material of composite membranes.Hollow fiber composite membranes were fabricated by coating the blend on polysulfone （PSf） hollow fiber substrate.Introduction of fluorine ion improved the separation performance of the membrane.The concentration of coating solution was adjusted to obtain a membrane with high permeance.The composite membrane showed good performance with the CO2 permeance of 30.4 GPU （1 GPU=10-6 cm3 （STP）/（cm 2 s cmHg））,and selectivities to CO2/N2,CO2/CH4,CO2/H2 and O2/N2 of 47.2,37.6,1.75 and 4.70,respectively.Potassium fluoride （KF）,due to its low cost,was also used as a substitute of CsF to prepare composite membrane and the permeation data showed that CsF can be replaced by KF.The effect of operating temperature on the permeation properties of the composite membrane was also investigated.
基金Project supported by the National Natural Science Foundation of China （or Young Scientists （Nos. 41001131 and 51009126）, the Action Plan for the Development of Western China of the Chinese Academy of Sciences （No. KZCX2-XB2-13）, the Knowledge Innovation Program of the Chinese Academy of Sciences （No. KSCX2-YW-N-003） and Research Fund for Excellent Doctoral Thesis of Xi＇an University of Technology （Nos. 602-210805 and 602-210804）.
文摘The separation of Sm（III） through stripping dispersion hollow fiber liquid membrane system （SDHFLM） containing feed phase adding acetate buffer solution and dispersion solution with HC1 solution as the stripping solution and membrane solution of di（2-ethylhexyl） phosphoric acid （p204） dissolved in kerosene, has been studied. A set of factors were studied, including pH value, initial concentration of Sm（III） and different ionic strength of feed phase, volume ratio of membrane solution and stripping solution （O/W）, HC1 concentration, carrier concentration, different stripping agents of dispersion phase on Sm（III） separation. Experimental results indicate that the optimum separa- tion conditions of Sm（III） were obtained as that HC1 concentration was 4.00 tool/L, p204 concentration was 0.150 mol/L, and volume ratio of membrane solution and stripping solution （O/W） was 1.00 in the dispersion phase, and pH value was 4.60 in the feed phase. Ionic strength had no obvious effect on separation of Sm（III）. When initial Sm（III） concentration was 1.00 × 10^-4 mol/L, the separation rate of Sm（III） was up to 93.5% in 85 min. The kinetic equation was developed in terms of the law of mass diffusion and the theory of interface chemistry. The modeled results were in good agreement with the experiment data.
基金supported by the Leading Academic Discipline Project of SHNU (No.DZL807)Innovation Program of Shanghai Municipal Education Commission (No.09YZ163)Shanghai Municipal Natural Science Foundation (No.09ZR1423300)
文摘Perfluorosulfonic acid/Polysulfone(PFSA/PSf) hollow fiber composite membranes have been prepared by dip-coating method using PSf ultrafiltration(UF) membrane as substrate with recovered PFSA.The composite membranes were applied to the pervaporation separation of 95% ethanol(EtOH)/H2O mixture.SEM images show that the thickness of the PFSA skin layer of the composite membranes is about 2 μm,much thinner than those of other PFSA composite membranes revealed in the literatures.Effects of annealing temperature,coating solution concentration and counter-ions of PFSA on the pervaporation performances of the composite membranes were investigated.The total flux decreases and separation factor increases with the increase of annealing temperature.The highest permeation flux of 3230 g m-2 h-1 and a separation factor of 5.4 is obtained for the composite membrane annealed at 80°C.The lowest permeation flux of 396 g m-2 h-1 and a separation factor of 27.7 is obtained for the composite membrane annealed at 160°C.The permeation performances of the PFSA/PSf composite membrane are evidently influenced by the counter-ions of PFSA.The flux sequence of the PFSA/PSf composite membranes with different counter-ions is H+】Li+】Ca2+】Mg2+】Na+】K+】Ba2+】Fe3+】Al3+,and the separation factor sequence is H+【Li+【Al3+【Na+【Mg2+【Ca2+【K+ 【Ba2+【Fe3+.The apparent activation energy △Eapp values of the composite membranes with different counter-ions were calculated by Arrhenius law.The sequence of △Eapp values for the membranes with monovalent counter-ions is Li+】Na+】K+.There are very little variations of △Eapp values between the composite membranes with three divalent counterions(Mg2+,Ca2+ and Ba2+),and the △Eapp values of the composite membranes with two trivalent counterions(Fe3+ and Al3+) are relatively high.
基金financially supported by the National Natural Science Foundation of China (No. 51473031)Shanghai International S&T Cooperation Fund (No. 16160731302)。
文摘In this work, ultra-high molecular weight polyethylene (UHMWPE) microfiltration hollow fiber membranes prepared via the thermally induced phase separation (TIPS) method were modified by chemically bounding hydrophilic silica (SiO2) nanoparticles onto the surface to improve anti-fouling performance. A range of testing techniques including attenuated total reflection Flourier transformed infrared spectroscopy(ATR-FTIR), X-ray photoelectron spectroscopy (XPS), field emission scanning electron microscopy (FE-SEM), water contact angle, mechanical test,filtration and anti-fouling performance were carried out to discuss the influence of different modification conditions on the properties of the membranes. The prepared hollow fiber membranes display the significantly excellent performance when the vinyl trimethoxy silane (VTMS) concentration was 13%, the pH value of the hydrolyzate was 4 and the hydrolysis reaction time was 6 h. In particular, the hydrophilicity of modified membranes was improved effectively, resulting in the enhancement of membrane anti-fouling properties. The results of this work can be consulted for improving the anti-fouling performance of the UHMWPE microfiltration hollow fiber membrane applied in the field of water purification.
文摘With the rapid development of membrane technology in water treatment,there is a growing demand for membrane products with high performance.The inorganic hollow fiber membranes are of great interest due to their high resistance to abrasion,chemical/thermal degradation,and higher surface area/volume ratio therefore they can be utilized in the fields of water treatment.In this study,the alumina(Al_(2)O_(3))hollow fiber membranes were prepared by a combined phase-inversion and sintering method.The organic binder solution(dope)containing suspended Al_(2)O_(3) powders was spun to a hollow fiber precursor,which was then sintered at elevated tempera-tures in order to obtain the Al_(2)O_(3) hollow fiber membrane.The dope solution consisted of polyethersulfone(PES),N-methyl-2-pyrrolidone(NMP)and polyvinylpyrrolidone(PVP),which were used as polymer binder,solvent and additive,respectively.The prepared Al_(2)O_(3) hollow fiber membranes were characterized by a scanning electron microscope(SEM)and thermal gravimetric analysis(TG).The effects of the sintering temperature and Al_(2)O_(3)/PES ratios on the morphological structure,pure water flux,pore size and porosity of the membranes were also investigated extensively.The results showed that the pure water flux,maximum pore size and porosity of the prepared membranes decreased with the increase in Al_(2)O_(3)/PES ratios and sintering temperature.When the Al_(2)O_(3)/PES ratio reached 9,the pure water flux and maximum pore size were at 2547L/m 2$h and 1.4μm,respectively.Under 1600℃ of sintering temperature,the pure water flux and maximum pore size reached 2398L/(m^(2)@h)and 2.3μm,respectively.The results showed that the alumina hollow fiber membranes we prepared were suitable for the microfiltration process.The morphology investigation also revealed that the prepared Al_(2)O_(3) hollow fiber membrane retained its’asymmetric structure even after the sintering process.
基金financially supported by the National Natural Science Foundation of China for Young Scientists(Nos. 51109197 and 51009126)the Action Plan for the Development of Western China of the Chinese Academy of Sciences (No.KZCX2-XB2-13)+1 种基金the Knowledge Innovation Program of the Chinese Academy of Sciences(No.KSCX2-YW-N -003)Research Fund for Excellent Doctoral Thesis of Xi'an University of Technology(Nos.602-210805 and 602-210804)
文摘Stripping dispersion hollow fiber liquid membrane system（SDHFLM） containing feed phase adding acetate buffer solution and dispersion solution with HNO_3 solution as the stripping solution and membrane solution of 2-ethyl hexyl phosphoric acid-mono-2-ethylhexyl ester（PC-88A） dissolved in kerosene,has been studied for the extraction of Sm^（3＋）.Many factors including pH value, volume ratio of membrane solution to stripping solution（OAV） and carrier concentration on Sm^（3＋） extraction were investigated. Experimental results indicate that the optimum extraction conditions of Sm^（3＋） were obtained as that PC-88A concentration was 0.120 mol/L,and OAV was 1.00 in the dispersion phase,and pH value was 4.80 in the feed phase.When initial Sm^（3＋） concentration was 1.20×10^（-4） mol/L,the extraction percentage of Sm^（3＋） was up to 92.8%in 160 min.
