Porous polyvinylidene fluoride-co-hexafluropropylene(PVDF-HFP)hollow fiber membranes were fabricated through a wet spinning process.In order to improve the membrane structure,composition of the polymer solution was ad...Porous polyvinylidene fluoride-co-hexafluropropylene(PVDF-HFP)hollow fiber membranes were fabricated through a wet spinning process.In order to improve the membrane structure,composition of the polymer solution was adjusted by studying ternary phase diagrams of polymer/solvent/non-solvent.The prepared membranes were used for sweeping gas membrane distillation(SGMD)of 20 wt% ethylene glycol(EG)aqueous solution.The membranes were characterized by different tests such as N2 permeation,overall porosity,critical water entry pressure(CEPw),water contact angle and collapsing pressure.From FESEM examination,addition of 3 wt% glycerol in the PVDF-HFP solution,produced membranes with smaller finger-likes cavities,higher surface porosity and smaller pore sizes.Increasing the polymer concentration up to 21 wt% resulted in a dense spongy structure which could significantly reduce the N2 permeance.The membrane prepared by 3 wt% glycerol and 17 wt% polymer demonstrated an improved structure with mean pore size of 18 nm and a high surface porosity of 872 m^−1.CEPw of 350 kPa and overall porosity of 84% were also obtained for the improved membrane.Collapsing pressure of the membranes relatively improved by increasing the polymer concentration.From the SGMDtest,the developed membrane represented a maximumpermeate flux of 28 kg·m^−2·h^−1 which is almost 19% higher than the flux of plain membrane.During 120 h of a long-termSGMD operation,a gradual flux reduction of 30% was noticed.In addition,EG rejection reduced from 100% to around 99.5% during 120 h of the operation.展开更多
A review on the polymeric hollow fibers membranes for gas separation has been conducted. In order to deyelop high performance membranes for gas separation, there are a few technology challenges awaiting the chemical e...A review on the polymeric hollow fibers membranes for gas separation has been conducted. In order to deyelop high performance membranes for gas separation, there are a few technology challenges awaiting the chemical engineers to overcome. There are four major challenges, namely: 1) material selection and synthesis; 2) fabrication of hollow fiber membranes with an ultra- thin dense selective layer; 3) materials against plasticization; and 4) aging. In each area, we summarize the scientific accomplishments and technical difficulties.展开更多
Extraction kinetics of phenol with N,N di(1 methyl heptyl) acetamide kerosene using hollow fiber membrane extractor has been studied. The rate regularities and kinetic types of forward and backward extraction were obt...Extraction kinetics of phenol with N,N di(1 methyl heptyl) acetamide kerosene using hollow fiber membrane extractor has been studied. The rate regularities and kinetic types of forward and backward extraction were obtained respectively by determining the forward and backward extraction rate under various experimental conditions. The mass transfer mechanism was discussed. Both the forward and backward extraction of phenol might be controlled by diffusion processes, and the diffusion resistance for both forward and backward extraction mainly exists in aqueous phase. In addition, ways to optimize the extraction process of phenol were discussed as well.展开更多
A numerical study on the conjugated heat-mass transfer of helical hollow fiber membrane tube bank(HFMTB)for seawater desalination was carried out.Physical and mathematical models of fluid flow,temperature and humidity...A numerical study on the conjugated heat-mass transfer of helical hollow fiber membrane tube bank(HFMTB)for seawater desalination was carried out.Physical and mathematical models of fluid flow,temperature and humidity distribution were constructed to investigate the influences of flow type,Reynolds number,and temperature on the conjugated heat-mass transfer performance of hollow fibers in the distillation membrane module.The conjugated heat-mass transfer characteristics of HFMTB were discussed by utilizing the friction coefficient,Nusselt number(Nu),and Sherwood number(Sh).Results demonstrate that a distillation efficiency enhancement of 29%compared to the straight HFMTB has been detected for four-helical HFMTB configuration,though the friction coefficient of such a module is about 4 times of their straight counterparts.The values of average Nu and Sh numbers are increasing with tube number,which improves distillation efficiency.The effect of flow type has been studied by employing the upstream and downstream flows to the double-helical HFMTB,demonstrating upstream flow type is more conducive to the heat-mass transfer process.Both the outlet air humidity(ω)and distillation efficiency(η)decrease with the air-side Reynolds number(Rea)and inlet air temperature in the helical HFMTB while increasing with the solution-side Reynolds number(Re_(S))and inlet solution temperature.Overall,the obtained results indicate that helical HFMTB applying upstream flow has great potential to achieve high-performance SGMD for seawater desalination.It is anticipated that the present work can assist in a better understanding of the membrane desalination process in HFMTB and thus provide theoretical suggestions for further optimization and development.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
EVAL hollow fiber membrane adsorbents filled with powder D061-type cation exchange resin were prepared through dry-wet spinning process,using hydrophilic copolymer EVAL as the fiber substrate.The microstructures of th...EVAL hollow fiber membrane adsorbents filled with powder D061-type cation exchange resin were prepared through dry-wet spinning process,using hydrophilic copolymer EVAL as the fiber substrate.The microstructures of the membrane adsorbents were observed,and the pure water fluxes,BSA rejection,and static adsorption capacities of membrane adsorbents for BSA were measured.The effect of the resin-filled content on membrane performance has been discussed.The results showed that EVAL hollow fiber membrane adsorbents filled with D061-type cation exchange resins had good adsorption capacity,and the adsorption capacity increased with the quantity of the resin-filled content.The static protein adsorption capacity was 77.14 mg BSA/g membrane adsorbents when D061 resin loading content was 65%at pH 4.5.展开更多
Using Donnan Steric Partitioning Model(DSPM),the data for the rejection of four salts having common co-ion(LiCl, NaCl,KCl,Na2SO4)were obtained and they show the characters of the polyethersulfone(PES)nanofiltration(NF...Using Donnan Steric Partitioning Model(DSPM),the data for the rejection of four salts having common co-ion(LiCl, NaCl,KCl,Na2SO4)were obtained and they show the characters of the polyethersulfone(PES)nanofiltration(NF)membrane in terms of three parameters:an effective pore radius(rp),the ratio of effective thickness over porosity(λ/Ak)and an effective charge density(X).Good agreement between experimental data and prediction data using the three parameters mentioned above was obtained.A theoretical model was developed to predict the transport performance of electrolyte through the hollow fiber composite NF membrane.The model prediction is in good agreement with experimental results based on the method by modern numerical solution.展开更多
In this paper the mass transfer behaviors of Fe(Ⅲ), Co(Ⅱ) and Ni(Ⅱ) with Cyanex302(bis(2,4,4- trimethylpentyl)monothiophosphinic acid) from sulfate medium by using hollow fiber membrane in counter-currently circula...In this paper the mass transfer behaviors of Fe(Ⅲ), Co(Ⅱ) and Ni(Ⅱ) with Cyanex302(bis(2,4,4- trimethylpentyl)monothiophosphinic acid) from sulfate medium by using hollow fiber membrane in counter-currently circulating operation were studied. The effect of acidity in aqueous solution and the extractant concentration on the mass transfer coefficient (Kw) was discussed. The reaction mechanism of membrane extraction was considered as a false one series reaCtion and the rate controlling step was membrane resistance. When the value of Kw arrived at 1.0 × 10-6 m/s, △pH:CoFe equaled tO 6.225, and △pH:NiFe was bigger than △p HCoFe.展开更多
We have studied the mixed gas permeation in hollow fiber membrane modules using two approaches: namely, the co- current plug flow model and the complete mixing model with the combination of experimental data. Elucidat...We have studied the mixed gas permeation in hollow fiber membrane modules using two approaches: namely, the co- current plug flow model and the complete mixing model with the combination of experimental data. Elucidation was made to determine the permeance of CO2 and CH4 and the selectivity of CO2/CH4 in a polyimide hollow fiber membrane permeator It is found that the intrinsic gas separation properties of hollow fibers for mixed gases can be accurately determined based on (1) the cocurrent plug now model, and (2) the complete mixing model with the assumption of averaged retentate concentration of the feed and the retentate outlet.展开更多
Extracorporeal membrane oxygenator(ECMO) has been in development for nearly 70 years, and the oxygenator has gone through several generations of optimizations, with advances from bubble oxygenators to membrane oxygena...Extracorporeal membrane oxygenator(ECMO) has been in development for nearly 70 years, and the oxygenator has gone through several generations of optimizations, with advances from bubble oxygenators to membrane oxygenators leading to more and more widespread use of ECMO. Membrane is the core of a ECMO system and the working mechanism of membrane oxygenator depends on the membrane material,from PDMS flat membrane to PMP hollow fiber membrane, which have experienced three generations.Blood compatibility on the surface of the membrane material is very vital, which directly determines the use duration of the oxygenator and can reduce the occurrence of complications. The mechanism of mass transfer is the basis of oxygenator operation and optimization. This review summarizes the membrane development history and preparation technology, modification approaches and mass transfer theory in the process of oxygen and blood exchange. We hoped that this review will provide more ideas for the study of gas blood exchange membrane.展开更多
Currently,artificial-membrane lungs consist of thousands of hollow fiber membranes where blood flows around the fibers and gas flows inside the fibers,achieving diffusive gas exchange.At both ends of the fibers,the in...Currently,artificial-membrane lungs consist of thousands of hollow fiber membranes where blood flows around the fibers and gas flows inside the fibers,achieving diffusive gas exchange.At both ends of the fibers,the interspaces between the hollow fiber membranes and the plastic housing are filled with glue to separate the gas from the blood phase.During a uniaxial centrifugation process,the glue forms the“potting.”The shape of the cured potting is then determined by the centrifugation process,limiting design possibilities and leading to unfavorable stagnation zones associated with blood clotting.In this study,a new multiaxial centrifugation process was developed,expanding the possible shapes of the potting and allowing for completely new module designs with potentially superior blood flow guidance within the potting margins.Two-phase simulations of the process in conceptual artificial lungs were performed to explore the possibilities of a biaxial centrifugation process and determine suitable parameter sets.A corresponding biaxial centrifugation setup was built to prove feasibility and experimentally validate four conceptual designs,resulting in good agreement with the simulations.In summary,this study shows the feasibility of a multiaxial centrifugation process allowing greater variety in potting shapes,eliminating inefficient stagnation zones and more favorable blood flow conditions in artificial lungs.展开更多
The properties of aviation fuel have a great influence on the performance of oxygenconsuming inerting systems. Based on the establishment of the catalytic inerting process, the flow relationship of each gas component ...The properties of aviation fuel have a great influence on the performance of oxygenconsuming inerting systems. Based on the establishment of the catalytic inerting process, the flow relationship of each gas component flowing through the catalytic reactor was derived. The mathematical model of the gas concentration in the gas phase of the fuel tank was established based on the mass conservation equation, and the fuel tank model was verified by performing experiments.The results showed that the fuel type exerts a considerably higher influence on the performance of the oxygen-consuming inerting system compared to the corresponding influence on the hollow fiber membrane system, and the relative magnitude of the inerting rates of the four fuel types is RP5 > RP3 > RP6 > JP8. In addition, a higher catalytic efficiency or fuel load rate corresponds to a higher rate of decrease of the oxygen concentration in the gas phase, and the inerting time is inversely proportional to the suction flow rate of the fan. When different fuels are used, the amount of cooling gas and water released from the inerting system are different. Therefore, the influence of fuel type on the system performance should be extensively considered in the future.展开更多
文摘Porous polyvinylidene fluoride-co-hexafluropropylene(PVDF-HFP)hollow fiber membranes were fabricated through a wet spinning process.In order to improve the membrane structure,composition of the polymer solution was adjusted by studying ternary phase diagrams of polymer/solvent/non-solvent.The prepared membranes were used for sweeping gas membrane distillation(SGMD)of 20 wt% ethylene glycol(EG)aqueous solution.The membranes were characterized by different tests such as N2 permeation,overall porosity,critical water entry pressure(CEPw),water contact angle and collapsing pressure.From FESEM examination,addition of 3 wt% glycerol in the PVDF-HFP solution,produced membranes with smaller finger-likes cavities,higher surface porosity and smaller pore sizes.Increasing the polymer concentration up to 21 wt% resulted in a dense spongy structure which could significantly reduce the N2 permeance.The membrane prepared by 3 wt% glycerol and 17 wt% polymer demonstrated an improved structure with mean pore size of 18 nm and a high surface porosity of 872 m^−1.CEPw of 350 kPa and overall porosity of 84% were also obtained for the improved membrane.Collapsing pressure of the membranes relatively improved by increasing the polymer concentration.From the SGMDtest,the developed membrane represented a maximumpermeate flux of 28 kg·m^−2·h^−1 which is almost 19% higher than the flux of plain membrane.During 120 h of a long-termSGMD operation,a gradual flux reduction of 30% was noticed.In addition,EG rejection reduced from 100% to around 99.5% during 120 h of the operation.
文摘A review on the polymeric hollow fibers membranes for gas separation has been conducted. In order to deyelop high performance membranes for gas separation, there are a few technology challenges awaiting the chemical engineers to overcome. There are four major challenges, namely: 1) material selection and synthesis; 2) fabrication of hollow fiber membranes with an ultra- thin dense selective layer; 3) materials against plasticization; and 4) aging. In each area, we summarize the scientific accomplishments and technical difficulties.
文摘Extraction kinetics of phenol with N,N di(1 methyl heptyl) acetamide kerosene using hollow fiber membrane extractor has been studied. The rate regularities and kinetic types of forward and backward extraction were obtained respectively by determining the forward and backward extraction rate under various experimental conditions. The mass transfer mechanism was discussed. Both the forward and backward extraction of phenol might be controlled by diffusion processes, and the diffusion resistance for both forward and backward extraction mainly exists in aqueous phase. In addition, ways to optimize the extraction process of phenol were discussed as well.
基金This work was supported by the Key Special Project for Introduced Talents Team of Southern Marine Science and Engineering Guangdong Laboratory(Guangzhou)(GML2019ZD0108)Science and Technology Planning Project of Guangdong Province,China(2017A050501046)+1 种基金Natural Science Foundation of Guangdong Province(2017A030310185)Science and Technology Program of Guangzhou,China(202102021199).
文摘A numerical study on the conjugated heat-mass transfer of helical hollow fiber membrane tube bank(HFMTB)for seawater desalination was carried out.Physical and mathematical models of fluid flow,temperature and humidity distribution were constructed to investigate the influences of flow type,Reynolds number,and temperature on the conjugated heat-mass transfer performance of hollow fibers in the distillation membrane module.The conjugated heat-mass transfer characteristics of HFMTB were discussed by utilizing the friction coefficient,Nusselt number(Nu),and Sherwood number(Sh).Results demonstrate that a distillation efficiency enhancement of 29%compared to the straight HFMTB has been detected for four-helical HFMTB configuration,though the friction coefficient of such a module is about 4 times of their straight counterparts.The values of average Nu and Sh numbers are increasing with tube number,which improves distillation efficiency.The effect of flow type has been studied by employing the upstream and downstream flows to the double-helical HFMTB,demonstrating upstream flow type is more conducive to the heat-mass transfer process.Both the outlet air humidity(ω)and distillation efficiency(η)decrease with the air-side Reynolds number(Rea)and inlet air temperature in the helical HFMTB while increasing with the solution-side Reynolds number(Re_(S))and inlet solution temperature.Overall,the obtained results indicate that helical HFMTB applying upstream flow has great potential to achieve high-performance SGMD for seawater desalination.It is anticipated that the present work can assist in a better understanding of the membrane desalination process in HFMTB and thus provide theoretical suggestions for further optimization and development.
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.
基金sponsored by the project of Key Nature Science Foundation of Tianjin(No.043803911)the National Natural Science Foundation of China(Grant No.50473025)Open project of State Key Lab of Heavy Oil(University of petroleum(East China)No.2008-10).
文摘EVAL hollow fiber membrane adsorbents filled with powder D061-type cation exchange resin were prepared through dry-wet spinning process,using hydrophilic copolymer EVAL as the fiber substrate.The microstructures of the membrane adsorbents were observed,and the pure water fluxes,BSA rejection,and static adsorption capacities of membrane adsorbents for BSA were measured.The effect of the resin-filled content on membrane performance has been discussed.The results showed that EVAL hollow fiber membrane adsorbents filled with D061-type cation exchange resins had good adsorption capacity,and the adsorption capacity increased with the quantity of the resin-filled content.The static protein adsorption capacity was 77.14 mg BSA/g membrane adsorbents when D061 resin loading content was 65%at pH 4.5.
基金Project(20806094)supported by the National Natural Science Foundation of ChinaProject(2008SK1001)supported by Energy-saving and Emission-reducing Major Special Projects of Department of Science&Technology of Hunan Province,ChinaProjects(K0901082-11,K0902123-11)supported by Plan on Science and technology Bureau of Changsha,China
文摘Using Donnan Steric Partitioning Model(DSPM),the data for the rejection of four salts having common co-ion(LiCl, NaCl,KCl,Na2SO4)were obtained and they show the characters of the polyethersulfone(PES)nanofiltration(NF)membrane in terms of three parameters:an effective pore radius(rp),the ratio of effective thickness over porosity(λ/Ak)and an effective charge density(X).Good agreement between experimental data and prediction data using the three parameters mentioned above was obtained.A theoretical model was developed to predict the transport performance of electrolyte through the hollow fiber composite NF membrane.The model prediction is in good agreement with experimental results based on the method by modern numerical solution.
基金Supported by the National Natural Science Foundahon of China(No. 29771028, No. 29801004) and State Key Project of Fundamental
文摘In this paper the mass transfer behaviors of Fe(Ⅲ), Co(Ⅱ) and Ni(Ⅱ) with Cyanex302(bis(2,4,4- trimethylpentyl)monothiophosphinic acid) from sulfate medium by using hollow fiber membrane in counter-currently circulating operation were studied. The effect of acidity in aqueous solution and the extractant concentration on the mass transfer coefficient (Kw) was discussed. The reaction mechanism of membrane extraction was considered as a false one series reaCtion and the rate controlling step was membrane resistance. When the value of Kw arrived at 1.0 × 10-6 m/s, △pH:CoFe equaled tO 6.225, and △pH:NiFe was bigger than △p HCoFe.
文摘We have studied the mixed gas permeation in hollow fiber membrane modules using two approaches: namely, the co- current plug flow model and the complete mixing model with the combination of experimental data. Elucidation was made to determine the permeance of CO2 and CH4 and the selectivity of CO2/CH4 in a polyimide hollow fiber membrane permeator It is found that the intrinsic gas separation properties of hollow fibers for mixed gases can be accurately determined based on (1) the cocurrent plug now model, and (2) the complete mixing model with the assumption of averaged retentate concentration of the feed and the retentate outlet.
基金financial support of the National Key Research and Development Program of China (2020YFC0862903)the National Natural Science Foundation of China (22078146)+1 种基金the Key Research and Development program of Jiangsu Province (BE2021022)the Natural Science Foundation of Jiangsu Province (BK20200091)。
文摘Extracorporeal membrane oxygenator(ECMO) has been in development for nearly 70 years, and the oxygenator has gone through several generations of optimizations, with advances from bubble oxygenators to membrane oxygenators leading to more and more widespread use of ECMO. Membrane is the core of a ECMO system and the working mechanism of membrane oxygenator depends on the membrane material,from PDMS flat membrane to PMP hollow fiber membrane, which have experienced three generations.Blood compatibility on the surface of the membrane material is very vital, which directly determines the use duration of the oxygenator and can reduce the occurrence of complications. The mechanism of mass transfer is the basis of oxygenator operation and optimization. This review summarizes the membrane development history and preparation technology, modification approaches and mass transfer theory in the process of oxygen and blood exchange. We hoped that this review will provide more ideas for the study of gas blood exchange membrane.
文摘Currently,artificial-membrane lungs consist of thousands of hollow fiber membranes where blood flows around the fibers and gas flows inside the fibers,achieving diffusive gas exchange.At both ends of the fibers,the interspaces between the hollow fiber membranes and the plastic housing are filled with glue to separate the gas from the blood phase.During a uniaxial centrifugation process,the glue forms the“potting.”The shape of the cured potting is then determined by the centrifugation process,limiting design possibilities and leading to unfavorable stagnation zones associated with blood clotting.In this study,a new multiaxial centrifugation process was developed,expanding the possible shapes of the potting and allowing for completely new module designs with potentially superior blood flow guidance within the potting margins.Two-phase simulations of the process in conceptual artificial lungs were performed to explore the possibilities of a biaxial centrifugation process and determine suitable parameter sets.A corresponding biaxial centrifugation setup was built to prove feasibility and experimentally validate four conceptual designs,resulting in good agreement with the simulations.In summary,this study shows the feasibility of a multiaxial centrifugation process allowing greater variety in potting shapes,eliminating inefficient stagnation zones and more favorable blood flow conditions in artificial lungs.
基金supported by National Natural Science Foundation of China Civil Aviation Joint Fund (No.U1933121)Postgraduate Research & Practice Innovation Program of Jiangsu Province (No.KYCX19_0198)The Fundamental Research Funds for the Central Universities and Priority Academic Program Development of Jiangsu Higher Education Institutions。
文摘The properties of aviation fuel have a great influence on the performance of oxygenconsuming inerting systems. Based on the establishment of the catalytic inerting process, the flow relationship of each gas component flowing through the catalytic reactor was derived. The mathematical model of the gas concentration in the gas phase of the fuel tank was established based on the mass conservation equation, and the fuel tank model was verified by performing experiments.The results showed that the fuel type exerts a considerably higher influence on the performance of the oxygen-consuming inerting system compared to the corresponding influence on the hollow fiber membrane system, and the relative magnitude of the inerting rates of the four fuel types is RP5 > RP3 > RP6 > JP8. In addition, a higher catalytic efficiency or fuel load rate corresponds to a higher rate of decrease of the oxygen concentration in the gas phase, and the inerting time is inversely proportional to the suction flow rate of the fan. When different fuels are used, the amount of cooling gas and water released from the inerting system are different. Therefore, the influence of fuel type on the system performance should be extensively considered in the future.
