A new aromatic diamine,3,5-diaminobenzoylpiperazine （3,5-DABP）,was synthesized from 3,5-diaminobenzoic acid and 1-formyl piperazine.The structure of 3,5-DABP was identified by FT-IR spectra and 1H NMR spectra.With 3...A new aromatic diamine,3,5-diaminobenzoylpiperazine （3,5-DABP）,was synthesized from 3,5-diaminobenzoic acid and 1-formyl piperazine.The structure of 3,5-DABP was identified by FT-IR spectra and 1H NMR spectra.With 3,5-DABP as aqueous monomer and trimesoyl chloride （TMC） as organic monomer,thin film composite （TFC） nanofiltration membranes were prepared by interfacial polymerization technology.The salt rejection order of these TFC membranes is Na2SO4MgSO4MgCl2NaCl.This sequence indicates that the membranes are negatively charged.展开更多
Thin-film composite(TFC) reverse osmosis(RO) membranes are playing the dominating role in desalination.Tremendous efforts have been put in the studies on the polyamide selective layers. However, the effect of the subs...Thin-film composite(TFC) reverse osmosis(RO) membranes are playing the dominating role in desalination.Tremendous efforts have been put in the studies on the polyamide selective layers. However, the effect of the substrate layers is far less concerned. In this review, we summarize the works that consider the impacts of the substrates, including pore sizes, surface hydrophilicity, on the processes of interfacial polymerization and consequently on the morphologies of the active layers and on final RO performances of the composite membranes. All the works indicate that the pore sizes and surface hydrophilicity of the substrate evidently influence the RO performances of the composite membranes. Unfortunately, we find that the observations and understandings on the substrate effect are frequently varied from case to case because of the lack of substrates with uniform pores and surface chemistries. We suggest using track-etched membranes or anodized alumina membranes having relatively uniform pores and functionalizable pore walls as model substrates to elucidate the substrate effect.Moreover, we argue that homoporous membranes derived from block copolymers have the potential to be used as substrates for the large-scale production of high-performances TFC RO membranes.展开更多
In the development of the composite gas separation membranes for post-combustion CO_2 capture, little attention is focused on the optimization of the membrane supports, which satisfy the conditions of this technology....In the development of the composite gas separation membranes for post-combustion CO_2 capture, little attention is focused on the optimization of the membrane supports, which satisfy the conditions of this technology. The primary requirements to the membrane supports are concerned with their high CO_2 permeance. In this work, the membrane supports with desired characteristics were developed as high-permeance gas separation thin film composite(TFC) membranes with the thin defect-free layer from the crosslinked highly permeable polymer, poly[1-(trimethylsilyl)-1-propyne](PTMSP). This layer is insoluble in chloroform and can be used as a gutter layer for the further deposition of the CO_2-selective materials from the organic solvents. Crosslinking of PTMSP was performed using polyethyleneimine(PEI) and poly(ethyleneglycol) diglycidyl ether(PEGDGE) as crosslinking agents. Optimal concentrations of PEI in PTMSP and PEGDGE in methanol were selected in order to diminish the undesirable effect on the final membrane gas transport characteristics. The conditions of the kiss-coating technique for the deposition of the thin defect-free PTMSP-based layer, namely, composition of the casting solution and the speed of movement of the porous commercial microfiltration-grade support, were optimized. The procedure of post-treatment with alcohols and alcohol solutions was shown to be crucial for the improvement of gas permeance of the membranes with the crosslinked PTMSP layer having thickness ranging within 1-2.5 μm. The claimed membranes showed the following characteristics: CO_2 permeance is equal to 50—54 m^3(STP)/(m^2 h bar)(18,500—20,000 GPU), ideal CO_2/N_2 selectivity is 3.6-3.7, and their selective layers are insoluble in chloroform. Thus, the developed highpermeance TFC membranes are considered as a promising supports for further modification by enhanced CO_2 selective layer formation.展开更多
A lightweight flexible thermally stable composite is fabricated by com-bining silica nanofiber membranes(SNM)with MXene@c-MWCNT hybrid film.The flexible SNM with outstanding thermal insulation are prepared from tetrae...A lightweight flexible thermally stable composite is fabricated by com-bining silica nanofiber membranes(SNM)with MXene@c-MWCNT hybrid film.The flexible SNM with outstanding thermal insulation are prepared from tetraethyl orthosilicate hydrolysis and condensation by electrospinning and high-temperature calcination;the MXene@c-MWCNT_(x:y)films are prepared by vacuum filtration tech-nology.In particular,the SNM and MXene@c-MWCNT_(6:4)as one unit layer(SMC_(1))are bonded together with 5 wt%polyvinyl alcohol(PVA)solution,which exhibits low thermal conductivity(0.066 W m^(-1)K^(-1))and good electromagnetic interference(EMI)shielding performance(average EMI SE_(T),37.8 dB).With the increase in func-tional unit layer,the overall thermal insulation performance of the whole composite film(SMC_(x))remains stable,and EMI shielding performance is greatly improved,especially for SMC_(3)with three unit layers,the average EMI SET is as high as 55.4 dB.In addition,the organic combination of rigid SNM and tough MXene@c-MWCNT_(6:4)makes SMC_(x)exhibit good mechanical tensile strength.Importantly,SMC_(x)exhibit stable EMI shielding and excellent thermal insulation even in extreme heat and cold environment.Therefore,this work provides a novel design idea and important reference value for EMI shielding and thermal insulation components used in extreme environmental protection equipment in the future.展开更多
Polyamide(PA)-based thin-film composite membranes exhibit enormous potential in water purification,owing to their facile fabrication,decent performance and desirable stability.However,the thick PA active layer with hi...Polyamide(PA)-based thin-film composite membranes exhibit enormous potential in water purification,owing to their facile fabrication,decent performance and desirable stability.However,the thick PA active layer with high transport resistance from the conventional interfacial polymerization hampers their applications.The controllable fabrication of a thin PA active layer is essential for high separation efficiency but still challenging.Herein,a covalent organic framework TpPa-1 interlayer was firstly deposited on a polyethersulfone(PES)substrate to reduce the thickness of PA active layer in interfacial polymerization.The abundant pores of TpPa-1 increase the local concentration of amine monomers by adsorbing piperazine molecules,while hydrogen bonds between hydrophilic groups of TpPa-1 and piperazine molecules slow down their diffusion rate.Arising from those synergetic effects,the PA active layer is effectively reduced from 200 nm to 120 nm.By optimizing TpPa-1 interlayer and PA active layer,the water flux of resultant membranes can reach 171.35 L·m^-2·h^-1·MPa^-1,which increased by 125.4%compared with PA/PES membranes,while the rejection rates of sodium sulfate and dyes solution remained more than 90%and 99%,respectively.Our strategy may stimulate rational design of ultrathin PA-based nanofiltration membranes with high performances.展开更多
In this work, the effects of support surface pore structures(including surface pore size, surface pore density and surface porosity) on the performance of thin film composite(TFC) gas separation membrane over a wide p...In this work, the effects of support surface pore structures(including surface pore size, surface pore density and surface porosity) on the performance of thin film composite(TFC) gas separation membrane over a wide pressure range(from 0.3 to 2.0 MPa) were studied. To fulfill it, the polysulfone(PSf) supports with different surface pore structures were prepared. Two kinds of wide-accepted polymeric membrane materials, i.e., polyvinylamine(PVAm) and Pebax 1657 copolymer, were used as skin layer materials. We pointed out for the first time that the support surface average pore size and pore density could affect the chain mobility of polymer of skin layer at the support surface pore entrance, then, can affect the TFC membrane performance. Besides, we also discussed the effects of support on the TFC membrane performance when the feed pressure changes for the first time. This work can provide guidance for choosing a suitable support for TFC gas separation membrane.展开更多
Organic compounds are widely used in both industry and daily life,and composite bilayer films with organic compound-triggered bending properties are promising for applications of transducers,soft robotics,and so on.He...Organic compounds are widely used in both industry and daily life,and composite bilayer films with organic compound-triggered bending properties are promising for applications of transducers,soft robotics,and so on.Here,a universal and straightforward strategy to generate composite bilayer films with organic compoundtriggered bending properties is demonstrated.The composite bilayer films with organic compound-triggered bending properties are designed with bilayer structures,in which one layer is a porous polymeric membrane with appropriate solubility parameter that matches the value of organic solvents in order to produce prominent affinity to the solvent molecules,and the other layer is reduced graphene oxide membrane stacked on the porous polymeric membrane as an inert layer for restraining the swelling of the polymeric membrane on one side.Guided by matching the solubility parameters between solvent and polymer,a significant bending curvature of 27.3 cm-1 is obtained in acetone vapor.The results in this study will provide valuable guidance for designing and developing functional composite materials with significant organic compound-triggered bending properties.展开更多
In this study a thin film composite （TFC） membrane with a Pebax/Task-specific ionic liquid （TSIL） blend selective layer was prepared. Defect-flee Pebax/TSIL layers were coated successfully on a polysulfone ultrafi...In this study a thin film composite （TFC） membrane with a Pebax/Task-specific ionic liquid （TSIL） blend selective layer was prepared. Defect-flee Pebax/TSIL layers were coated successfully on a polysulfone ultrafiltration porous support with a poly- dimethylsiloxane （PDMS） gutter layer. Different parameters in the membrane preparation （e.g. concentration, coating time） were investigated and optimized. The morphology of the membranes was studied by scanning electron microscopy （SEM）, while the thermal properties and chemical structures of the membrane materials were investigated by thermo-gravimetric ana- lyzer （TGA）, differential scanning calorimetry （DSC） and Fourier transform infrared spectroscopy （FTIR）. The CO2 separation performance of the membrane was evaluated using a mixed gas permeation test. Experimental results show that the incorpora- tion of TSIL into the Pebax matrix can significantly increase both C02 permeance and CO2/N2 selectivity. With the presence of water vapor, the membrane exhibits the best CO2/N2 selectivity at a relative humidity of around 75%, where a CO2 permeance of around 500 GPU and a CO2/N2 selectivity of 46 were documented. A further increase in the relative humidity resulted in higher CO： permeance but decreased COIN2 selectivity. Experiments also show that CO2 permeance decreases with a CO2 partial pressure increase, which is considered a characteristic in facilitated transport membranes.展开更多
Polyamide thin film composite membranes have dominated current reverse osmosis market on account of their excellent separation performances compared to the integrally skinned counterparts.Despite their very promising ...Polyamide thin film composite membranes have dominated current reverse osmosis market on account of their excellent separation performances compared to the integrally skinned counterparts.Despite their very promising separation performance,chlorine-induced degradation resulted from the susceptibility of polyamide toward chlorine attack has been regarded as the Achilles’s heel of polyamide thin film composite.The free chlorine species present during chlorine treatment can impair membrane performance through chlorination and depolymerization of the polyamide selective layer.From material point of view,a chemically stable membrane is crucial for the sustainable application of membrane separation process as it warrants a longer membrane lifespan and reduces the cost involved in membrane replacement.Various strategies,particularly those involved membrane material optimization and surface modifications,have been established to address this issue.This review discusses membrane degradation by free chlorine attack and its correlation with the surface chemistry of polyamide.The advancement in the development of chlorine resistant polyamide thin film composite membranes is reviewed based on the state-of-the-art surface modifications and tailoring approaches which include the in situ and postfabrication membrane modifications using a broad range of functional materials.The challenges and future directions in this field are also highlighted.展开更多
Forward osmosis(FO)as an energy-saving membrane process has attracted much attention in food concentration,water treatment,and desalination.Thin film composite(TFC)membrane is the most popular FO membrane,but it suffe...Forward osmosis(FO)as an energy-saving membrane process has attracted much attention in food concentration,water treatment,and desalination.Thin film composite(TFC)membrane is the most popular FO membrane,but it suffers from the internal concentration polarization(ICP),which significantly limits the water flux and FO efficiency.In this report,we demonstrate a novel and high-performing thin film nanocomposite(TFN)membrane that employs a hydrophilic interlayer composed of imogolite nanotubes(INTs)and polydopamine(PDA).The INTs can be adhered to the porous substrate by the self-polymerization of PDA,and the as-prepared PDA/INTs interlayer displays a nanostructured network with outstanding hydrophilicity.The detailed investigation was conducted to understand the relationship between the structure and property of the PDA/INTs interlayer and the morphology and performance of the TFN membrane.The TFN membrane with the PDA/INTs interlayer performs a thinner and smoother polyamide selective layer.Correspondingly,the TFN membrane shows a water flux of 18.38 L·m^(-2)·h^(-1),which is 2.18 times of the pristine TFC membrane.Moreover,the TFN membrane has a minimized structural parameter(577μm),almost a half of that of the pristine one(949μm).It reveals that the ICP effect of TFC membrane can be effectively alleviated by using a hydrophilic PDA/INTs interlayer.This TFN membrane with a satisfactory water permeability is promising in terms of future applications.展开更多
Drinking water scarcity is an ever-increasing global concern. This issue appears as a greater threat to the countries with no access to sea water resources or rivers, since their potential water resources are only lim...Drinking water scarcity is an ever-increasing global concern. This issue appears as a greater threat to the countries with no access to sea water resources or rivers, since their potential water resources are only limited to ground waters only. There are serious concerns with the treatment of ground water resources, including landfill leachates, agricultural contaminations(pesticides,herbicides, and fertilizers), and rural contaminations. Membrane separation has been proved to be the governing technology in water and wastewater treatment plants, as these methods are responsible for more than half of the market share of the world's desalination capacity. This study intends to offer a holistic view of the groundwater contamination with specific focus on Saskatchewan province in Canada, and the recent efforts in the groundwater treatment using thin film composite membrane technology. This study begins with an introduction of the general aspects of ground water and membrane separation, polluting agents, and their sources.It is followed by a discussion of Saskatchewan's groundwater status and various issues.Furthermore, the recent research that became available since 2010 is reviewed in details and the results are summarized with respect to purification efficiency. Different affecting parameters in a groundwater-thin film composite system are synthesized and an in-depth overview is presented.展开更多
基金Supported by the National Natural Science Foundation of China（21076176） the Research and Development Project of Tangshan（10140201C-3）+1 种基金 the Research and Development Project of Hebei Province（07275113） the Research Fund of Tangshan Normal College
文摘A new aromatic diamine,3,5-diaminobenzoylpiperazine （3,5-DABP）,was synthesized from 3,5-diaminobenzoic acid and 1-formyl piperazine.The structure of 3,5-DABP was identified by FT-IR spectra and 1H NMR spectra.With 3,5-DABP as aqueous monomer and trimesoyl chloride （TMC） as organic monomer,thin film composite （TFC） nanofiltration membranes were prepared by interfacial polymerization technology.The salt rejection order of these TFC membranes is Na2SO4MgSO4MgCl2NaCl.This sequence indicates that the membranes are negatively charged.
基金Supported by the National Basic Research Program of China(2015CB655301)the Natural Science Foundation of Jiangsu Province(BK20150063)the Project of Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD)
文摘Thin-film composite(TFC) reverse osmosis(RO) membranes are playing the dominating role in desalination.Tremendous efforts have been put in the studies on the polyamide selective layers. However, the effect of the substrate layers is far less concerned. In this review, we summarize the works that consider the impacts of the substrates, including pore sizes, surface hydrophilicity, on the processes of interfacial polymerization and consequently on the morphologies of the active layers and on final RO performances of the composite membranes. All the works indicate that the pore sizes and surface hydrophilicity of the substrate evidently influence the RO performances of the composite membranes. Unfortunately, we find that the observations and understandings on the substrate effect are frequently varied from case to case because of the lack of substrates with uniform pores and surface chemistries. We suggest using track-etched membranes or anodized alumina membranes having relatively uniform pores and functionalizable pore walls as model substrates to elucidate the substrate effect.Moreover, we argue that homoporous membranes derived from block copolymers have the potential to be used as substrates for the large-scale production of high-performances TFC RO membranes.
基金supported by the European Community's Seventh Framework Program FP7 under the grant agreement no.608555(HiPerCap)
文摘In the development of the composite gas separation membranes for post-combustion CO_2 capture, little attention is focused on the optimization of the membrane supports, which satisfy the conditions of this technology. The primary requirements to the membrane supports are concerned with their high CO_2 permeance. In this work, the membrane supports with desired characteristics were developed as high-permeance gas separation thin film composite(TFC) membranes with the thin defect-free layer from the crosslinked highly permeable polymer, poly[1-(trimethylsilyl)-1-propyne](PTMSP). This layer is insoluble in chloroform and can be used as a gutter layer for the further deposition of the CO_2-selective materials from the organic solvents. Crosslinking of PTMSP was performed using polyethyleneimine(PEI) and poly(ethyleneglycol) diglycidyl ether(PEGDGE) as crosslinking agents. Optimal concentrations of PEI in PTMSP and PEGDGE in methanol were selected in order to diminish the undesirable effect on the final membrane gas transport characteristics. The conditions of the kiss-coating technique for the deposition of the thin defect-free PTMSP-based layer, namely, composition of the casting solution and the speed of movement of the porous commercial microfiltration-grade support, were optimized. The procedure of post-treatment with alcohols and alcohol solutions was shown to be crucial for the improvement of gas permeance of the membranes with the crosslinked PTMSP layer having thickness ranging within 1-2.5 μm. The claimed membranes showed the following characteristics: CO_2 permeance is equal to 50—54 m^3(STP)/(m^2 h bar)(18,500—20,000 GPU), ideal CO_2/N_2 selectivity is 3.6-3.7, and their selective layers are insoluble in chloroform. Thus, the developed highpermeance TFC membranes are considered as a promising supports for further modification by enhanced CO_2 selective layer formation.
基金the China Scholarship Council(2021)the Deanship of Scientific Research at Northern Border University,Arar,KSA for funding this research work through the project number“NBU-FPEJ-2024-249-03”.
文摘A lightweight flexible thermally stable composite is fabricated by com-bining silica nanofiber membranes(SNM)with MXene@c-MWCNT hybrid film.The flexible SNM with outstanding thermal insulation are prepared from tetraethyl orthosilicate hydrolysis and condensation by electrospinning and high-temperature calcination;the MXene@c-MWCNT_(x:y)films are prepared by vacuum filtration tech-nology.In particular,the SNM and MXene@c-MWCNT_(6:4)as one unit layer(SMC_(1))are bonded together with 5 wt%polyvinyl alcohol(PVA)solution,which exhibits low thermal conductivity(0.066 W m^(-1)K^(-1))and good electromagnetic interference(EMI)shielding performance(average EMI SE_(T),37.8 dB).With the increase in func-tional unit layer,the overall thermal insulation performance of the whole composite film(SMC_(x))remains stable,and EMI shielding performance is greatly improved,especially for SMC_(3)with three unit layers,the average EMI SET is as high as 55.4 dB.In addition,the organic combination of rigid SNM and tough MXene@c-MWCNT_(6:4)makes SMC_(x)exhibit good mechanical tensile strength.Importantly,SMC_(x)exhibit stable EMI shielding and excellent thermal insulation even in extreme heat and cold environment.Therefore,this work provides a novel design idea and important reference value for EMI shielding and thermal insulation components used in extreme environmental protection equipment in the future.
基金supported by the Open Project Program of State Key Laboratory of Petroleum Pollution Control(Grant No.PPC2017014)CNPC Research Institute of Safety and Environmental Technology。
文摘Polyamide(PA)-based thin-film composite membranes exhibit enormous potential in water purification,owing to their facile fabrication,decent performance and desirable stability.However,the thick PA active layer with high transport resistance from the conventional interfacial polymerization hampers their applications.The controllable fabrication of a thin PA active layer is essential for high separation efficiency but still challenging.Herein,a covalent organic framework TpPa-1 interlayer was firstly deposited on a polyethersulfone(PES)substrate to reduce the thickness of PA active layer in interfacial polymerization.The abundant pores of TpPa-1 increase the local concentration of amine monomers by adsorbing piperazine molecules,while hydrogen bonds between hydrophilic groups of TpPa-1 and piperazine molecules slow down their diffusion rate.Arising from those synergetic effects,the PA active layer is effectively reduced from 200 nm to 120 nm.By optimizing TpPa-1 interlayer and PA active layer,the water flux of resultant membranes can reach 171.35 L·m^-2·h^-1·MPa^-1,which increased by 125.4%compared with PA/PES membranes,while the rejection rates of sodium sulfate and dyes solution remained more than 90%and 99%,respectively.Our strategy may stimulate rational design of ultrathin PA-based nanofiltration membranes with high performances.
基金Supported by the National Natural Science Foundation of China(21436009)the National High-tech Research and Development Program(2012AA03A611)the Program of Introducing Talents of Discipline to Universities(B06006)
文摘In this work, the effects of support surface pore structures(including surface pore size, surface pore density and surface porosity) on the performance of thin film composite(TFC) gas separation membrane over a wide pressure range(from 0.3 to 2.0 MPa) were studied. To fulfill it, the polysulfone(PSf) supports with different surface pore structures were prepared. Two kinds of wide-accepted polymeric membrane materials, i.e., polyvinylamine(PVAm) and Pebax 1657 copolymer, were used as skin layer materials. We pointed out for the first time that the support surface average pore size and pore density could affect the chain mobility of polymer of skin layer at the support surface pore entrance, then, can affect the TFC membrane performance. Besides, we also discussed the effects of support on the TFC membrane performance when the feed pressure changes for the first time. This work can provide guidance for choosing a suitable support for TFC gas separation membrane.
基金Supported by the National Natural Science Foundation of China(21490582,21622604)the Program for Changjiang Scholars and Innovative Research Team in University(IRT15R48)the State Key Laboratory of Polymer Materials Engineering(sklpme2017-3-03,sklpme2014-1-01).
文摘Organic compounds are widely used in both industry and daily life,and composite bilayer films with organic compound-triggered bending properties are promising for applications of transducers,soft robotics,and so on.Here,a universal and straightforward strategy to generate composite bilayer films with organic compoundtriggered bending properties is demonstrated.The composite bilayer films with organic compound-triggered bending properties are designed with bilayer structures,in which one layer is a porous polymeric membrane with appropriate solubility parameter that matches the value of organic solvents in order to produce prominent affinity to the solvent molecules,and the other layer is reduced graphene oxide membrane stacked on the porous polymeric membrane as an inert layer for restraining the swelling of the polymeric membrane on one side.Guided by matching the solubility parameters between solvent and polymer,a significant bending curvature of 27.3 cm-1 is obtained in acetone vapor.The results in this study will provide valuable guidance for designing and developing functional composite materials with significant organic compound-triggered bending properties.
基金supported by the Research Council of Norway through the CLIMIT program (MCIL-CO2 project, 21732)the National Natural Science Fund for Distinguished Young Scholars (21425625) from China
文摘In this study a thin film composite （TFC） membrane with a Pebax/Task-specific ionic liquid （TSIL） blend selective layer was prepared. Defect-flee Pebax/TSIL layers were coated successfully on a polysulfone ultrafiltration porous support with a poly- dimethylsiloxane （PDMS） gutter layer. Different parameters in the membrane preparation （e.g. concentration, coating time） were investigated and optimized. The morphology of the membranes was studied by scanning electron microscopy （SEM）, while the thermal properties and chemical structures of the membrane materials were investigated by thermo-gravimetric ana- lyzer （TGA）, differential scanning calorimetry （DSC） and Fourier transform infrared spectroscopy （FTIR）. The CO2 separation performance of the membrane was evaluated using a mixed gas permeation test. Experimental results show that the incorpora- tion of TSIL into the Pebax matrix can significantly increase both C02 permeance and CO2/N2 selectivity. With the presence of water vapor, the membrane exhibits the best CO2/N2 selectivity at a relative humidity of around 75%, where a CO2 permeance of around 500 GPU and a CO2/N2 selectivity of 46 were documented. A further increase in the relative humidity resulted in higher CO： permeance but decreased COIN2 selectivity. Experiments also show that CO2 permeance decreases with a CO2 partial pressure increase, which is considered a characteristic in facilitated transport membranes.
基金support provided by the Ministry of Higher Education Malaysia under Malaysia Research University Network Grant(Grant No.4L862)the research support provided by Universiti Teknologi Malaysia.
文摘Polyamide thin film composite membranes have dominated current reverse osmosis market on account of their excellent separation performances compared to the integrally skinned counterparts.Despite their very promising separation performance,chlorine-induced degradation resulted from the susceptibility of polyamide toward chlorine attack has been regarded as the Achilles’s heel of polyamide thin film composite.The free chlorine species present during chlorine treatment can impair membrane performance through chlorination and depolymerization of the polyamide selective layer.From material point of view,a chemically stable membrane is crucial for the sustainable application of membrane separation process as it warrants a longer membrane lifespan and reduces the cost involved in membrane replacement.Various strategies,particularly those involved membrane material optimization and surface modifications,have been established to address this issue.This review discusses membrane degradation by free chlorine attack and its correlation with the surface chemistry of polyamide.The advancement in the development of chlorine resistant polyamide thin film composite membranes is reviewed based on the state-of-the-art surface modifications and tailoring approaches which include the in situ and postfabrication membrane modifications using a broad range of functional materials.The challenges and future directions in this field are also highlighted.
基金financially supported by the Fundamental Research Funds for the Central Universities(No.2021qntd13)the Guangdong Basic and Applied Basic Research Foundation(No.2022A1515010021)。
文摘Forward osmosis(FO)as an energy-saving membrane process has attracted much attention in food concentration,water treatment,and desalination.Thin film composite(TFC)membrane is the most popular FO membrane,but it suffers from the internal concentration polarization(ICP),which significantly limits the water flux and FO efficiency.In this report,we demonstrate a novel and high-performing thin film nanocomposite(TFN)membrane that employs a hydrophilic interlayer composed of imogolite nanotubes(INTs)and polydopamine(PDA).The INTs can be adhered to the porous substrate by the self-polymerization of PDA,and the as-prepared PDA/INTs interlayer displays a nanostructured network with outstanding hydrophilicity.The detailed investigation was conducted to understand the relationship between the structure and property of the PDA/INTs interlayer and the morphology and performance of the TFN membrane.The TFN membrane with the PDA/INTs interlayer performs a thinner and smoother polyamide selective layer.Correspondingly,the TFN membrane shows a water flux of 18.38 L·m^(-2)·h^(-1),which is 2.18 times of the pristine TFC membrane.Moreover,the TFN membrane has a minimized structural parameter(577μm),almost a half of that of the pristine one(949μm).It reveals that the ICP effect of TFC membrane can be effectively alleviated by using a hydrophilic PDA/INTs interlayer.This TFN membrane with a satisfactory water permeability is promising in terms of future applications.
基金the Department of Chemical and Biological Engineering at the University of Saskatchewan for the support provided
文摘Drinking water scarcity is an ever-increasing global concern. This issue appears as a greater threat to the countries with no access to sea water resources or rivers, since their potential water resources are only limited to ground waters only. There are serious concerns with the treatment of ground water resources, including landfill leachates, agricultural contaminations(pesticides,herbicides, and fertilizers), and rural contaminations. Membrane separation has been proved to be the governing technology in water and wastewater treatment plants, as these methods are responsible for more than half of the market share of the world's desalination capacity. This study intends to offer a holistic view of the groundwater contamination with specific focus on Saskatchewan province in Canada, and the recent efforts in the groundwater treatment using thin film composite membrane technology. This study begins with an introduction of the general aspects of ground water and membrane separation, polluting agents, and their sources.It is followed by a discussion of Saskatchewan's groundwater status and various issues.Furthermore, the recent research that became available since 2010 is reviewed in details and the results are summarized with respect to purification efficiency. Different affecting parameters in a groundwater-thin film composite system are synthesized and an in-depth overview is presented.
