The development of multilayer composite membranes for CO_2 separation has gained increasing attention due to the desire for energy efficient technologies. Multilayer composite membranes have many advantages, including...The development of multilayer composite membranes for CO_2 separation has gained increasing attention due to the desire for energy efficient technologies. Multilayer composite membranes have many advantages, including the possibility to optimize membrane materials independently by layers according to their different functions and to reduce the overall transport resistance by using ultrathin selective layers, and less limitations on the material mechanical properties and processability. A comprehensive review is required to capture details of the progresses that have already been achieved in developing multilayer composite membranes with improved CO_2 separation performance in the past 15-20 years.In this review, various composite membrane preparation methods were compared, advances in composite membranes for CO_2/CH_4 separation,CO_2/N_2 and CO_2/H_2 separation were summarized with detailed data, and challenges facing for the CO_2 separation using composite membranes,such as aging, plasticization and long-term stability, were discussed. Finally the perspectives and future research directions for composite membranes were presented.展开更多
In practical engineering construction,multi-layered barriers containing geomembranes are extensively applied to retard the migration of pollutants.However,the associated analytical theory on pollutants diffusion still...In practical engineering construction,multi-layered barriers containing geomembranes are extensively applied to retard the migration of pollutants.However,the associated analytical theory on pollutants diffusion still needs to be further improved.In this work,general analytical solutions are derived for one-dimensional diffusion of degradable organic contaminant(DOC)in the multi-layered media containing geomembranes under a time-varying concentration boundary condition,where the variable substitution and separated variable approaches are employed.These analytical solutions with clear expressions can be used not only to study the diffusion behaviors of DOC in bottom and vertical composite barrier systems,but also to verify other complex numerical models.The proposed general analytical solutions are then fully validated via three comparative analyses,including comparisons with the experimental measurements,an existing analytical solution,and a finite-difference solution.Ultimately,the influences of different factors on the composite cutoff wall’s(CCW,which consists of two soil-bentonite layers and a geomembrane)service performance are investigated through a composite vertical barrier system as the application example.The findings obtained from this investigation can provide scientific guidance for the barrier performance evaluation and the engineering design of CCWs.This application example also exhibits the necessity and effectiveness of the developed analytical solutions.展开更多
Transportation structures such as composite pavements and railway foundations typically consist of multi-layered media designed to withstand high bearing capacity.A theoretical understanding of load transfer mechanism...Transportation structures such as composite pavements and railway foundations typically consist of multi-layered media designed to withstand high bearing capacity.A theoretical understanding of load transfer mechanisms in these multi-layer composites is essential,as it offers intuitive insights into parametric influences and facilitates enhanced structural performance.This paper employs an improved transfer matrix method to address the limitations of existing theoretical approaches for analyzing multi-layer composite structures.By establishing a twodimensional composite pavement model,it investigates load transfer characteristics and validates the accuracy through finite element simulation.The proposed method offers a straightforward analytical approach for examining internal interactions between structural layers.Case studies indicate that the concrete surface layer is the main load-bearing layer for most vertical normal and shear stresses.The soil base layer reduces the overall mechanical response of the substructure,while horizontal actions increase the risk of interfacial slip and cracking.Structural optimization analysis demonstrates that increasing the thickness of the concrete surface layer,enhancing the thickness and stiffness of the soil base layer,or incorporating gradient layers can significantly mitigate these risks of interfacial slip and cracking.The findings of this study can guide the optimization design,parameter analysis,and damage prevention of multi-layer composite structures.展开更多
The composite membrane of microcrystalline cellulose(MCC)with polyvinyl alcohol(PVA)was effectively synthesized using ionic liquids(ILs)as the solvent and dimethyl sulfone(DMSO)as the co-solvent through the phase conv...The composite membrane of microcrystalline cellulose(MCC)with polyvinyl alcohol(PVA)was effectively synthesized using ionic liquids(ILs)as the solvent and dimethyl sulfone(DMSO)as the co-solvent through the phase conversion method.The effects of IL structure and the IL/DMSO mass ratio on the solubility of MCC were investigated.The findings indicated that the composite solvent functioned as a non-derivative solvent for MCC dissolution.The inclusion of DMSO decreased the viscosity of ILs and enhanced the rate of MCC dissolution.The solubility of MCC reached 14.5%(mass)when the mass ratio of[Bmim]Cl to DMSO was 1:1.The fabricated MCC membrane exhibited a smooth surface and a dense structure.PVA@MCC demonstrated exceptional mechanical properties and a uniform structure at a mass ratio of 2:1,with an elongation at break of 76%and a tensile strength of 14.6 MPa.The effects of antibacterial agents on the morphology,transmittance,mechanical properties,and antibacterial efficiency of PVA@MCC were investigated.The findings revealed that PVA@MCC fortified with clove oil showcased a flat and smooth surface,devoid of stratification or aggregation,and demonstrated superior mechanical properties compared to its counterparts with chitosan and ZnO additions.The elongation at break of PVA@MCC with clove oil increased to 137.6%,while its tensile strength decreased to 10.4 MPa.PVA@MCC with clove oil exhibited an antibacterial efficiency exceeding 68%against Escherichia coli,Staphylococcus aureus,and Pseudomonas aeruginosa,thereby extending the shelf life of cherry tomatoes by an additional four days at ambient temperature.展开更多
The recovery of ionic liquids(ILs)has attracted growing attention as an indispensable process in“green”industrial applications.Forward osmosis(FO)has proven to be a sustainable method for concentrating the very dilu...The recovery of ionic liquids(ILs)has attracted growing attention as an indispensable process in“green”industrial applications.Forward osmosis(FO)has proven to be a sustainable method for concentrating the very dilute aqueous solutions of ILs at ambient temperature,in which semi-permeable membranes play a vital role in determining the recovery efficiency.Herein,we use interfacial polymerization method to prepare thin-film composite membranes consisting of polyamide skin layer and electrospun nanofibrous substrate with tunable water permeability and IL selectivity for osmotic enrichment of imidazolium ILs from their dilute aqueous solutions through FO process.The resulting FO membrane shows a compact polyamide layer with a thickness of 30-200 nm,guranteeing a high selectivity to ILs and water.Meanwhile,the nanofibrous substrate with large and interconnect pores as well as low tortuosity,providing mechanical and permeable support for the composite membranes.IL structure influences the osmotic pressure difference as well as the interactions with polyamide layer of the membrane and thus determines the whole concentration process.First,the alkyl chain growth augments the osmosis pressure difference between the ILs solution and draw solution,resulting in an enhancement in driving force of water osmosis and IL enrichment.Moreover,alkyl length aggravates external concentration polarization caused by the enhanced adsorption of ILs onto the skin layer via electrostatic and alkyl-πinteractions.Meanwhile,such adsorbed ILs further enhance the IL retention but decrease the reverse salt diffusion.Therefore,imidazolium ILs with varied alkyl lengths are ultimately enriched with a 100-fold increase in concentration from their dilute aqueous solutions with high IL/NaCl rejection and low IL loss.Remarkably,the final concentration of IL with longest alkyl length reaches the highest(6.4 mol·L^(-1)).This work provides the insights in respect to material preparation and process amelioration for IL recovery with high scalability at mild conditions.展开更多
Sulfide solid electrolytes with an ultrahigh ionic conductivity are considered to be extremely promising alternatives to liquid electrolytes for next-generation lithium batteries.However,it is difficult to obtain a th...Sulfide solid electrolytes with an ultrahigh ionic conductivity are considered to be extremely promising alternatives to liquid electrolytes for next-generation lithium batteries.However,it is difficult to obtain a thin solid electrolyte layer with good mechanical properties due to the weak binding ability between their powder particles,which seriously limits the actual energy density of sulfide all-solid-state lithium batteries(ASSLBs).Fortunately,the preparation of sulfide-polymer composite solid electrolyte(SPCSE)membranes by introducing polymer effectively reduces the thickness of solid electrolytes and guarantees high mechanical properties.In this review,recent progress of SPCSE membranes for ASSLBs is summarized.The classification of components in SPCSE membranes is first introduced briefly.Then,the preparation methods of SPCSE membranes are categorized according to process characteristics,in which the challenges of different methods and their corresponding solutions are carefully reviewed.The energy densities of the full battery composed of SPCSE membranes are further given whenever available to help understanding the device-level performance.Finally,we discuss the potential challenges and research opportunities for SPCSE membranes to guide the future development of high-performance sulfide ASSLBs.展开更多
Pervaporation has attracted considerable interest owing to its potential application in recovering biobutanol from biomass acetone-butanol-ethanol (ABE) fermentation broth. In this study, butanol was recovered from it...Pervaporation has attracted considerable interest owing to its potential application in recovering biobutanol from biomass acetone-butanol-ethanol (ABE) fermentation broth. In this study, butanol was recovered from its aqueous solution using a polydimethylsiloxane (PDMS)/ceramic composite pervaporation membrane. The effects of operating temperature, feed concentration, feed flow rate and operating time on the membrane pervaporation performance were investigated. It was found that with the increase of temperature or butanol concentration in the feed, the total flux through the membrane increased while the separation factor decreased slightly. As the feed flow rate increased, the total flux increased gradually while the separation factor changed little. At 40°C and 1% (by mass) butanol in the feed, the total flux and separation factor of the membrane reached 457.4 g·m?2·h?1 and 26.1, respectively. The membrane with high flux is suitable for recovering butanol from ABE fermentation broth.展开更多
The preparation of composite charge-mosaic membrane included spinning of hollow fiber as the supporting membrane, preparing a selective layer on the inside surface of the fiber by interfacial polymerization. The char...The preparation of composite charge-mosaic membrane included spinning of hollow fiber as the supporting membrane, preparing a selective layer on the inside surface of the fiber by interfacial polymerization. The charge-mosaic membranes show a high salt permeability while retaining sucrose. The charge-mosaic membrane can be effectively used to separate multivalent salts with organic matter of molecular weight great than 300 g/mol in industry.展开更多
In order to improve mechanical properties of soft poly(vinyl chloride)(PVC) films,we used commercial multi-layer graphene(MLG) with large size and high structural integrity as reinforcing fillers,and prepared MLG/PVC ...In order to improve mechanical properties of soft poly(vinyl chloride)(PVC) films,we used commercial multi-layer graphene(MLG) with large size and high structural integrity as reinforcing fillers,and prepared MLG/PVC composite films by using conventional melt-mixing methods.Microstructures,static and dynamic mechanical properties of the MLG/PVC composite films were investigated.The results showed that a small amount of MLG loading could greatly increase the mechanical properties of the MLG/PVC composites.The tensile modulus of the 0.96 wt%MLG/PVC composites was up to 40 MPa,increasing by31.3%in comparison to the neat PVC.Such a significant mechanical reinforcement was mainly attributed to uniform dispersion of the large-size MLG,good compatibility and strong interactions among MLG and plasticizers and PVC.展开更多
Traditional solvent recovery in the extraction step of edible oil processing is distillation,which consumes large amounts of energy.If the distillation is replaced by membrane process,the energy consumption can be red...Traditional solvent recovery in the extraction step of edible oil processing is distillation,which consumes large amounts of energy.If the distillation is replaced by membrane process,the energy consumption can be reduced greatly.In this work,two kinds of membrane,PDMS(polydimethylsiloxane) composite membrane and Zeolite filled PDMS membrane were prepared,in which asymmetric microporous PVDF(polyvinylidenefluoride) membrane prepared with phase inversion method was functioned as the microporous supporting layer in the flat-plate composite membrane.The different function compositions of the PDMS/PVDF composite membranes were characterized by reflection Fourier transform infrared(FTIR) spectroscopy.The surface and section of PDMS/PVDF composite membranes were investigated by scanning electron microscope(SEM).The PDMS NF(nanofiltration) membranes were then applied in the recovery of hexane from soybean oil/hexane miscellas(1:3,mass ratio).The effects of pressure(0.5-1.5 MPa),cross-linking temperature and PDMS layer thickness on membrane performances were investigated.The results indicated that both two kinds of NF membranes were promising for solvent recovery,and zeolite filled in PDMS NF membrane could enhance the separation performance.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
The pyromellitic dianhydride（PMDA） crosslinked poly（vinyl alcohol）（PVA） was coated on top of the PAN ultrafiltration membrane to form a PVA/PAN composite PV membranes for wastewater desalination. The composite m...The pyromellitic dianhydride（PMDA） crosslinked poly（vinyl alcohol）（PVA） was coated on top of the PAN ultrafiltration membrane to form a PVA/PAN composite PV membranes for wastewater desalination. The composite membranes have high application value in industrial wastewater treatment. By varying the membrane fabrication parameters including the weight percent（wt%） of the PMDA, the crosslink temperature and duration, membrane with the best desalination performance was obtained. The composite membrane with a 2-lm-thick PVA selective layer containing 20 wt% of PMDA and being crosslinked at 100 °C for 2 h showed the highest Na Cl rejection of 99.98% with a water flux of 32.26 L/（m^2 h）at 70 °C using the 35,000 ppm Na Cl aqueous solution as feed. FTIR spectroscopy, wide-angle X-ray diffraction, thermogravimetric analysis and scanning electron microscope have been used to characterize the structures and properties of both the crosslinked PVA dense films and PVA/PAN composite membranes. The effects of the concentrations of PMDA,the crosslinking time and temperature to the membrane water contact angle, swelling degree, salt rejection and water flux were systematically studied.展开更多
A novel inorganic-organic composite membrane,namely poly（vinylidene fluoride） PVDF-glass fiber（PGF） composite membrane,was prepared and reinforced by interfacial ultraviolet（UV）-grafting copolymerization to impr...A novel inorganic-organic composite membrane,namely poly（vinylidene fluoride） PVDF-glass fiber（PGF） composite membrane,was prepared and reinforced by interfacial ultraviolet（UV）-grafting copolymerization to improve the interfacial bonding strength between the membrane layer and the glass fiber.The interfacial polymerization between inorganic-organic interfaces is a chemical cross-linking reaction that depends on the functionalized glass fiber with silane coupling（KH570） as the initiator and the polymer solution with acrylamide monomer（AM） as the grafting block.The Fourier transform infrared spectrometer-attenuated total reflectance（FTIR-ATR） spectra and the energy dispersive X-ray（EDX） pictures of the interface between the glass fiber and polymer matrix confirmed that the AM was grafted to the surface of the glass fiber fabric and that the grafting polymer was successfully embedded in the membrane matrix.The formation mechanisms,permeation,and anti-fouling performance of the PGF composite membrane were measured with different amounts of AM in the doping solutions.The results showed that the grafting composite membrane improved the interfacial bonding strength and permeability,and the peeling strength was improved by 32.6% for PGF composite membranes with an AM concentration at 2 wt.%.展开更多
This work aims to evaluate the feasibility of the fabrication of nanostructured Cu/Al/Ag multi-layered composites by accumulative roll bonding(ARB),and to analyze the tensile properties and electrical conductivity of ...This work aims to evaluate the feasibility of the fabrication of nanostructured Cu/Al/Ag multi-layered composites by accumulative roll bonding(ARB),and to analyze the tensile properties and electrical conductivity of the produced composites.A theoretical model using strengthening mechanisms and some structural parameters extracted from X-ray diffraction is also developed to predict the tensile strength of the composites.It was found that by progression of ARB,the experimental and calculated tensile strengths are enhanced,reach a maximum of about 450 and 510 MPa at the fifth cycle of ARB,respectively and then are reduced.The electrical conductivity decreased slightly by increasing the number of ARB cycles at initial ARB cycles,but the decrease was intensified at the final ARB cycles.In conclusion,the merit of ARB to fabricate this type of multi-layered nanocomposites and the accuracy of the developed model to predict tensile strength were realized.展开更多
In this study, a poly（ether block amide） （Pebax 1657） composite membrane applied for COa capture was prepared by coating Pebax 1657 solution on polyacrylonitrile （PAN） ultrafiltration membrane. Ethanol/water mix...In this study, a poly（ether block amide） （Pebax 1657） composite membrane applied for COa capture was prepared by coating Pebax 1657 solution on polyacrylonitrile （PAN） ultrafiltration membrane. Ethanol/water mixture was used as the solvent of Pebax and the effects of ethanol/water mass ratios and Pebax concentration on the permeation properties of composite membrane were studied. To enhance the com- posite membrane permeance, the gutter layer, made from reactive amino silicone crosslinking with potydimethylsiloxane （PDMS）, was de- signed. The influence of crosslinldng degree of the gutter layer on membrane performance was investigated. As a result, a Pebardamino- PDMS/PAN multilayer membrane with hexane resistance was developed, showing CO2 permeance of 350 GPU and CO2/N2 selectivity over 50. The blend of polyethylene glycol dimethyl ether （PEG-DME） with Pebax as coating material was studied to further improve the membrane performance. After being combined with PEG-DME additive, CO2 permeance of the final Pebax-PEG-DME/amino-PDMS/PAN composite membrane reached 400 GPU above with CO2/Na selectivity over 65.展开更多
Graphene oxide（GO） membranes play an important role in various nanofiltration applications including desalination, water purification, gas separation, and pervaporation. However, it is still very challenging to achi...Graphene oxide（GO） membranes play an important role in various nanofiltration applications including desalination, water purification, gas separation, and pervaporation. However, it is still very challenging to achieve both high separation efficiency and good water permeance at the same time. Here, we synthesized two kinds of GO-based composite membranes i.e. reduced GO（rGO）@MoO2 and rGO@WO3 by in-situ growth of metal nanoparticles on the surface of GO sheets. They show a high separation efficiency of ～100% for various organic dyes such as rhodamine B, methylene blue and evans blue, along with a water permeance over 125 Lm（-2） h（-1） bar（-1）. The high water permeance and rejection efficiency open up the possibility for the real applications of our GO composite membranes in water purification and wastewater treatment. Furthermore, this composite strategy can be readily extended to the fabrication of other ultrathin molecular sieving membranes for a wide range of molecular separation applications.展开更多
Poly（bis（phenoxy）phosphazene） （SPBPP）/phosphotungstic acid （PWA）/silica composite membranes for fuel cells were prepared. The composite membranes were characterized by using FTIR, TGA and SEM techniquies. Inco...Poly（bis（phenoxy）phosphazene） （SPBPP）/phosphotungstic acid （PWA）/silica composite membranes for fuel cells were prepared. The composite membranes were characterized by using FTIR, TGA and SEM techniquies. Incorporation of PWA particles and silica particles into the SPBPP polymer matrix and a specific interaction between them were confirmed by FTIR spectra. TGA results showed that the composite membranes had high thermal stability. Homogeneous distribution of PWA and silica particles within the SPBPP matrix was verified by SEM micrographs. The doped membranes showed increased water uptake and proton conductivity.展开更多
Composite membranes have attracted increasing attentions owing to their potential applications for CO2 separation. In this work, ceramic supported polydimethylsiloxane （PDMS） and poly （ethylene glycol） diacrylate ...Composite membranes have attracted increasing attentions owing to their potential applications for CO2 separation. In this work, ceramic supported polydimethylsiloxane （PDMS） and poly （ethylene glycol） diacrylate （PEGDA） composite membranes were prepared. The microstructure and physicochemical properties of the compos- ite membranes were characterized. Preparation conditions were systematically optimized. The gas separation performance of the as-prepared membranes was studied by pure gas and binary gas permeation measurement of CO〉 N2 and H〉 Experiments showed that PDMS, as silicone rubber, exhibited larger permeance and lower separation factors. Conversely, PEGDA composite membrane presented smaller gas permeance but higher ideal selectivity for CO2/N2. Compared to the performance of those membranes using polymeric supports or freestanding membranes, the two kinds of ceramic supported composite membranes exhibited higher gas permeance and acceptable selectivity. Therefore, the ceramic supported composite membrane can be expected as a candidate for CO2 separation from light gases.展开更多
Fouling-resistant ceramic-supported polymer composite membranes were developed for removal of oil-in-water （O/W） mieroemulsions. The composite membranes were featured with an asymmetric three-layer structure, i.e., ...Fouling-resistant ceramic-supported polymer composite membranes were developed for removal of oil-in-water （O/W） mieroemulsions. The composite membranes were featured with an asymmetric three-layer structure, i.e., a porous ceramic membrane substrate, a polyvinylidene fluoride （PVDF） ultrafiltration sub-layer, and a polyamide/polyvinyl alcohol （PVA） composite thin top-layer. The PVDF polymer was east onto the tubular porous ceramic membranes with an immersion precipitation method, and the polyamide/PVA composite thin top-layer was fabricated with an inteffaeial polymerization method. The effects of the sub-layer composition and the recipe in the inteffaeial polymerization for fabricating the top-layer on the structure and performance of composite membranes were systematically investigated. The prepared composite membranes showed a good performance for treating the O/W microemulsions with a mean diameter of about 2.41μm. At the operating pressure of 0.4MPa, the hydraulic permeability remained steadily about 190L·m^-2·h^-1, the oil concentration in the permeate was less than 1.6mg·L^-1, and the oil rejection coefficient was always higher than 98.5% throughout the operation from the beginning.展开更多
Composite polyurethane(PU)-SiO_2 hollow fiber membranes were successfully prepared via optimizing thetechnique of dry-jet wet spinning,and their pressure-responsibilities were confirmed by the relationships of pure wa...Composite polyurethane(PU)-SiO_2 hollow fiber membranes were successfully prepared via optimizing thetechnique of dry-jet wet spinning,and their pressure-responsibilities were confirmed by the relationships of pure water flux-transmembrane pressure(PWF-TP)for the first time.The origin for this phenomenon was analyzed on the basis of membranestructure and material characteristics.The effects of SiO_2 content on the structure and properties of membrane wereinvestigated.The experimental results indicated that SiO_2 in membrane created a great many interfacial micro-voids andplayed an important role in pressure-responsibility,PWF and rejection of membrane:with the increase of SiO_2 content,theability of membrane recovery weakened,PWF increased,and rejection decreased slightly.展开更多
基金supported by the Research Council of Norway through the CLIMIT program(MCIL-CO_2 project,215732)the European Union Seventh Framework Programme(FP7/2007-2013)in HiPerCap project under grant agreement n°608555
文摘The development of multilayer composite membranes for CO_2 separation has gained increasing attention due to the desire for energy efficient technologies. Multilayer composite membranes have many advantages, including the possibility to optimize membrane materials independently by layers according to their different functions and to reduce the overall transport resistance by using ultrathin selective layers, and less limitations on the material mechanical properties and processability. A comprehensive review is required to capture details of the progresses that have already been achieved in developing multilayer composite membranes with improved CO_2 separation performance in the past 15-20 years.In this review, various composite membrane preparation methods were compared, advances in composite membranes for CO_2/CH_4 separation,CO_2/N_2 and CO_2/H_2 separation were summarized with detailed data, and challenges facing for the CO_2 separation using composite membranes,such as aging, plasticization and long-term stability, were discussed. Finally the perspectives and future research directions for composite membranes were presented.
基金Project(2023YFC3707800)supported by the National Key Research and Development Program of China。
文摘In practical engineering construction,multi-layered barriers containing geomembranes are extensively applied to retard the migration of pollutants.However,the associated analytical theory on pollutants diffusion still needs to be further improved.In this work,general analytical solutions are derived for one-dimensional diffusion of degradable organic contaminant(DOC)in the multi-layered media containing geomembranes under a time-varying concentration boundary condition,where the variable substitution and separated variable approaches are employed.These analytical solutions with clear expressions can be used not only to study the diffusion behaviors of DOC in bottom and vertical composite barrier systems,but also to verify other complex numerical models.The proposed general analytical solutions are then fully validated via three comparative analyses,including comparisons with the experimental measurements,an existing analytical solution,and a finite-difference solution.Ultimately,the influences of different factors on the composite cutoff wall’s(CCW,which consists of two soil-bentonite layers and a geomembrane)service performance are investigated through a composite vertical barrier system as the application example.The findings obtained from this investigation can provide scientific guidance for the barrier performance evaluation and the engineering design of CCWs.This application example also exhibits the necessity and effectiveness of the developed analytical solutions.
基金supported by Fundamental Research Funds for the Central Universities(No.lzujbky-2024-05)Innovation Foundation of Provincial Education Department of Gansu(2024B-005)+2 种基金Scientific Department of Gansu(24CXGA083,24CXGA024,JK2024-28,JK2024-32 and 23CXJA0007)Industrial Support Plan Project of Provincial Education Department of Gansu(2025CYZC-003 and CYZC-2024-10)the Hunan Natural Science Foundation Science and Education Joint Fund Project(2022JJ60109).
文摘Transportation structures such as composite pavements and railway foundations typically consist of multi-layered media designed to withstand high bearing capacity.A theoretical understanding of load transfer mechanisms in these multi-layer composites is essential,as it offers intuitive insights into parametric influences and facilitates enhanced structural performance.This paper employs an improved transfer matrix method to address the limitations of existing theoretical approaches for analyzing multi-layer composite structures.By establishing a twodimensional composite pavement model,it investigates load transfer characteristics and validates the accuracy through finite element simulation.The proposed method offers a straightforward analytical approach for examining internal interactions between structural layers.Case studies indicate that the concrete surface layer is the main load-bearing layer for most vertical normal and shear stresses.The soil base layer reduces the overall mechanical response of the substructure,while horizontal actions increase the risk of interfacial slip and cracking.Structural optimization analysis demonstrates that increasing the thickness of the concrete surface layer,enhancing the thickness and stiffness of the soil base layer,or incorporating gradient layers can significantly mitigate these risks of interfacial slip and cracking.The findings of this study can guide the optimization design,parameter analysis,and damage prevention of multi-layer composite structures.
基金financial support of the Scientific Research Funds of Huaqiao University(605-50Y17073),Xiamen,China.
文摘The composite membrane of microcrystalline cellulose(MCC)with polyvinyl alcohol(PVA)was effectively synthesized using ionic liquids(ILs)as the solvent and dimethyl sulfone(DMSO)as the co-solvent through the phase conversion method.The effects of IL structure and the IL/DMSO mass ratio on the solubility of MCC were investigated.The findings indicated that the composite solvent functioned as a non-derivative solvent for MCC dissolution.The inclusion of DMSO decreased the viscosity of ILs and enhanced the rate of MCC dissolution.The solubility of MCC reached 14.5%(mass)when the mass ratio of[Bmim]Cl to DMSO was 1:1.The fabricated MCC membrane exhibited a smooth surface and a dense structure.PVA@MCC demonstrated exceptional mechanical properties and a uniform structure at a mass ratio of 2:1,with an elongation at break of 76%and a tensile strength of 14.6 MPa.The effects of antibacterial agents on the morphology,transmittance,mechanical properties,and antibacterial efficiency of PVA@MCC were investigated.The findings revealed that PVA@MCC fortified with clove oil showcased a flat and smooth surface,devoid of stratification or aggregation,and demonstrated superior mechanical properties compared to its counterparts with chitosan and ZnO additions.The elongation at break of PVA@MCC with clove oil increased to 137.6%,while its tensile strength decreased to 10.4 MPa.PVA@MCC with clove oil exhibited an antibacterial efficiency exceeding 68%against Escherichia coli,Staphylococcus aureus,and Pseudomonas aeruginosa,thereby extending the shelf life of cherry tomatoes by an additional four days at ambient temperature.
基金supported by the National Natural Science Foundation of China(No.52173095)the MOE Key Laboratory of Macromolecular Synthesis and Functionalization,Zhejiang University(No.2023MSF05)。
文摘The recovery of ionic liquids(ILs)has attracted growing attention as an indispensable process in“green”industrial applications.Forward osmosis(FO)has proven to be a sustainable method for concentrating the very dilute aqueous solutions of ILs at ambient temperature,in which semi-permeable membranes play a vital role in determining the recovery efficiency.Herein,we use interfacial polymerization method to prepare thin-film composite membranes consisting of polyamide skin layer and electrospun nanofibrous substrate with tunable water permeability and IL selectivity for osmotic enrichment of imidazolium ILs from their dilute aqueous solutions through FO process.The resulting FO membrane shows a compact polyamide layer with a thickness of 30-200 nm,guranteeing a high selectivity to ILs and water.Meanwhile,the nanofibrous substrate with large and interconnect pores as well as low tortuosity,providing mechanical and permeable support for the composite membranes.IL structure influences the osmotic pressure difference as well as the interactions with polyamide layer of the membrane and thus determines the whole concentration process.First,the alkyl chain growth augments the osmosis pressure difference between the ILs solution and draw solution,resulting in an enhancement in driving force of water osmosis and IL enrichment.Moreover,alkyl length aggravates external concentration polarization caused by the enhanced adsorption of ILs onto the skin layer via electrostatic and alkyl-πinteractions.Meanwhile,such adsorbed ILs further enhance the IL retention but decrease the reverse salt diffusion.Therefore,imidazolium ILs with varied alkyl lengths are ultimately enriched with a 100-fold increase in concentration from their dilute aqueous solutions with high IL/NaCl rejection and low IL loss.Remarkably,the final concentration of IL with longest alkyl length reaches the highest(6.4 mol·L^(-1)).This work provides the insights in respect to material preparation and process amelioration for IL recovery with high scalability at mild conditions.
基金supported by grants from the National Natural Science Foundation of China(Nos.52072136,52172229,52272201,52302303,51972257)Yanchang Petroleum-WHUT Joint Program(No.yc-whlg-2022ky-05)Fundamental Research Funds for the Central Universities(Nos.104972024RSCrc0006,2023IVA106)for financial support。
文摘Sulfide solid electrolytes with an ultrahigh ionic conductivity are considered to be extremely promising alternatives to liquid electrolytes for next-generation lithium batteries.However,it is difficult to obtain a thin solid electrolyte layer with good mechanical properties due to the weak binding ability between their powder particles,which seriously limits the actual energy density of sulfide all-solid-state lithium batteries(ASSLBs).Fortunately,the preparation of sulfide-polymer composite solid electrolyte(SPCSE)membranes by introducing polymer effectively reduces the thickness of solid electrolytes and guarantees high mechanical properties.In this review,recent progress of SPCSE membranes for ASSLBs is summarized.The classification of components in SPCSE membranes is first introduced briefly.Then,the preparation methods of SPCSE membranes are categorized according to process characteristics,in which the challenges of different methods and their corresponding solutions are carefully reviewed.The energy densities of the full battery composed of SPCSE membranes are further given whenever available to help understanding the device-level performance.Finally,we discuss the potential challenges and research opportunities for SPCSE membranes to guide the future development of high-performance sulfide ASSLBs.
基金Supported by the National Basic Research Program of China（2009CB623406） the National Natural Science Foundation of China（20990222）+1 种基金 the Natural Science Foundation of Jiangsu Province（SBK200930313） the“Six Kinds of Important Talents”Program of Jiangsu Province（2007007）
文摘Pervaporation has attracted considerable interest owing to its potential application in recovering biobutanol from biomass acetone-butanol-ethanol (ABE) fermentation broth. In this study, butanol was recovered from its aqueous solution using a polydimethylsiloxane (PDMS)/ceramic composite pervaporation membrane. The effects of operating temperature, feed concentration, feed flow rate and operating time on the membrane pervaporation performance were investigated. It was found that with the increase of temperature or butanol concentration in the feed, the total flux through the membrane increased while the separation factor decreased slightly. As the feed flow rate increased, the total flux increased gradually while the separation factor changed little. At 40°C and 1% (by mass) butanol in the feed, the total flux and separation factor of the membrane reached 457.4 g·m?2·h?1 and 26.1, respectively. The membrane with high flux is suitable for recovering butanol from ABE fermentation broth.
文摘The preparation of composite charge-mosaic membrane included spinning of hollow fiber as the supporting membrane, preparing a selective layer on the inside surface of the fiber by interfacial polymerization. The charge-mosaic membranes show a high salt permeability while retaining sucrose. The charge-mosaic membrane can be effectively used to separate multivalent salts with organic matter of molecular weight great than 300 g/mol in industry.
基金financial supports from the Ministry of Science and Technology of China(No.2012AA030303)the Hundred Talents Program of Chinese Academy of Sciences(No.CAS2012)the Fund for Creative Research Groups(No.51221264)
文摘In order to improve mechanical properties of soft poly(vinyl chloride)(PVC) films,we used commercial multi-layer graphene(MLG) with large size and high structural integrity as reinforcing fillers,and prepared MLG/PVC composite films by using conventional melt-mixing methods.Microstructures,static and dynamic mechanical properties of the MLG/PVC composite films were investigated.The results showed that a small amount of MLG loading could greatly increase the mechanical properties of the MLG/PVC composites.The tensile modulus of the 0.96 wt%MLG/PVC composites was up to 40 MPa,increasing by31.3%in comparison to the neat PVC.Such a significant mechanical reinforcement was mainly attributed to uniform dispersion of the large-size MLG,good compatibility and strong interactions among MLG and plasticizers and PVC.
基金Supported by the State Key Development Program for Basic Research of China （2009CB623404） the National Natural Science Foundation of China （20736003 20906056） the National High Technology Research and Development Program of China （2007AA06Z317 2008EG111021）
文摘Traditional solvent recovery in the extraction step of edible oil processing is distillation,which consumes large amounts of energy.If the distillation is replaced by membrane process,the energy consumption can be reduced greatly.In this work,two kinds of membrane,PDMS(polydimethylsiloxane) composite membrane and Zeolite filled PDMS membrane were prepared,in which asymmetric microporous PVDF(polyvinylidenefluoride) membrane prepared with phase inversion method was functioned as the microporous supporting layer in the flat-plate composite membrane.The different function compositions of the PDMS/PVDF composite membranes were characterized by reflection Fourier transform infrared(FTIR) spectroscopy.The surface and section of PDMS/PVDF composite membranes were investigated by scanning electron microscope(SEM).The PDMS NF(nanofiltration) membranes were then applied in the recovery of hexane from soybean oil/hexane miscellas(1:3,mass ratio).The effects of pressure(0.5-1.5 MPa),cross-linking temperature and PDMS layer thickness on membrane performances were investigated.The results indicated that both two kinds of NF membranes were promising for solvent recovery,and zeolite filled in PDMS NF membrane could enhance the separation performance.
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 Higher Education and High-quality and World-class Universities (PY201618)the National Natural Science Foundation of China (Contract Grant Number 51373014)the National Natural Science Foundation of China (Contract Grant Number 51403012)
文摘The pyromellitic dianhydride（PMDA） crosslinked poly（vinyl alcohol）（PVA） was coated on top of the PAN ultrafiltration membrane to form a PVA/PAN composite PV membranes for wastewater desalination. The composite membranes have high application value in industrial wastewater treatment. By varying the membrane fabrication parameters including the weight percent（wt%） of the PMDA, the crosslink temperature and duration, membrane with the best desalination performance was obtained. The composite membrane with a 2-lm-thick PVA selective layer containing 20 wt% of PMDA and being crosslinked at 100 °C for 2 h showed the highest Na Cl rejection of 99.98% with a water flux of 32.26 L/（m^2 h）at 70 °C using the 35,000 ppm Na Cl aqueous solution as feed. FTIR spectroscopy, wide-angle X-ray diffraction, thermogravimetric analysis and scanning electron microscope have been used to characterize the structures and properties of both the crosslinked PVA dense films and PVA/PAN composite membranes. The effects of the concentrations of PMDA,the crosslinking time and temperature to the membrane water contact angle, swelling degree, salt rejection and water flux were systematically studied.
基金supported by the National Natural Science Foundation of China (No.51278483)the Institute of Chinese Academy of Sciences in cooperation projects (ZNGZ2011023)the Daqi Technology of Beijing Co.LTD (04F0261601)
文摘A novel inorganic-organic composite membrane,namely poly（vinylidene fluoride） PVDF-glass fiber（PGF） composite membrane,was prepared and reinforced by interfacial ultraviolet（UV）-grafting copolymerization to improve the interfacial bonding strength between the membrane layer and the glass fiber.The interfacial polymerization between inorganic-organic interfaces is a chemical cross-linking reaction that depends on the functionalized glass fiber with silane coupling（KH570） as the initiator and the polymer solution with acrylamide monomer（AM） as the grafting block.The Fourier transform infrared spectrometer-attenuated total reflectance（FTIR-ATR） spectra and the energy dispersive X-ray（EDX） pictures of the interface between the glass fiber and polymer matrix confirmed that the AM was grafted to the surface of the glass fiber fabric and that the grafting polymer was successfully embedded in the membrane matrix.The formation mechanisms,permeation,and anti-fouling performance of the PGF composite membrane were measured with different amounts of AM in the doping solutions.The results showed that the grafting composite membrane improved the interfacial bonding strength and permeability,and the peeling strength was improved by 32.6% for PGF composite membranes with an AM concentration at 2 wt.%.
文摘This work aims to evaluate the feasibility of the fabrication of nanostructured Cu/Al/Ag multi-layered composites by accumulative roll bonding(ARB),and to analyze the tensile properties and electrical conductivity of the produced composites.A theoretical model using strengthening mechanisms and some structural parameters extracted from X-ray diffraction is also developed to predict the tensile strength of the composites.It was found that by progression of ARB,the experimental and calculated tensile strengths are enhanced,reach a maximum of about 450 and 510 MPa at the fifth cycle of ARB,respectively and then are reduced.The electrical conductivity decreased slightly by increasing the number of ARB cycles at initial ARB cycles,but the decrease was intensified at the final ARB cycles.In conclusion,the merit of ARB to fabricate this type of multi-layered nanocomposites and the accuracy of the developed model to predict tensile strength were realized.
文摘In this study, a poly（ether block amide） （Pebax 1657） composite membrane applied for COa capture was prepared by coating Pebax 1657 solution on polyacrylonitrile （PAN） ultrafiltration membrane. Ethanol/water mixture was used as the solvent of Pebax and the effects of ethanol/water mass ratios and Pebax concentration on the permeation properties of composite membrane were studied. To enhance the com- posite membrane permeance, the gutter layer, made from reactive amino silicone crosslinking with potydimethylsiloxane （PDMS）, was de- signed. The influence of crosslinldng degree of the gutter layer on membrane performance was investigated. As a result, a Pebardamino- PDMS/PAN multilayer membrane with hexane resistance was developed, showing CO2 permeance of 350 GPU and CO2/N2 selectivity over 50. The blend of polyethylene glycol dimethyl ether （PEG-DME） with Pebax as coating material was studied to further improve the membrane performance. After being combined with PEG-DME additive, CO2 permeance of the final Pebax-PEG-DME/amino-PDMS/PAN composite membrane reached 400 GPU above with CO2/Na selectivity over 65.
基金supported by the Ministry of Science and Technology of China (No. 2016YFA0200101)the National Natural Science Foundation of China (Nos. 51325205, 51290273, and 51521091)+1 种基金the Chinese Academy of Sciences (KGZD-EW-303-1, and KGZDEW-T06)the support of CAS-TWAS President Fellowship
文摘Graphene oxide（GO） membranes play an important role in various nanofiltration applications including desalination, water purification, gas separation, and pervaporation. However, it is still very challenging to achieve both high separation efficiency and good water permeance at the same time. Here, we synthesized two kinds of GO-based composite membranes i.e. reduced GO（rGO）@MoO2 and rGO@WO3 by in-situ growth of metal nanoparticles on the surface of GO sheets. They show a high separation efficiency of ～100% for various organic dyes such as rhodamine B, methylene blue and evans blue, along with a water permeance over 125 Lm（-2） h（-1） bar（-1）. The high water permeance and rejection efficiency open up the possibility for the real applications of our GO composite membranes in water purification and wastewater treatment. Furthermore, this composite strategy can be readily extended to the fabrication of other ultrathin molecular sieving membranes for a wide range of molecular separation applications.
文摘Poly（bis（phenoxy）phosphazene） （SPBPP）/phosphotungstic acid （PWA）/silica composite membranes for fuel cells were prepared. The composite membranes were characterized by using FTIR, TGA and SEM techniquies. Incorporation of PWA particles and silica particles into the SPBPP polymer matrix and a specific interaction between them were confirmed by FTIR spectra. TGA results showed that the composite membranes had high thermal stability. Homogeneous distribution of PWA and silica particles within the SPBPP matrix was verified by SEM micrographs. The doped membranes showed increased water uptake and proton conductivity.
基金Supported by the National Basic Research Program of China （2009CB623406）, the National Natural Science Foundation of China （20990222） and the Natural Science Foundation of Jiangsu Province （BK2009021, SBK200930313）.
文摘Composite membranes have attracted increasing attentions owing to their potential applications for CO2 separation. In this work, ceramic supported polydimethylsiloxane （PDMS） and poly （ethylene glycol） diacrylate （PEGDA） composite membranes were prepared. The microstructure and physicochemical properties of the compos- ite membranes were characterized. Preparation conditions were systematically optimized. The gas separation performance of the as-prepared membranes was studied by pure gas and binary gas permeation measurement of CO〉 N2 and H〉 Experiments showed that PDMS, as silicone rubber, exhibited larger permeance and lower separation factors. Conversely, PEGDA composite membrane presented smaller gas permeance but higher ideal selectivity for CO2/N2. Compared to the performance of those membranes using polymeric supports or freestanding membranes, the two kinds of ceramic supported composite membranes exhibited higher gas permeance and acceptable selectivity. Therefore, the ceramic supported composite membrane can be expected as a candidate for CO2 separation from light gases.
基金Supported by the Trans-century Training Programme Foundation for the Talents by the Ministry of Education of China (No.2002-48).
文摘Fouling-resistant ceramic-supported polymer composite membranes were developed for removal of oil-in-water （O/W） mieroemulsions. The composite membranes were featured with an asymmetric three-layer structure, i.e., a porous ceramic membrane substrate, a polyvinylidene fluoride （PVDF） ultrafiltration sub-layer, and a polyamide/polyvinyl alcohol （PVA） composite thin top-layer. The PVDF polymer was east onto the tubular porous ceramic membranes with an immersion precipitation method, and the polyamide/PVA composite thin top-layer was fabricated with an inteffaeial polymerization method. The effects of the sub-layer composition and the recipe in the inteffaeial polymerization for fabricating the top-layer on the structure and performance of composite membranes were systematically investigated. The prepared composite membranes showed a good performance for treating the O/W microemulsions with a mean diameter of about 2.41μm. At the operating pressure of 0.4MPa, the hydraulic permeability remained steadily about 190L·m^-2·h^-1, the oil concentration in the permeate was less than 1.6mg·L^-1, and the oil rejection coefficient was always higher than 98.5% throughout the operation from the beginning.
文摘Composite polyurethane(PU)-SiO_2 hollow fiber membranes were successfully prepared via optimizing thetechnique of dry-jet wet spinning,and their pressure-responsibilities were confirmed by the relationships of pure water flux-transmembrane pressure(PWF-TP)for the first time.The origin for this phenomenon was analyzed on the basis of membranestructure and material characteristics.The effects of SiO_2 content on the structure and properties of membrane wereinvestigated.The experimental results indicated that SiO_2 in membrane created a great many interfacial micro-voids andplayed an important role in pressure-responsibility,PWF and rejection of membrane:with the increase of SiO_2 content,theability of membrane recovery weakened,PWF increased,and rejection decreased slightly.
