The recovery or capture of one or more components from gas mixture by membrane separation has become a research focus in recent years.This study investigates the gas-membrane solution equilibrium,for which Henry's...The recovery or capture of one or more components from gas mixture by membrane separation has become a research focus in recent years.This study investigates the gas-membrane solution equilibrium,for which Henry's law is not applicable if the gas phase is a mixture.This problem can be solved by using UNIQUAC model to calculate the activity coefficient of gas dissolved in the membrane.A method was proposed in this study to obtain the gas-membrane interaction parameter for UNIQUAC model.By the experiments of gas permeation through polydimethylsiloxane PDMS membrane,the solubility coefficients of some gases(N2,CO2,CH4) were measured.Through non-linear fitting UNIQUAC model to the experimental results from this study and in literature(H2,O2,C3H8),the gas-membrane interaction parameters for these gases were obtained.Based on these parameters,the activity coefficients of the dissolved gas were calculated by UNIQUAC model,and their values agree well with the experimental data.These results confirm the feasibility and effectiveness of the proposed method,which makes it possible to better predict gas-membrane solution equilibrium.展开更多
Ultra-fine silicalite-1 particles were modified with four kinds of chlorosilanes （dodecyltrichlorosilane, octyltrichlorosilane, hexadecyltrichlorosilane and octadecyltrichlorosilane） and characterized by FI-IR, TGA,...Ultra-fine silicalite-1 particles were modified with four kinds of chlorosilanes （dodecyltrichlorosilane, octyltrichlorosilane, hexadecyltrichlorosilane and octadecyltrichlorosilane） and characterized by FI-IR, TGA, contact angle measurements and BET analysis. It was found that the surface hydrophobicity of silicalite-1 particles was improved significantly as the alkyl group was strongly bonded to the particle surface. Modified silicalite-1 particles were incorporated into PDMS （poly（dimethylsiloxanediol）） membranes, which were applied for the pervaporation separation of ethanol/water mixtures. The effect of surface properties, zeolite loading and operation conditions on pervaporation performance of the membranes was investigated. The separation factor of PDMS membranes filled with modified silicalite-1 increased considerably compared with that filled with unmodified ones, and the total flux decreased with increasing zeolite loading. The solution and diffusion selectivity of hybrid membranes were also measured to explain the pervaporation properties of silicalite-1 filled PDMS membranes. It was found that modification of silicalite-1 with dodecyltrichlorosilane effectively improved the solution and diffusion selectivity of silicalite-1 filled PDMS membranes with high zeolite loading. This may be attributed to the high surface hydrophobicity of modified silicalite-1 and its good integration with PDMS membranes. Both the high separation factor and solution selectivity indicated that modification of silicalite-1 with chlorosilanes was an effective method to improve the selectivity of silicalite-1/PDMS hybrid membranes for ethanol.展开更多
In the experiment,PDMS membrane with NaY molecular sieve filling were chosen as the experimental objects and the flux of phenol and removal efficiency of phenol as evaluation index,the effect of the system operating t...In the experiment,PDMS membrane with NaY molecular sieve filling were chosen as the experimental objects and the flux of phenol and removal efficiency of phenol as evaluation index,the effect of the system operating temperature,the flow rate,liquid membrane downstream pressure,operation time,and filling proportion of NaY molecular sieve on pervaporation treatment efficiency for wastewater from coal gasification were investigated. With the increase of temperature and feed flow rate,pervaporation flux and phenol removal efficiency increases. The decrease of the membrane downstream pressure and elevating NaY molecular sieve filling proportion may result in the increase of flux and then phenol removal efficiency improves. When NaY molecular sieve filling proportion is 45% ,treatment efficiency is the best for coal gasification wastewater containing 1850 mg/L phenol as the flux of phenol was 12948. 23 mg/(h·m2) .展开更多
Worldwide environment has resulted in a limit on the sulfur content of gasoline.It is urgent to investigate the desulfurization of gasoline.The polydimethylsiloxane(PDMS)/polyetherimide(PEI)composite membranes were pr...Worldwide environment has resulted in a limit on the sulfur content of gasoline.It is urgent to investigate the desulfurization of gasoline.The polydimethylsiloxane(PDMS)/polyetherimide(PEI)composite membranes were prepared by casting a PDMS solution onto porous PEI substrates and characterized by scanning electron microscope(SEM).The membranes were used for sulfur removal from gasoline by pervaporation.The effects of feed temperature,sulfur content in the feed and PDMS layer thickness on membrane performance were investigated,and an activation energy of permeation was obtained.Experimental results indicated that higher feed temperature yielded higher total flux and lower sulfur enrichment factor.The total flux varied little with the increase of sulfur content in the feed,but the sulfur enrichment factor first increased with the amount of thiophene added into the gasoline,and then the variation was little.The increase of PDMS layer thickness resulted in a smaller flux but a larger sulfur enrichment factor.The result indicates that the PDMS/PEI composite membranes are promising for desulfurization by pervaporation.展开更多
The effects of different solvent/water coagula-tion mediums,different coagulation bath temperatures(CBT)and different coagulants on the performance,morphology and thermal stability of polysulfone mem-branes were inves...The effects of different solvent/water coagula-tion mediums,different coagulation bath temperatures(CBT)and different coagulants on the performance,morphology and thermal stability of polysulfone mem-branes were investigated.The CO_(2)/CH_(4),H_(2)/CH_(4) and H_(2)/N_(2) separation performance of the membranes were studied by gas permeation.Changing the N,N-dimethyl acetamide(DMAc)/water coagulation medium ratio from pure water to 90/10 vol%,resulted in a complete disappearance of the macrovoids throughout the polysulfone(PSf)polymeric matrix.The PSf membrane prepared in a CBT of 25℃ showed the best gas separation performance with ideal selectivities of 46.29,39.81 and 51.02 for H_(2)/CH_(4),CO_(2)/CH_(4) and H_(2)/N_(2) respectively,and permeances of 25 and 21.5 GPU for H_(2) and CO_(2) at 25℃ and 10 bar respectively.By increasing the amount of solvent in the gelation bath,the selectivities of H_(2)/CH_(4),CO_(2)/CH_(4) and H_(2)/N_(2) were dramatically reduced from 46.29,39.81 and 51.02 to 16.08,20.2 and 18.5 respectively at 25℃ and 10 bar.Reducing the CBT from 80℃ to 5℃ led to a complete elimination of macrovoids.Using methanol as a coagulant resulted in a less selective membrane compared with membranes from ethanol and water coagulants.The H_(2) and CO_(2) permeances were respectively about 3 and 9 times more than those for ethanol and water coagulants.Coated membranes were heated at different temperatures to investigate the suppression of undesirable CO_(2) plasticiza-tion.The membranes were stabilized against CO_(2) plasticization by a heat-treatment process.展开更多
Skin wounds are common in accidental injuries,and the intricacies of wound repair are closely linked to endogenous electric fields.Electrical stimulation plays a pivotal role in the restorative processes of skin injur...Skin wounds are common in accidental injuries,and the intricacies of wound repair are closely linked to endogenous electric fields.Electrical stimulation plays a pivotal role in the restorative processes of skin injuries,encompassing collagen deposition,angiogenesis,inflammation,and re-epithelialization.Employing electrical stimulation therapy replicates and enhances the effects of endogenous wound electric fields by applying an external electric field to the wound site,thereby promoting skin wound healing.In this study,we developed a self-powered repetitive mechanical impacts-electrical stimulation(RMI-ES)system utilizing a BaTiO_(3)/polydimethylsiloxane(PDMS)piezoelectric composite film.Compared to conventional electrical stimulation devices,the fabricated piezoelectric composite film efficiently harvests energy from the pressure applied by the stimulation device and the tensile force occurring during natural rat activities.The results demonstrated that piezoelectric stimulation generated by the composite membrane expedited the cell cycle,promoting fibroblast proliferation.Additionally,piezoelectric stimulation induced favorable changes in fibroblast gene expression,including increased expression of transforming growth factor-β1(TGF-β1),connective tissue growth factor(CTGF),collagen 1,collagen 3,vascular endothelial growth factor(VEGF),and alpha-smooth muscle actin(α-SMA),while reducing interleukin-6(IL-6)expression.Transcriptome analysis revealed that piezoelectric stimulation may induce fibroblast migration,proliferation,and collagen expression by influencing PI3K/AKT serine/threonine kinase(AKT)pathways.Further confirmation through the addition of the PI3K inhibitor LY294002 validated that piezoelectric stimulation can regulate the repair process after skin injury through the pathway.Importantly,in vivo results demonstrated that the electric field at the wound site effectively promoted wound healing,reduced inflammation,and stimulated collagen deposition and neovascularization.This study emphasizes the role of the piezoelectric membrane as an effective,safe,and battery-free electrical stimulator crucial for skin wound healing.展开更多
文摘The recovery or capture of one or more components from gas mixture by membrane separation has become a research focus in recent years.This study investigates the gas-membrane solution equilibrium,for which Henry's law is not applicable if the gas phase is a mixture.This problem can be solved by using UNIQUAC model to calculate the activity coefficient of gas dissolved in the membrane.A method was proposed in this study to obtain the gas-membrane interaction parameter for UNIQUAC model.By the experiments of gas permeation through polydimethylsiloxane PDMS membrane,the solubility coefficients of some gases(N2,CO2,CH4) were measured.Through non-linear fitting UNIQUAC model to the experimental results from this study and in literature(H2,O2,C3H8),the gas-membrane interaction parameters for these gases were obtained.Based on these parameters,the activity coefficients of the dissolved gas were calculated by UNIQUAC model,and their values agree well with the experimental data.These results confirm the feasibility and effectiveness of the proposed method,which makes it possible to better predict gas-membrane solution equilibrium.
基金supported by the Major State Basic Research Program of China(No.2009CB623404)National Natural Science Foundation of China(Nos.20736003,20676067)+2 种基金National High Technology Research and Development Program of China(Nos.2007AA06Z317,2008EG111021)Foundation of Ministry of Education of China (No.20070003130)Foundation of the State Key Laboratory of Chemical Engineering(SKL-ChE-08A01)
文摘Ultra-fine silicalite-1 particles were modified with four kinds of chlorosilanes （dodecyltrichlorosilane, octyltrichlorosilane, hexadecyltrichlorosilane and octadecyltrichlorosilane） and characterized by FI-IR, TGA, contact angle measurements and BET analysis. It was found that the surface hydrophobicity of silicalite-1 particles was improved significantly as the alkyl group was strongly bonded to the particle surface. Modified silicalite-1 particles were incorporated into PDMS （poly（dimethylsiloxanediol）） membranes, which were applied for the pervaporation separation of ethanol/water mixtures. The effect of surface properties, zeolite loading and operation conditions on pervaporation performance of the membranes was investigated. The separation factor of PDMS membranes filled with modified silicalite-1 increased considerably compared with that filled with unmodified ones, and the total flux decreased with increasing zeolite loading. The solution and diffusion selectivity of hybrid membranes were also measured to explain the pervaporation properties of silicalite-1 filled PDMS membranes. It was found that modification of silicalite-1 with dodecyltrichlorosilane effectively improved the solution and diffusion selectivity of silicalite-1 filled PDMS membranes with high zeolite loading. This may be attributed to the high surface hydrophobicity of modified silicalite-1 and its good integration with PDMS membranes. Both the high separation factor and solution selectivity indicated that modification of silicalite-1 with chlorosilanes was an effective method to improve the selectivity of silicalite-1/PDMS hybrid membranes for ethanol.
文摘In the experiment,PDMS membrane with NaY molecular sieve filling were chosen as the experimental objects and the flux of phenol and removal efficiency of phenol as evaluation index,the effect of the system operating temperature,the flow rate,liquid membrane downstream pressure,operation time,and filling proportion of NaY molecular sieve on pervaporation treatment efficiency for wastewater from coal gasification were investigated. With the increase of temperature and feed flow rate,pervaporation flux and phenol removal efficiency increases. The decrease of the membrane downstream pressure and elevating NaY molecular sieve filling proportion may result in the increase of flux and then phenol removal efficiency improves. When NaY molecular sieve filling proportion is 45% ,treatment efficiency is the best for coal gasification wastewater containing 1850 mg/L phenol as the flux of phenol was 12948. 23 mg/(h·m2) .
基金Supported by the National Basic Research Program of China(2009CB623404)the National Natural Science Foundation of China(50708109,20736003)the National High Technology Research and Development Program of China(2007AA06Z317)
文摘Worldwide environment has resulted in a limit on the sulfur content of gasoline.It is urgent to investigate the desulfurization of gasoline.The polydimethylsiloxane(PDMS)/polyetherimide(PEI)composite membranes were prepared by casting a PDMS solution onto porous PEI substrates and characterized by scanning electron microscope(SEM).The membranes were used for sulfur removal from gasoline by pervaporation.The effects of feed temperature,sulfur content in the feed and PDMS layer thickness on membrane performance were investigated,and an activation energy of permeation was obtained.Experimental results indicated that higher feed temperature yielded higher total flux and lower sulfur enrichment factor.The total flux varied little with the increase of sulfur content in the feed,but the sulfur enrichment factor first increased with the amount of thiophene added into the gasoline,and then the variation was little.The increase of PDMS layer thickness resulted in a smaller flux but a larger sulfur enrichment factor.The result indicates that the PDMS/PEI composite membranes are promising for desulfurization by pervaporation.
基金grateful for the support provided by the Ferdowsi University of Mashhad(Grant No.35462)we are also indebted to the National Iranian Oil Refining and Distribution Company for its financial support.
文摘The effects of different solvent/water coagula-tion mediums,different coagulation bath temperatures(CBT)and different coagulants on the performance,morphology and thermal stability of polysulfone mem-branes were investigated.The CO_(2)/CH_(4),H_(2)/CH_(4) and H_(2)/N_(2) separation performance of the membranes were studied by gas permeation.Changing the N,N-dimethyl acetamide(DMAc)/water coagulation medium ratio from pure water to 90/10 vol%,resulted in a complete disappearance of the macrovoids throughout the polysulfone(PSf)polymeric matrix.The PSf membrane prepared in a CBT of 25℃ showed the best gas separation performance with ideal selectivities of 46.29,39.81 and 51.02 for H_(2)/CH_(4),CO_(2)/CH_(4) and H_(2)/N_(2) respectively,and permeances of 25 and 21.5 GPU for H_(2) and CO_(2) at 25℃ and 10 bar respectively.By increasing the amount of solvent in the gelation bath,the selectivities of H_(2)/CH_(4),CO_(2)/CH_(4) and H_(2)/N_(2) were dramatically reduced from 46.29,39.81 and 51.02 to 16.08,20.2 and 18.5 respectively at 25℃ and 10 bar.Reducing the CBT from 80℃ to 5℃ led to a complete elimination of macrovoids.Using methanol as a coagulant resulted in a less selective membrane compared with membranes from ethanol and water coagulants.The H_(2) and CO_(2) permeances were respectively about 3 and 9 times more than those for ethanol and water coagulants.Coated membranes were heated at different temperatures to investigate the suppression of undesirable CO_(2) plasticiza-tion.The membranes were stabilized against CO_(2) plasticization by a heat-treatment process.
基金supported by the National Natural Science Foundation of China(Nos.31870967 to W.L.and 81701841 to W.B.W.)the National Key R&D Program of China(No.2018YFC1105800 to W.L.)。
文摘Skin wounds are common in accidental injuries,and the intricacies of wound repair are closely linked to endogenous electric fields.Electrical stimulation plays a pivotal role in the restorative processes of skin injuries,encompassing collagen deposition,angiogenesis,inflammation,and re-epithelialization.Employing electrical stimulation therapy replicates and enhances the effects of endogenous wound electric fields by applying an external electric field to the wound site,thereby promoting skin wound healing.In this study,we developed a self-powered repetitive mechanical impacts-electrical stimulation(RMI-ES)system utilizing a BaTiO_(3)/polydimethylsiloxane(PDMS)piezoelectric composite film.Compared to conventional electrical stimulation devices,the fabricated piezoelectric composite film efficiently harvests energy from the pressure applied by the stimulation device and the tensile force occurring during natural rat activities.The results demonstrated that piezoelectric stimulation generated by the composite membrane expedited the cell cycle,promoting fibroblast proliferation.Additionally,piezoelectric stimulation induced favorable changes in fibroblast gene expression,including increased expression of transforming growth factor-β1(TGF-β1),connective tissue growth factor(CTGF),collagen 1,collagen 3,vascular endothelial growth factor(VEGF),and alpha-smooth muscle actin(α-SMA),while reducing interleukin-6(IL-6)expression.Transcriptome analysis revealed that piezoelectric stimulation may induce fibroblast migration,proliferation,and collagen expression by influencing PI3K/AKT serine/threonine kinase(AKT)pathways.Further confirmation through the addition of the PI3K inhibitor LY294002 validated that piezoelectric stimulation can regulate the repair process after skin injury through the pathway.Importantly,in vivo results demonstrated that the electric field at the wound site effectively promoted wound healing,reduced inflammation,and stimulated collagen deposition and neovascularization.This study emphasizes the role of the piezoelectric membrane as an effective,safe,and battery-free electrical stimulator crucial for skin wound healing.
