开发从工业废气流中回收氢气的高效分离技术,对于满足日益增长的氢气需求起着重要作用。坎塔布里亚大学化学与生物分子工程系Inmaculada Ortiz教授在《分离纯化技术》(Separation and Purification Technology)期刊发表文章表明:通过将...开发从工业废气流中回收氢气的高效分离技术,对于满足日益增长的氢气需求起着重要作用。坎塔布里亚大学化学与生物分子工程系Inmaculada Ortiz教授在《分离纯化技术》(Separation and Purification Technology)期刊发表文章表明:通过将具有分子筛特性的无机填料(ZIF-8)掺入Matrimid聚合物基体中,合成了混合基质中空纤维膜。展开更多
In this work, the zeolite-Y was ion-exchanged by introducing silver cations into the framework of microsized nano-porous sodium zeolite-Y using a liquid-phase ion exchanged method. The Ag+ion-exchanged zeolite, was th...In this work, the zeolite-Y was ion-exchanged by introducing silver cations into the framework of microsized nano-porous sodium zeolite-Y using a liquid-phase ion exchanged method. The Ag+ion-exchanged zeolite, was then embedded into the Matrimid5218 matrix to form novel mixed matrix membranes(MMMs). The particles and MMMs were characterized by ultraviolet-visible diffuse reflectance spectroscopy(UV–vis DRS), N2adsorption–desorption isotherm, X-ray diffraction(XRD), Fourier transform infrared(FTIR) and scanning electron microscopy(SEM). Furthermore, the effects of filler content(0–20wt%) on pure and mixed gas experiments, feed pressure(2–20 bar) and operating temperature(35–75 oC)on CO2/CH4transport properties of Matrimid/Ag Y MMMs were considered. Characterization results confirmed an appropriate ion-exchange treatment of the zeolites. The SEM results confirmed the superior interfacial adhesion between polymer and zeolites, particularly in the case of Matrimid/Ag Y membranes.This is due to the proper silverous zeolite/Matrimid functional groups’ interactions. The gas permeation results showed that the CO2permeability increased about 123%, from 8.34 Barrer for pure Matrimid to18.62 Barrer for Matrimid/Ag Y(15 wt%). The CO2/CH4selectivity was improved about 66%, from 36.3 for Matrimid to 60.1 for Matrimid/Ag Y(15 wt%). The privileged gas separation performance of Matrimid/Ag Y(15 wt%) was the result of a combined effect of facilitated transport mechanism of Ag+ions as well as the intrinsic surface diffusion mechanism of Y-type zeolite. In order to survey the possibility of using the developed MMMs in industry, the CO2-induced plasticization effect and mixed gas experiment were accomplished. It was deduced that the fabricated MMMs could maintain the superior performance in actual operating conditions.展开更多
In order to develop high performance composite membranes for alcohol permselective pervaporation(PV),poly(dimethylsiloxane)/ZIF-8(PDMS/ZIF-8)coated polymeric hollow fiber membranes were studied in this research.First,...In order to develop high performance composite membranes for alcohol permselective pervaporation(PV),poly(dimethylsiloxane)/ZIF-8(PDMS/ZIF-8)coated polymeric hollow fiber membranes were studied in this research.First,PDMS was used for the active layer,and Torlon?,PVDF,Ultem?,and Matrimid?with different porosity were used as support layer for fabrication of hollow fiber composite membranes.The performance of the membranes varied with different hollow fiber substrates was investigated.Pure gas permeance of the hollow fiber was tested to investigate the pore size of all fibers.The effect of support layer on the mass transfer in hydrophobic PV composite membrane was investigated.The results show that proper porosity and pore diameter of the support are demanded to minimize the Knudsen effect.Based on the result,ZIF-8 was introduced to prepare more selective separation layer,in order to improve the PV performance.The PDMS/ZIF-8/Torlon?membrane had a separation factor of 8.9 and a total flux of 847 g·m-2·h-1.This hollow fiber PDMS/ZIF-8/Torlon?composite membrane has a great potential in the industrial application.展开更多
The application of aramid fiber(AF)/polyetheretherketone(PEEK)composites is currently hindered by the inert surface and poor wettability of AF,resulting in weak interfacial adhesion and poor mechani-cal properties.Sur...The application of aramid fiber(AF)/polyetheretherketone(PEEK)composites is currently hindered by the inert surface and poor wettability of AF,resulting in weak interfacial adhesion and poor mechani-cal properties.Surface coating and the introduction of nanostructures have been proven to be effective approaches to address this problem.Herein,a simple hybrid sizing agent has been developed to modify the AF surface,consisting of soluble polyimide(PI)as a compatibilizer,carboxyl-functionalized carbon nanotubes(CNT-COOH)as a rigid unit,and aramid nanofibers(ANF)as a flexible component.The syner-getic effects of PI and the multiscale flexible-rigid structure(CNT-COOH/ANF)contribute to the formation of chemical and physical bonds between AF and PEEK matrix,further improving the interfacial adhesion and stress transfer efficiency.Attributed to the enhanced wettability and roughness of AF,compared with unsized AF,the flexural strength(220.97 MPa),modulus(13.26 GPa),ILSS(13.36 MPa),and storage modu-lus(12.93 GPa)of the AF/PEEK composite increase by 132.60%,99.00%,18.97%,and 82.70%respectively.Additionally,the flexible-rigid nanonetwork facilitates the penetration of the PEEK resin into pore spaces.This simple and effective approach exhibits promising potential in enhancing the interfacial bonding of AF/PEEK composites.展开更多
One type of new light-responsive hierarchical metal organic framework(MOF) has been successfully prepared using Co(NO_(3))_(3)·6H_(2)O as the metal salt and 4,4’-azobenzenedicarboxylic acid as the ligand by micr...One type of new light-responsive hierarchical metal organic framework(MOF) has been successfully prepared using Co(NO_(3))_(3)·6H_(2)O as the metal salt and 4,4’-azobenzenedicarboxylic acid as the ligand by microwave method for the first time. It is found that MOF [Co(Az DC)] exhibits a light-responsive characteristic to SO_(2)adsorption due to the presence of azo group from the ligand. The light-responsive hierarchical MOFs are incorporated into Matrimid■ 5218(PI) matrix to prepare mixed matrix membranes(MMMs) for gas separation application. The morphology, crystallinity, chain mobility and thermal stability of MMMs are explored. Results show that Co(Az DC) may elevate both the CO_(2)(SO_(2)) permeability and CO_(2)(SO_(2))/N_(2)selectivity of the MMMs. In particular,the Co(Az DC) doped MMMs exhibit the significantly improved CO_(2)(SO_(2))/N_(2)selectivity from 33(123) for PI control membrane to 78(420) for MMMs, overcoming the 2008 Robeson upper bound for CO_(2)/N_(2)system. Sizesieving effect of Co(Az DC) with pore size 0.35 nm enhances the selectivity, while the –N=N– group from Co(Az DC) shows affinity to CO_(2)molecular rather than N_(2), also elevating selectivity of MMMs. In brief, enhanced selectivity of high-performance membrane is attributed to incorporation of Co(Az DC) particles, which displays synergistic effects both in size-sieving and CO_(2)-philic interaction for CO_(2)/N_(2)separation. Smart highly selective interface is constructed in MMMs by switching the configuration of MOFs from cis to trans. The SO_(2)permeability and SO_(2)/N_(2)selectivity of MMMs are investigated under both visible light and ultraviolet light states, and the SO_(2)/N_(2)separation performance under visible light is notably improved in comparison with that under ultraviolet light state.展开更多
文摘开发从工业废气流中回收氢气的高效分离技术,对于满足日益增长的氢气需求起着重要作用。坎塔布里亚大学化学与生物分子工程系Inmaculada Ortiz教授在《分离纯化技术》(Separation and Purification Technology)期刊发表文章表明:通过将具有分子筛特性的无机填料(ZIF-8)掺入Matrimid聚合物基体中,合成了混合基质中空纤维膜。
文摘In this work, the zeolite-Y was ion-exchanged by introducing silver cations into the framework of microsized nano-porous sodium zeolite-Y using a liquid-phase ion exchanged method. The Ag+ion-exchanged zeolite, was then embedded into the Matrimid5218 matrix to form novel mixed matrix membranes(MMMs). The particles and MMMs were characterized by ultraviolet-visible diffuse reflectance spectroscopy(UV–vis DRS), N2adsorption–desorption isotherm, X-ray diffraction(XRD), Fourier transform infrared(FTIR) and scanning electron microscopy(SEM). Furthermore, the effects of filler content(0–20wt%) on pure and mixed gas experiments, feed pressure(2–20 bar) and operating temperature(35–75 oC)on CO2/CH4transport properties of Matrimid/Ag Y MMMs were considered. Characterization results confirmed an appropriate ion-exchange treatment of the zeolites. The SEM results confirmed the superior interfacial adhesion between polymer and zeolites, particularly in the case of Matrimid/Ag Y membranes.This is due to the proper silverous zeolite/Matrimid functional groups’ interactions. The gas permeation results showed that the CO2permeability increased about 123%, from 8.34 Barrer for pure Matrimid to18.62 Barrer for Matrimid/Ag Y(15 wt%). The CO2/CH4selectivity was improved about 66%, from 36.3 for Matrimid to 60.1 for Matrimid/Ag Y(15 wt%). The privileged gas separation performance of Matrimid/Ag Y(15 wt%) was the result of a combined effect of facilitated transport mechanism of Ag+ions as well as the intrinsic surface diffusion mechanism of Y-type zeolite. In order to survey the possibility of using the developed MMMs in industry, the CO2-induced plasticization effect and mixed gas experiment were accomplished. It was deduced that the fabricated MMMs could maintain the superior performance in actual operating conditions.
基金Supported by the National Natural Science Foundation of China(21706003)the National High Technology Research and Development Program of China(2015AA03A602)+1 种基金the High-Caliber Talents Project of Beijing Municipal Institutions(CIT&TCD20170305)the China Scholarship Council(201406540011).
文摘In order to develop high performance composite membranes for alcohol permselective pervaporation(PV),poly(dimethylsiloxane)/ZIF-8(PDMS/ZIF-8)coated polymeric hollow fiber membranes were studied in this research.First,PDMS was used for the active layer,and Torlon?,PVDF,Ultem?,and Matrimid?with different porosity were used as support layer for fabrication of hollow fiber composite membranes.The performance of the membranes varied with different hollow fiber substrates was investigated.Pure gas permeance of the hollow fiber was tested to investigate the pore size of all fibers.The effect of support layer on the mass transfer in hydrophobic PV composite membrane was investigated.The results show that proper porosity and pore diameter of the support are demanded to minimize the Knudsen effect.Based on the result,ZIF-8 was introduced to prepare more selective separation layer,in order to improve the PV performance.The PDMS/ZIF-8/Torlon?membrane had a separation factor of 8.9 and a total flux of 847 g·m-2·h-1.This hollow fiber PDMS/ZIF-8/Torlon?composite membrane has a great potential in the industrial application.
文摘The application of aramid fiber(AF)/polyetheretherketone(PEEK)composites is currently hindered by the inert surface and poor wettability of AF,resulting in weak interfacial adhesion and poor mechani-cal properties.Surface coating and the introduction of nanostructures have been proven to be effective approaches to address this problem.Herein,a simple hybrid sizing agent has been developed to modify the AF surface,consisting of soluble polyimide(PI)as a compatibilizer,carboxyl-functionalized carbon nanotubes(CNT-COOH)as a rigid unit,and aramid nanofibers(ANF)as a flexible component.The syner-getic effects of PI and the multiscale flexible-rigid structure(CNT-COOH/ANF)contribute to the formation of chemical and physical bonds between AF and PEEK matrix,further improving the interfacial adhesion and stress transfer efficiency.Attributed to the enhanced wettability and roughness of AF,compared with unsized AF,the flexural strength(220.97 MPa),modulus(13.26 GPa),ILSS(13.36 MPa),and storage modu-lus(12.93 GPa)of the AF/PEEK composite increase by 132.60%,99.00%,18.97%,and 82.70%respectively.Additionally,the flexible-rigid nanonetwork facilitates the penetration of the PEEK resin into pore spaces.This simple and effective approach exhibits promising potential in enhancing the interfacial bonding of AF/PEEK composites.
基金financially supported by the National Natural Science Foundation of China(Nos.21706189,21978217,21676201)Science and Technology Plans of Tianjin(18JCQNJC06800,18PTSYJC00190,17PTSYJC00050)+2 种基金Tianjin Natural Science Foundation(No.18JCYBJC89400)Tianjin Municipal Education Commission Scientific Research Project(2017KJ074)University Students?innovation and entrepreneurship training program(202010058050,202110058127)。
文摘One type of new light-responsive hierarchical metal organic framework(MOF) has been successfully prepared using Co(NO_(3))_(3)·6H_(2)O as the metal salt and 4,4’-azobenzenedicarboxylic acid as the ligand by microwave method for the first time. It is found that MOF [Co(Az DC)] exhibits a light-responsive characteristic to SO_(2)adsorption due to the presence of azo group from the ligand. The light-responsive hierarchical MOFs are incorporated into Matrimid■ 5218(PI) matrix to prepare mixed matrix membranes(MMMs) for gas separation application. The morphology, crystallinity, chain mobility and thermal stability of MMMs are explored. Results show that Co(Az DC) may elevate both the CO_(2)(SO_(2)) permeability and CO_(2)(SO_(2))/N_(2)selectivity of the MMMs. In particular,the Co(Az DC) doped MMMs exhibit the significantly improved CO_(2)(SO_(2))/N_(2)selectivity from 33(123) for PI control membrane to 78(420) for MMMs, overcoming the 2008 Robeson upper bound for CO_(2)/N_(2)system. Sizesieving effect of Co(Az DC) with pore size 0.35 nm enhances the selectivity, while the –N=N– group from Co(Az DC) shows affinity to CO_(2)molecular rather than N_(2), also elevating selectivity of MMMs. In brief, enhanced selectivity of high-performance membrane is attributed to incorporation of Co(Az DC) particles, which displays synergistic effects both in size-sieving and CO_(2)-philic interaction for CO_(2)/N_(2)separation. Smart highly selective interface is constructed in MMMs by switching the configuration of MOFs from cis to trans. The SO_(2)permeability and SO_(2)/N_(2)selectivity of MMMs are investigated under both visible light and ultraviolet light states, and the SO_(2)/N_(2)separation performance under visible light is notably improved in comparison with that under ultraviolet light state.
