The fabrication of a separation layer on the inner surface of a hollow fiber (HF) substrate to form an HF composite membrane offers exciting opportunities for industrial applications, although challenges remain. This ...The fabrication of a separation layer on the inner surface of a hollow fiber (HF) substrate to form an HF composite membrane offers exciting opportunities for industrial applications, although challenges remain. This work reports on the fabrication of a polydimethylsiloxane (PDMS) composite membrane on the inner surface of a single-channel or multi-channel ceramic HF via a proposed coating/crossflow approach. The nanostructures and transport properties of the PDMS HF composite membranes were optimized by controlling the polymer concentration and coating time. The morphology, surface chemistry, interfacial adhesion, and separation performance of the membranes were characterized by fieldemission scanning electron microscope (FE-SEM), attenuated total reflection Fourier-transform infrared (ATR-FTIR) spectroscopy, the nano-indentation/scratch technique, and pervaporation (PV) recovery of bio-butanol, respectively. The formation mechanism for the deposition of the PDMS layer onto the inner surface of the ceramic HF was studied in detail. The optimized inner surface of the PDMS/ceramic HF composite membranes with a thin and defect-free separation layer exhibited a high flux of ~1800 gm-2h-1 and an excellent separation factor of 35–38 for 1 wt% n-butanol/water mixtures at 60 C. The facile coating/cross-flow methodology proposed here shows great potential for fabricating inner-surface polymer-coated HFs that have broad applications including membranes, adsorbents, composite materials, and more.展开更多
Affordable hydrophobic hollow fibre membranes were prepared using kaolin and alumina based ceramic powders via a combined phase inversion and sintering technique,followed by a grafting with fluoroalkylsilane(FAS).The ...Affordable hydrophobic hollow fibre membranes were prepared using kaolin and alumina based ceramic powders via a combined phase inversion and sintering technique,followed by a grafting with fluoroalkylsilane(FAS).The crux of the matter in this paper is to study the changes in the properties of the hollow fibre membranes(gas permeation,mechanical strength,pore size,porosity,tortuosity,morphology,and contact angle)by the addition of alumina(Al2O3)to the pure kaolin with mono or multiparticle sizes.By varying the overall loading and particle size of alumina addition,different morphologies of the membranes were obtained due to the differences in the path lengths during phase inversion process for each solvent and nonsolvent exchange.The successful grafting with FAS was evidenced by the increase in contact angle from nearly equal to zero degree before grafting to 140°after grafting.Kaolin-alumina-4,one of the hollow fibres fabricated in this work,achieved a mean pore size of 0.25μm with the bending strength of 96.4 MPa and high nitrogen permeance of 2.3×10^(-5) mol·m^(-2)·Pa^(-1)·s^(-1),which makes the hollow fibre most suitable for the membrane contactor application.展开更多
With the rapid development of membrane technology in water treatment,there is a growing demand for membrane products with high performance.The inorganic hollow fiber membranes are of great interest due to their high r...With the rapid development of membrane technology in water treatment,there is a growing demand for membrane products with high performance.The inorganic hollow fiber membranes are of great interest due to their high resistance to abrasion,chemical/thermal degradation,and higher surface area/volume ratio therefore they can be utilized in the fields of water treatment.In this study,the alumina(Al_(2)O_(3))hollow fiber membranes were prepared by a combined phase-inversion and sintering method.The organic binder solution(dope)containing suspended Al_(2)O_(3) powders was spun to a hollow fiber precursor,which was then sintered at elevated tempera-tures in order to obtain the Al_(2)O_(3) hollow fiber membrane.The dope solution consisted of polyethersulfone(PES),N-methyl-2-pyrrolidone(NMP)and polyvinylpyrrolidone(PVP),which were used as polymer binder,solvent and additive,respectively.The prepared Al_(2)O_(3) hollow fiber membranes were characterized by a scanning electron microscope(SEM)and thermal gravimetric analysis(TG).The effects of the sintering temperature and Al_(2)O_(3)/PES ratios on the morphological structure,pure water flux,pore size and porosity of the membranes were also investigated extensively.The results showed that the pure water flux,maximum pore size and porosity of the prepared membranes decreased with the increase in Al_(2)O_(3)/PES ratios and sintering temperature.When the Al_(2)O_(3)/PES ratio reached 9,the pure water flux and maximum pore size were at 2547L/m 2$h and 1.4μm,respectively.Under 1600℃ of sintering temperature,the pure water flux and maximum pore size reached 2398L/(m^(2)@h)and 2.3μm,respectively.The results showed that the alumina hollow fiber membranes we prepared were suitable for the microfiltration process.The morphology investigation also revealed that the prepared Al_(2)O_(3) hollow fiber membrane retained its’asymmetric structure even after the sintering process.展开更多
文摘The fabrication of a separation layer on the inner surface of a hollow fiber (HF) substrate to form an HF composite membrane offers exciting opportunities for industrial applications, although challenges remain. This work reports on the fabrication of a polydimethylsiloxane (PDMS) composite membrane on the inner surface of a single-channel or multi-channel ceramic HF via a proposed coating/crossflow approach. The nanostructures and transport properties of the PDMS HF composite membranes were optimized by controlling the polymer concentration and coating time. The morphology, surface chemistry, interfacial adhesion, and separation performance of the membranes were characterized by fieldemission scanning electron microscope (FE-SEM), attenuated total reflection Fourier-transform infrared (ATR-FTIR) spectroscopy, the nano-indentation/scratch technique, and pervaporation (PV) recovery of bio-butanol, respectively. The formation mechanism for the deposition of the PDMS layer onto the inner surface of the ceramic HF was studied in detail. The optimized inner surface of the PDMS/ceramic HF composite membranes with a thin and defect-free separation layer exhibited a high flux of ~1800 gm-2h-1 and an excellent separation factor of 35–38 for 1 wt% n-butanol/water mixtures at 60 C. The facile coating/cross-flow methodology proposed here shows great potential for fabricating inner-surface polymer-coated HFs that have broad applications including membranes, adsorbents, composite materials, and more.
基金support from Universiti Teknologi Malaysia under Research University Grant Tier 1(Project No.Q.J130000.2546.12H25)Flagship UTMShine(Project No.Q.J130000.2446.03G29)Nippon Sheet Glass Foundation for Materials Science and Engineering under Overseas Research Grant Scheme(Project No.Q.J130000.2446.03G29)。
文摘Affordable hydrophobic hollow fibre membranes were prepared using kaolin and alumina based ceramic powders via a combined phase inversion and sintering technique,followed by a grafting with fluoroalkylsilane(FAS).The crux of the matter in this paper is to study the changes in the properties of the hollow fibre membranes(gas permeation,mechanical strength,pore size,porosity,tortuosity,morphology,and contact angle)by the addition of alumina(Al2O3)to the pure kaolin with mono or multiparticle sizes.By varying the overall loading and particle size of alumina addition,different morphologies of the membranes were obtained due to the differences in the path lengths during phase inversion process for each solvent and nonsolvent exchange.The successful grafting with FAS was evidenced by the increase in contact angle from nearly equal to zero degree before grafting to 140°after grafting.Kaolin-alumina-4,one of the hollow fibres fabricated in this work,achieved a mean pore size of 0.25μm with the bending strength of 96.4 MPa and high nitrogen permeance of 2.3×10^(-5) mol·m^(-2)·Pa^(-1)·s^(-1),which makes the hollow fibre most suitable for the membrane contactor application.
文摘With the rapid development of membrane technology in water treatment,there is a growing demand for membrane products with high performance.The inorganic hollow fiber membranes are of great interest due to their high resistance to abrasion,chemical/thermal degradation,and higher surface area/volume ratio therefore they can be utilized in the fields of water treatment.In this study,the alumina(Al_(2)O_(3))hollow fiber membranes were prepared by a combined phase-inversion and sintering method.The organic binder solution(dope)containing suspended Al_(2)O_(3) powders was spun to a hollow fiber precursor,which was then sintered at elevated tempera-tures in order to obtain the Al_(2)O_(3) hollow fiber membrane.The dope solution consisted of polyethersulfone(PES),N-methyl-2-pyrrolidone(NMP)and polyvinylpyrrolidone(PVP),which were used as polymer binder,solvent and additive,respectively.The prepared Al_(2)O_(3) hollow fiber membranes were characterized by a scanning electron microscope(SEM)and thermal gravimetric analysis(TG).The effects of the sintering temperature and Al_(2)O_(3)/PES ratios on the morphological structure,pure water flux,pore size and porosity of the membranes were also investigated extensively.The results showed that the pure water flux,maximum pore size and porosity of the prepared membranes decreased with the increase in Al_(2)O_(3)/PES ratios and sintering temperature.When the Al_(2)O_(3)/PES ratio reached 9,the pure water flux and maximum pore size were at 2547L/m 2$h and 1.4μm,respectively.Under 1600℃ of sintering temperature,the pure water flux and maximum pore size reached 2398L/(m^(2)@h)and 2.3μm,respectively.The results showed that the alumina hollow fiber membranes we prepared were suitable for the microfiltration process.The morphology investigation also revealed that the prepared Al_(2)O_(3) hollow fiber membrane retained its’asymmetric structure even after the sintering process.
