Composite hollow fiber membrane

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Thin Film Composite and/or Thin Film Nanocomposite Hollow Fiber Membrane for Water Treatment, Pervaporation and Gas/Vapor Separation

Thin Film Composite and/or Thin Film Nanocomposite Hollow Fiber Membrane for Water Treatment, Pervaporation and Gas/Vapor Separation

PRO can be viewed as an intermediate process between FO and RO, where hydraulic pressure is applied in the opposite direction of the osmotic pressure gradient (similar to RO). Loeb and Norman [36] proposed pressure-retarded osmosis (PRO) process. In a PRO process, water flows naturally from a low salinity stream (feed water) at an ambient pressure across a semi-permeable membrane to a pressurized high salinity stream (draw solution) driven by the osmotic pressure difference across the membrane. Chou et al. [37] first time reported the fabrication of thin-film composite hollow fiber membranes which could be used in PRO process. Composite hollow fiber membrane was prepared by depositing a thin layer of PA on PES hollow fiber via IP. The main reagents used were m-phenylenediamine (MPD), trimesoyl chloride (TMC) and cyclohexane. From the performance test, it was revealed that The TFC PRO hollow fiber membranes have a water permeability (A) of 9.22 × 10 −12 m/(s Pa), salt permeability (B) of 3.86 × 10 −8 m/s and structural
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Gas Permeation Modeling through a Multilayer Hollow Fiber Composite Membrane

Gas Permeation Modeling through a Multilayer Hollow Fiber Composite Membrane

A time-dependent 2D axisymmetric model was developed for a hollow fiber composite membrane which is composed of poly (styrene-b-butadiene- b-styrene), triblock copolymer (SBS) with a rubbery character that is coated on a polyacrylonitrile (PAN) porous support [27]. A bundle of the membrane fibers modulated in a dead end membrane holder. According to the experimental paper, in this study, in spite of the common multilayer membranes, SBS selective layer was coated on the external surface of the PAN support, and because of the porous PAN support is used only for mechanical stability, it has no important role in species transport, or in turn, in the mass transfer mechanism and the separation performance. As well as in a constant height for a fiber, its radius and consequently the membrane surface area increases. Therefore, the amounts of species transport across the membrane or the mass flow rate increase that has no considerable effects on the permeability and selectivity.
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Membrane distillation for textile wastewater treatment using polyvinylidene fluoride cloisite 15A hollow fiber composite membranes

Membrane distillation for textile wastewater treatment using polyvinylidene fluoride cloisite 15A hollow fiber composite membranes

To date, membrane distillation (MD) has been regarded as a potential candidate in treating textile effluents as this thermally-driven membrane process has unique advantages over pressure-driven membrane processes. However, the main challenge for the MD process to be practically used in textile industry is the difficulty of getting a membrane with desirable characteristics. In this work, polyvinylidene fluoride incorporated Cloisite 15A hollow fiber composite membranes were developed for textile wastewater treatment using direct contact membrane distillation (DCMD) system. The effects of polymer concentrations, types of additives and Cloisite 15A clay loadings on the membrane properties and its DCMD performance were investigated. Membrane made of 12 wt% PVDF was found to be the best performing membrane based on its overall separation performance in comparison to the membranes prepared with higher PVDF concentration. In terms of additive, ethylene glycol (EG) was found to be better pore former agent as compared to polyvinylpyrrolidone (PVP). The 12 wt% PVDF membrane with EG as additive was further modified by Cloisite 15A at different loadings. Results showed that the PVDF membrane incorporated with 3 wt% Cloisite 15A (PVDF-3% C15A) was the best composite membrane in terms of permeate flux (10.13 ± 0.18 kg m -2 h -1 ) and dye rejection (>99%). Its membrane contact angle, wetting pressure, mean pore size and surface roughness was reported to improve upon addition of 3 wt% Cloisite 15A. Besides, this membrane also exhibited the highest thermal stability, mechanical strength and overall porosity compared to other composite membranes. In view of this, PVDF-3% C15A membrane was selected for further studied using synthetic dyeing solutions containing dyes and salts. With respect to separation performance, higher rejections were able to achieve in all experimental tests, regardless of operating conditions, which indicate the potential of PVDF-3% C15A membrane in producing purified water from synthetic dyeing solutions. The membrane was further subjected to another experiment using real textile wastewater collected from a textile factory located in Kulai, Johor. The treated water was analyzed with respect to biological oxygen demand (BOD 5 ), chemical
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Fabrication and Modification of Thin-Film Composite Hollow Fiber NF Membranes

Fabrication and Modification of Thin-Film Composite Hollow Fiber NF Membranes

In order to analyze the surface topology of the polyamide coated membranes in detail, the membranes’ surface were scanned by the AFM. Figures 7-9 showed the AFM images as well as roughness analysis by taking a horizontal section in the image frame for samples. In the images, the brightest areas indicate the highest points of the membrane surface and the dark regions show valleys or pores. Figure 7 shows the surface AFM images of the PSF membranes prepared with various TETA concentration in the aqueous phase. It visually seems that the membranes roughness prepared with TETA is lower than that of the original PSF NF membrane. Also, decreasing roughness by increasing TETA concentration could be due to expansion of the IP reaction, possibly leading to the formation of the polyamide smoothly active layer. In this condition, decreasing the roughness might cause lower fouling. Table 3 demonstrates a decreasing trend in roughness with addition of additive. As can be seen in Figure 8, images recorded for composite membranes confirm that SiO 2 nanoparticles were successfully coated onto the
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Rational design and synthesis of molecular sieving, photocatalytic, hollow fiber membranes for advanced water treatment applications

Rational design and synthesis of molecular sieving, photocatalytic, hollow fiber membranes for advanced water treatment applications

In this study, the syntheses of the composite hollow fibers were optimized for physicochemical, mechanical and photocatalytic properties by changing the calcination temperatures (500 to 1000 °C for 8 h) followed by times (2 to 8 h at 600 °C). It was found that by increasing the calcination temperature from 500 to 900 °C that the hollow fibers show a decreasing trend in bending modulus and photocatalysis. This was respectively due to the effect of thermal decomposition of the polymer binder and thermally-induced transformation of anatase to rutile phases of the titania nanoparticles. By limiting the calcination temperature to 600 °C, it was demonstrated that the hollow fiber membranes displayed multi-functional properties. The titania nanoparticles within these hollow fibers retained a high proportion of the anatase phase whilst the polymer binder was partially decomposed and pyrolyzed to form an amorphous, microporous carbon, which not only enhanced the surface area and pore volume, but also overcoming the trade-off between the bending modulus (~34 MPa) and photocatalytic degradation (> 90%) of AO7. The membrane performance of optimized photocatalytic hollow fibers (600-3h and 600-6h) were found to fully reject AO7 whilst producing purified water in the permeate stream via molecular-sieving process. The 600-3h membrane achieved the highest water fluxes of 6.9 (H 2 O/dark), 12.9 (H 2 O/UV) 4.8
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Surface modified hollow fiber membrane contactor for carbon dioxide absorption and desorption

Surface modified hollow fiber membrane contactor for carbon dioxide absorption and desorption

et al. 2012a, 2012b, Khulbe at al. 2007, Bolong et al. 2009). For example, the hydrophobic SMM was used to improve the surface hydrophobicity of polyetherimide (PEI) flat sheet membranes for membrane distillation (Khayet et al. 2009). The hydrophobic SMM was used to change the hydrophobicity of polyethersulfone (PES) ultrafiltration flat sheet membranes for the separation of humic acid from water. Their results showed that the mean pore size of the surface modified membrane was lower than the unmodified membrane, which leads to higher fouling resistance (Zhang et al. 2003). The hydrophobic SMM was added into a PVDF casting solution and the effects of the solvent evaporation time and the SMM concentration in the casting dope were investigated. The surface modified membranes were also used in pervaporation experiments to separate water/chloroform mixtures (Khayet et al. 2002b). The authors also studied the blending of hydrophobic SMM into the casting solution to make a composite hydrophilic/hydrophobic membrane for the DCMD process. The composite membrane has a thin hydrophobic top layer which facilitates the transfer of vapor through the membrane, and a thick hydrophilic sublayer which reduces the heat loss across the membrane (Khayet et al. 2006). Bakeri et al. (2012b) fabricated surface modified PEI hollow fiber membranes where they used SMM as additive in the spinning dope. They evaluated the performance of the surface modified membranes in a contactor application for CO 2 absorption. Their results showed that
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Nanoparticles Retention Potential of Multichannel Hollow Fiber Drinking Water Production Membrane

Nanoparticles Retention Potential of Multichannel Hollow Fiber Drinking Water Production Membrane

This study aims to investigate the potential of nanoparticle retention of ultrafi ltration (UF) multichannel hollow fi ber membrane. Filtration experiments of fl uorescent silica nanoparticles (NPs) (10 and 100 nm) and CdTe quantum dots (1.5 nm) suspensions were carried out under diff erent operating conditions to analyze the retention rate (RT), the fouling zone and the membrane productivity. Fouling mechanism occurring during the experiment has been correlated with the distribution profi les of NPs obtained during the membrane autopsy after fi ltration by Confocal Laser Scanning Microscopy (CLSM). Results show that large NPs are totally retained on the membrane surface. Medium NPs pass through the membrane at the beginning of the fi ltration and are gradually stopped in the membrane skin before forming a deposit on the membrane surface. The retention rate of small NPs also increases over time and an in-depth fouling of the membrane (skin + support) has been identifi ed. Mass balance and determination of NPs surface deposit thickness, in the case of a fi ltration cake, determined by CLSM and scanning electron microscopy (SEM) allowed the estimation of NPs amount trapped in the membrane structure (skin or support) and have been compared to the fouling resistance observed during the fi ltration run. The CLSM analysis of the membrane on its section presents, in that study, a signifi cant interest because of the high accuracy of the measures: 538.16 nm compared to the 5000 nm reported in a previous study.
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Detailed modelling and optimal design of membrane separation systems

Detailed modelling and optimal design of membrane separation systems

hollow-fiber gas separation membranes. and Rao G.H. Approximate design equations for reverse osmosis desalination by spiral-wound modules. Membrane separation technologies: Current devel[r]

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Assessing sustainability performance of polymer processing: case study of hollow fiber membrane

Assessing sustainability performance of polymer processing: case study of hollow fiber membrane

Abstract. Sustainability nowadays has become new evolution of quality and efficiency indicator for product and process. Key performance of certain product or process need to be quantified throughout it is life cycle. Polymer processing is one of the chemical processes that need attention in term of sustainability. Hence this paper presents the development of sustainability framework for assessing the sustainability performance of hollow fiber membrane module by considering the reaction of each raw material and process involved. Assessment was carried out by applying fuzzy logic approach by developing its linguistic variables and fuzzy code according the requirement. A framework to assess the sustainability performance for hollow fiber membrane processing was proposed in order to identify its sustainability score for each sustainability element; environmental, economical and social.
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Determination of parameters for sustainability assessment of hollow fiber membrane module life cycle

Determination of parameters for sustainability assessment of hollow fiber membrane module life cycle

The system boundary consists of five sub-systems that represent every life cycle stages. The input and output flow crossing the system boundary will be used as parameters to develop sustainability indicators for hollow fiber membrane module. Figure 2 shows the steps for identifying the sustainability indicator. System boundary need to be selected either cradle to gate, cradle to grave, gate to grave or gate to gate approach. Then, the input and output flow need to be identified such as type of material, energy, chemical involve, cost, emission solid waste, chemical waste, and others. Next, parameters involve will be classified and grouped before assign it to the respective categories; environmental, economical, and social.
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Structure Change of Polyethersulfone Hollow Fiber Membrane Modified with Pluronic F127, Polyvinylpyrrolidone, and Tetronic 1307

Structure Change of Polyethersulfone Hollow Fiber Membrane Modified with Pluronic F127, Polyvinylpyrrolidone, and Tetronic 1307

Hydrophilic polyethersulfone (PES) hollow fiber membranes were prepared via non-solvent induced phase separation (NIPS) by addition of polymeric additives as a membrane modifying agent. The effect of the addition of hydrophilic surfactant Pluronic F127, Polyivinylpyrrolidone (PVP), and Tetronic 1307 on the performance of the final PES hol- low-fiber membrane was investigated. The morphology of fabricated hollow fiber membrane observed by scanning electron microscopy (SEM) indicated that all of membrane had a skin layer on the surface and finger like macrovoid structure inside the hollow fiber. The addition of 5 wt% polymeric surfactant on the polymer solution results in mem- brane with improved length and number of macrovoid structure. Sponge formation both near inner surface and near outer surface of hollow fiber membrane was another impact of addition of polymeric additives, which is led to de- crease of water permeability of these membrane. Water contact angle measurement was performed to investigate the hy- drophilicity property of resulted membrane. It is confirmed that the modified PES hollow fiber membranes had lower water contact angle than that of the original membrane, which indicate that the modified PES membrane with additives has high hydrophilic.
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Separation of Carboxylic Acids from Aqueous Solutions using Hollow Fiber Membrane Contactors

Separation of Carboxylic Acids from Aqueous Solutions using Hollow Fiber Membrane Contactors

The performance of three membrane modules PS, PES, and PVDF with the two extractants namely ethyl acetate and diisopropyl ether for the separation of three carboxylic acids (formic, acetic, and propionic acid) are summarized with the data in the above plots. Figure 3 explains the carboxylic acid concentration obtained in the solvent phase with time for the individual acids. The extraction phase concentration (mg/mL) was found to be higher for DIPE as a solvent for the formic acid with the PS membrane, and EA obtained the higher concentration for the acetic acid and the propionic acid with the PS and PES membranes. The constancy of the extract phase concentration with respect EA as the solvent indicates that the membrane resistant for the mass transfer nearly negligible and is mainly controlled by the affinity of the solvent which appears to be less compared to EA. Increased rate of the extractant concentration up to 6 minutes and slow down afterward concerning DIPE as a solvent also indicate that the membrane resistance is not the controlling step but the solvent affinity. Because of the higher affinity initially, the rate of the increase in concentration is high but progressively slows down due to reducing the driving force (concentration difference).
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Removal of Lead (II) from Battery Industry Wastewater by HFSLM - Volume 3 Number 2 (Apr. 2012) - IJCEA

Removal of Lead (II) from Battery Industry Wastewater by HFSLM - Volume 3 Number 2 (Apr. 2012) - IJCEA

The results indicated that the volumetric flow rate of feed and stripping solution at 100 mL/min obtained the highest percentage of extraction and stripping of lead ions about 99.40% and 97.15%, respectively. The percentage of extraction and stripping decreased with the increasing of the volumetric flow rate. The volumetric flow rate of feed solution plays an important role on the percentage of extraction and stripping of lead (II). Due to the low volumetric flow rate, the resident time of the relevant molecule in the reaction is higher than high volumetric flow rate. The high volumetric flow rate may remove the carrier from the support of liquid membrane and deteriorate the membrane system that can be seen from poor liquid membrane stability and lower percentages of extraction [37], [38].
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Study of shear rates in spinning process of 
		Kaolin/polyethersulfone (PESF) 
		membrane precursor: Effect on fiber morphology

Study of shear rates in spinning process of Kaolin/polyethersulfone (PESF) membrane precursor: Effect on fiber morphology

The influence of shear stress induced by spinneret geometry on morphology of Kaolin/PESf hollow fiber membranes has been studied. Different extrusion rates at two different rheology properties were introduced on a straight spinneret resulting in various shear rates. The hollow fiber membrane were spun using the wet spinning method to decouple the effect of shear and elongation stress due to gravity stretched drawing and bore fluid rate factors. The morphology of the spun hollow fiber was observed under Scanning Electron Microscope (SEM). Shear rates at the tip of the spinneret annulus were calculated and visualize using a computational fluid dynamics model. Simulation data shows that extrusion rate increment increases the shear rate at the spinneret wall while fluid velocity maximize at the centre of annulus. The maximum shear rate recorded was 431 s -1 at an extrusion pressure of 0.5 bar. It is observed that higher shear rates increases the density of the finger like voids and ultimately affect the hollow fiber performance in general.
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Hollow Fiber Microporous Membrane Liquid Liquid Extraction for Determination     of Polybrominated Diphenyl Ethers at       Trace Levels in Sewage Sludge with Gas Chromatography Electron Capture Detection

Hollow Fiber Microporous Membrane Liquid Liquid Extraction for Determination of Polybrominated Diphenyl Ethers at Trace Levels in Sewage Sludge with Gas Chromatography Electron Capture Detection

Depending on the analyte hydrophobicity, a two or three phase extraction system is applied. In two-phase LPME that is also called microporous membrane liq- uid-liquid extraction (MMLLE), the organic solvent filled in the lumen and the pores of the hollow fiber acts as acceptor phase and is used to extract hydrophobic analytes from an aqueous sample which is donor phase. The acceptor phase can then be analyzed with gas chro- matography or HPLC in the normal phase mode. The three phase system (aq/org/aq), or supported liquid membrane (SLM) extraction, involves extraction of polar compounds from an aqueous sample matrix, through an organic phase in the pores of the hollow fiber into a new aqueous phase inside the lumen of the hollow fiber. Analytical techniques such as reversed phase HPLC and capillary electrophoresis can be used for analysis of ex- tracts from three-phase LPME [16,17]. In the present study a two phase hollow fiber microextraction method is applied to extract PBDEs from sewage sludge samples and gas chromatography (GC) with electron capture de- tector was used as final analysis. The aim was to propose an inexpensive and simple method for environmental laboratories, where thousands of samples are analyzed annually.
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Supported Liquid Membrane in Metal Ion Separation: An Overview

Supported Liquid Membrane in Metal Ion Separation: An Overview

a schematic representation of different types of liquid membranes [4, 5]. BLM usually consists of a bulk aqueous feed and one receiving phase separated by a bulk organic water-immiscible liquid phase in a U-shaped tube. BLMs are usually used for studying a new carrier and evaluation of its transmission characteristics. Since the mass transfer surface of BLM is not considerable, it is unfavorable to be commercialized [4]. In the ELM, the receiving phase is emulsified in a liquid membrane. The emulsion is then dispersed in the feed solution and mass transfer from the feed to the emulsified receiving phase takes place. Liquid membranes can be either aqueous or organic, however, the majority of publications have considered them to be organic [5-7] . In SLM, the organic phase which plays the role of the liquid membrane fills the pores of a porous polymer support and stabilizes by means of capillary forces. In the next step, the polymer saturated with organic solution is located between the receiving and the feed phases and then, mass transfer between two phases occurs. Since the membrane phase is usually hydrophobic, an extraction agent is added as a carrier to make a complex at the interface of the membrane and feed phase. The carrier facilitates the mass transfer between the receiving and the feed phases. To adjust the membrane phase viscosity, another organic material is sometimes added to the membrane phase as a diluent. In some cases, a special material is added to the membrane as a phase modifier to prevent emulsion layer formation at the interfaces. So far, only a few review papers have been published in liquid membrane field. In 1999, Gyves et al. [8] published a review paper on SLM. They explained the concept of SLM and investigated the development of theoretical models validated by the experimental results. Furthermore, they gave a concise report of most research accomplished in the field of SLM for metal removal until 1999.
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Ionic liquid loaded hollow fiber membrane as a solid phase microextraction fiber; application in determination of aromatic
hydrocarbons in water samples

Ionic liquid loaded hollow fiber membrane as a solid phase microextraction fiber; application in determination of aromatic hydrocarbons in water samples

A laboratory-made SPME device was used in all experiments. Coating surface morphology was studied using a 1430VP Zeiss-Leo scanning electron microscope at university of mohaghegh ardabili (Ardabil, Iran). Thermal stability of the fiber was studied using thermogravimetric analyzer (Mettler Toledo, Columbus, OH, USA). RCT basic model heater-stirrer (IKA, Staufen, Germany) was used to make temperature adjustments and for sample agitation.

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Simulation of CO2 and H2S Removal Using Methanol in Hollow Fiber Membrane Gas Absorber (HFMGA)

Simulation of CO2 and H2S Removal Using Methanol in Hollow Fiber Membrane Gas Absorber (HFMGA)

phase mass transfer through diffusion without dispersing one phase within another. Such a device employs a po- rous membrane acts as a non-selective barrier between both phases where the gas and the absorbent solution flow on two sides of a membrane [5]. The membranes are usually microporous and can be both hydrophobic and hydrophilic. Hydrophobic microporous membranes like polypropylene (PP), polytetrafluoroethylene (PTFE) and polyvinylidene fluoride (PVDF) membranes have received increasing attention in recent years for using in membrane gas absorbers because of their good hydro- phobicity [7]. These membrane absorber systems, gene- rally in the form of hollow fibers with diameters of 0.5 mm - 1 mm in densely packed membrane modules, pro- vide a high interfacial area (500 m 2 /m 3 - 2000 m 2 /m 3 )
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STUDY ON THE MECHANICAL PROPERTIES OF GLASS FIBER REINFORCED HOLLOW GLASS MICROSPHERE EPOXY LAMINATED COMPOSITE

STUDY ON THE MECHANICAL PROPERTIES OF GLASS FIBER REINFORCED HOLLOW GLASS MICROSPHERE EPOXY LAMINATED COMPOSITE

continuously as the HGMs contents increases in epoxy matrix.The maximum load and stress to failure of the glass fiber-epoxy laminate is varied according to the contents of HGMs presents in epoxy matrix. Flexural Young’s modulus, stress to failure and strain to failure are listed in Table-2. It is important to note that the deflection at the midpoint of specimen in presence of HGMs contents is very less as compared to the pure glass fiber-epoxy laminates.

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Numerical simulation of heat and mass transfer in direct membrane distillation in a hollow fiber module with laminar flow

Numerical simulation of heat and mass transfer in direct membrane distillation in a hollow fiber module with laminar flow

To properly understand the complicated combination of mass and heat transfers in the MD process, the temperature distributions adjacent to the membrane surfaces along the module length should be fully described. Unfortunately, it is impossible to attain temperature information via the most widely used non-intrusive experimental approaches such as the flow visualization with dye, Particle Image Velocimetry (PIV) and Direct Observation through the Membrane (DOTM), etc. These observational techniques are not able to provide sufficient flow and thermal field information in the boundary layers [2]. To acquire heat transfer coefficients in the MD process, some researchers [3] have replaced the membranes with aluminum film and others [4-8] have conducted mathematical modeling using semi-empirical correlations and resistance-in-series model to predict the temperature distributions.
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