Polyvinylidene Fluoride Hollow Fiber Membranes Research Articles

Removal of Cadmium from Industrial Wastewater Using Water-Soluble Polymer via Hollow Fiber Membranes

The removal of toxic and polluting metal ions from industrial effluents, water supplies, as well as mine waters is an important challenge to avoid one of the major causes of water and soil pollution. To enable further processing and achieve recovery of metals, separation should be selective. One separation technique, which can meet this requirement, is polymer-enhanced ultra filtration (PEUF). Ultra filtration membranes would only retain macromolecular solutes. PEUF uses water-soluble polymeric agents to complex easily interesting metallic ions and give them a macromolecular size. Binding of metal ions to water soluble polymers enables us to separate them from solution and retain them when they are pumped through an ultra filtration membrane. In the present work Polyetherimide (PEI) is used as water soluble polymer for removal of cadmium ions from waste water via hollow fiber membrane contactor module. Polyvinylidene fluoride (PVDF) hollow fiber membrane contactor is used for this purpose. The PVDF fiber was custom made using thermal induced phase separation techniques. Experimental observations reveal that when PEI concentration increases the percentage removal of Cd (II) also increases. The molecular weight of PEI has positive impact on Cd (II) retention. The pH value of feed has effect on Cd (II) withholding. The percentage of removal increases with solution pH value. Recycling either retentate; the part of a solution that does not cross the membrane; or permeate have no effect on removal. Increase of mixing time before operation increases metal ions removal rate

Separation and concentration of milk proteins with a submerged membrane vibrational system

A transverse vibrating membrane filtration system was used for the separation and concentration of milk proteins at low operating temperatures using 0.04µm polyvinylidene fluoride (PVDF) hollow fibre membranes. Filtration was carried out using skim milk and milk protein concentrate solutions (MPC60, MPC66, MPC71) to simulate different stages of the concentration process. It was found that the submerged membrane system with the aid of membrane vibration can maintain very high transmission of whey proteins (α-Lactalbumin and β-Lactoglobulin) while fully rejecting casein micelles. Furthermore, low transmembrane pressure (TMP) rise was observed during long term filtration experiments conducted over a 24h period for high viscosity MPC60 and MPC66 solutions (12.93cP and 21.06cP at 10°C) at a constant permeate flux of 10L/m2 h and 5L/m2 h respectively. Interestingly, the TMP was observed to rise and then stabilise at approximately 18 kPa even when operated at a supra-critical flux of 17–19L/m2 h during MPC60 filtration, indicating that the application of membrane vibration can prevent further membrane fouling. In addition, a comparison of the transverse vibration system with a conventional cross-flow system showed that the vibrating system had significantly better system performance and separation efficiency.

Hybrid Solvent ([emim][Ac]+water) To Improve the CO2 Capture Efficiency in a PVDF Hollow Fiber Contactor

Postcombustion processes based on membrane contactors and ionic liquids have emerged in recent years as an alternative to traditional systems used to capture CO2. In this work, nondispersive absorption in a polyvinylidene fluoride (PVDF) hollow fiber membrane contactor was used as a CO2 capture system. The ionic liquid (IL) 1-ethyl-3-methylimidazolium acetate ([emim][Ac]) was chosen for the study due to its chemical reaction with CO2. Different amounts of distilled water were added to [emim][Ac] to address the issues associated with the viscosity of the ionic liquid. The presence of water may also facilitate the binding of CO2. The purpose of this combined sorbent containing water and an ionic liquid comprising a carboxylate moiety such as acetate, which provides reversible chemical interaction with CO2, was to achieve competitive efficiencies with traditional processes based on power stations and alkanolamines. The best combination of water–IL was found to be, 70% [emim][Ac]–30 vol % water. This mixture ...

Integrating a novel TS-af-HFM NF process for portable treatment of oilfield produced water

A novel two-stage anti-fouling hollow fiber membrane (TS-af-HFM) nanofiltration (NF) process was integrated with a super hydrophobic organic silica modified polyvinylidene fluoride (PVDF/Si-R) hollow fiber membrane and a super hydrophilic silica modified polyethersulfone (PES/SiO2) based TFC hollow fiber membrane for portable treatment of oilfield produced water. The performance of the TS-af-HFM NF system was investigated in terms of organics removal efficiency, permeate water flux and salt rejection. The result showed that the PVDF/Si-R membrane can dramatically remove dissolved organics from the produced water in the first stage, with the organics rejection efficiency up to 98.7%. Meanwhile, the PES/SiO2 TFC membrane showed encouraging desalination ability with a relatively low operating pressure in the second stage. The high-efficient removal of dissolved organics in the first stage effectively eliminated the organics fouling occurred during the desalination process in the second stage. The variation of feed rate (0.05–0.2ml/min) and operating pressure (0–30psi) in the first stage has no significant effect on the performances of the TS-af-HFM NF system. However, with the increase of operating pressure from 50psi to 80psi in the second stage, the permeate water flux and salt rejection efficiency linearly increased. The system showed attractive regeneration ability for oilfield produced water treatment application.

Study on the interfacial activation of dual surfactants in the process of forming porous membranes

In order to regulate the microstructure of separation membranes and further investigate the mechanism of membrane preparation. Polyvinylidene fluoride (PVDF) hollow fiber membranes were fabricated by NIPS using dual surfactants (Span80 and Tween80) as the additive. Exactly, the dual surfactants have the specific value of Hydrophilic-Lipophilic Balance (HLB). Here we evaluated the Hydrophilic-Lipophilic Balance offset value (ΔHLB) on the membrane relative properties such as the pure water flux, SEM etc. As results indicated, in the membrane preparation process of NIPS, the surfactant could activate the interface of polymer concentrated phase when the casting dope transits from the stable region to the unstable region. Also, when the value of HLB approached to 10, the interfacial activation of the dual surfactants was obvious, eventually leading to more pores on the skin layer. Meanwhile the membrane intrinsic resistance was the lowest. They are also featured by the most probable aperture moving toward the maximum pore size. Most importantly, compared to the separation membrane without the surfactant, the pure water flux increased by 277%, reaching up to 1015L/(hm2). This research introduces a new pore-making strategy of the surfactant interfacial activation on polymer concentrated phase, which involves a novel film-forming mechanism in NIPS.

Functional Properties of Punica granatum L. Juice Clarified by Hollow Fiber Membranes

There is currently much interest in pomegranate juice because of the high content of phenolic compounds. Moreover, the interest in the separation of bioactive compounds from natural sources has remarkably grown. In this work, for the first time, the Punica granatum L. (pomegranate) juice—clarified by using polyvinylidene fluoride (PVDF) and polysulfone (PSU) hollow fiber (HF) membranes prepared in the laboratory—was screened for its antioxidant properties by using different in vitro assays, namely 2,2-diphenyl-1-picrylhydrazyl (DPPH), 2,2'-azino-bis-(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS), Ferric Reducing Antioxidant Power (FRAP), and β-carotene bleaching tests, and for its potential inhibitory activity of the carbohydrate-hydrolysing enzymes, α-amylase and α-glucosidase. The effects of clarification on quality characteristics of the juice were also investigated in terms of total phenols, flavonoids, anthocyanins, and ascorbic acid. Experimental results indicated that PVDF membranes presented a lower retention towards healthy phytochemicals in comparison to PSU membranes. Accordingly, the juice clarified with PVDF membranes showed the best antioxidant activity. Moreover, the treatment with PVDF membranes produced a clarified juice with 2.9-times fold higher α-amylase inhibitory activity in comparison to PSU (IC50 value of 75.86 vs. 221.31 μg/mL, respectively). The same trend was observed using an α-glucosidase inhibition test. These results highlight the great potential of the clarified juice as a source of functional constituents.

Effect of Ethylene Glycol on Polymeric Membrane Fabrication for Membrane Distillation

Membrane distillation (MD) is a membrane separation process first introduced in 1963 by Bodell whereby the major driving force is by vapor pressure difference between the feed and permeate induced by temperature gradient. The MD applications mainly focus on seawater desalination and other industry application such as extraction of fruit juice. In this study, hydrophobic polyvinylidene fluoride (PVDF) hollow fiber membranes were fabricated by wet/dry phase inversion method with 1-methyl-2-pyrrolidone (NMP) as solvents and ethylene glycol (EG) as non solvent additives. The effect of the additives on the membrane formation was studied based on the results from membrane morphology investigation through scanning electron microscope (SEM) and porosity calculation based on gravitational method. The SEM image indicated the membrane morphology changed from finger like layer extending from inner to outer surface to a finger like layer separated by microvoid attributed addition of ethylene glycol which might lead to permeate flux enhancement. Furthers, results from the gravitational test reveal that the addition of ethylene glycol demonstrated a positive effect on the porosity of the membrane. Later, the membranes were tested by membrane distillation process in sodium chloride removal varying feed inlet temperature to investigate the permeate flux performance of the membrane.

Preparation of anticoagulant polyvinylidene fluoride hollow fiber hemodialysis membranes.

In this study, polyvinylidene fluoride (PVDF) hollow fiber membranes (HFMs) were modified by coating with polyvinyl alcohol (PVA) and chitosan. The influences of PVA and chitosan amount on PVDF membrane mechanical and separation performance were investigated. The results showed that the modified PVDF membranes had better mechanical and separation performance when the amount of PVA and chitosan was 20 mg/m2. At the same time, the biocompatibility of PVDF membranes was also investigated. Compared with virgin PVDF membranes, the modified PVDF membranes showed better anticoagulation, hydrophilicity, less bovine serum albumin (BSA) adsorption, and lower hemolytic ratio. The anticoagulation behavior of modified PVDF membranes coating with PVA had been obviously improved. Prothrombin time (PT) and activated partial thromboplastin time (APTT) of the modified PVDF membrane are 44.8 s and 72.5 s while the PT and APTT of virgin PVDF membrane are 15.6 s and 37.3 s. The advancing water contact angle (WCA) and BSA adsorption of the modified PVDF membrane coating with PVA are 24° and 23 mg/m2 while virgin PVDF membrane is 52° and 49 mg/m2. However, further biocompatibility evaluation is needed to obtain a more comprehensive conclusion.

Study of PVDF/Si-R hybrid hollow fiber membranes for removal of dissolved organics from produced water by membrane adsorption

Abstract Polyvinylidene fluoride (PVDF) and hydrophobic silica sol (Si-R) hybrid hollow fiber membranes were fabricated by dry-jet wet spinning. The morphology and surface roughness of the PVDF/Si-R hybrid membranes were examined by scanning electron microscope (SEM) and atomic force microscopy (AFM), respectively. FTIR and contact angle analysis were used to characterize hydrophobic Si-R particles in the hybrid membrane. The membrane adsorption efficiency for dissolved organics including BETX (benzene, toluene, ethyl benzene and xylene) and two fatty acids: hexanoic acid and octanoic acid, as well as the membrane regeneration ability, were investigated by membrane adsorption experiments under different pressures, feed rates and temperatures. The results revealed that the hybrid hollow fiber membranes showed a microcellular structure rather than the typical asymmetrical structure of neat PVDF hollow fiber membranes. As the membrane collecting velocity increased, the hybrid hollow fiber membranes possessed enhanced surface roughness on both inner and outer surface. The adsorption efficiency of the PVDF/Si-R hybrid hollow fiber membrane was three times higher than that of the neat PVDF membrane. The adsorption efficiency of hybrid hollow fiber membranes increased with the increase of testing pressure; however, it decreased with the increase in feed rate, and was not influenced by temperature in the range of 0–80 °C. With membrane collecting velocity of 424 cm/min, the PVDF/Si-R hybrid membrane exhibited adsorption efficiency of 94.5% and 96.7% for benzene and octanoic acid, with membrane adsorption capacities of 208.1 mg/g and 173.9 mg/g. respectively. The hybrid membrane also showed high regeneration ability with 500 ppm benzene as feed solution. The PVDF/Si-R hollow fiber membrane offers an attractive possibility for the removal of dissolved organics in oilfield produced water.

Ageing of polyvinylidene fluoride hollow fiber membranes in sodium hypochlorite solutions

In order to study the effect of cleaning operations on polyvinylidene fluoride (PVDF) hollow fiber membrane stability, ageing of two PVDF based membranes (one is additive free, the other contains hydrophilic additives) in contact with sodium hypochlorite solutions with various pH values has been studied. The aim of this experimental study was to identify the degradation mechanisms and to gain a better understanding of the effect of the (macro)molecular structure changes on the mechanical and functional properties of the membranes. In both membranes, double bond formation, chain scission and crosslinking are observed and all these processes (except crosslinking) are faster in acidified solutions than in natural NaOCl solutions (pH 11.5). It can be deduced that if ionic processes such as dehydrofluorination occur, radical processes resulting from the presence of hypochlorous acid and perhaps its coexistence with the ClO− ion, predominate in acidified solutions. The presence of non-fluorinated aliphatic or cycloaliphatic additives, which are highly reactive with bleach, accelerates chain scission at the expense of crosslinking. In the chosen conditions (135 days in 4000 ppm bleach solutions at 40°C), PVDF chains are degraded but not enough to induce polymer embrittlement. While in the additive free membrane no significant change of the use properties has been observed, the polymeric additives of the other membrane are completely destroyed, leading to a decrease of the membrane hydrophilicity, but their destruction improves the membrane selectivity by a decrease of the average porosity.

Highly porous PVDF hollow fiber membranes for VMD application by applying a simultaneous co-extrusion spinning process

Highly porous polyvinylidene fluoride (PVDF) hollow fiber membranes are of great interest for membrane contactor applications such as sea water desalination by membrane distillation in order to enhance the flux of the process. For the first time in this paper, porous hydrophobic PVDF asymmetric hollow fiber membranes with a high outer surface porosity for use in vacuum membrane distillation (VMD) were successfully fabricated by applying a simultaneous co-extrusion spinning process through the non-solvent induced phase separation (NIPS) method. In this approach, five kinds of dual-layer composite membranes were prepared by employing different inner and outer polymer dopes. Single-layer membrane was also fabricated through the conventional dry-jet wet phase inversion method. Results revealed that the introduction of the simultaneous co-extrusion spinning process greatly increased the outer surface porosity of the dual-layer composite membranes. It was also observed that the VMD flux of the dual-layer membranes spun through the simultaneous co-extrusion spinning process was 54% higher than the single-layer membrane fabricated by the conventional dry-jet wet phase inversion method. A VMD flux as high as 61.8kg/(m2h) at 70°C was obtained for the novel dual-layer composite membranes.

A comparative study on the structure of developed porous PVDF and PEI hollow fiber membrane contactors for CO2 absorption

The structure of polyvinylidene fluoride (PVDF) and polyetherimide (PEI) hollow fiber membranes was developed by formulation of the polymer solutions and regulating spinning parameters. The cloud point diagrams of polymer/solvent/non-solvent were obtained to investigate phase inversion behavior of the solutions. The prepared membranes were characterized in terms of morphology, overall porosity, gas permeation, collapsing pressure, wetting resistance and mass transfer resistance. The gas–liquid membrane contactor modules were prepared to study CO2 absorption performance of the membranes. The PEI and PVDF membranes presented finger-like and sponge-like structure, respectively. Both membranes showed good surface porosity due to enhancement of phase inversion by addition of glycerol to the spinning solutions. The PVDF membrane presented mean pore size of 0.09 μm with low mass transfer resistance and high wetting resistance. At water velocity of 0.03 m/s, the PVDF membrane indicated CO2 flux of 1.5 × 10−3 mol/m2 s which was 35 % higher than the flux of the PEI membrane. Due to the improved structure of the membranes, a significantly high CO2 flux was obtained at the same operating condition compared to the reported membranes in the literature. The developed membranes can be used as promising alternatives for cost-effective gas–liquid membrane contactor systems.

Modeling and simulation of CO2 removal in a polyvinylidene fluoride hollow fiber membrane contactor with computational fluid dynamics

This study was an attempt to develop a comprehensive two-dimensional model for removal of carbon dioxide in a polyvinylidene fluoride (PVDF) hollow fiber membrane contactor (HFMC) utilizing the computational fluid dynamics (CFD) technique. Governing equations were solved in three sections using a finite element method. Distilled water was used as a liquid absorbent in a non-wetting mode. Effectively, a comparison was made between the simulation predictions of the model and the experimental data in order to validate the developed model, which resulted into significant corroboration between them. The simulation results showed that removal percentage of CO2 was encouraged by increasing liquid velocity. However, it was decreased by increasing gas velocity and liquid absorbent temperature. Moreover, the simulation results revealed that increasing fiber length and membrane porosity had a positive effect on the removal efficiency. It was also indicated that counter-current flow arrangement was superior to co-current at the same operating conditions by investigating the results for both flow arrangements. In this model, two different equations were used for estimating the diffusion coefficient of CO2 in water, which the results for the removal efficiency were different.

Preparation of continuous NH2–MIL-53 membrane on ammoniated polyvinylidene fluoride hollow fiber for efficient H2 purification

A thin and continuous NH2–MIL-53 layer composed of Al(III) and 2-amino terephthalic acid has been successfully deposited on an ammoniated polyvinylidene fluoride (PVDF) hollow fiber under harsh synthetic conditions in N,N-dimethyl formamide (DMF) precursor solution at 423K. In order to enhance the solvent resistance and thermal stability of membrane, the hollow fiber was ammoniated by ethanediamine to become cross-linked. The amino groups formed on its surface provided high-density heterogeneous nucleation sites for strong adhesive growth of NH2–MIL-53. Results showed that the thin NH2–MIL-53 layer on ammoniated PVDF hollow fiber was inter-grown with thickness of only about 8μm. After activation by DMF at 423K for 5h and drying under vacuum at 423K for 12h, its permeance and ideal separation factor of H2/CO2 increased 330 and 5.46 times respectively. The prepared NH2–MIL-53/PVDF hollow fiber membrane exhibited excellent H2 permeance of 54.20×10−7mols−1m−2Pa−1 as well as the high ideal separation factor of 30.37, 24.07, 27.85 and 27.31 for H2/CO2, H2/O2, H2/N2 and H2/CH4, respectively. The composite membrane can also efficiently separate the H2/CO2 mixture with H2 permeance of 42.13×10−7mols−1m−2Pa−1 and separation factor of 32.35, which showed to be the highest separation factors among those reported for polymer supported MOF membranes.

Preparation of dual‐layer acetylated methyl cellulose hollow fiber membranes via co‐extrusion using thermally induced phase separation and non‐solvent induced phase separation methods

ABSTRACTDual‐layer acetylated methyl cellulose (AMC) hollow fiber membranes were prepared by coupling the thermally induced phase separation (TIPS) and non‐solvent induced phase separation (NIPS) methods through a co‐extrusion process. The TIPS layer was optimized by investigating the effects of coagulant composition on morphology and tensile strength. The solvent in the aqueous coagulation bath caused both delayed liquid–liquid demixing and decreased polymer concentration at the membrane surface, leading to porous structure. The addition of an additive (triethylene glycol, (TEG)) to the NIPS solution resolved the adhesion instability problem of the TIPS and NIPS layers, which occurred due to the different phase separation rates. The dual‐layer AMC membrane showed good mechanical strength and performance. Comparison of the fouling resistance of the AMC membranes with dual‐layer polyvinylidene fluoride (PVDF) hollow fiber membranes fabricated with the same method revealed less fouling of the AMC than the PVDF hollow fiber membrane. This study demonstrated that a dual‐layer AMC membrane with good mechanical strength, performance, and fouling resistance can be successfully fabricated by a one‐step process of TIPS and NIPS. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 42715.

The improvement of water flux and mechanical strength of PVDF hollow fiber membranes by stretching and annealing conditions

Polyvinylidene fluoride (PVDF) hollow fiber membranes prepared by thermally-induced phase separation (TIPS) have excellent porosity but weak tensile strength. In this study, we stretched and annealed these hollow fiber membranes in an attempt to improve their tensile strength and water permeability. This was done by introducing a stretching process into the manufacturing process. In this study, the stretching temperature ranged from 30 to 90 °C, the stretching speed ranged between 4 and 60 mm/s, and the stretching ratio was varied between 100 and 200%. According to field-emission scanning electron microscopy (SEM) images, the structure of the surface varied under different stretching conditions. The tensile strength was increased as the degree of stretching increased, and annealing conditions of 130 °C for 2 h resulted in an increase in the crystallinity. These results indicate that changing the stretching conditions can increase the water permeability and the mechanical strength of the membrane by more than 20%; these improvements are brought about by changes in the surface structure of the membrane.

Application of nano TiO2 modified hollow fiber membranes in algal membrane bioreactors for high-density algae cultivation and wastewater polishing

Polyvinylidene fluoride (PVDF) hollow fiber membranes with nano-TiO2 (5% of PVDF by mass, average size=25nm) additives were fabricated and applied for high-density algae (Chlorella vulgaris) cultivation. At the average light intensity of 121μmol/m2/s, the algal membrane bioreactors (A-MBR) operated at a hydraulic retention time of 0.5d and an average solids retention time of 25d had an average algae biomass concentration of 2350±74mg/L (in COD units) and algal biomass production rate of 6.5±0.1g/m2/d. The A-MBRs removed an average of 78% of phosphorus from the wastewater at the initial total phosphorus concentrations ranging from 3.5 to 8.6mg/L. The nano TiO2-embedded membranes had improved surface hydrophilicity with its total resistance about 50% lower than that of the control. This study demonstrated that PVDF/TiO2 nanocomposite membranes had a better antifouling property for high-density algae cultivation and wastewater polishing.

Deacidification of crude palm oil using PVA-crosslinked PVDF membrane

Over recent years, there has been an explosive growth of interest in the development of alternative approaches for crude palm oil (CPO) refining. During a typical refinery process, free fatty acid (FFA) is one of the key objectionable impurities that need to be reduced if not completely removed from CPO in order to minimize their detrimental effects on the oil quality. Polyvinylidene fluoride (PVDF) membrane shows great potential in removing FFA from CPO owing to its hydrophobic properties, high mechanical strength and good thermal stability. However, low concentration of FFA in CPO, which is normally ranging from 3% to 5%, has hindered the capability of the membranes to separate the trace amount of FFA from the bulk. Thus, modification of PVDF membrane is essential to enhance the interaction between the membrane surface and FFA molecules, facilitating efficient FFA removal. In order to achieve this purpose in the present study, the outer surface of PVDF hollow fiber membranes was crosslinked with polyvinyl alcohol (PVA). Glutaraldehyde (GA) was used as a crosslinking agent to avoid the PVA dissolution. Despite the negligible morphological change observed in the resultant membranes upon PVA crosslinking, the contact angle has been significantly reduced in proportional to the concentration of PVA used for the crosslinking, suggesting the decrease in membrane hydrophobicity. Additionally, the average roughness of the crosslinked PVDF membranes increased with the increasing PVA concentration. The results obtained suggested that the PVDF hollow fiber crosslinked with 100ppm PVA exhibited the highest FFA rejection of 5.93% after 3h of operation. In addition, the membrane also showed good result in reducing the content of phosphorus in the permeate and partial reduction of its color intensity. This study served as the first attempt of CPO deacidification through UF membrane system without the addition of any chemical during the filtration process.

Preparation and properties of PVDF hollow fiber membrane for desalination using air gap membrane distillation

The polyvinylidene fluoride (PVDF) hollow fiber membrane was prepared for membrane distillation through thermally induced phase separation (TIPS) using glyceryl triacetate (GTA) and dibutyl sebacate (DBS) as the mixed diluents. The bicontinuous structure of membrane pore was obtained in the case: PVDF/GTA/DBS is 25wt.%:22.5wt.%:62.5wt.%, and the coagulation bath is the water of 20°C. The membrane porosity and mechanical strength are 0.64 and 2.7MPa, respectively. The PVDF membrane was characterized using the measurement of the liquid entry pressure (LEPw), scanning electron microscopy (SEM), mean pore, porosity and mechanical strength. The prepared PVDF membrane was tested in an AGMD process for desalination with 7.0wt.% NaCl solution as the feed. The permeate water flux (JD) and gained output ratio (GOR) simultaneously reach to 5.5kg/m2h and 6.2. The prepared PVDF membrane can be operated continuously for 240h without any significant change to JD and GOR, indicating that the prepared PVDF hollow fiber membrane by TIPS method may be of great potential to be utilized in AGMD process for desalination.

Structure design and performance study on braid-reinforced cellulose acetate hollow fiber membranes

A novel braid-reinforced (BR) cellulose acetate (CA) hollow fiber membrane consisting of separation layer and ‘hybrid’ braid was reported in this study. The ‘hybrid’ braid containing CA and polyacrylonitrile (PAN) fiber not only provided the membrane well interfacial bonding state but also overcame the negative effect of CA fiber׳s swelling on membrane permeability. The influences of braid composition and CA concentration on the structure and performance of BR CA membranes were investigated. There were two kinds of interfaces between the braid and the separation layer, which were named homogeneous-reinforced (HMR) interface and heterogeneous-reinforced (HTR) interface. Taking into account both interfacial bonding state and membrane permeability, the best ratio of the fibers in the braid was 2/1(CA/PAN). Increased CA concentration brought about reduced permeate flux and increased protein rejection. The BR CA membranes exhibited excellent anti-fouling property with flux recovery rates higher than 80%. The tensile strength of BR CA hollow fiber membranes varied from 16.0MPa to 62.9MPa by adjusting the braid composition. The BR CA membrane showed similar performance with the commercial hydrophilic polyvinylidene fluoride (PVDF) hollow fiber membrane during the filtration of milk solution, and the flux could be recovered by chemical cleaning.