Microporous Hollow Fiber Membrane Research Articles

Preparation of high-performance PVDF hollow fiber microporous membranes via the c-TIPS process with water-insoluble solvent as the second solvent

Triethyl phosphate (TEP) is a promising solvent for the c-TIPS process given its high boiling point and water miscibility. However, casting solutions containing high TEP concentration generally trigger gelation, giving a dense outer surface in PVDF membrane. In this work, we fabricated PVDF hollow fiber membranes with a porous outer surface and excellent mechanical strength via a complex thermally induced phase separation (c-TIPS) method and applied them in the DCMD process. A water-insoluble solvent, dibasic ester solvents (DBEs), was used as the second solvent to modulate the phase separation process of the PVDF/TEP system. The mass transfer between the coagulation bath and the DBEs solvent was analyzed. It could decrease the polymer-solvent interactions and the rate of solvent efflux in the coagulation bath, contributing to the development of a porous membrane structure. When the weight ratio of TEP/DMA was 1, the optimized PVDF hollow fiber membrane exhibited a tensile strength of 8.34 MPa, an average pore diameter of 0.14 μm, giving the permeate flux of 18.56 ± 2.5 kg m−2 h−1 in DCMD and excellent operational stability when subjected to high brine concentration. Thus, the fabrication method shows a promising potential for tailoring the surface porosity and bulk structure. The PVDF membranes developed in this study demonstrate potential for use in membrane distillation and related applications.

A high-throughput sample preparation approach for the determination of nonsteroidal anti-inflammatory drugs in urine samples through membrane-based microextraction employing a green supramolecular solvent

Nonsteroidal anti-inflammatory drugs (NSAIDs) are a class of drugs with antipyretic, analgesic, and anti-inflammatory effects widely used worldwide. This study aimed at developing an environmentally friendly and high-throughput sample preparation method for the determination of six NSAIDs in urine samples followed by high-performance liquid chromatography coupled to diode-array detection (HPLC-DAD). The experimental workflow consisted of hollow-fiber microporous membrane liquid-liquid extraction (HF-MMLLE) using a supramolecular solvent immobilized into the porous of polypropylene hollow membranes (1 cm length). These membranes were attached to a 96-well plate system to permit multiple extractions simultaneously. Under the optimized conditions, limits of detection (LODs) and limits of quantification (LOQs) ranged from 6.06 to 30.3 µg/L and from 20 to 100 µg/L, respectively. The linear ranges varied from 20 to 1000 µg/L for indomethacin and diclofenac, from 50 to 1000 µg/L for ketoprofen and ibuprofen, and from 100 to 1000 µg/L for naproxen and fenoprofen. The coefficients of determination (R²) ranged from 0.9735 to 0.9997. Intraday precision ranged from 6.13 to 20.11 %, interday precision varied from 2.87 to 20.72 %, and accuracy ranged from 92.49 to 126.89 %. Moreover, the recently proposed Sample Preparation Metric of Sustainability (SPMS) was employed to evaluate the greenness of the sample preparation technique resulting in a score of 8.0, which is highly satisfactory according to the concepts of green analytical chemistry.

Characterization and comparative evaluation of polysulfone and polypropylene hollow fiber membranes for blood oxygenators

AbstractBlood oxygenators are used to saturate oxygen levels and remove carbon dioxide from the body during cardiopulmonary bypass. Although the natural lung is hydrophilic, commercially used oxygenator materials are hydrophobic. Surface hydrophobicity weakens blood compatibility, as long‐term contact with the blood environment may lead to different degrees of blood activity. Polysulfone may be considered an alternative hydrophilic material in the design of oxygenators. Therefore, it may be directed toward developing hydrophilic membranes. This study aims to investigate the feasibility of achieving blood gas transfer with a polysulfone‐based microporous hollow fiber membrane and compare it with the commercially available polypropylene membranes. Structural differences in the membrane morphology, surface hydrophilicity, tortuosity, mass transfer rate, and material properties under different operation conditions of temperature and flow rates are reported. The polysulfone membrane has a water contact angle of 81.3°, whereas a commercial polypropylene membrane is 94.5°. The mass transfer resistances (s/m) for the polysulfone and polypropylene membranes are calculated to be 4.8 × 104 and 1.5 × 104 at 25°C, respectively. The module made of polysulfone was placed in the cardiopulmonary bypass circuit in parallel with the commercial oxygenator, and pH, pO2, pCO2 levels, and metabolic activity were measured in blood samples.

Development, characterization, and applications of a portable analyzer for continuous monitoring of H2S in gas streams

A bench-scale analyzer for continuous monitoring of H2S in gas streams was previously described (2012 Sens. Actuators B 162 377–83). The analyzer was based on the exothermic reaction between the scrubbed H2S, in alkaline solution, with hydrogen peroxide. The analyzer offers several advantages but suffers from a relatively slow response time (i.e. 7 min) and a relatively low sensitivity (limit of detection = 100 ppm). In the present work, a substantially improved detector design and direct mixing of the gas with the liquid reagents are described. The improved detector, in the form of a coiled thin-walled stainless-steel (SS) tube also acts as a compartment for direct gas absorption and reaction with sodium hydroxide and hydrogen peroxide reagents, which eliminates the need for a gas scrubber based on microporous hollow fiber membranes (HFMs). The average temperature of the SS coil was measured by three thermocouples attached to the outer surface of the coil with thermally conductive epoxy. The improved detector design and the simplified scheme proved very successful in achieving six times faster response (i.e. 70 s) and ten times more sensitive response (i.e. 10 ppm) in the gas stream and improved repeatability (coefficient of variation = 0.55%). In addition, the previously reported advantages, such as excellent signal stability, wide dynamic range (up to 5% H2S) and convenient tuning of the sensitivity and linearity by varying the ratio between the gas and reagent flow rates were perfectly retained. The improved detector is utilized to construct a compact portable version of the H2S analyzer (∼6 kg), which provides a stand-alone operation for real-time monitoring of H2S in the gas stream for up to 4 h prior to the need for reagent refill or battery recharge. The applications of the described portable analyzer in monitoring H2S removal from H2S–N2 gas stream using an HFM contactor and absorption solvent, and in the determination of sulfide ions in liquid samples are presented. A comparison between the response of the present portable H2S analyzer and a commercial analyzer is also presented.

Polypropylene hollow fiber membrane prepared with green binary diluents via TIPS: Effects of spinning process parameters and VMD desalination performance

Environmental-friendly castor oil (CO) and soybean oil (SO) were used as mixed diluents to spin polypropylene (PP) hollow fiber microporous membrane (HFMM) via thermally induced phase separation. With the addition of castor oil, the cloud point temperature gradually increases, and the region of liquid-liquid phase separation becomes larger. The membrane pore structure changes from a spherulitic form to a continuous sponge-like pore structure. Particularly, the effects of spinning process parameters (spinning speed, spinneret temperature and bore liquid temperature) on HFMM properties (e.g., mechanical properties, water contact angle, pore size and pore size distribution) and desalination performance of vacuum membrane distillation (VMD) were further studied. A higher spinning speed and smaller temperature difference between dope and spinneret/bore fluid increase pore size and reduce membrane porosity. The PP HFMM produced under the spinneret temperature of 160 °C, the bore fluid temperature of 113 °C, and spinning speed of 16.1 m/min reached relatively high VMD desalination performance both feeding 10 g/L NaCl solution (water flux 18.4 kg/m2·h and salt rejection 99.99 %) and petrochemical saline wastewater (water flux 14.0 kg/m2·h and salt rejection 99.5 %). This paper has important guiding significance for the mass production of PP HFMMs.

Determination of hormones in urine by hollow fiber microporous membrane liquid–liquid extraction associated with 96-well plate system and HPLC-FLD detection

In this work, hollow-fiber microporous membrane liquid–liquid extraction (HF-MMLLE) was associated with a 96-well plate system for the determination of estrone, 17-β-estradiol, estriol and 17-α-ethinylestradiol in urine samples. This method exhibited some advantages, such as low cost, easy application, high-throughput and environmentally-friendly aspects. The type of organic solvent to fill the membrane, ionic strength effect, sample dilution, extraction and desorption time, and desorption solvent were examined. After the optimizations, the conditions were comprised of 45 min of extraction, 1-octanol as organic solvent and 15% (w/v) of NaCl; methanol was used as desorption solvent, and the desorption time was fixed at 10 min. The dilution of the sample increased the sensitivity due to the reduction of matrix effects; thus, urine samples were diluted 40-fold. The limits of detection ranged from 0.03 μg L−1 for 17-β-estradiol to 15 μg L−1 for estrone, and the limits of quantification ranged from 0.1 μg L−1 for 17-β-estradiol to 10 μg L−1 for estrone. The intra-day precision varied from 1.0% for estriol to 13.3% for 17-α-ethinylestradiol, and inter-day precision varied from 7.3% for estrone to 18.1% for estriol. The relative recoveries varied from 82 to 118%.

Multiclass determination of endocrine disruptors in urine by hollow fiber microporous membrane and liquid chromatography

A simple and rapid methodology was developed using hollow fiber membrane microporous and a 96-well plate system for a high throughput multiclass determination of endocrine disruptors in human urine (diclofenac, diazepam, carbamazepine, ibuprofen, naproxen, carbofuran, methyl parathion, 17-α-ethynyl estradiol, bisphenol A and benzophenone). The quantification and detection of the chemicals were carried out by an HPLC-diode array detector. The fixed conditions for carrying out the method optimization were 1.5 mL of sample and 300 μL of solvent desorption. Multivariate and univariate models were applied to optimize the parameters of the method, achieving the following conditions: 20% diluted urine, 1-octanol of extraction solvent impregnated in the microporous membrane, 70 min extraction in pH 3.0 and 30 min with a mixture of 75% methanol and 25% acetonitrile (v/v) for the desorption. The R2 were ≤ 0.9973 for ibuprofen. The LOD ranged from 3.3 to 16.7 ng mL−1 and the LOQ from 10 to 50 ng mL−1. Relative recoveries ranged from 71% to 126%. The repeatability (n = 3) ranged from 0.22% to 12.01%, and the intermediate precision (n = 9) ranged from 0.13% to 17.76%. The method presents a good alternative for the determination of different classes of compounds in human urine.

Low-cost silica based ceramic supported thin film composite hollow fiber membrane from guinea corn husk ash for efficient removal of microplastic from aqueous solution

In this study, an economic silica based ceramic hollow fiber (HF) microporous membrane was fabricated from guinea cornhusk ash (GCHA). A silica interlayer was coated to form a defect free silica membrane which serves as a support for the formation of thin film composite (TFC) ceramic hollow fiber (HF) membrane for the removal of microplastics (MPs) from aqueous solutions. Polyacrylonitrile (PAN), polyvinyl-chloride (PVC), polyvinylpyrrolidone (PVP) and polymethyl methacrylate (PMMA) are the selected MPs The effects of amine monomer concentration (0.5 wt% and 1 wt%) on the formation of poly (piperazine-amide) layer via interfacial polymerization over the GCHA ceramic support were also investigated. The morphology analysis of TFC GCHA HF membranes revealed the formation of a poly (piperazine-amide) layer with narrow pore arrangement. The pore size of TFC GCHA membrane declined with the formation of poly (piperazine-amide) layer, as evidenced from porosimetry analysis. The increase of amine concentration reduced the porosity and water flux of TFC GCHA HF membranes. During MPs filtration, 1 wt% (piperazine) based TFC GCHA membrane showed a lower transmission percentage of PVP (2.7%) and other suspended MPs also displayed lower transmission. The impact of humic acid and sodium alginate on MPs filtration and seawater pretreatment were also analyzed.

Measure microbial activity driven oxygen transfer in membrane aerated biofilm reactor from supply side

This short communication demonstrates for the first time a solely microbial activity driven oxygen influx across a microporous hollow fibre membrane via tracking changes in volume and gas composition of entrapped air supply. A U-shape manometer was used to directly reflect gas influx due to microbial activities. A pressure difference of several hundred pascal was created to draw oxygen while 25 mg-N/L of ammonium was oxidized into nitrite by active biofilm at a hydraulic retention time of 6 h. Calibrated and normalized gas compositions before and after the experiment were processed to unveil the gas exchange and estimate the actual oxygen influx across the membrane. A solely microbial activity driven oxygen influx of 10.7 mg O2/m2/h was observed. Measuring oxygen transfer from supply side provides a more straight-forward perspective on the role of active biofilm in membrane aerated biofilm reactor. The capability of the microbial activity to uptake oxygen on its own could potentially lead to greater energy savings in some MABR applications when strict aeration control is not needed.

INFLUENCIA DE LAS CONDICIONES DE OPERACIÓN EN EL REFINO DE BIOGAS PARA PRODUCIR BIOMETANO MEDIANTE CONTACTORES DE MEMBRANA

In this paper, the behavior of micro-porous hollow fiber membrane contactors has been studied for biogas upgrading under different operational conditions. Physical solvents, as deionized water and sodium chloride solution, were initially used. In these cases, carbon dioxide absorption was dependent upon liquid phase flow. Sodium hydroxide was subsequently used as a comparative chemical absorption solvent. In this case, CO2 mass transfer increased by increasing gas velocity which was attributed to the excess of reactive hydroxide ions present in the solvent. Under optimum conditions, with two membrane contactors operating in series, it was possible to obtain a gas stream with more than 99% of pure methane using deionized water as solvent. The same yields were obtain with NaOH as solvent, but in this case working with just one membrane module, that is, reducing by half the available surface area for molecules diffusion. At constant liquid to gas flow ratios, better separation behavior was targeted at pressures higher than 2.0 barg. When dealing with solvent reuse without regeneration, NaOH is the only adsorbent allowing a high number of solvent recirculation cycles. This aspect could be very interesting for the economy of the process. Keywords: biogas, biomethane, gas-liquid absorption, membrane contactors, biogas upgrading, natural gas substitute

Three-Dimensional Microporous Hollow Fiber Membrane Microfluidic Device Integrated with Selective Separation and Capillary Self-Driven for Point-of-Care Testing.

The novel 3D microfluidic concept of "lab-on-hollow fiber membrane (HFM)" was presented for multifunctional and rapid biological assays, integrating sample size sieving and colorimetric quantification in an HFM. Herein, microporous HFMs with a gradient pore size and high hydrophilic flux were used as microfluidic device substrates. The membrane pores selectively trapped macromolecules within the inner surface, while allowing free diffusion of smaller molecules, including glucose and protein. The microfluidic flow rate in HFM closely followed the Lucas-Washburn and Laplace's models, indicating that the microfluidics facilitated the upward flow of the fluid by microcapillary action without external pumping. Subsequently, for sensing of different biomolecules, a highly sensitive fluorescent or optical chromogenic reagent was immobilized in HFM by an electrostatic interaction. Pyronin G fluorescence reagent was quenched by blood glucose, and the quenching efficiency showed a good linear correlation with glucose concentration (1-22 mM, R2 = 0.997). Moreover, this sensing platform was then further applied for the analysis of urine protein or glucose in the visible spectrum, with a wide testing range. Compared to traditional 2D flat membrane devices, this 3D-HFM microfluidic device exhibited excellent sensing versatility and color rendering uniformity with enhanced sensitivity. Target molecules screening, conditioning, enzymatic recognition, and signal readout of biomolecules have all been implemented on this device, which has paved the way to highly sensitive assays on point-of-care testing (POCT).

Experimental investigation of heat and moisture transfer performance of CaCl2/H2O-SiO2 nanofluid in a gas–liquid microporous hollow fiber membrane contactor

In this study, aqueous solution of CaCl2/SiO2 nanoparticles has been used as a desiccant in a gas–liquid hollow fiber membrane (HFM) air dehumidifier contactor system. The heat and mass (H/M) transfer properties HFM energy exchanger with CaCl2/H2O-SiO2 as desiccant solution studied experimentally for first time. Effects of different parameters on H/M transfer characteristics of system, including the nanoparticle concentration, liquid flow rate and liquid temperature were examined experimentally. The experiments arranged for desiccant temperatures of 20 °C and 26 °C, desiccant solutions of 0, 1%wt and 2%wt concentration and flow rates of 1.1, 1.25, 1.4 and 1.7 ml/s. The results indicated that the influence of particles on moisture removal rate is the greatest for the conditions of highest solution temperature and the highest particle. By introducing nanofluid solution as liquid desiccant in system the enhancing effect of reducing desiccant temperature on moisture removal lessens and declined to zero by increasing the solution flow rate with a high descending rate. For 2%wt nanoparticle concentration by 53% increase of absorbent flow rate, the value of temperature effectiveness reduced by 30%. This justifies adiabatic application of hollow fiber membrane systems with nanofluid desiccant.

Selective separation of CH4 and CO2 using membrane contactors

In this paper, the behavior of micro-porous hollow fiber membrane contactors is analyzed for biogas upgrading under different operational conditions. Physical solvents, as deionized water and sodium chloride solution, were initially used. In these cases, carbon dioxide absorption was dependent upon liquid phase flow. After these experiments, sodium hydroxide was used as chemical absorbent in order to compare results. In this case, an increasing in gas velocity resulted in a higher CO2 mass transfer. This effect was associated to the increase of reactive hydroxide ions available in the solvent. Under optimum conditions, with two membrane contactors operating in series, it was possible to obtain a gas stream with more than 99% of pure methane using deionized water as solvent. The same yields were obtain with NaOH as solvent, but in this case working with just one membrane module, that is, reducing by half the available surface area for molecules diffusion. At constant liquid to gas flow ratios, better separation behavior was targeted at pressures higher than 2.0 barg. When dealing with solvent reuse without regeneration, NaOH is the only absorbent allowing a high number of solvent recirculation cycles. This aspect could be very interesting for the economy of the process.

Evaluation of microporous hollow fibre membranes for mass transfer of H2 into anaerobic digesters for biomethanization

AbstractBACKGROUNDWith high surface‐to‐volume ratios, hollow fibre membranes offer a potential solution to improving gas–liquid mass transfer. This work experimentally determined the mass transfer characteristics of commercially available microporous hollow fibre membranes and compared these with the mass transfer from bubble column reactors. Both mass transfer systems are considered for biological methanization, a process that faces a challenge to enhance the H2 gas–liquid mass transfer for methanogenic Archaea to combine H2 and CO2 into CH4.RESULTSPolypropylene membranes showed the highest mass transfer rate of membranes tested, with a mass transfer coefficient for H2 measured as kL = 1.2 × 10−4 ms−1. These results support the two‐film gas–liquid mass transfer theory, with higher mass transfer rates measured with an increase in liquid flow velocity across the membrane. Despite the higher mass transfer rate from polypropylene membranes and with a liquid flow across the membrane, a volumetric surface area of α = 10.34 m−1 would be required in a full‐scale in situ biological methanization process with much larger values potentially required for high‐rate ex situ systems.CONCLUSIONSThe large surface area of hollow fibre membranes required for H2 mass transfer and issues of fouling and replacement costs of membranes are challenges for hollow fibre membranes in large‐scale biological methanization reactors. Provided that the initial bubble size is small enough (de < 0.5 mm), calculations indicate that microbubbles could offer a simpler means of transferring the required H2 into the liquid phase at a head typical of that found in commercial‐scale anaerobic digesters. © 2019 The Authors. Journal of Chemical Technology & Biotechnology published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Performance Comparison between Polyvinylidene Fluoride and Polytetrafluoroethylene Hollow Fiber Membranes for Direct Contact Membrane Distillation.

Increasing water demand coupled with projected climate change puts the Southwestern United States at the highest risk of water sustainability by 2050. Membrane distillation offers a unique opportunity to utilize the substantial, but largely untapped geothermal brackish groundwater for desalination to lessen the stress. Two types of hydrophobic, microporous hollow fiber membranes (HFMs), including polytetrafluoroethylene (PTFE) and polyvinylidene fluoride (PVDF), were evaluated for their effectiveness in direct contact membrane distillation (DCMD). Water flux and salt rejection were measured as a function of module packing density and length in lab-scale systems. The PVDF HFMs generally exhibited higher water flux than the PTFE HFMs possibly due to thinner membrane wall and higher porosity. As the packing density or module length increased, water flux declined. The water production rate per module, however, increased due to the larger membrane surface area. A pilot-scale DCMD system was deployed to the 2nd largest geothermally-heated greenhouse in the United States for field testing over a duration of about 22 days. The results demonstrated the robustness of the DCMD system in the face of environmental fluctuation at the facility.

Modelling and optimisation of gas-liquid mass transfer in a microporous hollow fiber membrane aerated bioreactor used to produce surfactin

Aeration by a membrane contactor is a convenient method to produce surfactin, a bacterial surfactant compound, while avoiding foam to overflow as it is the case with most of aerated bioreactors equipped with gas sparger. This work helps improving knowledge on oxygen transfer in membrane-aerated bioreactors and optimizing the adjustment of culture aeration performances. In this work, oxygenation of a surfactin solution was studied in a bioreactor aerated by a microporous hollow fiber membrane contactor. First, a dimensional analysis was coupled in an innovative way with a fractional design of experiments, thus reducing greatly the number of experiments. Then, the analysis of the model helped to understand thoroughly the influence of the four main parameters, namely the liquid flow rate inside the fibers, the gas pressure outside the fibers, the liquid volume in the tank and the amount of surfactant in the bulk. Empirical process relationships were proposed to predict either the volumetric oxygen transfer coefficient (kLa) or the liquid-side oxygen transfer coefficient (kL) (with an average standard deviation < 11%). The liquid flow rate, the liquid volume and the gas pressure were found to be significantly influencing unlike the surface tension. The validity of the relationships with surfactin fermentations obtained at a larger scale was demonstrated.

TIPS behavior for IPP/nano-SiO2 blend membrane formation and its contribution to membrane morphology and performance

Abstract In the present work, the TIPS behavior of isotactic polypropylene (iPP)/di-n-butyl phthalate (DBP)/dioctyl phthalate (DOP)/nano-SiO2 system and the competition relation between liquid–liquid phase separation and polymer crystallization are successfully adjusted by adding nano-SiO2. The liquid–liquid phase separation temperature of the system increases with increasing nano-SiO2 content. Besides, iPP crystallization temperature is also changed after adding nano-SiO2. IPP/nano-SiO2 blend hollow fiber microporous membrane is prepared via TIPS method. SEM photos show that the membrane exhibits mixed morphology combining cellular structure relating to liquid–liquid phase separation and branch structure originating from polymer crystallization. The relative weight of cellular structure first decreases and then increases with the increase of nano-SiO2 content. Furthermore, porosity, connectivity among pores and pure water flux of the membrane first increase and then decrease with increasing nano-SiO2 content. However, mechanical performance of the membrane is improved at all times with increasing nano-SiO2 content.

Modeling for design and operation of high-pressure membrane contactors in natural gas sweetening

Over the past decade, membrane contactors (MBC) for CO2 absorption have been widely recognized for their large intensification potential compared to conventional absorption towers. MBC technology uses microporous hollow-fiber membranes to enable effective gas and liquid mass transfer, without the two phases dispersing into each other. The main contribution of this paper is the development and verification of a predictive mathematical model of high-pressure MBC for natural gas sweetening applications, based on which model-based parametric analysis and optimization can be conducted. The model builds upon insight from previous modeling studies by combining 1-d and 2-d mass-balance equations to predict the CO2 absorption flux, whereby the degree of membrane wetting itself is calculated from the knowledge of the membrane pore-size distribution. The predictive capability of the model is tested for both lab-scale and pilot-scale MBC modules, showing a close agreement of the predictions with measured CO2 absorption fluxes at various gas and liquid flowrates, subject to a temperature correction to account for the heat of reaction in the liquid phase. The results of a model-based analysis confirm the advantages of pressurized MBC operation in terms of CO2 removal efficiency. Finally, a comparison between vertical and horizontal modes of operation shows that the CO2 removal efficiency in the latter can be vastly superior as it is not subject to the liquid static head and remediation strategies are discussed.

The Study of Carbon Dioxide Removal in Membrane Module by Single and Mixture of Alkanolamine Aqueous Solutions

This work presents an investigation on the performance of CO2absorption into aqueous alkanolamine solution using a hollow fiber membrane gas–liquid contactor. Aqueous solution of ethanolamine (MEA), diethanolamine (DEA), 2–amino–2–methyl–1–propanol (AMP) and piperazine anhydrous (PZ) were chosen as the absorption liquids. A microporous hollow fiber membrane made of polyvinylidene fluoride (PVDF) was used as the medium for gasliquid absorption process. In this study, the operating temperature is fixed at 30°C, while the flowrate of CO2 and alkanolamine were in the range of 1000–5000 ml/min and 50–280 ml/min respectively. The feed gas was introduced directly to the shell of the module at 1–1.5 bar and the liquid flowed through the fiber lumen side. The CO2 transfer through the membrane was found to be reaction controlled and dependent on the type of amine used. The use of piperazine as an accelerator in the mixture of the absorption liquids gives a good impact on increasing the performance for the rate of CO2 transfer.

Mass Transfer and Fluid Hydrodynamics in Sealed End Hydrophobic Hollow Fiber Membrane Gas-liquid Contactors

Hollow fiber membrane modules have been extensively used as gas-liquid contactor devices to provide a high surface area within a small volume. Hollow fiber membrane contactors have been demonstrated in a wide range of application such as in gas stripping and gas absorption. In this study the performance of sealed end hydrophobic microporous hollow fiber membranes contactors were evaluated to remove dissolved oxygen from water via vacuum degassing process. Hollow fibers membranes used in the experiment were hydrophobic microporous polypropylene of 650 μm in outer diameter, 130 μm wall thickness and nominal pore size of 0.2 μm. Based on the experimentalresult the sealed end membrane contactor can remove oxygen from water as high as 3.4-gram oxygen per square meter of membrane area per hour. The oxygen flux decreases with increasing module-packing density for the same water velocity. The same effect also occurred for the mass transfer coefficient of the membrane contactors. The mass transfer coefficients were independent of fiber length within the range of study. Hydrodynamics analysis of the contactors showed that at the same Reynolds number pressure drops increase with increasing packing density due to an increase in friction between fibers and water.