• Membrane Journal
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• v.22 no.6
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• pp.470-480
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• 2012

In this study, for a linear tubular membrane with constant diameter the mass balance considering permeate velocity of the each unit length was established. On this basis, mathematical modelling of flows in a pipe was solved using nonlinear second order differential equations as well as steady-state equation. Since this equation is nonlinear, Gauss-Seidel method or another iteration method were used to solve the differential equations. Simulation algorithm for numerical solutions was presented. Also since the permeate flow is varied as operating condition, the solution of equations at each conditions using numerical integrations such as Simpson's rules was used. In order to analyze and compare simulation results, we have performed experiments using a hollow fiber membrane with almost identical tubular membrane. Comparison of theoretical and experimental results, pressure drop, flow rate, and permeate flow in a hollow fiber membrane, were illustrated.

• Membrane Journal
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• v.30 no.2
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• pp.138-148
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• 2020

The purpose of this study was to identify the cleaning efficiency of fouled multi-bore hollow fiber membranes after purification of contaminated water. The PSf (polysulfone) based hollow fiber membrane manufactured by Pure & B Tech Co., Ltd. Was used in this study. The antifouling characteristics during the water treatment were studied using bovine serum albumin (BSA) as a model compound and the chemical resistance was evaluated after long-term impregnation in sodium hypochlorite (NaOCl) solution and Citric acid to understand the long term stability of the membranes. Water permeability and mechanical strength of the membranes after prolonged chemical exposure was measured to observe the change in mechanical stability and long term performance of the membrane. moreover, the recovery efficiency was also evaluated after chemical enhanced backwashing of a membrane contaminated with bovine serum albumin. The PSf hollow fiber membrane exhibited excellent chemical resistance, and it was confirmed that the efficiency of sodium hypochlorite was high as a result of chemical enhanced backwashing.

• Membrane Journal
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• v.20 no.4
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• pp.312-319
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• 2010

Carbon membrane materials have received considerable attention for the gas separation including hydrocarbon mixture of ingredients of the volatile organic compounds(VOCs) because they possess their higher selectivity, permeability, and thermal stability than the polymeric membranes. The use of activated carbon membranes makes it possible to separate continuously the VOCs mixture by the selective adsorption-diffusion mechanism which the condensable components are preferentially adsorbed in to the micropores of the membrane. The activated carbon hollow fiber membranes with uniform adsorptive micropores on the wall of open pores and the surface of the membranes have been fabricated by the carbonization of a thin film of phenolic resin deposited on porous alumina hollow fiber membrane. Oxidation, carbonization, and activation processing variables were controlled under different conditions in order to improve the separation characteristics of the activated carbon membrane. Properties of activated carbon hollow fiber membranes and the characterization of a gas permeation by pyrolysis conditions were studied. As the result, the activated carbon hollow fiber membranes with good separation capabilities by the molecular size mechanism as well as selective adsorption on the pores surface followed by surface diffusion effective in the recovery hydrocarbons have been obtained. Therefore, these activated carbon membranes prepared in this study are shown as promising candidate membrane for separation of VOCs.

• Membrane Journal
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• v.28 no.6
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• pp.379-387
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• 2018

This study was conducted to improve the membrane characteristics and performance by increasing hydrophilicity by adding additives to the ultrafiltration polysulfone (PSf) hollow fiber membrane. The mixed matrix membranes (MMMs) were prepared by dispersing 15 nm of fumed silica (FS) in the spinning solution at 0.1, 0.3 and 0.5 wt%. SEM analysis was carried out to confirm the cross-section and surface condition. It was confirmed that mean pore radius of the hollow fiber increased by 4 nm as FS was added. In addition, contact angle measurement was carried out for the hydrophilicity analysis of hollow fiber membranes, and it was confirmed that the hydrophilicity of MMMs were increased by adding of FS. In the case of water permeability, the membrane including FS showed 91~96 LMH and showed 5~11% more increase than PSf membrane. In the antifouling performance test, relative flux reduction ratios of FS mixed hollow fiber membranes were lower than that of PSf membranes, and it was confirmed that increase of hydrophilicity hinders adsorption of hydrophobic BSA on the membrane surface.

• Proceedings of the Membrane Society of Korea Conference
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• 2004.05b
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• pp.144-146
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• 2004

Various polymeric hollow fiber membranes have been prepared and been used widely due to their high surface area per unit volume and high permselectivity. However, the organic materials are only limited to mild operating conditions because of their weak thermal stability and ease of fouling.(omitted)

• Proceedings of the Membrane Society of Korea Conference
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• 2002.05a
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• pp.163-167
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• 2002

• Macromolecular Research
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• v.10 no.2
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• pp.127-134
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• 2002

Microporous polypropylene hollow fiber membrane was fabricated from isotactic polypropylene-soybean oil system by melt spinning process. Addition of nucleating agent accelerated the crystallization rate and elevated the crystallization temperature. Nucleating agent increased the number of nuclei and spherulites, which offered more inter-spherulitic amorphous sites for stretching. Benzoic acid, adipic acid, and dibenzylidene sorbitol were selected as nucleating agents, and their characteristics and effects were investigated by thermal and optical analyses. Spherulite growth and micropore formation characteristics were correlated with the kind of nucleating agent. Benzoic acid and adipic acid showed the remarkable nucleating effect, while dibenzylidene sorbitol was less effective than those. Nucleating agents also helped the sample have uniform microporous structure. Increase of nucleating agent composition enhanced the nucleation effect to some extent. Nucleating agents played very important roles in enhancing the membrane porosity and water flux.

• Membrane Journal
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• v.7 no.2
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• pp.84-94
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• 1997

The performances of both module sets made by different methods for helical module were compared. All experiments were conducted simultaneously at the same transmembrane pressure and energy cosumption per membrane area. The effects of Dean vortices for reducing concentration polarization and fouling were low for the first module set. The increase of 115% for permeate flux improvement(permeate flux difference ${\times}100$/pemeate flux of linear module) was measured. The second module set was more effective in reducing concentration polarization and fouling.

• Journal of Drive and Control
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• v.16 no.2
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• pp.66-71
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• 2019

In this study, flow analysis and dehumidification experiments were performed on hollow fiber membrane module to confirm the dehumidification characteristics for its different configurations. The CFD for the three different models was conducted using $30^{\circ}C$ temperature and 30%RH inlet humidity for quantitative analysis. Each model has different shape parameters i.e. the number of baffles. Comparison between flow analysis results and dehumidification experiment results revealed a percentage error of about 5%. The difference in relative humidity between the inlet and outlet for each model was calculated using flow analysis data. It was established that the difference in relative humidity of the inlet and outlet for the refined model with three baffles was highest among the three modeled modules of hollow fiber membrane module, i.e. around 9%.

• Membrane Journal
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• v.29 no.6
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• pp.362-376
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• 2019

In this study, hydrophilic coating characteristics of PVDF [poly(vinylidene fluoride)] hollow fiber membranes with flower type cross-section prepared by thermally induced phase separation were studied. The hollow fiber used in this study was provided from PureEnvitech Co. Ltd., and the hydrophilic coating experiment was performed with different concentration and number of coating of PEBAX 1657, 2533 and 3533 block copolymer solution using a dip coating method. The hydrophilic coated hollow fiber membrane was characterized to scanning microscope and contact angle measurements to determine the degree of hydrophilization. As a result of SEM characterization, it was confirmed that the thickness of the coating layer increased as the coating concentration increased and the number of coatings increased. Contact angle of surface of hollow fibers decreased as the concentration of the coating solution increased and the number of coatings increased. Gas permeance of oxygen gas was measured for the application of the hydrophilized hollow fiber to Membrane Areated Biofilm Reactor. As a result of gas permeation test, it was confirmed that gas permeance decreased with increasing coating concentration and number of coatings, and the more hydrophilized hollow fiber coated with PEBAX 1657 showed lower gas permeance than those coated with PEBAX 2533 and 3533.