• Membrane Journal
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• v.29 no.3
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• pp.140-146
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• 2019

In this study, a selective layer of poly styrene sulfonic acid (PSSA) and polyethyleneimine (PEI) was formed by layer-by-layer method onto a porous polyacrylonitrile (PAN) hollow fiber membrane as the suppoter membrane. The salting out method was used by adding Mg salt to the coating solution. Several experimental conditions of the ionic strength, polymer concentration, and coating time were investigated, and the flux and rejection were measured at the operating pressure of 2 atm for 100 mg/L of NaCl, $MgCl_2$, and $CaSO_4$ as the feed solution. The membranes coated with PSSA 20,000 ppm, coating time 3 minutes, ionic strength 1.0, PEI 30,000 ppm, coating time 1 minute, and ionic strength 0.1 were observed the best. In the 100 ppm NaCl, $MgCl_2$, and $CaSO_4$ feed solutions, the flux of 20.4, 19.4, and 18.7 LMH, and the rejection of 67, 90, and 66.6%, respectively.

• Membrane Journal
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• v.15 no.2
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• pp.147-156
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• 2005

It is well-known that polyethersulfone (PES) has high $CO_2$ selectivity over $N_2\;(or\;CH_4)$ and excellent pressure resistance of $CO_2$ plasticization among muy commercialized engineering plastics[1-4]. Asymmetric PES hollow fiber membranes for flue gas separation were developed by dry-wet spinning technique. The dope solution consists of PES, NMP and acetone. Water and water/NMP mixtures are used in outer and inner coagulants, respectively. Gas permeation rate (i.e., permeance) and $CO_2/N_2$ selectivity were measured with pure gas, respectively and the micro-structure of hollow fiber membranes was characterized by scanning electron microscopy. The effects of polymer concentration, ratio of NMP to acetone, length of air gap, evaporation condition and silicone coating were investigated on the $CO_2/N_2$ separation properties of the hollow fibers. Optimized PES hollow fiber membranes exhibited high permeance of $25\~50$ GPU and $CO_2/N_2$ selectivity of $30\~40$ at room temperature and have the apparent skin layer thickness of about $0.1\;{\mu}m$. The developed PES hollow fiber membranes, would be a good candidate suitable for the flue gas separation process.

• Membrane and Water Treatment
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• v.13 no.6
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• pp.291-301
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• 2022

In this study, cement/PVDF hollow-fiber hybrid membranes were prepared via a mixed process of diffusion-induced phase separation and hydration. The presence of X-ray diffraction peaks of Ca(OH)₂, an AFt phase, an AFm phase, and C-S-H phase confirmed the hydration reaction. Good hydrophilicity was obtained. The cross-sectional and surface morphologies of the hybrid membranes showed that an asymmetric pore structure was formed. Hydration products comprising parallel plates of Ca(OH)₂, fibrous ettringite AFt, and granulated particles AFm were obtained gradually. For the hybrid membranes cured for different time, the pore-size distribution was similar but the porosity decreased because of blocking of the hydration products. In addition, the water flux decreased with hydration time, and carbon retention was 90% after 5 h of rejection treatment. Almost all the Zn²⁺ ions were adsorbed by the hybrid membrane. The above results proved that the obtained membrane could be alternative as basement membrane for separation application.

• Membrane Journal
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• v.32 no.4
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• pp.227-234
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• 2022

Wastewater is released from leather, textile, paint, wood, or dye processing industries as well as petroleum refining industries. Wastewater from these industries contains water pollutant such as heavy metals and nitrogen compounds and has high chemical oxygen demand (COD). While there various filtering pollutants from wastewater for safe disposal, membrane-based technology is one of the most efficient methods for its high efficiency and low cost. Among various membranes, zeolite membranes gain spotlight for its cost-effectiveness and have undergone a lot of research. This review is focused on recent progress in zeolite membrane for wastewater treatment in following order: i) wastewater treatment, ii) microfiltration membrane, iii) hollow fiber membrane, and iv) ultrafiltration membrane.

• Proceedings of the Membrane Society of Korea Conference
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• 2001.05a
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• pp.139-141
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• 2001

• Proceedings of the Membrane Society of Korea Conference
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• 2001.05a
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• pp.101-103
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• 2001

• Proceedings of the Membrane Society of Korea Conference
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• 2003.05a
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• pp.67-70
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• 2003

• Proceedings of the Membrane Society of Korea Conference
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• 1999.10b
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• pp.77-80
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• 1999

• Proceedings of the Membrane Society of Korea Conference
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• 1999.10b
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• pp.117-119
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• 1999

• Proceedings of the Membrane Society of Korea Conference
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• 2002.11a
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• pp.139-141
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• 2002