• Membrane and Water Treatment
• /
• v.9 no.1
• /
• pp.43-51
• /
• 2018

Hollow fiber (HF) membranes are gaining wide interest over flat membranes due to their compaction and high area to surface volume ratio. This work addresses the fabrication of HF from polysulfone (PS) and polyethersulfone (PES) using N-methylpyrrolidone (NMP) as solvent in addition to other additives to achieve desired characteristics. The semi-pilot spinning system includes jacketed vessel, four spinneret block, coagulation and washing baths in addition to dryer and winder. Different parameters affecting dry-wet spinning phase inversion process were investigated. Dope compositions of PES, NMP and polyvinyl pyrrolidone (PVP) of varying molecular weights as additive were addressed. Some critical parameters of importance were also investigated. Those include dope flow rate, air gap, coagulation & washing baths and drying temperatures. The measured dope viscosity was in the range from 1.7 to 36.5 Pa.s. Air gap distance was adjusted from 20 to 45 cm and coagulation bath temperature from 20 to $46^{\circ}C$. The HF membranes were characterized by scanning electron microscope (SEM), atomic force microscope (AFM) and mechanical properties. Results indicated prevalence of finger like structure and average surface roughness from about 29 to 78.3 nm. Profile of stress strain characteristics revealed suitability of the fibers for downstream interventions for fabrication of thin film composite membrane. Different empirical correlations were formulated which enable deeper understanding of the interaction of the above mentioned variables. Data of pure water permeability (PWP) confirmed that the fabricated samples fall within the microfiltration (MF)-ultrafiltration (UF) range of membrane separation.

• Proceedings of the Membrane Society of Korea Conference
• /
• 2004.05b
• /
• pp.168-171
• /
• 2004

이산화탄소는 메탄, 오존, 산화질소, CFC등의 온실기체 중 약 50%를 차지하는 물질로서 이산화탄소 발생의 저감과 함께 회수 기술의 개발을 통한 배출량 억제는 환경적 측면에서 대단히 중요한 것으로 간주되고 있다. 따라서 각종 산업분야에서 발생하는 다양한 성분을 가진 다성분계 배가스내에 존재하는 10%내외의 이산화탄소만을 분리정제 농축하여 메탄, 메탄올 등의 다른 화학물질의 제조의 원료, 신에너지원, 고부가가치의 신제품 등으로 전환하는 연구가 활발히 진행 중이다.(중략)

• Proceedings of the Membrane Society of Korea Conference
• /
• 1994.10a
• /
• pp.60-61
• /
• 1994

복합막은 기존의 비대칭막에 비해서 극히 얇은 표면층을 형성할 수 있다. 이러한 복합막은 배제율도 우수할 뿐만아니라 투과속도 또한 매우 큰 특징을 가지고 있으며, 해수의 담수화를 비롯하여 초순수 제조 등 각종 산업분야에서 많이 응용되고 있다. 우수한 분리막을 제조하기 위해서는 막의 표면층을 보다 더 치밀하고 얇게 형성할 수 있어야 한다. 이렇게 하기 위해서는 지지막 또한 매우 중요한 요인으로 작용한다. 표면층이 치밀하고, 가능한 한 porosity가 큰 지지막을 제조해야한다. 따라서 본 연구에서는 고분자 물질로 Polyethersulfone을 사용하여 지지막을 만들었다. 이 지지막위에 계면중합법으로 NF/RO용 복합막을 제조하였다. 높은 투과 속도 및 염의 배제율이 우수한 복합막을 제조하기 위해서 먼저 Polymer 농도, 첨가제 종류및 농도 등에 의한 각종 제막조건에 따른 지지막의 성능을 조사하였다. 여기에 Monomer 농도를 변화시켜서 계면중합으로 복합막을 제조하여 그 성능 변화를 측정하였다.

• Proceedings of the Membrane Society of Korea Conference
• /
• 1995.04a
• /
• pp.22-23
• /
• 1995

한외여과막이 순수제조, 고분자물질의 분리, 폐수처리 등에 쓰이기 시작되면서, 높은 투과율, 내화학성, 충전밀도를 갖는 모듈이 요구되었다. 따라서 polysulfone(이하 PSf)을 막의 재질로 사용한 중공사형모듈이 주로 개발되었다. 그러나 본 연구에서는 PSf보다 투과율, 기계적 강도, 열적강도 및 화학적 성질 면에서 뛰어난 polythersulfone(이하 PES)을 막의 재질로 선택하였다. 또한, 지금까지는 수백 ${\AA}$에서 1mm정도의 외경(O.D.)을 갖는 중공사막이 개발되었다. 따라서 상당히 높은 충전밀도를 갖는 모듈은 개발되었으나, 점성이 높은 feed를 처리할 때, fouling이 큰 문제로 대두되었으며, 중공사막보다 외경이 큰 관형 막은 fouling에는 비교적 강하나, 충전밀도가 낮아서 단위부피당 flux가 낮은 단점을 갖고 있다. 따라서, 중공사막과 관형 막의 중간형태인 외경 2mm이상의 capillary membrane은 강한 fouling 저항과 비교적 높은 단위 부피당 투과율을 갖는다.

• Membrane Journal
• /
• v.30 no.1
• /
• pp.46-56
• /
• 2020

In this study, poly (ether-block-amide) (PEBAX)/poly (ethylene) glycoldiacrylate (PEGDA)/zeolitic imidazolate framework-8 (ZIF-8)-polyethersulfone (PES) composite membranes were prepared. The gas permeation properties of N₂ and CO₂ were investigated for each composite membrane. First, the gas permeability in the PEBAX/PEGDA-PES composite membrane decreased with increasing PEGDA content for each molecular weight at PEGDA250, PEGDA575, and PEGDA-700 g/mol. The CO₂/N₂ selectivity showed a constant value and gradually increased with increasing PEGDA content after 30 wt% PEGDA, and PEBAX/PEGDA250 50 wt%-PES prepared by adding PEGDA250 g/mol 50 wt% showed a selectivity of 15.1. This is because as the PEGDA content increases, the number of diacrylate groups increases, and the CO₂ affinity due to the ether structure of PEGDA increases. Gas permeation properties according to ZIF-8 were investigated for composite membranes of PEGDA 0 to 30 wt%, with CO₂/N₂ selectivity almost constant for each molecular weight. The permeability of N₂ and CO₂ gradually increased with increasing ZIF-8 content, and CO₂/N₂ selectivity was the highest at 3.4 in PEBAX/PEGDA250 g/mol 30 wt%/ZIF-8 20 wt%-PES composite membrane.

• Membrane Journal
• /
• v.33 no.6
• /
• pp.439-446
• /
• 2023

Ceramic membranes are generally used for various industrial processes operating under extreme conditions because of its high thermal and chemical stability. However, due to the trade-off phenomenon of permeability and mechanical strength, preparation of high permeability-high strength membrane is necessary. In this study, the change in characteristics and performances of ceramic membranes was analyzed depending on the type of polymer binder and its mixing ratio. Because the solubility between solvent and polymer binder was higher in PSf (polysulfone) than in PES (polyethersulfone), the viscosity and discharge pressure of the PSf-based dope solution were higher than those of PES-based dope solution. When PSf was used as a polymer binder, ceramic membrane showed high mechanical strength and low water permeability due to the dense structure. On the other hand, in case of PES, the mechanical strength was slightly reduced and the water permeability was increased. It was confirmed that the optimum mixing ratio of the PSf and PES with high water permeability and mechanical strength was 9:1.

• Membrane Journal
• /
• v.18 no.3
• /
• pp.214-218
• /
• 2008

Protain affinity membranes based on PES-BSA was preapared by the electrospinning method. The process problem caused by the electrospining was solved by using HFB having high solubility and boiling point. It was expecting that the mass production of protein affinity membrane would be possible with broad range of optimized temperature and humidity. BSA in the PES nanofiber was confirmed by the color change from colorless to violet during the biuret test. The buffer solution with DMSO showed that the amount of elution was 5 times higher than the one when the buffer solution without DMSO was used. This is due to the restriction effect of DMSO on the dissociation of L-tryptophan from BSA during the washing step.

• Environmental Engineering Research
• /
• v.23 no.3
• /
• pp.316-322
• /
• 2018

In this study, the effects of polymer concentration and additive in the formation of asymmetric nanofiltration (NF) membrane were evaluated. The membrane fabrication was carried out via dry/wet phase inversion technique. A new formulation of dope solution with polymer concentration ranging between 17 wt% to 21 wt% and the present of additive was developed. The results show that the permeate flux gradually decreases as polymer concentration increased, until $2.5969L/m^2h$ and increased the rejection up to 98.7%. Addition of additive, polyethylene glycol 600 increased dyes rejection up to 99.8% and decreased the permeate flux to $3.6501L/m^2h$. This indicates that the addition of polyethylene glycol additive led towards better membrane performance. The morphological characteristics of NF membrane were analysed using a Scanning Electron Microscopy.

• Macromolecular Research
• /
• v.9 no.5
• /
• pp.285-291
• /
• 2001

The polysulfone(PSf)/polyethersulfone(PES) blend membranes were prepared by an immersion precipitation method. N-methyl-2-pyrrolidone(NMP) was used as a solvent and water as a nonsolvent. The composition of the coagulation bath and the dope polymer concentration as well as the blend ratio of two polymers were varied. The membrane morphologies were interpreted on the basis of the phase diagram of the PSf/PES/NMP/water system. As the solvent content in the coagulation bath increased in the single polymer system, the number of macrovoids decreased and the morphology was changed from finger-like to cellular structure. In the given bath condition phase separation occurs earlier for the solutions of PSf/PES blend than for those of single polymer. A horizontally layered structure and horizontal protuberances inside the macrovoid were observed for the membranes formed from PSf/PES blend solutions. This peculiar structure formation can be interpreted by a PSf-rich/PES-rich phase separation followed by a polymer-rich/polymer-lean phase separation during the exchange of solvent and nonsolvent.

• Proceedings of the Membrane Society of Korea Conference
• /
• 2005.11a
• /
• pp.133-147
• /
• 2005

In order to investigate applicability for 2,2,2-trifluoroethyl methacrylate (TFEMA) produced by esterification of 2,2,2-trifluoroethanol(TFEA) and methacrylic acid(MA) using pervaporation membrane, poly(vinyl alcohol) (PVA) composite membranes were prepared with glutaraldehyde(GA) onto porous polyethersulfone(PES) support. The degree of crosslinking and thickness of PVA coating layer were analyzed by swelling test and SEM(scanning electron microscopy), respectively. Pervaporation test was done with two feed mixures; TFEA/water, MA/water. The pervaporation data were obtained as a function of content of crosslinking agent, feed composition, and operating temperature, respectively. In case of TFEA-water(90/10 wt%) feed mixture at $80^{\circ}C$, the optimized membrane showed the high permeation flux of 1.5 $kg/m^2hr$ and separation factor of 320. In case of MA-water(90/10 wt%) feed mixture, the membranealso showed high permeation flux of 2.3 $kg/m^2hr$ and separation factor of 740 in same conditions.