• 멤브레인
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• 제11권1호
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• pp.22-28
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• 2001

이온성 고분자에 비이온성 고분자를 섞어 이온 함량을 조절함으로써 다양한 전하량을 갖는 이온성 막을 제조하였다. 비이온성 고분자로는 폴리비닐알콜, 음이온성 고분자로는 알긴산 나트륨, 양이온성 고분자로는 키토산을 사용하였으며, 이들 이온성 고분자막을 사용하여 여러 전해질 수용액에 대한 투과 및 분리특성을 관찰하였다. 막 내부에 이온성 고분자 함량이 많을수록 친수성 특성을 보였으며, 순수투과 및 용액투과 속도가 증가함을 관찰할 수 있었고, 또한 투과속도는 막의 팽윤 거동에 의해 결정됨을 확인할 수 있었다. 용질 배제율의 경우는 막과 투과용질간의 정전기적 인력, 즉 Donnan exclusion에 의해 결정이 되며, 정전기적 인력이 비슷한 경우는 분자체 효과에 의해 분리됨이 관찰되었다.

• Membrane and Water Treatment
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• 제3권2호
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• pp.123-131
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• 2012

This study investigated the extraction and stripping performance of PIMs consisting of PVC and Aliquat 336. Extraction and stripping of three representative heavy metals - namely $Cd^{2+}$, $Cu^{2+}$, and $Zn^{2+}$ - by the synthesized membranes were evaluated as a function of sodium chloride concentration and under different stripping solutions (0.01 M $HNO_3$, Milli-Q water, 0.01 M HCl and 0.01 M NaOH), respectively. Results reported here indicate that the formation of negatively charged metal chloride complex species was responsible for the extraction of the target metal to PIMs. Experimental results and thermodynamic modeling of the speciation of chloro metal complexes further confirm that the extraction selectivity between $Cd^{2+}$, $Cu^{2+}$ and $Zn^{2+}$ can be controlled by regulating the chloride concentration of the feed solution. An acidic solution without any chloride was the most effective stripping solution, followed by Milli-Q water, and a diluted hydrochloric acid solution. On the other hand, the stripping of metals from PIMs did not occur when a basic stripping solution was used.

• 대한전기학회논문지:전기물성ㆍ응용부문C
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• 제52권7호
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• pp.298-304
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• 2003

IPMC(Ionic Polymer-Metal Composite) is a highly sensitive actuator that shows a large deformation in presence of low applied voltage. Generally, IPMC can be fabricated by electroless plating of platinum on both sides of a Nafion (perfluorosulfonic acid) film. When a commercial Nafion film is used as a base structure of the IPMC membrane, the micro-pump structure and the IPMC membrane are fabricated separately and then later assembled, which makes the fabrication inefficient. Therefore, fabrication of an IPMC membrane and the micro-pump structure on a single wafer without the need of assembly have been developed. The silicon wafer was partially etched to hold liquid Nafion to be casted and a 60-${\mu}{\textrm}{m}$ thick IPMC membrane was realized. IPMC membranes with various size were fabricated by casting and they showed 4-2${\mu}{\textrm}{m}$ displacements from $4mm{\times}4mm$ , $6mm{\times}6mm$, $8mm{\times}8mm$ membranes at the applied voltage ranging from 2Vp-p to 5Vp-p at 0.5Hz. The displacement of the fabricated IPMC membranes is fairly proportional to the membrane area and the applied voltage.

• Korean Membrane Journal
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• 제2권1호
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• pp.36-47
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• 2000

This paper deals with the separation of MTBE-methanol mixtures using crosslinked Poly(vinyl alcohol)(PVA) membranes with sulfur-succinic acid(SSA) as a crosslinking agent by pervaporation and vapor permeation technique. The operating temperatures, methanol concentration in feed mixtures, and SSA concentrations in PVA membranes were varied to investigate the separation performance of PVA/SSA membranes and the optimum separation characteristics by pervaporation and vapor permeation. And also, for PVA/SSA membranes, the swelling measurements were carried out to study the transport phenomena. The swelling measurements were carried out for pure MTBE and methanol, and MTBE/methanol=90/10, 80/20 mixtures using PVA/SSA membranes with varying SSA compositions. There are two factors of the membrane network and the hydrogen bonding. In pervaporation separation was also carried out for MTBE/methanol=90/10, 80/20 mixtures at various temperatures. The sulfuric acid group in SSA took an important role in the membrane performance. The crosslinking effect might be over the hydrogen bonding effect due to the sulfuric acid group at 3 and 5% SSA membranes, and this two factors act vice versa on 7% SSA membrane. In this case, the 5% SSA membrane shows the highest separation factor of 2,095 with the flux of 12.79g/㎡$.$hr for MTBE/methanol=80/20 mixtures at 30$^{\circ}C$ which this mixtures show near the azeotopic composition. Compared to pervaporation, vapor permeation showed less flux and similar separation factor. In this case, the flux decreased significantly because of compact structure and the effect of hydrogen bonding. In vapor permeation, density or concentration of methanol in vaporous feed is lower than that of methanol in liquid feed, as a result, the hydrogen bonding portion between the solvent and the hydroxyl group in PVA is reduced in vapor permeation. In this case, the 7% SSA membranes shows the highest separation factor of 2,187 with the flux of 4.84g/㎡$.$hr for MTBE/methanol=80/20 mixtures at 30$^{\circ}C$.

• Membrane and Water Treatment
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• 제12권1호
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• pp.43-49
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• 2021

The Commercial polymeric membranes like Polysulfone (PSF), Polyvinylidene difluoride (PVDF) and Polyacrylonitrile (PAN) which are an integral part of water purification investigation were chosen for the shockwave (SW) exposure experiment. These membranes were prepared by blending polymer (wt. %) / DMF (solvent) followed by phase-inversion casting technique. Shockwaves are generated by using Reddy Tube lab module (Table-top Shocktube) with range of pressure (1.5, 2.5 and 5 bar). Understanding the changes in membrane before and after shock wave treatment by parameters, i.e., pure water flux (PWF), rejection (%), porosity, surface roughness (AFM), morphology (SEM) and contact angle which can significantly affect the membrane's performance. Flux values PSf membranes shows increase, 465 (pristine) to 524 (1.5wt%) LMH at 50 Psi pressure and similar enhancement was observed at 100Psi (625 to 696 LMH). Porosity also shows improvement from 73.6% to 76.84% for 15wt% PSf membranes. It was observed that membranes made of polymers such as PAN and PSF (of high w/w %) exhibits some resistance against shockwaves impact and are stable compared to other membranes. Shockwave pressure of up to 1.5 bar was sufficient enough to change properties which are crucial for performance. Membranes exposed to a maximum pressure of 5 bar completely scratched the surface and with minimum pressure of 1.5bar is optimum enough to improve the water flux and other parameters. Initial results proved that SW may be suitable alternative route to minimize/control membrane fouling and improve efficiency.

• 멤브레인
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• 제4권1호
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• pp.9-29
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• 1994

The development of separation technology is an important research subject as is clear from its role in the Japanese government's research and development program for basic technology for the next generation(1981~1990). Japan is poor not only in mineral resources but also in energy resources and if a sudden change occurs in oil producing facility or an accident occurs in a nuclear power plant, then energy policy must undergo changes and economic foundations may collapse. Japan has already experienced this. Although, oil prices are stable at present and Japan can import oil at low cost due to the yen appreciation, Japan needs to promote development work for any new energy crisis that may come in the future. This has been the motive for gas separation membrane development in Japan. The study of gas permeation through polymer membranes, which is the basis for membranes for gas separation, at Japanese universities began many years ago, but interest in membranes for gas separation was aroused mainly by the Government. The development of gas separation membranes in Japan started with membranes for oxygen separation on an industrial scale.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2004년도 Asia Display / IMID 04
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• pp.369-372
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• 2004

Orientation of E7 liquid crystals(LCs) confined to 200 nm-diameter cylindrical cavities of Anodisc membranes are investigated by FTIR dichroism techniques. The cavity walls of the confining pores are chemically modified with different perfluorinated carboxylic acids (PCA, $C_nF_{2n+1}$COOH, n=3, 4, 5, 6). From the FTIR spectra of PCA treated alumina Anodsic membranes, we found the salt formation between -COOH group of PCA and Anodisc membrane. From the FTIR spectra of LC filled Anodisc membranes, we found abrupt alignment direction change of LC molecules between n=4 and 5 for 1 mM PCA treated Anodisc membranes, from parallel to perpendicular direction to the cavity walls. But 5mM PCA treated Anodisc membranes, alignment direction of LC molecules changed between n=3 and n=4, from parallel to perpendicular direction.

• Macromolecular Research
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• 제10권4호
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• pp.209-214
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• 2002

Miscibility of polysulfone (PSf) with various hydrophilic copolymers was explored. Among these blends, PSf gives homogeneous mixtures with poly(1-vinylpyrrolidone-co-styrene) copolymers [P(VP-S)] when these copolymers contained VP from 68 to 88 wt%. Microporous membranes for the ultrafiltration process were prepared from PSf blends with P(VP-S) copolymers. The membranes prepared from the PSf/(VP-S) blends exhibited higher water flux than the membranes prepared from PSf irrespective of the VP content. The solute rejection examined with the membranes fabricated from the miscible blends was similar to that of PSf membrane. However, the solute rejection examined with the membranes fabricated from the immiscible blends was lower than that of PSf membranes.

• 한국수산과학회지
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• 제49권6호
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• pp.815-822
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• 2016

The cationic biopolymer chitosan has several applications in medicine. Chitosan is the deacetylated derivative of chitin, the second most abundant naturally occurring polymer. Recent studies have investigated the relationship between chitosan and antibacterial activity. However, the molecular interactions and mechanisms have not been detailed. This study used molecular dynamics simulations to study interactions between chitosan and anionic bacterial membranes (POPE-POPG) and electrically neutral non-bacterial membranes (POPC). We calculated the free energy using umbrella sampling to compare the interactions between membranes and chitosan in different protonation states. Fully protonated chitosan interacted most strongly with the bacterial membranes, but weakly with non-bacterial membranes. These results suggest that electrostatic interactions are the main mechanism of the antibacterial activity of chitosan, and they provide insights into the design of novel antibacterial and antimicrobial agents.

• 한국막학회:학술대회논문집
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• 한국막학회 2004년도 Proceedings of the second conference of aseanian membrane society
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• pp.51-54
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• 2004

Utilization of membranes offers the promise of extraordinary energy savings if successfully applied to hydrocarbon-hydrocarbon and other organic separations. Membranes are bound to enter into refining and petrochemical operations involving liquid separations once appropriate materials and modules are developed. Hybrid processes such as utilizing membrane modules to break azeotropes formed during distillation are particularly attractive because they offer less process complexity and reduced capital investment[1,2].(omitted)