• Macromolecular Research
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• 제12권6호
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• pp.553-558
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• 2004

An ultrafiltration membrane (polyethersulfone, PM 10) was surface-modified by treating it with low-tem­perature plasmas of oxygen, acrylic acid (AA), acetylene, diaminocyolohexane (DACH), and hexamethyldisiloxane (HMDSO). The effects that these modifications have on the filtration efficiency of a membrane in waste water treat­ment were investigated. The oxygen, AA, and DACH plasma-treated membranes became more hydrophilic. The water contact angles ranged from < $10^{\circ}\;to\;55^{\circ}$ depending on the type of plasma and the treatment conditions. The oxygen plasma-treated membranes displayed a higher initial flux $(312-429\%),$ but lower rejection $(6-91\%),$ than did an untreated membrane. The AA plasma-treated membranes displayed lower or higher initial flux $(42-156\%),$ depending upon the treatment conditions, but higher rejection $(224-295\%)$ in all cases. The DACH plasma-treated membranes displayed lower initial flux. All of them, especially the AA plasma-treated membrane, displayed improved fouling resistance with either a slower or no flux decline. Acetylene and HMDSO plasma-treated membranes became more hydrophobic and displayed both lower initial flux and lower fouling resistance.

• 한국막학회:학술대회논문집
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• 한국막학회 1998년도 춘계 총회 및 학술발표회
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• pp.99-101
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• 1998

1. Introduction : The conventional grafting polymerization technique requires chemically reactive groups on the surface as well as on the polymer chains. For this reason, a series of prefunctionalization steps are necessary for covalent grafting. The surface prefunctionalizational technique for grafting can be used to ionization radiation, UV, plasma, ion beam or chemical initiators. Of these techniques, radiation method is one of the useful methods because of uniform and rapid creation of active radical sites without catalytic contamination in grafted samples. If the diffusion of monomer into polymer is large enough to come to the inside of polymer substrate, a homogeneous and uniform grafting reaction can be carried out throughout the whole polymer substrate. Radiation-induced grafting method may attach specific functional moieties to a polymeric substrate, such as preirradiation and simultaneous irradiation. The former is irradiated at backbone polymer in vacuum or nitrogen gas and air, and then subsequent monomer grafting by trapped or peroxy radicals, while the latter is irradiated at backbone polymer in the presence of the monomer. Therefore, radiation-induced polymerization can be used to modification of the chemical and physical properties of the polymeric materials and has attracted considerable interest because it imparts desirable properties such as blood compatibility. membrane quality, ion excahnge, dyeability, protein adsorption, and immobilization of bioactive materials. Synthesizing biocompatible materials by radiation method such as preirradiation or simultaneous irradiation has often used $\gamma$-rays to graft hydrophilic monomers onto hydrophobic polymer substrates. In this work, in attempt to produce surfaces that show low levels of anti-fouling of bovine serum albumin(BSA) solutions, hydroxyethyl methacrylate(HEMA) was grafted polypropylene membrane surfaces by preirradiation technique. The anti-fouling effect of the polypropylene membrane after grafting was examined by permeation BSA solution.

• 접착 및 계면
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• 제15권1호
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• pp.1-8
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• 2014

이온 교환막은 전기투석, 확산투석, Redox flow 전지, 연료전지 등 다양하고 넓은 분야에서 사용되고 있다. 초음파를 이용하여 만들어진 PVC 양이온 교환막을 시간을 변화시켜 가면서 술폰화 반응에 의해 제조하였다. 술폰화제로 황산을 사용하였으며, 술폰화 PVC 양이온 교환막의 기본구조와 특성을 FT-IR, EDX, Water uptake, 이온교환용량(IEC), 전기저항(ER), 전도도, 이온수송수 및 표면 morphology를 SEM 분석하였다. FT-IR 스펙트럼 분석결과 술폰화 PVC 양이온 교환막에 술폰산기가 도입되었음을 확인하였으며 멤브레인의 Water uptake, IEC, 전기 저항 및 ion transport number의 최대값은 각각 40.2%, 0.87 meq/g, $35.2{\Omega}{\cdot}cm^2$ 및 0.88이었다.

• 멤브레인
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• 제32권6호
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• pp.411-426
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• 2022

다양한 장치에 대한 광범위한 의존으로 에너지는 현대 생활에서 중요한 역할을 하고 있다. 전통적인 에너지원은 많은 환경 및 건강 문제를 안고 있어, 환경과 건강에 미치는 영향을 최소화하면서 에너지 수요를 충족할 수 있는 대체 가능한 에너지원이 시급히 필요하다. 이러한 관점에서 연료전지, 특히 음이온 교환막 연료전지는 고가의 촉매를 사용하지 않는 빠른 반응속도, 컴팩트한 디자인, 수소 이외의 연료 선택 가능성 및 보다 저렴한 연료의 사용이 가능한 특성으로 인하여 다른 연료전지에 비해 큰 주목을 받고 있다. 그럼에도 이온전도성이 높고 화학적, 기계적으로 안정적인 음이온 교환막의 개발이 부진한 것이 주요 장애물이 되어 왔고, 그래핀 기반 고분자 복합막이 AEMFC용 전해질막으로 등장하게 되었다. 2D 구조, 높은 기계적 강도, 높은 내화학성 및 표면적과 같은 그래핀의 견고한 구조 및 물리적 특성은 음이온교환막의 성능 개선에 도움이 된다고 보고되고, 그래핀 및 그 유도체를 사용하는 전해질막의 연구가 중요하게 되었으나, 그래핀 재료의 높은 잠재력에도 지나친 응집 경향으로 나타나는 문제점이 지적되고 있어 그래핀 유도체의 표면 개질은 응집을 완화하고 그래핀이 가지는 잠재적 성능을 이끌어내는데 꼭 필요하다. 따라서 본 고에서는 그래핀과 유도체의 표면 개질과 연료 전지용 AEM 제조에서 그 역할에 초점을 맞추어서 논의하고자 한다.

• Membrane and Water Treatment
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• 제10권6호
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• pp.461-469
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• 2019

In the present work, we present a new effective hydrophilicity modifier for polysulfone (PSf) membrane. Firstly, amphiphilic nanocellulose (ANC) with different substitution degrees (SD) was synthesized by esterification reaction with nanocellulose (NC) and dodecyl succinic anhydride (DDSA). The SD and morphology of ANC were characterized by titration method and transmission electron microscopy (TEM). Then, the polysulfone (PSf)/ANC blend membranes were prepared via an immersion phase inversion method. The influence of SD on the morphology, structure and performances of PSf/ANC blend membrane were carefully investigated by Fourier transform infrared spectroscopy (FTIR), scanning electron microscope (SEM), mechanical property test, contact angle measuring instrument and filtration experiment. The results showed that the mechanical property, hydrophilicity and anti-fouling property of all the PSf/ANC blend membranes were higher than those of pure PSf membrane and PSf/NC membrane, and the membrane properties were increased with the increasing of SD values. As ANC-4 has the highest SD value, PSf/ANC-4 membrane exhibited the optimal membrane properties. In conclusion, the prepared ANC can be used as an additive to improve the hydrophilicity and anti-fouling properties of polysulfone (PSf) membrane.

• Bulletin of the Korean Chemical Society
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• 제32권7호
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• pp.2351-2357
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• 2011

Three new metal-organic copper(II) complexes, $[Cu(H_2PZTC)_2]_n{\cdot}2nH_2O$ (1), $[Cu(HPZTC){\cdot}2H_2O]_n{\cdot}2nH_2O$ (2), and $Cu_2[(PZHD)(OH)(H_2O)_2]_n$ (3) ($H_3PZTC$ = pyrazine-2,3,5-tricarboxylic acid, $PZHD^{3-}$ = 2-hydroxypyrazine-3,5-dicarboxylate), have been synthesized from $Cu(II)/H_3PZTC$ system under different synthetic conditions, and characterized by single-crystal X-ray diffraction, elemental analysis, IR spectroscopy and thermogravimetric analysis. In complexes 1 and 2, $H_3PZTC$ ligands loose one and two protons, which were transformed into $H_2PZTC^-$ anion and $HPZTC^{2-}$ dianion under different preparation condition, respectively. Furthermore, two ligands coordinate with Cu(II) cations in different modes, leading to the formation of the different chain structures. In complex 3, $H_3PZTC$ ligand was converted into a new ligand-PZHD by in situ decarboxylation and hydroxylation under a higher pH value than that for complexes 1 and 2. PZHD ligands link the Cu(II) cations to form a 2D layer structure. These results demonstrate that the preparation conditions, including pH value and reaction temperature etc, play an important role in the construction of complexes based on $H_3PZTC$ ligand.

• 한국막학회:학술대회논문집
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• 한국막학회 1994년도 춘계 총회 및 학술발표회
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• pp.55-56
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• 1994

There has been many attempts to improve the membrane performance using pervaporation processes[l-3]. They are 1) blending polymer with the high flux and one with high selectivity, 2) an incorporation of functional groups interacting with permeants into a membrane through copolymerization or modification, 3) composite membrane or asymmetric membrane structure with a thin skin layer which acts as a selective layer. Among them, a polymeric membrane containing ion complex group receives an extensive attention recently because ionic complex is known to activate the water transport through ion-dipole interaction. It is especially advantageous in the separation of organic-water system. We applied the ideas of the activation of water transport through ion-dipole. We have reported on the in-sire complex membrane to separate water from aqueous aceiic acid and pyridme solution[4-5] based on the simple acid-base theory. Water transport was enhanced through in-situ complex between pyridine moiety in the membrane and the incoming acetic acid in the feed. In this case, catalytic transport mechanism was proposed. In the present study we used pyridine solution as a feed and the sulfonic acid group in the membrane.

• Membrane and Water Treatment
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• 제6권3호
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• pp.173-187
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• 2015

The goal of present work is the preparation of a novel positively charged nanofiltration (NF) membrane and its development for the cation removal of aqueous solutions. This NF membrane was fabricated by the surface modification of polysulfone (PSf) ultrafiltration support. The active top-layer was formed by interfacial cross-linking polymerization of poly(ethyleneimine) (PEI) with p-xylylene dichloride (XDC) and then quaternized with methyl iodide to form a perpetually positively charged layer. In order to improve the efficiency of nanofiltration membrane, the concentration of PEI, XDC and methyl iodide solutions, PEI coating and cross-linking time have been optimized. As a result, a high water flux and high $CaCl_2$ rejection (1,000 ppm) was obtained for the composite membrane with values of $18.29L/m^2.h$ and 93.62% at 4 bar and $25^{\circ}C$, respectively. The rejections of NF membrane for different salt solutions followed the order of $Na_2SO_4$ < $MgSO_4$ < NaCl < $CaCl_2$. Molecular weight of cut off (MWCO) was calculated via retaining of PEG solutions with different molecular weights that finally, it revealed the Stokes and hydrodynamic radius of 1.457 and 2.507 nm on the membrane selective layer, respectively. The most efficient positively charged nanofiltration membrane exhibited a $Ni^{2+}$ rejection of 96.26% for industrial wastewater from Shamse Hadaf Co. (Kashan, Iran).

• Membrane and Water Treatment
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• 제2권4호
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• pp.207-223
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• 2011

Supported Liquid Membranes (SLMs) have been widely studied as feasible alternative to traditional processes for separation and purification of various chemicals both from aqueous and organic matrices. This technique offers various advantages like active transport, possibility to use expensive extractants, high selectivity, low energy requirements and minimization of chemical additives. SLMs are not yet used at large scale in industrial applications, because of the low stability. In the present paper, after a brief overview of the state of the art of SLM technology the facilitated transport mechanisms of SLM based separation is described, also introducing the small and the big carrousel models, which are employed for transport modeling. The main operating parameters (selectivity, flux and permeability) are introduced. The problems related to system stabilization are also discussed, giving particular attention to the influence of membrane materials (solid membrane support and organic liquid membrane (LM) phase). Various approaches proposed in literature to enhance SLM stability are also reviewed. Modification of the solid membrane support, creating an additional layer on membrane surface, which acts as a barrier to LM phase loss, increases system stability, but the membrane permeability, and then the flux, decrease. Stagnant Sandwich Liquid Membrane (SSwLM), an implementation of the SLM system, results in both high flux and stability compared to SLM. Finally, possible large scale applications of SLMs are also reviewed, evidencing that if the LM separation process is opportunely carried out (no production of byproducts), it can be considered as a green process.

• 한국진공학회:학술대회논문집
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• 한국진공학회 1997년도 제12회 학술발표회 논문개요집
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• pp.104-104
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• 1997