• Membrane Journal
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• v.27 no.5
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• pp.441-448
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• 2017

In this study, the effects of membrane characteristics on the power generation performance in reverse electrodialysis (RED) have been investigated with pore-filled ion-exchange membranes (PFIEMs) prepared by employing a porous polyethylene substrate and the mixtures of three cross-linking agents. As a result, it was confirmed through the correlation analyses that the cross-linking degree and free volume of the PFIEMs were effectively controlled by mixing the cross-linking agents having different molecular sizes, influencing complexly the electrochemical characteristics of the membranes and the power generation performance in RED. In particular, the pore-filled cation-exchange membranes at the optimum cross-linking conditions exhibited the power generation performance superior to that of the commercial membranes and the pore-filled anion-exchange membranes also showed the excellent performance close to that of the commercial membrane.

• Membrane Journal
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• v.11 no.3
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• pp.109-115
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• 2001

Pore-filled ion-exchange membranes in which polypropylene(PP) microporous membrane was used as a nascent membrane were prepared by an in-situ cross-linking technique. Poly(vinylbenzyl chloride)(PVBCI) reacted with piperazine(PIP) or 1,4-diaminobicyclo[2,2,2]octane(DABCO) in a di-methylforamide(DMF) solution was filled in the pores of the microporous base membrane. After gellation the remaining chloromethyl groups were, then reacted with an amine such as trimethylamine to form positively charged, ammonium site. This will produce the pore-filled anion-exchange membrane. It was shown that this simple 2 step procedure gave dimensionally stable, pore-filled membranes in which the MG of polymer gel and degree of cross-linking could be easily controlled by the concentration of PVBCI and cross-linker in the starting DMF solution. Specially, high water permeability (7.8 kg/$m^2$hr, host membrane: PP3, MG: 73%, degree of cross-linking: 10%, crosslinker: PIP) at ultra low pressure(100 kPa) indicates the produced pore-filled membranes is usable as a water softening membrane.

• KSBB Journal
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• v.16 no.6
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• pp.533-537
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• 2001

${\alpha}$-lactalbumin and ${\beta}$-lactoglobulin in whey proteins were separated by high performance membrane chromatography (HPMC). The separation mechanism involved anion-exchange, and the stationary phase was anion CIM (Convective Interaction Media) DEAE, QA disk and cation exchanger SO$_3$(16${\times}$3 mm). Two types of mobile phase were used, buffer A (20 mM Tris-HCI, pH 7.3) and buffer B(buffer A + 1 M NaCl), As the amount of NaCl dissolved in buffer linearly increased, which enabled a gradient elution mode. The optimum mobile phase and operating condition (Buffer A/Buffer B = 100/0 - 30/70 vol%, gradient time 1 min, 30/70 - 10/90 vol.%, gradient time 2 min) were experimentally determined. In this experimental condition, ${\alpha}$-lacta1bumin, ${\beta}$-lactoglobulin were separated within 5 min at a mobile phase flow rate of 4 mL/min.

• Korean Journal of Microbiology
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• v.27 no.2
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• pp.117-123
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• 1989

Radioactive N-$\alpha$-p-nitrobenzoxycarbonyl (NBZ)-L-[2,$3-^{3}$H] arginyl diazomethane was used as an affinity label for the vacuolar arginine transporter in Neurospora crassa. Vacuolar matrix proteins were removed by fracturing the membranes with freeze-thaw method in dry ice/ethanol bath. Vacuolar membrane proteins were then wasged with 500mM NaCl to remove ionically bound derivatives and peripheral membrane proteins from vacuolar membranes. After dissolved in 1% Titon X-100, dissolved vacuolar memvrane proteins were separated with molecular sieve column chromatography, anion and cation exchange chromatographies. The arginine transporter was purified giving the purification factor of 1136.

• KSBB Journal
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• v.15 no.6
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• pp.605-608
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• 2000

Oligodeoxynucleotides (ODNs) were separated by high-performance membrane chromatography (HPMC), a combined system of chromatography and membrane. The separation mechanism involved anion-exchange, and the stationary phase was cation CIM (Convective Interaction Media) DEAE disk (16${\times}$3 mm). Two types of mobile phase were used, buffer A (20mM Tris-HCl, pH 7.4) and buffer B (buffer A + 1M NaCl). As the amount of NaCl dissolved in buffer linearly increased, the retention time shortened, which enabled a gradient elution mode. Based on the number of theoretical plates and resolution observed, the optimum mobile phase and operating condition (Buffer A/Buffer B=50/50 - 20/80 vol%, gradient time 2 min) were experimentally determined. In this experimental condition, ODNs were separated within 2 min at a mobile phase flow rate of 6 ml/min.

• Proceedings of the Membrane Society of Korea Conference
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• 1997.04b
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• pp.21-22
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• 1997

최근의 이온교환막은 종래의 양이온교환막의 표면에 polycation 등의 얇은 층을 덧붙인 다층막(multi-layer membrane)의 형태가 많이 이용되고 있으며, 정전기적 반발력의 차 등을 이용하여 원자가가 다른 이온들간의 투과성에 차를 부여하기 위하여 이용되고 있다. 이 때문에 polycation막을 통한 1가 이온과 2가 이온의 투과성을 연구하는 것은 우수한 이온교환막을 제작하는것 이상으로 중요하다. 본 연구에서는 고정전하농도(fixed charge density, $\Phi$ X)가 낮은 다공성 저전하음이온교환막을 제작하여, 양측에 대이온(counterion)은 같고 복이온(co-ion)이 다른 전해질용액을 두었을 경우에 관찰되는 막전위를 측정하였다. 이를 토대로 음이온교환막을 통한 막전위의 농도의존성에 관하여 검토하였으며, 비평형열역학(non-equilibrium thermodynamies)에 기초한 이론적 모델을 도입하여 실험치와 비교, 해석하였다.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.3 no.4
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• pp.269-278
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• 2005

In order to produce only a pH-controlled solution without discharging any unwanted solution, this work has developed a continuous electrolytic system with a pH-adjustment reservoir being placed before an ion exchange membrane-equipped electrolyzer, where as a target solution was fed into the pH-adjustment reservoir, some portion of the solution in the pH-adjustment reservoir was circulated through the cathodic or anodic chamber of the electrolyzer depending on the type of the ion exchange membrane used, and some other portion of the solution in the pH-adjustment reservoir was discharged from the electrolytic system through the other counter chamber with its pH being controlled. The internal circulation of the pH-adjustment reservoir solution through the anodic chamber in the case of using a cation exchange membrane and that through the cathodic chamber in the case of using an anion exchange membrane could make the solution discharged from the other counter chamber effectively acidic and basic, respectively. The phenomena of the pH being controlled in the system could be explained by the electro-migration of the ion species in the solution through the ion exchange membrane under a cell potential difference between anode and cathode and its consequently-occurring non-charge equilibriums and electrolytic water- split reactions in the anodic and cathodic chambers.

• Applied Chemistry for Engineering
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• v.18 no.1
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• pp.10-16
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• 2007

In this study, we examined the preparation and hydrolysis property of immobilized urease membrane to decompose harmful urea in the body and remove ammonia which was produced by its decomposition. Urease immobilized membrane was prepared by introducing anion-exchange group DEA into porous hollow-fiber membrane by radiation graft polymerization method, and immobilization of urease. When urease was immobilized at membrane introduced with anion-exchange group, the more increasing grafting rate, the more increasing immobilization amount. The result originates from the fact that a greater amount of protein was immobilized by forming a multilayer on the longer grafted chain. Meanwhile, the addition of the cross-linker was possible not only to suppress separation phenomenon produced during a washing process of immobilized urease membrane but also to enable the recycling of membrane. Urease Immobilized membrane with no separation phenomenon was prepared by cross-linking reaction for 5 h, and the hydrolysis rate of prepared urease immobilized membrane was over 98% and 50%, respectively, in 1 mol and 4 mol urea solutions.

• Journal of the Korean Electrochemical Society
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• v.26 no.4
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• pp.71-79
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• 2023

In this study, we employed anionic, cationic, and nonionic surfactants for the hydrophilization of porous substrates used in the fabrication of pore-filling membranes. We investigated the extent of hydrophilization based on the type of surfactant, its concentration, and immersion time. Furthermore, we used the hydrophilized substrates to produce pore-filling anion exchange membranes and compared their ion conductivity to determine the optimal hydrophilization conditions. For the ionic surfactants used in this study, we observed that hydrophilization progressed rapidly from the beginning of immersion when the applied concentration was 3.0 wt%, compared to lower concentrations (0.05, 0.5, and 1.0 wt%). In contrast, for the relatively larger molecular weight non-ionic surfactants, smooth hydrophilization was not observed. There was no apparent correlation between the degree of hydrophilization and the ion conductivity of the anion exchange membrane. This discrepancy suggests that an excessive hydrophilization process during the treatment of porous substrates leads to excessive adsorption of the surfactant on the sparse surfaces of the porous substrate, resulting in a significant reduction in porosity and subsequently decreasing the content of polymer electrolyte capable of ion exchange, thereby greatly increasing the electrical resistance of the membrane.

• Membrane Journal
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• v.27 no.3
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• pp.240-247
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• 2017

In this study, the heterogeneous ion exchange membranes prepared by the combination of the carbon electrode and mixed the cation and anion exchange polymers and polyvinylidene fluoride as the basic polymer together were made to recognize the efficiency of the salt removal for the application of the membrane capacitive deionization process. The mixing weight ratio of the solvent, basic polymer and ion exchange resin was 7 : 2 : 1 and this mixed solution was directly cast on the electrode. As for the operating conditions of the adsorption voltage and time, feed flow rate, desorption voltage and time of the feed solution NaCl 100 mg/L, the salt removal efficiencies (SRE) were measured. Apart from this NaCl, the $CaCl_2$ and $MgSO_4$ solutions were investigated in terms of SRE as well. Typically, SRE for NaCl 100 mg/L solution under the conditions of adsorption voltage/time, 1.5 V/3 min, desorption voltage/time -0.1 V/3 min, was shown 98%. And for the $CaCl_2$ and $MgSO_4$ solutions, the SREs of 70 and 59% were measured under the conditions of adsorption voltage/time, 1.2 V/3 min, desorption voltage/time -0.5 V/5 min, respectively.