• 한국전기화학회:학술대회논문집
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• 1999.10a
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• pp.31-31
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• 1999

• Membrane Journal
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• v.17 no.3
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• pp.210-218
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• 2007

CEDI-BPM(Continuous Electrodeionization-Bipolar Membrane) has advantages due to high ion permselectivity through ion exchange membranes and the production of $H^+$ and $OH^-$ ions on the bipolar membrane surfaces for regeneration of ion exchange resin during electrodeionization operation. In this study, hardness materials were removed by the CEDI-BPM without scale formation and the ion exchange resins were electrically regenerated during the operation. The adsorption characteristic of ion exchange resin surface, the influence of flow rate on the hardness removal and electric regeneration were investigated in the study. The removal efficiency of Ca was higher than that of Mg in the CEDI-BPM, which was related to the high adsorption capacity of Ca on the cation exchange resin. With increasing flow rate, the flux of Ca and Mg was enhanced by the permselectivity of a cation exchange membrane. In the electric regeneration of CEDI-BPM, it was shown that the regeneration efficiency was higher with a lower regeneration potential applied between cathode and anode.

• Journal of Electrochemical Science and Technology
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• v.10 no.2
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• pp.115-122
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• 2019

In order to improve the current efficiency and reduce the energy consumption in the electrosynthesis of ammonium persulfate, electrolytic properties of a perfluorosulfonic cation exchange membrane named PGN membrane and the $Al_2O_3$ ceramic membrane in the electrosynthesis of ammonium persulfate were studied and compared in a pilot electrolytic cell using a welded platinum titanium as the anode and a Pb-Sb alloy as the cathode. The effect of cell voltage, electrolyte flow rate and electrolysis time of the electrolytes on the current efficiency and the energy consumption were studied. The results indicated that the PGN membrane could improve current efficiency to 95.12% and reduce energy consumption to $1110kWh\;t^{-1}$ (energy consumption per ton of the ammonium persulfate generated) under the optimal operating conditions and the highest current efficiency of the $Al_2O_3$ ceramic membrane was 72.61% with its lowest energy consumption of $1779kWh\;t^{-1}$. Among 5 times of the electrolysis of the electrolytes, the lowest current efficiency of the PGN membrane was 85.25% with the highest energy consumption of $1244kWh\;t^{-1}$ while the lowest current efficiency of the $Al_2O_3$ ceramic membrane was 67.44% with the highest energy consumption of $1915kWh\;t^{-1}$, which suggested the PGN membrane could be used in the 5-stage electrolytic cell for the industrially continuous electrosynthesis of ammonium persulfate. Therefore the PGN membrane can be efficient to improve the current efficiency and reduce the energy consumption and can be applied in the industrial electrosynthesis of ammonium persulfate.

• Membrane and Water Treatment
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• v.4 no.3
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• pp.203-214
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• 2013

Laboratory tests were performed to determine the efficiency of dye solution desalination by electrodialysis. The study involved anionic dye and mineral salt recovery by obtaining two streams from a salt and dye mixture - dye-rich solution and salt solution. A standard anion-exchange and cation-exchange membranes or monovalent selective anion-exchange membranes were used in the ED stack. It was found that the separation efficiency was strongly dependent on the dye molecular weight. The best results for standard ion-exchange membranes were achieved for the desalination of Direct Black solution. Furthermore, the obtained results implied that the application of monovalent selective anion-exchange membranes improved the recovery of dye and salt solutions - the dye concentration in the diluate remained constant irrespective of the molecular weight of anionic dyes, whereas the salt recovery remained very high (99.5%).

• Korean Chemical Engineering Research
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• v.57 no.1
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• pp.65-72
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• 2019

In this study, heterogeneous ion exchange membranes were prepared by casting method with various mixing ratios of PPO ion-selective solution and ion exchange resin. Then heterogeneous bipolar membranes were prepared by using this. The water content of heterogeneous cation and anion exchange membranes were 60~80% respectively, the ion exchange capacity was 2.81~3.26 meq/g, 2.31~2.74 meq/g and electrical resistances were $1.65{\sim}1.45{\Omega}{\cdot}cm^2$ and $1.55{\sim}1.05{\Omega}{\cdot}cm^2$. The tensile strength of heterogeneous bipolar membrane was lower than that of PPO resin before functionalization ($700Kg_f/cm^2$). The tensile strength of heterogeneous bipolar membrane with catalyst layer was lower than that of non-catalytic heterogeneous bipolar membrane. The water splitting voltage of the heterogeneous bipolar membrane with catalyst layer was low and stable at a minimum of 1.7~1.8 V, maximum 3.9~4.0 V, and the water splitting voltage of the non-catalytic heterogeneous bipolar membrane was constant at 3.8~4.0 V.

• Membrane Journal
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• v.24 no.5
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• pp.386-392
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• 2014

Two commercial membranes (porous membrane and cation exchange membrane) were evaluated as a separator in the Zn-Br redox-flow battery (ZBRFB). The performance properties of ZBRFB were test in the current density of $20mA/cm^2$. The electromotive forces (OCV at SOC 100%) of ZBRFB using SF-600 (porous membrane) and Nafion 117 (cation exchange membrane) were 1.87 V and 1.93 V, respectively. The cycle performance of ZBRFB using each membrane was evaluated during 7 cycles. The performance of ZBRFB using SF-600 membrane was 89.76%, 83.46% and 74.88% for average current efficiency, average voltage efficiency and average energy efficiency, respectively. The performance of ZBRFB using Nafion117 membrane was 97.7%, 76.33% and 74.56% for average current efficiency, average voltage efficiency and average energy efficiency, respectively.

• Membrane Journal
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• v.26 no.6
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• pp.458-462
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• 2016

Saline water electrolysis, known as chlor-alkali (CA) membrane process, is an electrochemical process to generate valued chemicals such as chlorine, hydrogen and sodium hydroxide with high purities higher than 99%, using an electrolytic cell composed of cation exchange membrane, anode and cathode. It is necessary to reduce energy consumption per a unit chemical production. This issue can be solved by decreasing intrinsic resistance of the membrane and the electrodes and/or by reducing their interfacial resistance. In this study, the electron radiation grafting of a $Na^+$ ion-selective polymer was conducted onto a hydrocarbon sulfonated ionomer membrane with high chemical resistance. This approach was effective in improving electrochemical efficiency via the synergistic effect of relatively fast $Na^+$ ion conduction and reduced interfacial resistance.

• Membrane Journal
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• v.30 no.4
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• pp.276-281
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• 2020

A research was conducted on the removal of ion from the solution involving the alkali metal ion and chlorine ion using ion exchange resin. The cation exchange resin and anion exchange resin was used for the remove of metal ion (Na⁺ and K⁺) and chlorine ion (Cl^-), respectively. In the case of solution A (involving 36,633 ppm of Na⁺ and 57,921 ppm of Cl^-), the Na⁺ ion and Cl^- ion were removed over 99% within 20 min. In the case of solution B (involving 1,638 ppm of K⁺), the K⁺ ion was removed over 99% within 3 min.

• Membrane Journal
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• v.2 no.1
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• pp.49-58
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• 1992

Functionalized organic polymers have been used as supports for heterogenized homogeneous catalytic process[1]. Sprcific advantages of using these resins as support reagents have been reviewed[2-4]. These include: -ease of by-product separation from the main reaction product usuallyby simple filtration. -prevention of intermolecular reaction of reactive species or functional groups by simulating high dilution conditions[5]. -utility of the "fish-hook" principle in which a minor component in fished out of a large excess substrate by the insoluble polymer[6]. -the possibility of reusing recovered reagents as well as eliminating the use of volatile or noxious substances[7]. Catalysis by ion-exchange membranes is perhaps one of the latest examples of the use of a polymer-supported species. Conceptually, catalysts on membrane supports offer several possible advantages over traditional powder type systems. They are: (1) Membranes immobilize the catalyst, preventing agglomeration. (2) Filtration is unnecessary for the catalyst separation and so complete catalyst recovery is facilitated. (3) Catalytyic and separation processes can be combined, allowing membrane supported catalysts for the continous flow reactors. reactors.

• Membrane Journal
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• v.15 no.2
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• pp.175-186
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• 2005

An electrodialysis process was operated for a long period to investigate the scale formation on the membrane surface. During the desalination process, concentration of $Ca^{2+}$ and $SO_4^{2-}$ ions increased continuously in the concentrate compartment and eventually caused precipitation on the cation exchange membrane (Neosepta CMX) surface. During the initial scale formation, the performance of the process and membrane characteristics did not show significant changes, except the decrease in limiting current density of the CMX membrane occurring due to increase in the salt concentration in the concentrate compartment. Eventually, the limiting current density of the fouled CMX membrane dropped significantly to $300\;A/m^2$ as water dissociation occurred in the CMX membrane. It was concluded that the fouling was caused mainly by the scale formation on the cation exchange membrane surface in the concentrate and consequent water dissociation. Also the scale formation was reasonably predicted by the solubility of $CaSO_4$.