• Korean Journal of Food Science and Technology
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• v.27 no.3
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• pp.313-317
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• 1995

Ion exchange process was optimized to purify ultrafiltrated bean cooking water(BCW) for the production of soy-oligosaccharides. The ultrafiltrated BCW with cutoff MW(COMW) 20,000 membrane was treated with various ion exchange resins. Protein and ash were mostly removed by anion and cation exchange resins, respectively. Based upon removing capabilities for ash and protein, a cation exchange resin(SK1B) and an anion exchange resin(WA30) were selected. Protein and ash were more efficiently removed at low extract/resin ratios(ERR), but part of the oligosaccharides were concomitantly lost. When 2-step-ultrafiltrated BCW first with COMW 20,000 membrane and successively with COMW 5,000 membrane was treated with a mixed resin(SK1B : WA30 =1 : 2) at ERR 5.0, most oligosaccharides were recovered in a clear protein- and ash-free liquid.

• Transactions of the Korean hydrogen and new energy society
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• v.33 no.1
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• pp.28-37
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• 2022

In this study, we synthesized a poly(pheneylene oxide) (PPO)-based organic/inorganic composite membrane having silicotungstic acid (STA) for the development of an anion exchange membrane with excellent ionic conductivity and physicochemical stability. The organic/inorganic composite membranes were prepared by introducing different STA contents (0 wt%, 10 wt%, 30 wt%, and 50 wt%) into the quaternizaed(Q)-PPO matrix. The prepared anion exchange membranes were subjected to structural analysis by proton neclear magnetic resonance and Fourier transform infrared, and thermal behavior of membranes was confirmed by thermogravimetric analysis. Among the prepared composite membranes, the ion conductivity of Q-PPO/STA-50 (40.5 mS cm^-1) showed 1.46 times compared to that of the pristine membrane (27.6 mS cm^-1). Therefore, these results demonstrated that organic/inorganic composite membranes are promising candidates for application of anion exchange membranes.

• Membrane Journal
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• v.21 no.1
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• pp.91-97
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• 2011

In this study, the anionic exchange membranes were prepared through the impregnation of polyethylenimine (PEI) into porous polyethylene (PE) separator and then crosslinking with isophrhaloyl dichloride (IPC). To characterize the resulting membranes, the contact angles, FT-IR, ion exchnage capacity and ion conductivity were measured. The amide group is produced the reaction between amines in PEI and -COCl in IPC. In case of ion exchange capacity, 1.96 meq./g dry membrane at the reaction time, 30 sec was decreased to 1.14 meq./g dry membrane at 600 sec reaction time. The ion conductivity, $9.15{\times}10^{-2}S/cm$ at 30 sec reaction time, was obtained.

• Membrane Journal
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• v.27 no.5
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• pp.415-424
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• 2017

Commonly cation exchange membranes have been used for vanadium redox flow batteries. However, a severe vanadium ion cross-over causes low energy efficiency. Thus in this study, we prepared 3 different anion exchange membranes to investigate the effect on the membrane properties such as vanadium ion cross-over and long term stability. The base membranes were prepared by an electrolyte pore filling technique using vinyl benzyl chloride (VBC), divinylbenzene (DVB) within a porous polyethylene (PE) substrate. Then 3 different functional amines were introduced into the base membranes, respectively. These resulting membranes were evaluated by physico-chemical properties such as ion exchange capacity, dimensional stability, vanadium ion cross-over and membrane area resistance. Conclusively, TEA-functionalized membrane showed longest term stability than other membranes although all the membranes are similar to coulombic efficiency.

• Transactions of the Korean hydrogen and new energy society
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• v.29 no.5
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• pp.458-465
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• 2018

This study reports the fabrication of anion exchange membranes (AEMs) containing two kinds of functional groups: i) trimethylphosphite (TMP) and ii) trimethylamine (TMA). We carried out the synthesis of polymers to enhance thermal stability and ion conductivity. The alternative polymer was prepared using 2,2-bis(4-hydroxy-3-methylphenyl)propane and decafluorobiphenyl. The membrane was fabricated by solution casting method. The thermal stability of membranes was examined by TGA. The physiochemical properties of membranes were also investigated in terms of water uptake, swelling ratio, ion exchange capacity, and ion conductivity. The hydroxide ion conductivity of the membranes reached about 20.2 mS/cm for quaternary ammonium poly(arylene ether) (QA-PAE) containing TMA moiety and 5.1 mS/cm for quaternary phosphonium PAE (QP-PAE) containing TMP moiety at $90^{\circ}C$.

• Proceedings of the Membrane Society of Korea Conference
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• 2001.05a
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• pp.108-111
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• 2001

• Proceedings of the Membrane Society of Korea Conference
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• 2003.11a
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• pp.210-213
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• 2003

• Proceedings of the Membrane Society of Korea Conference
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• 2001.04a
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• pp.41-47
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• 2001

• Proceedings of the Membrane Society of Korea Conference
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• 2000.04a
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• pp.38-42
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• 2000

• Membrane and Water Treatment
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• v.9 no.3
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• pp.189-194
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• 2018

Electrochemical reduction of nitrate was studied using Zn, Cu and (Ir+Ru)-Ti cathodes and Pt/Ti anode in a cell divided by an ion exchange membrane. During electrolysis, effects of the different cathode types on operating parameters (i.e., voltage, temperature and pH), nitrate removal efficiency and by-products (i.e., nitrite and ammonia) formation were investigated. Ammonia oxidation rate in the presence of NaCl was also determined using the different ratios of hypochlorous acid to ammonia. The operating parameter values were similar for all types of cathode materials and were maintained relatively constant. Nitrate was well reduced and converted mostly to ammonia using Zn and Cu cathodes. Ammonia, produced as a by-product of nitrate reduction, was oxidized in the presence of NaCl in the electrochemical process and the oxidation performance was enhanced upon increasing the hypochlorous acid-to-ammonia ratio to 1.09:1. Zn and Cu cathodes promoted the nitrate reduction to ammonia and the produced ammonia was finally removed from solution by reacting with hypochlorite ions. Using Zn or Cu cathodes, instead of noble metal cathodes, in the electrochemical process can be an alternative technology for nitrate-containing wastewater treatment.