• Membrane Journal
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• v.32 no.5
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• pp.283-291
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• 2022

Hydrogen energy has received much attention as a solution to the supply of renewable energy and to respond to climate change. Hydrogen is the most suitable candidate of storing unused electric power in a large-capacity long cycle. Among the technologies for producing hydrogen, water electrolysis is known as an eco-friendly hydrogen production technology that produces hydrogen without carbon dioxide generation by water splitting reaction. Membranes in water electrolysis system physically separate the anode and the cathode, but also prevent mixing of generated hydrogen and oxygen gases and facilitate ion transfer to complete circuit. In particular, the key to next-generation anion exchange membrane that can compensate for the shortcomings of conventional water electrolysis technologies is to develop high performance anion exchange membrane. Many studies are conducted to have high ion conductivity and excellent durability in an alkaline environment simultaneously, and various materials are being searched. In this review, we will discuss the research trends and points to move forward by looking at the research on anion exchange membranes based on commercial polystyrene-b-poly(ethylene-co-butylene)-b-polystyrene (SEBS) block copolymers.

• Journal of Korean Society of Environmental Engineers
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• v.27 no.9
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• pp.965-969
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• 2005

Current density is an important operating parameter in the ion-exchange membrane process. We observed the effects of fouling of a Neosepta AMX anion-exchange membrane(Tokuyama Soda, Japan) in 0.02 M NaCl solution containing 100 mg/L sodium humate. Membrane fouling was analyzed by measuring the change in the electrical resistance in the under- and over-limiting current density regions. The experimental results found that membrane fouling was negligible at under-limiting current densities, but was increased significantly when an over-limiting current was supplied. After the fouling experiments, the current-voltage curves for the fouled membranes were measured. From the curves, we observed increased electric resistance and reduced limiting current density(LCD), caused by the accumulation of humic acid on the membrane surface. Furthermore, membrane fouling increased as the acidity of the electrolyte solution containing humic acid increased. This occurred because the fouling of an anion-exchange membrane is affected more by the physicochemical properties of the humic substance than by the surface charge of the humate.

• Proceedings of the Membrane Society of Korea Conference
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• 2002.05a
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• pp.65-68
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• 2002

• Proceedings of the Membrane Society of Korea Conference
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• 2002.11a
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• pp.61-64
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• 2002

• 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.32 no.6
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• pp.524-533
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• 2021

In this study, a series of anion conductive organic/inorganic composite membranes with excellent ionic conductivity and chemical stability were prepared by introducing graphene oxide (GO) inorganic nanofiller into the quaternized poly(phenylen oxide (Q-PPO) polymer matrix. The fabricated organic/inorganic composite membranes showed higher ionic conductivity than the pristine membrane. In particular, Q-PPO/GO 0.7 showed the highest ionic conductivity value of 143.2 mS/cm at 90℃, which was 1.56 times higher than the pristine membrane Q-PPO (91.5 mS/cm). In addition, the organic/inorganic composite membrane showed superior dimensional stability and alkaline stability compared to the pristine membrane, and the physicochemical stability was improved as the content of inorganic fillers increased. Therefore, we suggest that the as-prepared organic/inorganic composite membranes are very promising materials for anion exchange membrane applications with high conductivity and alkaline stability.

• Membrane Journal
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• v.32 no.5
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• pp.336-347
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• 2022

Reverse electrodialysis (RED) is one of the promising eco-friendly renewable energy technologies which can generate electricity from the concentration difference between seawater and freshwater by using ion-exchange membranes as a diaphragm. The ion-exchange membrane is a key component that determines the performance of RED, and must satisfy requirements such as low electrical resistance, high permselectivity, excellent durability, and low manufacturing cost. In this study, pore-filled anion-exchange membranes were fabricated using porous polymer substrates having various thicknesses and porosity, and the effects of ion-exchange polymer composition and membrane thickness on the power generation performance of RED were investigated. When the electrical resistance of the ion-exchange membrane is sufficiently low, it can be confirmed that the RED power generation performance is mainly influenced by the apparent permselectivity of the membrane. In addition, it was confirmed that the apparent permselectivity of the membranes can be improved through IEC, crosslinking degree, membrane thickness, surface modification, etc., and the optimum condition must be found in consideration of the trade-off relationship with electrical resistance.

• 한국전기화학회:학술대회논문집
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• 2005.07a
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• pp.297-300
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• 2005

• Membrane Journal
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• v.20 no.4
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• pp.335-341
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• 2010

This study focuses on the investigation of the anion exchange membrane through blending poly(ethylenimine) (PEI) and poly(vinyl alcohol) (PVA) varying the mixing ratio. To characterize the resulting membranes, the water content, contact angle, FT-IR, thermal gravimetric analysis, ion exchange capacity, ion conductivity and elastic modulus were measured. The PVA / PEI = 90 / 10 membrane showed the ion conductivity, $5.16{\times}10^{-2}S/cm$ and simultaneously the contact angle, $78.3^{\circ}$. According to TGA measurement, the resulting membranes seemed durable at room temperature. Through the modulus test, the mechanical properties increased with increasing PVA content and apparently the membranes looked very robust.

• Membrane Journal
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• v.8 no.3
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• pp.148-156
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• 1998

Diffusion dialysis is a membrane process driven by concentration difference using ion-exchange membranes and has been employed for many years for the acid recovery from acidic waste generated in steel, metal-refining and dectro-plating industries. Theoretically acid flux increases in propomon to the acid concentration difference. At acid concentrations higher than 3 N HCl, however, the acid flux had not increased linearly with the concentration difference. In this paper the effects of acid concentrations on diffusion dialysis for hydrochloric acid recovery and the acid transport mechanism in an anion exchange membrane were studied by membrane sorption tests and diffusion clialysis cell tests. The experimental results showed that the molecular diffusion was a major transport mechanism in a low acid concentration range and the proton leakage through an anion exchange membrane played an important role at higher acid concentrations. Also osmotic water transport and membrane dehydration retarded the transport of protons and caused the permeate flux to decrease.