• Membrane Journal
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• v.31 no.5
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• pp.315-326
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• 2021

Lithium ion battery (LIB) demands increase every year globally to reduce the burden on fossil fuels. LIBs are used in electric vehicles, stationary storage systems and various other applications. Lithium is available in seawater, salt lakes, and brines and its extraction using environmentally friendly and inexpensive methods will greatly relieve the pressure in lithium mining. Membrane separation processes, mainly nanofiltration (NF), is an effective way for the separation of lithium metal from solutions. Electrodialysis and electrolysis are other separation processes used for lithium separation. The process of reverse osmosis (RO) is already a well-established method for the desalination of seawater; therefore, modifying RO membranes to target lithium metals is an excellent alternative method in which the only bottleneck is the interfering presence of other metal elements in the solution. Selectively removing lithium by finding or developing suitable NF membranes can be challenging, but it is nonetheless an exciting area of research. This review discusses in detail about lithium recovery via nanofiltration, electrodialysis, electrolysis and other processes.

• Membrane Journal
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• v.32 no.4
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• pp.209-217
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• 2022

Ion exchange membrane (IEM) is an important class of membrane applied in batteries, fuel cells, chloride-alkali processes, etc to separate various mono and multivalent ions. The membrane process is based on the electrically driven force, green separation method, which is an emerging area in desalination of seawater and water treatment. Electrodialysis (ED) is a technique in which cations and anions move selectively along the IEM. Anion exchange membrane (AEM) is one of the important components of the ED process which is critical to enhancing the process efficiency. The introduction of cross-linking in the IEM improves the ion-selective separation performance due to the reduction of free volume. During the desalination of seawater by reverse osmosis (RO) process, there is a lot of dissolved salt present in the concentrate of RO. So, the ED process consisting of a monovalent cation-selective membrane reduces fouling and improves membrane flux. This review is divided into three sections such as electrodialysis (ED), anion exchange membrane (AEM), and cation exchange membrane (CEM).

• Prospectives of Industrial Chemistry
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• v.14 no.6
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• pp.21-28
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• 2011

이온교환막을 이용한 전기적 탈염기술은 막모듈 내에 양이온교환막과 음이온교환막을 교대로 장착시키고 모듈의 양단 전극에 전압을 적용함으로써 물속에 용존되어 있는 양이온과 음이온들을 전기의 힘을 이용하여 선택적으로 투과시키는 원리를 기반으로 하는 청정공정 기술이다. 이온교환막 공정은 전통적으로 산/알칼리의 생산, 산업폐수의 중금속의 제거, 해수의 담수화, 반도체 산업의 초순수의 제조, 해수에서 식염의 제조, 발효산업의 유기산 및 아미노산의 회수 등 다양한 산업분야에서 응용되어 왔다. 최근에는 이러한 기존의 응용분야에서 벗어나 새롭게 응용분야가 넓어지고 있다. 이온교환막과 다공성 탄소전극을 결합한 막축전식 해수담수화기술, 해수와 담수의 염도차를 이용한 역전기투석식 해수발전 등의 새로운 선택분리기능 및 응용분야를 가진 이온교환막의 개발 및 공정에 관한 연구가 활발히 이루어지고 있다. 그러나 국내에서는 이온교환막이 아직 상용화되지 않고 있어 이온교환막을 이용한 응용연구가 활발하게 진행되지 못하고 있어 그 개발이 시급하다. 본 논문에서는 먼저 이온교환막을 이용한 전기투석식 탈염기술, 물분해 전기투석, 전기탈이온 공정에 관한 동향을 조사하였다. 아울러 미래의 이온교환막의 응용기술인 해수담수화기술로서 역삼투법과 경쟁하여 에너지를 낮게 소모할 것으로 예상되는 분리막을 이용한 막축전식 탈염기술과 무한한 신재생에너지원인 해수와 담수를 이용한 역전기투석 해수발전기술에 대해 기술의 원리들과 최근의 연구동향 등을 정리하였다.

• The Korean Journal of Ecology
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• v.25 no.2
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• pp.101-107
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• 2002

Three species of Chenopodiaceae, i.e. Suaeda japonica, Salicomia herbacea, Beta vulgaris var. cicla, were investigated to compare the physiological characteristics through inoic balances and osmoregulations under different environmental salt gradients. Plats were harvested in two weeks from treatments with salt gradients (0, 50, 100, 200 and 400 mM NaCl) and mineral nutrition gradients(1/1, 1/5, 1/10 dilutions of Hoagland solution). Plants were analyzed for growth responses, ionic balances, osmolalities, conductivities, glycinebetaine and proline contents quantitatively. Three plants of Chenopodiaceae accumulated slats into tissues unlike some salt sensitive species, and showed unique adaptation patterns to overcome saline environments, i.e. strong growth stimulation for Salicomia herbacea, growth negative tolerance for Suaeda japonica, and growth positive tolerance for Beta vulgaris var. cicla. The absorption of inorganic Ca/sup 2+/ ions was inhibited remarkably due to the excess uptake of Na+ with increasing salinity. The K+ content in plants was significantly reduced with increasing salinity. Total nitrogen content was reduced as mineral nutritions and salinity increased. Conductivity and osmolality increased with increasing salinity regardless of mineral nutritions. The ranges of glycinebetaine and proline contents were 0.2∼2.5 μM/g plant water and 0.1∼0.6μM/g plant water, respectively.

• Proceedings of the Korean Radioactive Waste Society Conference
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• 2004.06a
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• pp.13-23
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• 2004

The characteristics of cesium and cobalt removal from soil around the TRIGA reactor using the electrokinetic method were analyzed and a device to restrain the pH increase in the soil column was suggested. When a NaCl solution was used as the electrolyte to raise the electric field strength, a precipitate was formed in the cathode in the soil column, resulting in a low removal efficiency. Thus, an acetate buffer solution (compound solution of $CH_3COONa$ and $CH_3COOH$) was injected into the soil column and acetic acid was periodically infected into the cathode reservoir to restrain any pH increase. Many $Cs^{2+}$ and $Co^{2+}$ ions were transferred by electromigration rather than electroosmosis during the initial remediation period, and no precipitate was formed in the soil column. 96% of the total amount of cesium in the soil column was removed after 5.9 days, while 94% of the total amount of cobalt was removed. Furthermore, the residual concentrations predicted by the developed model were similar to those obtained by experiment.

• Proceedings of the KAIS Fall Conference
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• 2009.12a
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• pp.1042-1045
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• 2009

역삼투식 해수담수화 (Sea Water Reverse Osmosis, SWRO) 공정에 의한 생산수는 pH가 낮고, 해수 내 존재하는 경도성분인 Ca, Mg 이온이 대부분 제거되기 때문에 상대적으로 매우 강한 부식성을 지니고 있다. 이를 음용수 및 공업용수로 이용 시 설비 및 배관계통에 심각한 부식문제를 유발할 수 있으며, 이를 방지하기 위한 처리공정과 부식성 제어 기술의 지속적인 개발이 요구되는 실정이다. SWRO 1단으로 처리 시 생산수의 전기전도도는 $150{\mu}S/cm$ 정도의 범위를 보이며, 2단 SWRO 과정을 거칠 시 전기전도도는 $100{\mu}S/cm$ 이하의 범위를 나타내는 것으로 알려져 있다. 본 연구에서는 SWRO 2단 처리수를 가정한 $20{\mu}S/cm{\sim}25{\mu}S/cm$ 범위의 전기전도도를 지닌 물을 실험 원수로 사용하여, 기존 방식제의 성분과 생산수의 특성을 고려한 효율적인 알칼리성 수처리제를 적용하고 그에 대한 부식성 제어 연구를 수행하였다. SWRO 생산수를 대상으로 부식방지기술을 개발하기 위해서는 부식제어와 관련된 수질 인자인 pH, 칼슘경도, 알칼리도의 조절과 LSI(Langelier Saturation Index)를 설정하는 것이 무엇보다도 중요하다. 본 연구에서는 해수담수화 공정의 생산수를 음용수 및 공업용수로 이용하기 위한 목표 수질을 pH 7.5~7.8, LSI 0 이상, 부가적으로 전기전도도는 $250{\mu}S/cm$ 이하로 설정하였으며, 연구목표 수질을 달성할 수 있는 부식억제제 및 알칼리성 수처리제의 적용을 통해 목표 수질에 대한 설정 근거를 마련하고자 하였다.

• Membrane Journal
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• v.27 no.5
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• pp.399-405
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• 2017

The zeta potential, called an electrokinetic potential, refers to the potential difference caused by electrodynamic phenomenon, which is a value obtained by quantifying the surface charge property. The zeta potential has been actively studied for membrane fouling, confirmation of modification and substituent confirmation through surface charge analysis. The methods of measurement for zeta potential were developed on the basis of electrophoresis, electrosmosis and streaming potential. Among them, it was known that the streaming potential method was suitable for the flat sheet membrane. So, in this study, aminated poly(styrene-ethylene-butylene-styrene) membranes were prepared by introducing ammonium groups and the streaming potentials of the prepared membranes were measured by using an electrokinetic potential analyzer (SurPASS) and the results were analyzed.

• Membrane Journal
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• v.33 no.3
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• pp.87-93
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• 2023

Electrodialysis (ED) is essential in separating ions through an ion exchange membrane. The disposal of brine generated from seawater desalination is a primary environmental concern, and its recycling through membrane separation technology is highly efficient. Alkali is produced by several chemical industries such as leather, electroplating, dyeing, and smelting, etc. A high concentration of alkali in the waste needs treatment before releasing into the environment as it is highly corrosive and has a chemical oxygen demand (COD) value. The concentration of calcium and magnesium is almost double in brine and is the perfect candidate for carbon dioxide adsorption, a major environmental pollutant. Sodium hydroxide is essential for the metal carbonation process which, is easily produced by the bipolar membrane electrodialysis process. Various strategies are available for its recovery, like reverse osmosis (RO), nanofiltration (NF), ultrafiltration (UF), and ED. This review discusses the ED process by ion exchange membrane for alkali recovery are discussed.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.32 no.10
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• pp.831-835
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• 2008

We present a continuous electrical cell lysis chip, using a DC bias voltage to generate the focused high electric field for cell lysis as well as the electroosmotic flow for cell transport. The previous cell lysis chips apply an AC voltage between micro-gap electrodes for cell lysis and use pumps or valves for cell transport. The present DC chip generates high electrical field by reducing the width of the channel between a DC electrode pair, while the previous AC chips reducing the gap between an AC electrode pair. The present chip performs continuous cell pumping without using additional flow source, while the previous chips need additional pumps or valves for the discontinuous cell loading and unloading in the lysis chambers. The experimental study features an orifice whose width and length is 20 times narrower and 175 times shorter than the width and length of a microchannel. With an operational voltage of 50 V, the present chip generates high electric field strength of 1.2 kV/cm at the orifice to disrupt cells with 100% lysis rate of Red Blood Cells and low electric field strength of 60 V/cm at the microchannel to generate an electroosmotic flow of $30{\mu}m/s{\pm}9{\mu}m/s$. In conclusion, the present chip is capable of continuous self-pumping cell lysis at a low voltage; thus, it is suitable for a sample pretreatment component of a micro total analysis system or lab-on-a-chip.

• Journal of Soil and Groundwater Environment
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• v.8 no.1
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• pp.9-16
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• 2003

A new method has been proposed and developed that solves the problem of decreasing electroosmotic flow rate by excess $H^{+}$ and precipitation of heavy metal by $OH^{-}$. An electrolytic solution was circulated between the anode and cathode compartments that enabled the pH at the anode and cathode to be controlled. The change of the soil pH by circulation systems affects the operation time, by lowering the rate of increase of the electric potential gradient, and the removal efficiency of heavy metals, by affecting the soil pH. Since there was no effluent from the cathode compartment in circulation system, there was no need to treat the wastewater after the experiment, which resulted in the reduction of influent electrolyte volume.