• Title/Summary/Keyword: electrolysis system

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Sterilization and ecofriendly neutralization of seawater using electrolysis (전기분해에 의한 해수살균 및 친환경 중화에 관한 연구)

  • Yang, Jeong-Hyeon;Choi, Jong-Beom;Yun, Yong-Sup
    • Journal of Advanced Marine Engineering and Technology
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    • v.41 no.3
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    • pp.276-280
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    • 2017
  • In this study, we investigated the effect of sterilization and the neutralization of treated ballast water using seawater electrolysis. The electrolysis apparatus has a cation-selective membrane for passing the cation and a titanium electrode in each cell. We examined the sterilization effect after an incubation period of 24 hr. The oxidation reaction during electrolysis caused, the solution to become strongly acidic due to the generation of a hydroxyl group, and the oxidation reduction potentials(ORP) was increased to 800 - 1200mV. After the reduction reaction, the solution became alkaline(pH 9 - 12), and ORP was decreased to - 900 - - 750 mV. It might be possible to control the pH of ballast water through electrolysis. In addition, we demonstrated the effects of sterilization of ballast water containing generated hypochlorous acid using electrolysis under high ORP condition.

Research and Development Trends in Seawater Electrolysis Systems and Catalysts (해수 수전해 시스템 및 촉매 연구 개발 동향)

  • Yoonseong Jung;Tuan Linh Doan;Ta Nam Nguyen;Taekeun Kim
    • Applied Chemistry for Engineering
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    • v.34 no.6
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    • pp.567-575
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    • 2023
  • Water electrolysis is undergoing active research as one of the promising technologies for producing effective green hydrogen. Using seawater directly as a raw material for a water electrolysis system can solve the problem of the limitations of existing freshwater raw materials, as seawater accounts for approximately 97% of the water on Earth. At the same time, abundant by-product materials can be obtained, representative examples of which are Cl2, ClO-, Br2, and Mg(OH)2 produced during electrolysis, depending on their composition and pH environment. In order to develop a successful seawater electrolysis system and oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) catalysts, it is necessary to understand the causes and consequences of reactions that occur in the seawater environment. Therefore, in this paper, we will investigate the reaction mechanism and characteristics of the seawater electrolysis system as well as the research and development trends of electrochemical catalysts used in anode and cathode electrodes.

Ammonia-nitrogen Removal in Sea Water by Using Electrolysis (전기분해법에 의한 해수내의 암모니아성 질소 제거)

  • 이병헌;이제근;길대수;곽순열
    • Journal of Aquaculture
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    • v.10 no.4
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    • pp.435-438
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    • 1997
  • Biological ammonia removal system have been used conventionally for the seawater fish farming. But this process requires long hydraulic retention times and large area. Also it has a trouble of NO3-N accumulation in the system. Therefore, this study was conducted to find out the feasibility of effective nitrogen removal efficiency in the sea water fish farming system by electolysis. As the result, electrolysis system showed a good ammonia and nitrate nitrogen removal and E. coli sterilization efficiencies. Because of the high salinities in the seawater for electron transfer, electrolysis is an effictive water treatment process for seawater fish farming. The relation among ammonia removal efficiency, hydraulic retention time (HRT) and electric wattage (watt) with 10 mm electrod distance isas follow ; log [$NH_4^$+-N(%)]=0.431log(HRT(sec)$\times$Watt)+0.88(r=0.950) And the relation between ammonia removal efficiency and residual chlorine concentration in the seawater is as follow; $$NH_4^+-N(%)=48\cdotlog[Residual\;chlorine(mg/\ell)+28(r=0.892)$$

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Hydrogen Production through High Temperature Steam Electrolysis System (고온 수증기 전해 수소제조)

  • Choi, Ho-Sang
    • Membrane Journal
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    • v.19 no.1
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    • pp.1-6
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    • 2009
  • Hydrogen energy id the 2nd clean energy able to be produced from the abundant resources, and the products of combustion or reaction do not spread an environmental pollution. Also, the hydrogen is the chemical media easily to transport and storage as energy source. The hydrogen production technology using by water splitting through electrolysis could be usable as a permanent renewable energy system without the environmental impact. The key technology of high temperature steam electrolysis is the development of an electrolyte rapidly to conduct an oxygen or proton ion decomposed from water. Subsequently, the important technology is to keep the joining technology of an electrolyte membrane and electrode materials to affect into the current efficiency.

Development of Molecular Dynamics Model for Water Electrolysis Ionomer (수전해용 이오노머 분자동역학 모델 개발)

  • Kang, Hoseong;Park, Chi Hoon;Lee, Chang Hyun
    • Membrane Journal
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    • v.30 no.6
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    • pp.433-442
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    • 2020
  • In this study, in order to build a molecular dynamics simulation model of ionomer for water electrolysis, an ionomer model that reflects the characteristics of a water electrolysis system in which excess water molecules exist was compared to an ionomer built according to the conventional simulation method of the fuel cells membrane. The final ionomer MD models have a strong phase separation and water channel that is one of the important characteristics of the perfluorinated ionomer, and are stable and water-insoluble under excessive water and high temperature conditions. In the ionomer MD models built in this study, the excess water molecules decrease an ion conductivity due to the dilution of ions, but increase a hydrogen diffusivity. Therefore, it is necessary to design the molecular structure of ionomers for water electrolysis in experimental studies as well as molecular dynamics studies according to the characteristics of the water electrolysis system reported in this study.

Hydrogen Production Systems through Water Electrolysis (물 전기분해에 의한 수소제조 기술)

  • Hwang, Gab-Jin;Choi, Ho-Sang
    • Membrane Journal
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    • v.27 no.6
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    • pp.477-486
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    • 2017
  • Hydrogen is one of energy storage systems, which could be transfer from electric energy to chemical energy or from chemical energy to electric energy, and is as an energy carrier. Water electrolysis is being investigating as one of the hydrogen production methods. Recently, water electrolysis receive attention for the element technology in PTG (power to gas) and PTL (power to liquid) system. In this paper, it was explained the principle and type for the water electrolysis, and recent research review for the alkaline water electrolysis.

Research and Development Trend of Electrolyte Membrane Applicable to Water Electrolysis System (수전해 시스템에 적용 가능한 전해질막 연구 개발 동향)

  • Im, Kwang Seop;Son, Tae Yang;Kim, Kihyun;Kim, Jeong F.;Nam, Sang Yong
    • Applied Chemistry for Engineering
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    • v.30 no.4
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    • pp.389-398
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    • 2019
  • Hydrogen energy is not only a solution to climate change problems caused by the use of fossil fuels, but also as an alternative source for the industrial power generation and automotive fuel. Among hydrogen production methods, electrolysis of water is considered to be one of the most efficient and practical methods. Compared to that of the fossil fuel production method, the method of producing hydrogen directly from water has no emission of methane and carbon dioxide, which are regarded as global environmental pollutants. In this paper, the alkaline water electrolysis (AWE) and polymer electrolyte membrane water electrolysis (PEMWE), which are one of the hydrogen production methods, were discussed. Recent research trends of hydrocarbon electrolyte membranes and the crossover phenomenon of electrolyte membranes were also described.

Effect of Substrates on the Microbial Communities in a Microbial Electrolysis Cell and Anaerobic Digestion Coupled System (기질에 따른 미생물 전해 전지-혐기성 소화의 미생물 군집 특성)

  • LEE, CHAE-YOUNG;HAN, SUN-KEE
    • Transactions of the Korean hydrogen and new energy society
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    • v.30 no.3
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    • pp.269-275
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    • 2019
  • This study was conducted to evaluate the microbial communities in coupled system of a microbial electrolysis cell and an anaerobic digestion. Glucose, butyric acid, propionic acid and acetic acid were used as substrates. The maximum methane production and methane production rate of propionic acid respectively were $327.9{\pm}6.7mL\;CH_4/g\;COD$ and $28.3{\pm}3.1mL\;CH_4/g\;COD{\cdot}d$, which were higher than others. Microbial communities' analyses indicated that acetoclastic methangens were predominant in all systems. But the proportion of hydrogenotrophic methanogens was higher in the system using propionic acid as a substrate when compared to others. In coupled system of a microbial electrolysis cell and anaerobic digestion, the methane production was higher as the distribution of hydrogen, which was generated by substrate degradation, and proportion of hydrogenotrophic methanogens was higher.

A Research Trend on Diaphragm Membranes Alkaline Water Electrolysis System (알칼리 수전해용 격리막 기술 연구동향)

  • Im, Kwang Seop;Son, Tae Yang;Jeong, Ha Neul;Kwon, Dong Jun;Nam, Sang Yong
    • Membrane Journal
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    • v.31 no.2
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    • pp.133-144
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    • 2021
  • Alkaline water electrolysis system is the oldest technology among various hydrogen production processes to produce green hydrogen with the least amount of greenhouse gas generated. Alkaline water electrolysis (AWE) system is used in alkaline atmosphere condition. In comparison to polymer electrolyte membrane water electrolysis (PEMWE), this system can utilize stable transition metals such as nickel, cobalt, and silver, as electrode catalysts. AWE is relatively inexpensive, and can easily be scaled up to large scale. The system is a mature technology, as it has been in operation since the beginning of the 20th century in MW-scale for hydrogen generation, and there are currently more than 20 commercial manufacturers. In this review, the basic principles of AWE, along with catalysts, electrodes, and diaphragm membranes, are summarized. Particularly, the research and development trends of the diaphragm membrane unit, which is the core component of an AWE, are discussed in detail.

Hydrogen Production from Water Electrolysis Driven by High Membrane Voltage of Reverse Electrodialysis

  • Han, Ji-Hyung;Kim, Hanki;Hwang, Kyo-Sik;Jeong, Namjo;Kim, Chan-Soo
    • Journal of Electrochemical Science and Technology
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    • v.10 no.3
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    • pp.302-312
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    • 2019
  • The voltage produced from the salinity gradient in reverse electrodialysis (RED) increases proportionally with the number of cell pairs of alternating cation and anion exchange membranes. Large-scale RED systems consisting of hundreds of cell pairs exhibit high voltage of more than 10 V, which is sufficient to utilize water electrolysis as the electrode reaction even though there is no specific strategy for minimizing the overpotential of water electrolysis. Moreover, hydrogen gas can be simultaneously obtained as surplus energy from the electrochemical reduction of water at the cathode if the RED system is equipped with proper venting and collecting facilities. Therefore, RED-driven water electrolysis system can be a promising solution not only for sustainable electric power but also for eco-friendly hydrogen production with high purity without $CO_2$ emission. The RED system in this study includes a high membrane voltage from more than 50 cells, neutral-pH water as the electrolyte, and an artificial NaCl solution as the feed water, which are more universal, economical, and eco-friendly conditions than previous studies on RED with hydrogen production. We measure the amount of hydrogen produced at maximum power of the RED system using a batch-type electrode chamber with a gas bag and evaluate the interrelation between the electric power and hydrogen energy with varied cell pairs. A hydrogen production rate of $1.1{\times}10^{-4}mol\;cm^{-2}h^{-1}$ is obtained, which is larger than previously reported values for RED system with simultaneous hydrogen production.