• 한국지구물리탐사학회:학술대회논문집
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• 2003.11a
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• pp.518-521
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• 2003

LCA (Life Cycle Assessment), that unifies the scale of various environmental impacts, and simulated annealing are applied to optimizing electrolysis of wastewater from PCB (Printed Circuit Board) production. The changes of environmental impact can be quantified with LCA and the total changes of environmental impacts can be expressed as a function of power consumed, Cu recycled, $Cl_2$, NOx and SOx discharged through restriction of feasible reactions. In a single-variate condition, the environmental optimum can be easily obtained through plotting and comparing each environmental impact value. In 8V potentiostatic electrolysis, the lowest environmental impact can be achieved after 90min. To optimize a multi-variate conditional system, simulated annealing can be applied and this can give the quick and near optimum in complex systems, where many input and output materials are involved, through experimentally measured values without a theoretical modeling.

• Proceedings of the KIPE Conference
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• 2010.07a
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• pp.570-571
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• 2010

To reduce the problem of ecocide, the plating equipment, water treatment system, electrolysis facility in ship need high current high power rectifier. This paper shows entire constitution of the proposed high-current rectifier for electrolysis of seawater, describes a way to design controller and analyzes output characteristic of the rectifier.

• Transactions of the Korean hydrogen and new energy society
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• v.30 no.4
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• pp.303-311
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• 2019

Reversible solid oxide fuel cell (RSOFC) has become a prospective device for energy storage and hydrogen production. Many studies have been conducted around the world focusing on system efficiency improvement and realization. The system should have not only high efficiency but also a certain level of simplicity for stable operation. External waste steam utilization was proved to remarkably increase the efficiency at solid oxide electrolysis system. In this study, RSOFC system coupled with waste steam was proposed and optimized in term of simplicity and efficiency. Ejector for fuel recirculation is selected due to its simple design and high stability. Three system configurations using ejector for fuel recirculation were investigated for performance of design condition. In parametric study, the system efficiencies at different current density were analyzed. The system configurations were simulated using validated lumped model in EBSILON(R) program. The system components, balance of plants, were designed to work in both electrolysis and fuel cell modes, and their off-design characteristics were taken into account. The base case calculation shows that, the system with suction pump results in slightly lower efficiency but stack can be operated more stable with same inlet pressure of fuel and air electrode.

• Transactions of the Korean hydrogen and new energy society
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• v.32 no.5
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• pp.285-292
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• 2021

To study the effect of the mixture ratio of Ni-Pt nanocatalysts on water electrolysis characteristics in anion exchange membrane system, Ni-Pt nanocatalysts were loaded on carbon black by using a spontaneous reduction reaction of acetylacetonate compounds. The loading weight of Ni-Pt nanocatalysts on the carbon black was measured by thermogravimetric analyzer and the elemental ratio of Ni and Pt was estimated by energy dispersive x-ray analyzer. It was found that the loading weight of Ni-Pt nanoparticles was 5.36-5.95 wt%, and the loading weight increased with increasing Pt wt%. As the Ni-Pt loading weight increased, the specific surface area decreased, because Ni-Pt nanoparticles block the pores of carbon black. It was confirmed by BET analysis and dynamic vapor sorption analysis. I-V characteristics were estimated.

• Journal of the Korea Institute of Military Science and Technology
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• v.20 no.4
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• pp.491-496
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• 2017

The hydrogen($H_2$) is promising energy carrier of renewable energy in the microgrid system such as small village and military base due to its high energy density, pure emission and convenient transportation. $H_2$ can be generated by photocatalytic water splitting, gasification of biomass and water electrolysis driven by solar cell or wind turbine. Solid oxide electrolysis cells(SOECs) are the most efficient way to mass production due to high operating temperature improving the electrode kinetics and reducing the electrolyte resistance. The SOECs are consist of nickel-yttria stabilized zirconia(NiO-YSZ) fuel electrode / YSZ electrolyte / lanthanum strontium manganite-YSZ(LSM-YSZ) air electrode due to similarity to Solid Oxide Fuel Cells(SOFCs). The Ni-YSZ most widely used fuel electrode shows several problems at SOEC mode such as degradation of the fuel electrode because of Ni particle's redox reaction and agglomeration. Therefore Ni-YSZ need to be replaced to an alternative fuel electrode material. In this study, We studied on the Double perovskite $PrBrMnO_{5+{\delta}}$(PBMO) due to its high electric conductivity, catalytic activity and electrochemical stability. PBMO was impregnated into the scaffold electrolyte $La_{0.8}Sr_{0.2}Ga_{0.85}Mg_{0.15}O_{3-{\delta}}$(LSGM) to be synthesized at low temperature for avoiding secondary phase generated when it exposed to high temperature. The Half cell test was conducted at SOECs and SOFCs modes.

• Membrane Journal
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• v.32 no.6
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• pp.496-513
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• 2022

In this study, we sought to verify the applicability of anion exchange membrane water electrolysis system using FAA-3-50, Neosepta-ASE, Sustainion grade T, and Fujifilm type 10, which are commercial anion exchange membranes. The morphology of the commercial membranes and the elements on the surface were analyzed using SEM/EDX to confirm the distribution of functional groups included in the commercial membranes. In addition, mechanical strength and decomposition temperature were measured using UTM and TGA to check whether the driving conditions of the water electrolyte were satisfied. The ion exchange capacity and ion conductivity were measured to understand the performance of anion exchange membranes, and the alkaline resistance of each commercial membrane was checked and durability test was performed because they were driven in an alkaline environment. Finally, a membrane-electrode assembly was manufactured and a water electrolysis single cell test was performed to confirm cell performance at 60℃, 70℃, and 80℃. The long-term cell test was measured 20 cycles at other temperatures to compare water electrolysis performance.

• Clean Technology
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• v.15 no.2
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• pp.116-121
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• 2009

In this paper, we investigated the effect of an indirect oxidation zone in an electrolysis reactor that used Ti/$IrO_2$ as the anode and SUS 316L as the cathode. Based on our preliminary results, the electrolysis reactor was operated with pole plate interval of 6 mm, current density 1.0 $A/dm^2L$ and electrolyte concentration 15%. The removal efficiency, COD (chemical oxygen demand), was additionally increased by 55% and 12.5${\sim}$15.0% in the direct and indirect oxidation zones, respectively. The removal efficiencies of T-N (total nitrogen) and T-P (total phosphorus) were found to be 88% and 75%, respectively. It was shown that the additional effect of the indirect oxidation zone on the removal was nearly negligible. Also, as the removal of COD,T-N and T-P took place during the initial2${\sim}$5 days of reaction, it was concluded that there was no need to extend the retention time of the electrolysis reactor.

• Journal of Environmental Health Sciences
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• v.38 no.6
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• pp.568-574
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• 2012

Objectives: The purpose of this experiment is to understand the phosphorus removal ratio effects of iron plates per unit of surface area through the iron electrolysis system, which consists of an anoxic basin, aerobic basin, and iron precipitation apparatus. Methods: Iron electrolysis, which uses an iron precipitation reactor in anoxic and oxic basins, consisted of iron plates with total areas of 400 $cm^2$, 300 $cm^2$ and 200 $cm^2$ respectively. The FNR process was operated with a hydraulic retention time and a sludge retention time of 12 hours and three days, respectively. Wastewater used in the experiments was prepared by dissolving $KH_2PO_4$ in influent water. Results: The iron plates 400 $cm^2$ (16.6 $mA/cm^2$), 300 $cm^2$ (13.3 $mA/cm^2$) and 200 $cm^2$ (7.3 $mA/cm^2$) in surface area in the phosphorus reactor had respective phosphorus of 2.4 mg/l, 2.7 mg/l and 3.2 mg/l in the effluent and phosphorus removal respective efficiencies of 90.3%, 89.1% and 87.1%. The effluent in the reactor, where the iron plate was not used, had relatively very low phosphorus removal efficiency showing phosphorus concentration of 15.3 mg/l and a phosphorus removal efficiency about 38.3%. Phosphorus removal per ferrous was 0.472 mgP/mgFe in the iron electrolysis system where the surface area of iron was low. Phosphorus pollution load per active surface area and the phosphorus removal efficiency had an interrelation of RE = -0.27LS + 89.0 (r = 0.85). Conclusion: With larger iron plate surface area, the elution of iron concentration and phosphorus removal efficiency was higher. The removal efficiency of phosphorus has decreased by increasing the initial phosphate concentration in the iron electrodes. This shows a tendency of decreasing phosphorus removal efficiency because of decreasing of iron deposition as the phosphorus pollution load per active surface area increases.

• Membrane Journal
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• v.32 no.6
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• pp.475-485
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• 2022

The continuous excessive consumption of fossil fuels is causing global warming, climate, and environmental crisis. Accordingly, hydrogen energy attracts attention among alternative energies of fossil fuels, because it has the advantage of not emitting pollutants and not having resource restrictions. Therefore, various studies are being conducted on a water electrolysis system for producing hydrogen and a fuel cell system for producing electricity by using hydrogen energy as a fuel. In this study, 3D ionomer models were produced by reflecting the excessive water condition of an anion-conductive ionomer material, which is one of the core materials of water electrolysis systems and fuel cells. Finally, by analyzing the structural stability and performance of the ionomer under an excessively hydrated condition, we suggested a performance improvement factor in the design of an anion conductive ionomer, a key material for water electrolysis systems and fuel cells.

• Membrane Journal
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• v.22 no.2
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• pp.95-103
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• 2012

To treat nitrate and non-biodegradable organics effectively in sewage, industrial wastewater and livestock wastewater, the activated sludge process integrated by a membrane separation and a porous electrode- electrolysis was proposed and its efficiency was investigated. The proposed system was consisted of 3 processes; activated sludge, membrane filtration and electrolysis. In the study, the membrane filtration played a role in reducing the load of the electrolysis to operate the proposed process stably. The electrolysis consisted of a porous electrode to increase the efficiency due to the extension of the specific surface area. Additionally, redox reaction in the electrolysis was induced by decomposing influent water as current was applied. As a result, hydrogen free radicals and oxygen radicals as intermediates were produced and they acted as oxidants to play a role in decomposing non-degradable organics. It was environmentally-friendly process because intermediates produced by porous electrode were used to treat waste matters without supplying external reagent. Experimental data showed that the proposed process was more excellent than activated sludge process. SS removal efficiencies of the proposed process, membrane filtration and activated sludge process were about 100%, about 100% and about 90%, respectively. COD removal efficiencies of the proposed system, membrane filtration and activated sludge process were about 92%, about 84% and about 78%, respectively. T-N removal efficiencies of the proposed system, membrane filtration and activated sludge process were about 88%, about 67%, and about 58%, respectively. The SS data showed that SS was efficiently removed in the single of the membrane filtration. The COD/T-N data showed that COD/T-N of membrane hybrid process was treated by removing a little soluble organics and SS, and that COD/T-N of electrolysis hybrid process was treated by oxidize organics with high removal rate.