• 한국환경과학회지
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• 제26권1호
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• pp.109-118
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• 2017

This study was conducted to investigate the effects of intermittent plasma and electrolysis treatments on lettuce (Lactuca sativa var. oak-leaf.), nutrient solution components ($NO_3{^-}-N$, $NH_4{^+}-N$, $PO{_4}^{3-}-P$, $K^+$, $Ca^{2+}$ and $Mg^{2+}$) and environmental parameters (electrical conductivity, total dissolved solids and pH). The recirculating hydroponic cultivation system consisted of planting port, LED lamp, water reservoir and circulating pump. Nutrient solution was circulated in the following order: reservoir ${\rightarrow}$ filtration-plasma or filtration-electrolysis ${\rightarrow}$ planting port ${\rightarrow}$ reservoir. The results showed that nutrient solution components and environmental parameters were changed by plasma or electrolysis treatment. Lettuce growth was not affected by the intermittent plasma or electrolysis treatment with 30 minutes or 90 minutes, respectively. The roots of the lettuce was damaged by excessive plasma and electrolysis treatment. Electrolysis treatment had greater effect on than plasma treatment because of the accumulation of high levels of TRO (Total Residual Oxidants).

• 멤브레인
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• 제32권6호
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• pp.475-485
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• 2022

지속적인 화석연료의 과도한 소비는 지구온난화와 기후환경 위기를 초래하고 있다. 이에 따라 화석연료의 대체 에너지 중 수소에너지가 주목받고 있는데, 수소에너지는 공해물질의 배출이 없고 자원적인 제약이 없다는 장점이 있다. 이에 따라 물의 전기분해를 이용하여 수소를 생산하는 수전해 시스템 및 수소에너지를 연료로 사용하여 전기를 생산하는 연료전지 시스템과 관련된 다양한 연구가 진행되고 있다. 본 연구에서는 수전해 시스템과 연료전지의 핵심 소재 중 하나인 음이온 전도성 이오노머 소재를 대상으로 과량의 수화 상태를 반영하여 3D 이오노머 모델을 제작하였다. 최종적으로 과량의 수화상태에서 이오노머의 구조적인 안정성과 성능 분석을 통해, 수전해 시스템과 연료전지의 핵심 소재인 음이온 전도성 이오노머 설계에 있어서 성능향상 인자를 제시하고자 하였다.

• 수산해양교육연구
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• 제28권5호
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• pp.1319-1328
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• 2016

Since Ballast Water Management Convention has been effected, BWTS, applied to new-building vessels and existing vessels, have been developed from many countries with various treatment methods. However, BWTS is mainly typed Electrolysis, Ozone and UV type. Approximately 70 products have been type approved by the Flag Administrations. For the new-building vessels, the vessels' design and construction have been considered for arrangements and installations for BWTS. However, existing vessels which already construction had finished have problem with selection of BWTS type for installation and arrangement. The selection of the most economized BWTS system is important though, CAPEX has not been made any significant differences. However, OPEX is more important factor. Consequently, detail analysis of OPEX is the key to the selection of the most economized BWTS system and also it can be the purpose of this study. The feasibility study on the main three type of BWTS (Electrolysis, Ozone and UV type) for 175K Bulk Carrier and 57K Cargo ship has been conducted for this study. Because, these three type of BWTS have been the most frequently installed and used and the two type of object vessels are consist of the 40% of the world merchant ship market. For this study, interest rate, project duration (operation time after installation), maintenance cost and fuel oil price are considered as major factor of feasibility study. In addition, expecting Interest rates to sensitivity analysis conducted for more accurate feasibility study. For 175K Bulk carrier, ozone treatment system is more economical than other types. For 57K cargo ship, UV type is considered more economical than other types. However, it is concluded that electrolysis type is more suitable compare to installation space, total weight and electrical power consumption.

• Korean Chemical Engineering Research
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• 제50권5호
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• pp.825-829
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• 2012

본 연구에서는 전기분해 처리된 해수의 유효염소농도와 온도에 의한 배가스 중 NO의 산화 특성을 실험적으로 살펴보았다. 실험은 무격막식 전해수가 채워진 버블링 반응기에 반응가스를 공급하여 NO 농도의 변화를 분석하였다. 폐순환 전기분해 시스템의 경우 정전류 조건에서 전해 시간이 길어질수록 전해수 내에 유효염소농도가 상승하였고, 전해수의 유효염소농도가 높을수록 NO가 $NO_2$로 산화되는 반응이 촉진됨을 확인하였다. 또한 동일한 유효염소농도를 가지는 전해수의 경우에도 온도가 높을수록 NO 산화율이 증가하였다.

• 한국항해항만학회지
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• 제41권3호
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• pp.79-86
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• 2017

선박의 항해 안전성을 유지하기 위하여 평형수 탱크에 주입 배출되는 선박평형수는 그 안에 포함되어 있는 각종 수중생물로 인하여 지역 해양 환경에 부정적인 영향을 주고 있다. 국제해사기구(IMO)는 선박평형수를 통한 수중생물의 이동을 막기 위해, 2004년 선박평형수와 침전물 통제 및 관리를 위한 국제협약을 채택하고 2016년 9월에 발효하여, 2017년 9월 이후 정기검사가 도래하는 모든 선박은 선박평형수 처리장치를 설치하도록 하였다. 선박평형수 처리 방식에는 활성물질을 이용하여 처리하는 전기분해식, 오존식, 약품식과 물리적인 처리방식인 필터, 자외선식 등으로 나누어 지며, 두 가지 방식을 혼용하여 사용하기도 한다. 일반적으로 비용과 효율 면에서 전기분해방식이 우수한 것으로 알려져 있다. 본 논문에서는 직접식 전기분해 선박평형수 처리장치의 기본 원리, 구성 요소, 육상 시험 내용을 고찰하였다. 육상시험은 정부시험 시설이 설치되어 있는 KIOST 거제분원에서 $300m^3/h$ 처리 용량의 장치로 수행하였다. 이 육상시험을 통해 직접식 전기분해 선박평형수 처리장치가 IMO에서 제시하고 있는 기준을 만족하고 다른 방식에 비해 효율적인 것을 확인하였다.

• 수산해양교육연구
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• 제29권3호
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• pp.665-676
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• 2017

Over the past several years, sea trade have increased traffic by ships which highlighted a problem of unwanted species invading the surrounding seas through ship's ballast water discharge. Maritime trade volume has continuously increased worldwide and the problem still exists. The respective countries are spending billions of dollars in an effort to clean up the contamination and prevent pollution. As part of an effort to solve marine environmental problem, BWM(Ballast Water Management) convention was adopted at a diplomatic conference on Feb. 13 2004. In order to comply harmoniously this convention by each country. This convention will be effective after 12 months from the date which 30 countries ratified accounting for more than 35% of the world merchant shipping volume. On Sep. 8 2016, Finland ratified this convention and effective condition was satisfied as 52 states and world merchant vessel fleet 35.1441%. Thus, after Sep. 8 2017, all existing vessels shall be equipped with BWTS(Ballast Water Treatment System) in accordance with D-2 Regulation, which physically handles ballast water from ballast water exchange system(D-1 Regulation). In this study, we analyzed in detail the optimal design method using the Risk Analysis and Evaluation technique which is mainly used in the manufacturing factory or the risky work site comparing with the traditional design concept method applying various criteria. The Risk Assessment Method is a series of processes for finding the Risk Factors in the design process, analyzing a probility of the accident and size of the accident and then quantifying the Risk Incidence and finally taking measures. In this study, this method was carried out for Electrolysis treatment type on DWT 180K Bulk Carrier using "HAZOP Study" method among various methods. In the Electrolysis type, 63 hazardous elements were identified.

• 한국수소및신에너지학회논문집
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• 제32권5호
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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.

• 상하수도학회지
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• 제33권5호
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• pp.379-388
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• 2019

Chlorination and UV illumination are being widely applied to inactivate a number of pathogenic microbials in the environment. Here, we evaluated the inactivation efficiency of individual and combined treatments of chlorination and UV under various aqueous conditions. UV dosage was required higher in waste water than in phosphate buffer to achieve the similar disinfecting efficiency. Free chlorine generated by electrolysis of waste water was abundant enough to inactivate microbials. Based on these, hybrid system composed of sequential treatment of electrolysis-mediated chlorination and UV treatment was developed under waste water conditions. Compared to individual treatments, hybrid system inactivated bacteria (i.e., E. coli and S. typhimurium) and viruses (i.e., MS-2 bacteriophage, rotavirus, and norovirus) more efficiently. The hybrid system also mitigated the photo re-pair of UV-driven DNA damages of target bacteria. The combined results suggested the hybrid system would achieve high inactivation efficiency and safety on various pathogenic microbials in wastewater.

• 한국해양공학회지
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• 제31권3호
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• pp.248-255
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• 2017

Many rivers and seas have been affected by environmental contamination. Therefore, city water supplies often require a high-degree purification treatment to provide safe drinking water. However, in order to achieve a high-degree purification treatment, a large amount of chlorine has to be added to sterilize city drinking water. The added chlorine reacts chemically with water and forms hypochlorous and chlorine ions. The hypochlorous ionizes with hypochlorous ions and hydrogen ions. As a result, the city water contains a large amount of chlorine ion. As such, when city water is used with domestic boilers, many kinds of heat exchangers, and the engines of vehicle and ships, there are often corrosion problems. In this study, alkali water was electrochemically made by electrolysis of city water, and corrosion properties between alkali and city water were investigated with an electrochemical method. Most of the chlorine ions are thought to not be contained in the alkali water because the alkali water is created in the cathodic chamber with an electrolysis process. In other words, the chlorine ion can be mostly removed by its migration from a cathodic chamber to an anodic chamber. Moreover, the alkali water also contains a large amount of hydroxide ion. The alkali water indicated relatively good corrosion resistance compared to the city water and the city water exhibited a local corrosion pattern due to the chlorine ion created by a high-degree purification treatment. In contrast, the alkali water showed a general corrosion pattern. Consequently, alkali water can be used with cooling water to inhibit local corrosion by chlorine ions in domestic boilers, various heat exchangers and the engine of ships and for structural steel in a marine structure.

• 한국수소및신에너지학회논문집
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• 제29권3호
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• pp.235-242
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• 2018

Hydrogen can be produced by reforming reaction of natural gas (NG) and biogas, or by water electrolysis. In this study, hydrogen production through water-electrolysis needs superheated steam above $700^{\circ}C$ for high efficiency. The production method of hydrogen like this was recommended for the 4-type processes for superheated steam ($700^{\circ}C$, 3 atm) by Bio-SRF combustion furnace. The 4-type processes to produce superheated steam at $700^{\circ}C$ from the heat source of SRF combustion furnace was simulated using PRO II. The optimum process was selected through exergy analysis. The difference of process 1 and 2 is to the order of depressure and heating process to change $180^{\circ}C$ and 7 atm to $700^{\circ}C$ and 3 atm. Process 3 and 4 is to utilize 25% of steam to generate superheated steam and remaining to use for the power generation by steam generator.