Hybrid Capacitive Deionization with Ag-coated Activated Carbon Electrodes for Nickel Treatment

Hongsik Yoon,Taijin Min,Gunhee Lee,Minkyu Jeon,Minsub Oh,Areum Kim 대한환경공학회 2023 Environmental Engineering Research Vol.28 No.5

Effects of characteristics of cation exchange membrane on desalination performance of membrane capacitive deionization

Yoon, Hongsik,Jo, Kyusik,Kim, Kwang Je,Yoon, Jeyong Elsevier 2019 Desalination Vol.458 No.-

<P><B>Abstract</B></P> <P>The ion exchange membrane (IEM) is a key component that helps achieve good performance in membrane capacitive deionization (MCDI). However, systematic researches have been limitedly conducted regarding the effect of IEM characteristics on MCDI performance. The aim of this study is to investigate the effects of the characteristics of the cation exchange membrane (CEM) on MCDI performance. Salt adsorption capacity (SAC), maximum average deionization rate (MADR), and charge efficiency were chosen to demonstrate MCDI performances.</P> <P>Only MADR was significantly affected by CEM characteristics. Additionally, MADR showed a positive relationship with the transport number divided by total electrical resistance (<I>R</I> <SUP>2</SUP> = 0.83). Therefore, CEM should have a high transport number and low electrical resistance for fast rate-capable MCDI. The correlations between CEM characteristics and MCDI performances revealed through this study are expected to further develop high-performance MCDI.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Cation exchange membrane (CEM) properties for membrane CDI (MCDI) were examined. </LI> <LI> Tested performance of MCDI were capacity, rate, and efficiency. </LI> <LI> Among them, the rate performance was the most sensitive to CEM properties. </LI> <LI> CEM with high transport number and low resistance showed good rate performance. </LI> </UL> </P>

Forward osmosis as appropriate technology with starch-based draw agent

Yoon, Hongsik,Kim, Jiye,Yoon, Jeyong Informa UK (Taylor Francis) 2016 Desalination and Water Treatment Vol.57 No.22

<P>The appropriate technology (AT) has been gaining attention for securing safe water resources in developing countries. Despite its promising energy-saving operation, forward osmosis (FO) system is a lack of suitable draw agent to be implemented as an AT. In this study, we propose a conceptual small-scale FO system with a starch-based draw agent. This FO system successfully produced about 17.3L/m(2)d of drinking water and achieved 95% of the arsenic removal rate using a starch paste combined with amylase as a draw agent. The osmotic pressure, which is necessary for producing permeate water, was generated by small molecules, such as maltose. These molecules were formed from the decomposition of starch by amylase. Because the draw agent used in this study is edible, the permeate water is directly drinkable without any further separation. In addition, diverse starch-containing foods such as flour, raw potatoes, raw sweet potatoes, and bananas were also confirmed as an alternative starch source for draw agent.</P>

A Porphyrin-Based Molecular Tweezer: Guest-Induced Switching of Forward and Backward Photoinduced Energy Transfer

Yoon, Hongsik,Lim, Jong Min,Gee, Hyuk-Chan,Lee, Chi-Hwa,Jeong, Young-Hwan,Kim, Dongho,Jang, Woo-Dong American Chemical Society 2014 JOURNAL OF THE AMERICAN CHEMICAL SOCIETY - Vol.136 No.4

<P>A bisindole-bridged-porphyrin tweezer (<B>1</B>), a pair of zinc porphyrins (<B>P</B><SUB><B>Zn</B></SUB>’s) connected to bisindole bridge (<B>BB</B>) via the Cu<SUP>I</SUP>-mediated alkyne–azide click chemistry, exhibited unique switching in forward and backward photoinduced energy transfer by specific guest bindings. The addition of Cu<SUP>2+</SUP> caused a change in electronic absorption and fluorescence quenching of <B>1</B>. MALDI-TOF-MS and FT-IR analyses indicated the formation of stable coordination complex between <B>1</B> and Cu<SUP>2+</SUP> (<B>1</B>-Cu(II)). Without Cu<SUP>2+</SUP> coordination, the excitation energy flows from <B>BB</B> to <B>P</B><SUB><B>Zn</B></SUB>’s with significantly high energy transfer efficiency. In contrast, the direction of energy flow in <B>1</B> was completely reversed by the coordination of Cu<SUP>2+</SUP>. The difference in fluorescence quantum yield between <B>1</B> and <B>1</B>-Cu(II) indicates that more than 95% of excitation energy of <B>P</B><SUB><B>Zn</B></SUB> flows into Cu(II)-coordinated <B>BB</B>. The energy transfer efficiency was further controlled by bidentate ligand coordination onto <B>1</B>-Cu(II). When pyrophosphate ion was added to <B>1</B>-Cu(II), the recovery of fluorescence emission from <B>P</B><SUB><B>Zn</B></SUB> was observed. The quantum mechanical calculations indicated that the Cu(II)-coordinated <B>BB</B> has square planar geometry, which can be distorted to form octahedral geometry due to the coordination of bidentate ligands.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/jacsat/2014/jacsat.2014.136.issue-4/ja4124048/production/images/medium/ja-2013-124048_0016.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/ja4124048'>ACS Electronic Supporting Info</A></P>

A Comparison between conservative Welfare States and Korean Childcare Policy, 1993-2003: A Discussion of Defamilization and Familization

Yoon HongSik,Chung Sulki 숙명여자대학교 아시아여성연구소 2009 Asian Women Vol.25 No.3

New acidification for the re-mineralization as post-treatment of seawater desalination process

Hongsik Yoon(윤홍식),Yu Chang Kim(김유창),Tae Jin Min(민태진),Sungil Lim(임성일),Geun Jo Park(박근조),Changhak Lee(이창학) 대한환경공학회 2020 대한환경공학회 학술발표논문집 Vol.2020 No.11

서울메트로 전동차의 출입문 DOS 함 및 DIR 계전기 접점 개선에 관한 연구

윤홍식(Hongsik-Yoon),이상섭(Sangsub-Lee) 한국철도학회 2015 한국철도학회 학술발표대회논문집 Vol.2015 No.10

본 연구는 전동차 출입문 관련장치(DIR 계전기, DOS, DCS 스위치)들을 개선하여 출입문과 관련된 고장들을 사전에 예방하기 위하여 시행하게 되었다. 운전실 DOS함 내에는 출입문 OPEN 스위치 2개가 4개의 직렬접점으로 연결되어 있고 CLOSE 스위치도 2개의 직렬접점으로 구성되어 있어서 한 개의 접점이 불량 또는 접점저항이 높으면 출입문이 열리지 않는 고장이 간혹 발생됨을 알게 되었다. 또한 역행회로 구성 및 도어등 점등 라인은 DIR1,2계전기 접점에 의하여 제어되며 본선 운행 중 장애발생 시 연동회로 혼선으로 운행지연 사례도 있었다. 이러한 고장원인을 파악하고 개선함으로써 승무원의 혼란 및 운행지연을 사전에 예방하고자 본 연구를 시작하게 되었다 The purpose of this study is to improve a train door related device (DIR relay, DOS, DCS switch) performed in advance to prevent the door associated with the failure. We know that the door located in the Cab DOS Box is consists of OPEN switch two to four connected to the serial contacts and CLOSE switch with two serial contacts if one contact is poor or the contact resistance , door does not open In addition, the configuration such as the lighting and the door driving circuit lines are controlled by a relay contact DIR1,2 The case, Interlocked circuit with crosstalk delay was also driving practices malfunctioning during operation in the main track. These identify the causes of errors and improved by confusion and delays for the crew was to begin this study to prevent in advance.

박정희 정권시기 한국 복지체제

윤홍식(Hongsik Yoon) 한국사회정책학회 2018 한국사회정책 Vol.25 No.1

본 연구는 한국현대사에 가장 논쟁적인 시기를 지나오면서 복지체제가 어떻게 변화해왔는지를 관찰했다. 복지체제는 수출주도형 경제성장의 필요에 조응하는 방식으로 변화했다. 1960년대 중반부터 시작된 경공업중심의 산업화는 농촌에 존재하고 있던 광범위한 유휴노동력을 흡수해 그들을 상품화시킴으로써 한국사회가 절대빈곤에서 벗어나는 계기를 마련했다. 하지만 노동력의 상품화에 조응하는 공적 탈상품화, 즉 사회보장제도는 매우 제한적인 영역과 대상에 국한해 제도화되었다. 실제로 탈상품화 제도는 노동력 재생산과 직접적 연관이 있는 영역에 국한되었고, 이마저도 농촌의 대체 가능한 유휴노동력이 풍부한 상황에서 그 대상은 매우 제한적이었다. 강제적 의료보험은 기업 부담을 이유로 거부되었고, 대규모 사업장을 중심으로 산재보험이 도입되었다. 1970년대에 들어서면서 한국 경제의 중심이 경공업에서 중화학공업으로 이동하기 시작하자 상품화된 노동력도 저숙련 여성노동력에서 숙련된 남성 노동력으로 변화했다. 수출중심의 대기업에 고용된 노동자들과 내수중심의 중소기업에 고용된 노동자들 간에 이중구조가 만들어지기 시작한 것도 바로 이 시기이다. 이에 따라 사회적 위험에 대응해 노동력 재생산을 지원하는 공적 탈상품화 제도도 대규모 사업장을 중심으로 제도화되었다. This study has examined how the welfare system has changed as it has passed through the most controversial period in Korean modern history. The welfare system has changed in a way that adapts to the need for export-led economic growth. Industrialization centered on light industry, which started in the mid-1960s, absorbed the labor force that existed in the rural areas and commodified them, thereby creating a momentum for Korean society to get out of poverty. However, the public de-commodification, ie social security system, adapted to the commodification of the labor force has been institutionalized only in a very limited area and people. Indeed, the de-commodification system was confined to the area directly linked to the reproduction of the labor force. Even so, the target was very limited in the abundance of labor in rural areas. Compulsory medical insurance was rejected because of corporate burden, and industrial accidents insurance was introduced centering on large-scale workplaces. As the Korean economy began to move from the light industry to the heavy industry in the 1970s, the commodificated labor force changed from a low skilled labor force to a skilled male labor force. It is at this time that dual structures have begun to be created between workers employed in export-oriented large enterprises and workers employed in domestic-oriented SMEs. Therefore, the system of de-commodification that supports the reproduction of labor power in response to social risks has also been institutionalized centering on large-scale workplaces.

고성능 하이브리드형 축전식 탈염 기술 개발을 위한 은 코팅 활성탄 전극 개발

윤홍식(Hongsik Yoon),김유창(Yu Chang Kim),조기성(Kisung Cho) 대한환경공학회 2020 대한환경공학회 학술발표논문집 Vol.2020 No.11

칼슘알지네이트 이온교환막을 활용한 경도 제거용 축전식 탈염 기술 개발

윤홍식 ( Hongsik Yoon ),민태진 ( Taijin Min ),이건희 ( Gunhee Lee ),박인용 ( Inyong Park ),한방우 ( Bangwoo Han ),강보식 ( Bo Sik Kang ),류경하 ( Kyungha Ryu ),이지호 ( Jiho Lee ) 한국산업융합학회 2021 한국산업융합학회 논문집 Vol.24 No.5

In this study, calcium alginate based cation exchange membrane was prepared and used to develop membrane capacitive deionization (MCDI) system for effective hardness control. As a major result, the MCDI with Ca-alginate membrane showed 27% better deionization capacity than the MCDI with a commercial cation exchange membrane. This superior improvement in the deionization capacity was expected to be due to the high ratio of transport number/electrical resistance (S_c/R_ratio) of Ca-alginate membrane. In addition, the MCDI with Ca-alginate membrane showed better deionization performance than the MCDI with Ca-alginate coating. This was because the space between the electrode and the Ca-alginate membrane was utilized for ion adsorption. The preliminary results indicated that the MCDI with Ca-alginate membrane can be a viable technique for the hardness control.