The membrane research in Korea Research Institute of Chemical Technology (KRICT) has played a leading role in the development of membrane technologies. For the past 30 years, the membrane research in KRICT has focused on expanding the fundamental knowledge in membrane technology, supported by the deep chemistry background in KRICT. Particularly, it has explored developing novel membrane materials and processes. The global interest in the membrane technology now is higher than ever, with its unparalleled energy efficiency compared to alternative separation processes. Based on increasing demand for membrane technologies, the membrane research in KRICT has been conducting in four main topics: 1) water and wastewater treatment including seawater desalination 2) greenhouse gas capture, 3) ion conducting membranes for energy conversion and storage, 4) industrial gas and liquid separation/purification processes. In this presentation, research achievements in membrane preparation and application conducted by KRICT will be introduced.
Though nonsolvent-induced phase separation has been used for decades to prepare polymeric membranes, it still remains a challenge to have clear insight into how the porous structure forms during membrane preparation. The presentation focuses on a point that is usually overlooked in the literature: phase separation may need time to occur. We found that the times, given and needed for phase separation to occur, play important roles in the formation of membrane pores, and they are strongly related to the degree of polymer chain entanglement in the casting solution, which can be well characterized by solution rheology. Examples will also be given to show how the knowledge about the phase separation time scales led to preparation of porous membranes with high inter-pore connectivity and polymer membranes with super-hydrophobic properties.
Recently, the Co-ZIF-8 molecular sieve has emerged as an excellent substitute for the ZIF-8 counterpart due to its potentially high C3H6/C3H8 separation performance. Here, for the first time, we investigated the effect of ZIF-67 molecular sieves in mixed matrix membranes (MMMs) for C3H6/C3H8 separations by integrating them into 6FDA-DAM polymeric matrix. Our current work demonstrated the superior C3H6/C3H8 separation performance of 6FDA-DAM/ZIF-67 MMMs, which was achieved mainly by the excellent size-based energetic selectivity of Co-ZIF-8 molecular sieves. Also, Co-ZIF-8 containing MMMs exhibited excellent physical aging resistance, further ensuring its potential application of the industrial C3H6/C3H8 separations.
CCS(CO2 capture and storage)는 발전소 등 고정배출원에서 CO2를 포집하고, 수송 및 저장하는 기술이다. 특히, 아민 흡수법은 CO2 포집 기술 중 가장 널리 알려진 공정이다. 하지만 큰 규모의 장치와 높은 재생에너지를 필요로 하는 문제점이 제기되고 있다. 따라서 기존 흡수 공정보다 고효율의 접촉막 연구가 주목받고 있다. 본 연구에서는 화학적, 열적 안정성이 뛰어난 세라믹 소재의 중공사막을 제조하였으며 SEM, 기체투과 특성 등을 분석하였다. 또한 이를 모듈화하여 아민흡수제를 이용한 CO2 흡수 실험을 수행하였다.
Carbonaceous materials have widely been used as sorbents. For advanced applications, fine-tuning porosity and polarity of carbonaceous materials is highly desired. Various control methods for porosity and polarity of carbonaceous materials are introduced and the designed carbonaceous materials are implemented for their intrinsic adsorption applications for various gas molecules (e.g., CO2, N2, H2), organic molecules, and metal ions.
About 130 million tons of ethylene and 55million tons of propylene have been produced every year in the world and thus, olefin production process is very important in the chemical process. Cryogenic distillation process has been used for olefin/paraffin separation commercially. but the process has been extremely high energy-consuming; about 20% of the energy of petrochemical industry have been consumed. Facilitated transport membranes (FTMs) could be a promising alternative for olefin/paraffin separation, We have prepared dense and composite FTMs using polymeric ion complex containing AgNO3. Excellent olfein/paraffin selectivity and olefin flux with the FTMs were obtained through pure gas permeation test. A simulation program based on the obtqined results was developed , which could predict the FTMs could provide high-purity olefin at high recovery from olefin/paraffin mixtrue at one-stage process.
The straight nanopores in cellulose acetate (CA) polymers for battery gel separators were generated by utilizing both Ni(NO3)2·6H2O and water pressure. When polymer film was exposed to water pressure, the continuous nanopores were generated after complexing with Ni(NO3)2·6H2O. These results could be explained by that polymer chains were weakened because of the plasticization effect of the Ni(NO3)2·6H2O incorporated into the CA. The well controlled CA membrane after water pressure treatment enabled fabrication of highly reliable cell by utilizing 2032-type coin cell structure. The resulting cell performance exhibited both the effect of the physical morphology of CA separator and the chemical interaction of electrolyte with CA polymer which facilitates the Li-ion in the cell.
The graft copolymer consisting of poly(vinyl chloride)-graft-poly(oxyethylene methacrylate) (PVC-g-POEM) was synthesized via atom transfer radical polymerization (ATRP) with a copper/ligand complex that functions as a reaction catalyst. Mesoporous perovskite with a high porosity and interfacial properties were synthesized via a solvothermal reaction using PVC-g-POEM as a structure-directing agent. A PVC-g-POEM graft copolymer with a worm-like morphology was utilized as a soft matrix to prepare a mixed matrix membrane (MMM) with mesoporous perovskite through a solution-casting method. The MMM with MgTiO3 25wt% exhibited a CO2 permeability improvement of 140% up to 138.7 Barrer without a large loss of CO2/N2 selectivity. Poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT-PSS) is a widely used conductive polymer in various electronic devices. We also reported the first use of PEDOT-PSS to enhance CO2 capture performance of all-polymeric membranes.
The anion exchange membrane fuel cells (AEMFCs) have been regarded as the promising power sources. To develop promising AEMs, the most important components in AEMFCs, the properties of the conducting groups as well as the polymer backbones should be both considered. We recently developed PPO-based anion exchange membranes having various conducting groups, including ammonium, imidazolium, mopholinium. The preparation, characterization and properties of the corresponding membranes will be discussed in detail.
Ionomer membranes which consist of polymer backbones attached with fixed charge groups have been traditionally used in various water treatment processes. Recently, they have also gained increased industrial importance in the applications to electrochemical energy processes such as reverse electrodialysis, fuel cells, redox flow batteries etc. A pore-filled ionomer membrane (PFIM), composed of an inert and tough porous substrate and an ionomer that fills the pores, is considered as a promising candidate for various commercial applications because they can be manufactured via a cheap process and also provide both high ion conductivity and excellent mechanical properties. We will introduce the results on the development of high performance PFIMs for various electrochemical applications.
Proton-exchange membrane (PEM) water electrolysis is a promising technology for hydrogen production. Meanwhile, recently, hydrogen water production has attracted great attention owing to the increasing demand in healthcare market. Therefore, hydrogen water production via PEM water electrolysis has also gained much interest. The PEM is the key component dominating the hydrogen production efficiency in the system. Although a Nafion meets the criteria for a number of key physical properties required for the operation in PEM water electrolysis, it is too expensive for commercial applications. In this work, therefore, we have developed the membrane electrode assembly (MEA) prepared with cost-effective pore-filled PEMs via a nonequilibrium impregnation-reduction (I-R) method.
최근 건강에 대한 관심이 급증하면서 식품과 마시는 물에 대한 관심은 어느 때 보다 높다. 과거에는 수분공급이라는 본연의 목적으로만 물을 중요하게 생각했으나, 최근에는 다양한 기능성을 나타내는 기능성 물들이 등장하였다. 본 연구에서는 건강한 성인 남녀를 대상으로 하여, 4 주 동안 정수와 수소수 섭취가 체내 항산화 능에 미치는 영향과 그 작용 메카니즘을 알아보고자 하였다. 물의 종류에 관계없이, 충분한 양의 수분 섭취는 체지방 감소 및 항산화력 증진에 도움을 줄 것으로 사료된다. 특히 수소수는 연령, 성별, 흡연 유무에 따라 효과가 다르게 나타나기도 하였으나, 전반적으로 체내 항산화능을 개선시키고 활성산소를 억제하며, 면역세포 조절 및 유전자발현 조절을 통해 항산화제로서의 가능성을 지니고 있음을 확인하였다.
Perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS) are reportedly detected in public drinking water supplies. The U.S. Environmental Protection Agency (EPA) considers these compounds emerging contaminants and PFOA and PFOS were placed on EPA’s Contaminant Candidate List and health advisory levels for them in drinking water were established at 70 ppt. NSF created protocol NSF P473, which established minimum requirements for materials, design, construction and performance of drinking water treatment systems to remove PFOA and PFOS. The basic test protocol methodologies for NSF P473 are based on organic contaminant reduction protocols under NSF/ANSI Standard 53 for activated carbon systems, and on health effects contaminant reduction protocols under NSF/ANSI Standard 58 for reverse osmosis (RO) systems.
산업발달과 함께 환경오염이 심해짐에 따라 환경성 질환 또한 증가하고 있다. 이에, 맑은 공기, 깨끗한 물에 대한 일반 대중들의 관심이 높아지면서 정수기, 공기청정기 등 오염물질로부터 노출을 감소시킬 수 있는 제품들이 필수 구매용품처럼 인식되어 가고 있다. 이러한 제품 수요는 증가하는 반면, 제품의 규제준수 및 제품 내 함유물질에 대한 안전성 측면에서의 관리체계는 부족한 실정이다. 국내ㆍ외적으로 살생물제를 포함한 화학물질 및 유해화학물질을 함유하고 있는 제품 사용으로 발생될 수 있는 인체/환경에 대한 노출을 관리하기 위한 규제가 강화되고 있으며, 유해물질 함유 제품에 대한 안전성 확인의 시급성 또한 거론되고 있으므로 소재개발에서부터 함유물질에 대한 규제 및 안전성 확인이 이뤄져야 한다.
캐나다 Alberta 지역의 Oil Sands는 bitumen과 crude oil을 대량 포함하고 있어 석유자원의 한정성을 대체할 수 있는 천연자원으로써 최근 Shale Gas와 함께 관심이 높아지는 추세이다. Oil Sands의 개발을 위해서는 extraction과 purification을 포함한 SAGD(steam-assisted gravity drainage) process를 거쳐야 하는데 이 과정에서 많은 양의 오염물을 포함하고 있는 OSPW(oil sands process-affected water)가 대량 발생하게 된다. 이를 위하여 캐나다 및 Alberta 주정부에서는 현재 다각적인 수처리 공정을 시도 하고 있으며, 그 중 분리막을 활용한 연구 내용 및 결과에 대해 소개하고자 한다.
Recently, among the water treatment technologies, the forward osmosis (FO) system has been received much attention due to the advantages in energy consumption. However, the practical application of the FO system has been limited because of the remaining obstacles such as the absence of both adequate osmotic agent and efficient membrane. In this study, polymers having lower critical solution temperature (LCST) and upper critical solution temperature (UCST), one of the thermal responsive characteristics, are used as the osmotic agents. These materials could be recovered easily by heating them to above their LCST and to below their UCST, respectively. Finally, we believe that our results will provide insight into the synthesis of osmotic agents for water treatment applications.
Owing to high energy efficiency and superior efficacy, membrane-based desalination processes have gained widespread implementation in a wide variety of water treatment applications. Tremendous research efforts on new membrane materials have been made to improve the separation performance of the state-of-the-art thin-film composite (TFC) membranes, particularly polyamide TFC membranes, hoping to overcome the permeability-selectivity trade-off relations. Currently, many nanomaterials such as zeolites, metal-organic frameworks (MOFs), graphene oxide (GO), and carbon nanotubes (CNTs) have been explored to enhance the separation performance of existing polymeric membranes, but it has been argued that the positive transformation of nanomaterials-embedded TFC membranes hold promising potential to realize the sustainable development of current desalination membranes. Here we have tried to discuss some misconceptions and challenging items delaying industrial-scale implementation of nanomaterialsembedded desalination membranes.
A salinity gradient power (SGP) system holds a great potential to generate continuous and clean electricity for 24 hours. Recently, incorporating with seawater reverse osmosis, SGP has been recognized as a alternative to solve the brine issue as well as energy saving. For commercialization, many scientists would sympathize that one of main hurdles is the limited performance of each membrane to extract the high power. In case of pressure retarded osmosis (PRO) closer to commercialization, the membrane must have the high water permeability and salt rejection. There are two type of modules; hollow fiber membranes and spiral type. Toray Chem. (Korea) already shows that 4th generation PRO module, but there is no still large size PRO hollow fiber modules. Therefore, this study presents 2 and 3 inch size of PRO hollow fiber membrane prepared by inside interfacial polymerization techniques.
Dimensional stability of polymer electrolyte membrane stands out always important issue as well as proton conductivity. The reinforced membrane can be a good solution to enhance the dimensional stability for not only perfluorosulfonic acid polymer but also hydrocarbon based polymer. In this study, we have prepared nanofiber reinforced polymer electrolyte membranes for proton exchange membrane fuel cells. The nanofiber reinforced PEMs was impregnated by introducing hydrocarbon polymer electrolytes into web-like substrate. Due to high porosity and the intrinsic structure of reinforced PEMs, dimensional stability are improved without sacrificing membrane performance. Consequently, reinforced PEMs exhibited higher physical properties than unreinforced PEMs.
레독스 흐름 전지(Redox flow battery)는 태양광, 풍력 등 재생에너지의 변동성을 수용하고, 원활한 전력의 공급 및 발전설비의 효율적인 활용을 위한 에너지 저장 시스템의 하나로 연구가 진행되고 있다. 특히 바나듐 레독스 흐름 전지(Vanadium Redox Flow battery, VRFB)는 재생에너지의 원활한 전력공급과 부하 평준화, 주파수 조절, 비상용 전력을 위한 에너지 저장 시스템으로 연구가 진행되고 있다. 바나듐 레독스 흐름 전지에서는 격막으로 이온교환막을 사용하고 있으며, 이온교환막의 바나듐 이온의 투과성, 막 저항은 전지의 전류효율, 전압효율에 영향을 미치고 있다. 본 발표에서는 VRFB용 이온교환막으로 요구되는 특성과 성능 측정 방법 등에 대해 설명하고자 한다.