• Bulletin of the Korean Chemical Society
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• 제22권6호
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• pp.616-622
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• 2001

Split-flow thin (SPLITT) cell Fractionation(SF) is a technique that allows separation of particulates and macromolecules into two fractions. A gravitational SF(GSF) system is constructed and tested for its applicability for separation of dust and ground water particulates. When tested with polystyrene latex particles, experimental data were in good agreements with theory. The 9.8 and 21.4㎛ polystyrene particles were successuflly separated in a continuous mode, where the mixture is continuously fed into the GSF channel allowing separation in a large sacle. The GSF system is successfully applied to continuous separation of dust and ground water particels based on the sedimentation coefficient, which is closely related to the particle size. The separations were confirmed by microscopy and energy-dispersive X-ray (EDX) analysos.

• 공업화학
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• 제28권4호
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• pp.410-419
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• 2017

지구온난화, 환경오염, 가뭄 등의 재해현상으로 인한 물 부족 현상이 진행됨에 따라 수자원의 활용성을 증가시키기 위한 원천기술의 개발과 연구들이 진행되고 있다. 그중 수처리 분리막 기술은 기존 물리화학적 및 생물학적 공정보다 수질 개선 효과가 우수하고 약품 사용이 배제된 환경친화적인 공정이다. 수처리 분리막은 오폐수처리, 정수처리, 해수담수처리, 이온교환 공정, 초순수 제조, 유기용매 분리 등 다양한 분야에 적용되며 분리막을 이용한 수처리 기술은 점차 응용 범위가 넓어지고 있는 추세이다. 수처리 분리막의 핵심 기술은 분리성능을 조절하기 위한 기공 사이즈를 조절하는 것으로써 더 나은 성능을 나타내는 분리막을 개발하기 위한 연구가 활발히 진행되고 있다. 본 총설에서는 수처리용 분리막의 특허 및 논문의 기술경쟁력 평가를 통하여 국가별, 기관별 발표 빈도수를 정리하였으며, 오폐수처리용 분리막, 정수처리용 분리막, 해수담수화용 분리막, 그리고 이온교환공정용 분리막에 대한 평가를 진행하고, 향후 연구 방향에 대하여 제시해 보고자 한다.

• 센서학회지
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• 제29권2호
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• pp.89-92
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• 2020

Polytetrafluoroethylene (PTFE) fibers are widely used in the textile industry, filter media, membrane distillation, electronic appliances, and construction. In this study, PTFE-polyethylene oxide (PEO) fibrous membranes were fabricated by emulsion electrospinning; subsequently, pure PTFE nanofibers were obtained via sintering. PTFE-PEO electrospinning solutions were prepared using different weight ratios to determine the optimized condition. As the ratio of the PEO increased, the fiber structure improved. Scanning electron microscopy and Fourier-transform infrared spectroscopy observations indicate that PEO is removed and PTFE fused gradually to form bonds among them during sintering. The obtained pristine PTFE membrane demonstrated hydrophobicity at 143.6° water contact angle and oleophilicity at 0° oil contact angle, which is known to be utilized for oil/water separation. A simple separation experiment was performed to remove oil droplets from water. The PTFE membrane exhibited good chemical stability and a high surface-area-to-volume nanofiber ratio. These excellent properties suggest that it is applicable to oil/water separation in harsh chemical environments.

• 멤브레인
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• 제22권2호
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• pp.77-94
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• 2012

내열성, 용매 저항성의 특징을 갖는 다공성 세라믹 소재를 이용한 무기 멤브레인이 기체분리(수소 분리, 이산화탄소 분리 등), 액체 분리(수처리, 폐수처리, 유기용매 분리 등) 등 여러 가지 분야로 그 응용이 확대되고 있다. 본 논문에서는 다공성 세라믹 멤브레인의 소재, 제조 방법에 따른 멤브레인의 구조 제어 및 성능 평가에 관한 연구를 소개하고, 멤브레인의 세공 크기에 따른 구조, 멤브레인의 특성을 이용한 여러 가지 기체 분리 및 액체 분리에 관한 연구 동향을 정리하였다.

• Membrane and Water Treatment
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• 제10권4호
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• pp.277-286
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• 2019

In 2014, the first demineralization plant, using nanofiltration (NF) membrane coupled with renewable energies was realized at Al Annouar high school of Sidi Taibi, Kenitra, Morocco. This project has revealed difficulties related to the membrane performances loss (pressure increase, flux decline, poor water quality of the produced water and increase of energy consumption), as consequences of membrane fouling. To solve this problem, an autopsy of the membrane was done in order to determine the nature and origin of the fouling. The samples of membrane and fouling were then analyzed by scanning electron microscopy using a scanning electron microscope (SEM) connected with an energy dispersive X-ray (EDX) detection system and X-ray diffractometer (XRD). Moreover, three cleaning solutions (hydrochloric acid, nitric acid and sulfuric acid) were tested and assessed in a single cleaning step to find the suitable one for the fouled membrane to regain its initial permeability and performances. The analysis of the experimental results showed that the fouling layer is mainly composed of calcium carbonate (inorganic fouling). Results showed also that the permeability is improved by the hydrochloric acid cleaning (pH=3) with a cleaning efficiency of 93%. Cleaning efficiency did not exceed 75 % with nitric acid (pH=3) and 40 % with sulfuric acid (pH=3).

• Ocean and Polar Research
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• 제38권4호
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• pp.331-338
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• 2016

Many studies using tracers have been conducted to understand a physical process in a system. Rain-on-snow could accelerate snowmelt processes, which influences the hydrological process in both temperate and polar regions. Hydrological and ecological conditions will be affected by the amount and timing of discharge reaching the bottom of a snowpack. The discharge consists of the rain-on-snow, pore water penetrating into the snowpack and natural meltwater. In this study, after a rain-on-snow experiment, we conducted an isotopic hydrograph separation to distinguish rainwater and pore water from meltwater. Using the isotopic data of snow and meltwater from Lee et al. (2010), two components were separated based on the assumption that rainwater and pore water are new water and natural meltwater is old water. After the second rain-on-snow experiment, the maximum contributions of rainwater and pore water reached up to 69% of the discharge and then decreased. During the study period, the measured total discharge was 4153 L and 40% (based on hydrogen isotope) of rainwater and pore water was calculated in the discharge, which is not consistent with what Lee et al. (2016) calculated using chemical separation (63%). This inconsistency can be explained by how an end-member was defined in both approaches. The contributions of artificial rainonsnow and pore water to melwater discharge range between the two methods. This study will suggest a mixing calculation from isotopic compositions of the Southern Ocean.

• 멤브레인
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• 제13권3호
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• pp.154-161
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• 2003

본 연구에서는 소수성 PTFE (Polytetrafluoroethylene) 분리막의 산소동위원소 분리특성을 확인하기 위해 물의 온도에 따른 수증기의 막 투과특성을 Air Cap Membrane Distillation (AGMD)과 Vacuum Enhanced Membrane Distillation (VEMD) 방법을 이용하여 각각 측정하였다. 투과된 수증기는 트랩에서 수거하여 투과플럭스 (permeation flux)를 측정하였고$ H_2^{16}O$와 $H_2^{18}O$의 성분비는 다이오드 레이저 흡수분광법을 이용하여 측정하였다. 분리막을 투과한 수증기에서 무거운 산소동위원소의 성분비가 감소함을 확인하였고 분리계수는 실험 조건에 따라 1.004~1.01로 측정되었다. 또한 분리막의 기공에 있는 공기가 산소동위원소의 분리에 미치는 영향을 확인하였고 기공내 공기가 없을 때 동위원소 분리계수가 증가함을 관찰하였다.

• 공업화학
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• 제10권2호
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• pp.319-323
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• 1999

비대칭 폴리에테르이미드막을 상전이 방법으로 제조하였고, 표면층 개질에서 NaOH 농도의 영향과 그에 따른 물/이소프로판올 혼합물 투과증발 분리에 대하여 연구하였다. 실험결과, 개질 용액의 농도가 증가할수록 폴리에테르이미드의 이미드 그룹이 가수분해에 의해서 쉽게 폴리아믹산 구조로 변하여 치밀층의 두께가 증가하였다. 따라서 사용된 NaOH 농도가 증가할수록 전반적인 투과도는 감소하였고, 선택도는 증가하였다. 그러나 NaOH 용액의 농도가 너무 높은 경우, 선택도가 오히려 감소하고 투과도는 증가되었다. 이러한 결과로부터, 비대칭 폴리에테르이미드막의 투과거동이 NaOH 농도에 크게 의존한다는 것을 알 수 있었다. 또한, NaOH로부터 개질된 막들의 투과증발 운전온도가 증가할수록 투과도와 선택도가 모두 증가되었다.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2022년도 학술발표회
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• pp.149-149
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• 2022

Accurate quantitative evaluation of baseflow contribution to streamflow is imperative to address seasonal drought vulnerability, flood occurrence and groundwater management concerns for efficient and sustainable water resources management in watersheds. Several baseflow separation algorithms using recursive filters, graphical method and tracer or chemical balance have been developed but resulting baseflow outputs always show wide variations, thereby making it hard to determine best separation technique. Therefore, the current global shift towards implementation of artificial intelligence (AI) in water resources is employed to compare the performance of deep learning models with conventional hydrograph separation techniques to quantify baseflow contribution to streamflow of Piney River watershed, Tennessee from 2001-2021. Streamflow values are obtained from the USGS station 03602500 and modeled to generate values of Baseflow Index (BI) using Web-based Hydrograph Analysis (WHAT) model. Annual and seasonal baseflow outputs from the traditional separation techniques are compared with results of Long Short Term Memory (LSTM) and simple Gated Recurrent Unit (GRU) models. The GRU model gave optimal BFI values during the four seasons with average NSE = 0.98, KGE = 0.97, r = 0.89 and future baseflow volumes are predicted. AI offers easier and more accurate approach to groundwater management and surface runoff modeling to create effective water policy frameworks for disaster management.

• 한국막학회:학술대회논문집
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• 한국막학회 1996년도 추계 총회 및 학술발표회
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• pp.34-39
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• 1996

There is much recent interests in applying membrane separation technologies, especially for organic liquid and vapor separation or removing dissolved organics from water. Pervaporation separation can separate azeotropic mixtures and mixtures close to boiling point, and it has a potential for energy saving process instead of distillation. Removal of chlorinated oraganics from water is other measure application for pervaporation separation. Contaminated pollutant must be removed from water, and a pervaporation can effectively remove the pollutant. Air pollution by organic vapor recently became serious enviromncntal problem, and removing organic vapor from air is important application of the membrane technology.