• 멤브레인
• /
• 제13권3호
• /
• pp.154-161
• /
• 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.

• 한국막학회:학술대회논문집
• /
• 한국막학회 1994년도 제2회 하계분리막 Workshop
• /
• pp.45-58
• /
• 1994

Over the last 20 years, membrane separation processes, such as reverse osmosis, ultrafiltration and microfiltration, have been widely adopted by different industries. Commercial uses of membrane have displaced conventional separation processes, such as distillation, evaporation, precoat filter and so on. Membrane separation processes are often more capital and energy efficient when compared with conventional separation processes. Membrane devices and systems are almost always compact and modular. These are the well-known advantages of membrane separation processes. The disadvantage of the membrane process is that the process does not have scale merit and thus the membrane process is suitable for the small and middle size applications. Energy saving is, of course, the biggest advantage of the membrane process, and in many industries the membrane processes are employed because of this reason. Membrane process has other big advantage. In many applications membrane processes provide much higher quality of product than conventional processes. The example is ultrapure water production by membrane processes in semiconductor industry. Conventional technologies never offer such good quality of pure water. If you can obtain both energy saving and higher quality of product at the same time by membrane processes, this is the best application of membrane processes. One example is the concentration of orange juice by membrane, which has already been commercialized in Japan. Comparing with the conventional vacuum evaporation process, juice concentrated by the membrane process has much better taste and flavor and the energy consumption in the membrane process is much less than the evaporation process. In this paper, first membrane separation technology will be classified and then Japanese membrane manufacturers and new modules and devices under development in Japan will be introduced. Fourth energy saving in membrane process will be discussed and finally practical applications of membrane processes in Japan will be shown.

• 한국막학회:학술대회논문집
• /
• 한국막학회 2000년도 추계 총회 및 국제학술발표회
• /
• pp.58-60
• /
• 2000

No Abstract, See Full Text

• Korean Membrane Journal
• /
• 제4권1호
• /
• pp.12-19
• /
• 2002

Nanofiltration of aqueous dye solutions was carried out using polyamide (PA) nanofiltration (NF) composite membranes. The PA composite membranes were prepared by the interfacial polymerization of piperazine (PIP) and trimesoyl chloride (TMC) on the surface of microporous polysulfone (PSf) ultrafi1tration (UF) membranes. After characterization in terms of their permeation performance and surface ionic property, they were used for the separation of dye solutions such as Direct Red 75, 80, 81, and Direct Yellow 8 and 27. The separation conditions were varied to study the factors affecting on the permeation performance of the membranes: different concentrations of dye solutions, operating temperature and time, and flow rate of a feed solution. The surface property of the membrane, especially its ionic property, as a function of operating time was examined with a zeta-potentiometer and the relationship between the surface chemistry of the membrane and its permeation properties was also studied.

• 멤브레인
• /
• 제8권2호
• /
• pp.69-76
• /
• 1998

막분리기술은 다른 분리기술에 비해 에너지절약형이며 또 비교적 대량으로 분리를 수행할 수 있다는 장점이 있어 근래 산업 현장에서 많이 이용되고 있다. 특히 mass separating agent를 사용하지 않고, 상변화를 수반하지 않는 순조건에서 실시할 수 있다는 특성으로 인하여 생물물질의 생산 및 회수에 있어서 막분리의 사용이 크게 증가하고 있다. 근래에 들어 막의 재지라 분리 module의 개발 등에 의해 fouling, 농도분극현상 등, 막분리의 근본적 문제점들이 많이 해결되고 있을 뿐 아니라, 기존의 조분리의 영역을 넘어서 정밀분리에로의 발전이 가시화되고 있다. 또한 생물분리기술의 추세인 복합분리와 동시분리의 측면에 있어서도 막분리의 응용성은 우수하여, 향후 생물공학 제품의 생산에 있어 막분리 기술의 역할은 막대할 것으로 사료된다.

• Membrane and Water Treatment
• /
• 제13권6호
• /
• pp.291-301
• /
• 2022

In this study, cement/PVDF hollow-fiber hybrid membranes were prepared via a mixed process of diffusion-induced phase separation and hydration. The presence of X-ray diffraction peaks of Ca(OH)₂, an AFt phase, an AFm phase, and C-S-H phase confirmed the hydration reaction. Good hydrophilicity was obtained. The cross-sectional and surface morphologies of the hybrid membranes showed that an asymmetric pore structure was formed. Hydration products comprising parallel plates of Ca(OH)₂, fibrous ettringite AFt, and granulated particles AFm were obtained gradually. For the hybrid membranes cured for different time, the pore-size distribution was similar but the porosity decreased because of blocking of the hydration products. In addition, the water flux decreased with hydration time, and carbon retention was 90% after 5 h of rejection treatment. Almost all the Zn²⁺ ions were adsorbed by the hybrid membrane. The above results proved that the obtained membrane could be alternative as basement membrane for separation application.

• Bulletin of the Korean Chemical Society
• /
• 제25권5호
• /
• pp.687-693
• /
• 2004

Composite membranes with a titania layer were prepared by soaking-rolling method with the titania sol of nanoparticles formed in the sol-gel process and investigated regarding the vapor permeation of various organic mixtures. The support modification was conducted by pressing $SiO_2$ xerogel of 500 nm in particle size under 10 MPa on the surface of a porous stainless steel (SUS) substrate and designed the multi-layered structure by coating the intermediate layer of ${\gamma}-Al_2O_3$. Microstructure of titania membrane was affected by heat-treatment and synthesis conditions of precursor sol, and titania formed at calcination temperature of 300$^{\circ}C$ with sol of [$H^+$]/[TIP]=0.3 possessed surface area of 210 $m^2$/g, average pore size of 1.25 nm. The titania composite membrane showed high $H_2/N_2$ selectivity and water/ethanol selectivity as 25-30 and 50-100, respectively. As a result of vapor permeation for water-alcohol and alcohol-alcohol mixture, titania composite membrane showed water-permselective and molecular-sieve permeation behavior. However, water/methanol selectivity of the membrane was very low because of chemical affinity of permeants for the membrane by similar physicochemical properties of water and methanol.

• 한국막학회:학술대회논문집
• /
• 한국막학회 2003년도 The 4th Korea-Italy Workshop
• /
• pp.21-24
• /
• 2003

Methane steam reforming (MSR) was studied in a membrane reactor (MR) with a Pd-based and a porous alumina membranes. MRs showed methane conversion higher than that foresaw by the thermodynamic equilibrium for a traditional reactor (TR). Silica membranes prepared at KRICT were characterized with permeation tests on single gases ($N_2$, $H_2$ and $CH_4$). These silica membranes can be also used for high temperature applications such as $H_2$ separation $CO_2$ hydrogenation for methanol production is another reaction where $H_2O$ selective removal can be performed with these silica membranes.

• Membrane and Water Treatment
• /
• 제10권2호
• /
• pp.127-137
• /
• 2019

The D2EHPA/TBP co-extractants immobilized PolyHIPE membrane can be used for the selective separation of Mn (II) from Co (II). By solvent-nonsolvent method, D2EHPA/TBP co-extractants can be effectively immobilized into PolyHIPE membrane. The pore structure of PolyHIPE membrane and the presence of TBP enhance the stability of immobilized co-extractants. The optimal operating conditions for the separation of Mn (II) and Co (II) are feeding phase at pH 5.5, sulfuric acid concentration in the stripping phase of about 50 g/L and stirring speed at 400 rpm. The D2EHPA/TBP co-extractants ratio of 5:1 shows synergetic effect on Mn/Co separation factor about 22.74. The removal rate and recovery rate of Mn (II) is about 98.4 and 97.1%, respectively, while for Co (II) the transport efficiency is insignificant. The kinetic study of Mn (II) transport shows that high initial flux, $J_f^o=80.1({\mu}mol/m^2s)$, and maxima stripping flux, $J_s^{max}=20.8({\mu}mol/m^2s)$, can be achieved with D2EHPA/TBP co-extractants immobilized PolyHIPE membrane. The stability and reusability study shows that the membrane can maintain a long term performance with high efficiency. High purity of Co (II) and Mn (II) can be recovered from the feeding phase and stripping phase, respectively.

• Korean Membrane Journal
• /
• 제9권1호
• /
• pp.27-33
• /
• 2007

PVDF membrane formation via TIPS was performed for PVDF/DBP and PVDF/DMP systems. PVDF/DBP system showed solid-liquid phase separation behavior, while PVDF/DMP system has liquid-liquid phase separation characteristic as well as solid-liquid phase separation characteristic. PVDF contents and cooling conditions had great influence on structure, and the effects of each parameter were examined. Spherulitic structure was obtained due to the dominant PVDF crystallization. Diluent rejected to the outside of spherulite occupied the surface of the PVDF spherulites to result in the microporous spherulite formation and micro-void between spherulites. PVDF/DMP system had competitive solid-liquid and liquid-liquid phase separation depending on the cooling path.