• Membrane Journal
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• v.28 no.5
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• pp.297-306
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• 2018

This review focused carbon-free hydrogen productions from ammonia decomposition including inorganic membranes, catalysts and the presently studied reactor configurations. It also contains general information about hydrogen productions from hydrocarbons as hydrogen carriers. A Pd-based membrane (e.g. a porous ceramic or porous metallic support with a thin selective layer of Pd alloy) shows its efficiency to produce the high purity hydrogen. Ru-based catalysts consisted of Ru, support, and promoter are the efficient catalysts for ammonia decomposition. Packed bed membrane reactor (PBMR), Fluidized bed membrane reactor (FBMR), and membrane micro-reactor have been studied mainly for the optimization and the improvement of mass transfer limitation. Various types of reactors, which contain various combinations of hydrogen-selective membranes (i.e. Pd-based membranes) and catalysts (i.e. Ru-based catalysts) including catalytic membrane reactor, have been studied for carbon-free hydrogen production to achieve high ammonia conversion and high hydrogen flux and purity.

• Membrane Journal
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• v.22 no.2
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• pp.95-103
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• 2012

To treat nitrate and non-biodegradable organics effectively in sewage, industrial wastewater and livestock wastewater, the activated sludge process integrated by a membrane separation and a porous electrode- electrolysis was proposed and its efficiency was investigated. The proposed system was consisted of 3 processes; activated sludge, membrane filtration and electrolysis. In the study, the membrane filtration played a role in reducing the load of the electrolysis to operate the proposed process stably. The electrolysis consisted of a porous electrode to increase the efficiency due to the extension of the specific surface area. Additionally, redox reaction in the electrolysis was induced by decomposing influent water as current was applied. As a result, hydrogen free radicals and oxygen radicals as intermediates were produced and they acted as oxidants to play a role in decomposing non-degradable organics. It was environmentally-friendly process because intermediates produced by porous electrode were used to treat waste matters without supplying external reagent. Experimental data showed that the proposed process was more excellent than activated sludge process. SS removal efficiencies of the proposed process, membrane filtration and activated sludge process were about 100%, about 100% and about 90%, respectively. COD removal efficiencies of the proposed system, membrane filtration and activated sludge process were about 92%, about 84% and about 78%, respectively. T-N removal efficiencies of the proposed system, membrane filtration and activated sludge process were about 88%, about 67%, and about 58%, respectively. The SS data showed that SS was efficiently removed in the single of the membrane filtration. The COD/T-N data showed that COD/T-N of membrane hybrid process was treated by removing a little soluble organics and SS, and that COD/T-N of electrolysis hybrid process was treated by oxidize organics with high removal rate.

• Proceedings of the Korean Vacuum Society Conference
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• 2016.02a
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• pp.403.2-403.2
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• 2016

Porous materials play a significant role in energy storage and conversion applications such as catalyst support for polymer electrolyte membrane fuel cell. In particular, hierarchical porous materials with both micropores (poresize, ${\delta}$ < 2 nm) and regularly arranged mesopores (2 nm < ${\delta}$ < 50 nm) are known to greatly enhance the efficiency of catalytic reactions by providing enormous surface area as well as fast mass transport channels for both reactants and products from/to active sites. Although it is generally agreed that the microscopic structure of the porous materials directly affects the performance of these catalytic reactions, neither detailed mechanisms nor fundamental understanding are available at hand. In this study, we propose an atomistic model of hierarchical nanostructured porous carbons (HNPCs) in molecular dynamics simulations. By performing a systematic study, we found that structural features of the HNPC can be independently altered by tuning specific synthesis parameters, while remaining other structures unchanged. In addition, we show some structure-property relations including mechanical and gas transport properties.

• Proceedings of the Membrane Society of Korea Conference
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• 1996.04a
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• pp.1-4
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• 1996

유화제의 물리화학적인 성질을 이용하여 O/W와 W/O에멀젼을 제조하는 방법(예:PIT method, D-phase method)은 이제까지 많은 연구가 진행되어 왔으며, colloid mill, homogenizer, ultrasonic emulsifier와 같은 유화장치도 지속적으로 개발 및 개선되고 있다. 하지만 이들 방법은 공정의 정확한 조절이 어려우며, 제조된 에멀젼의 입자크기 분포가 다분산적(polydispersed)이라는 단점을 가지고 있다. 이를 극복하기 위한 방법으로 1980년대 중반에 일본에서 처음으로 개발된 막유화법이 있다. 이 기술은 pouous glass membrane 가운데 기공크기(pore size)가 균일한 SPG(Shirasu Porous Glass)막을 사용하여 균일한 입자분포를 가지는 에멀젼을 제조하는 것이다. 한편 막유화에 사용되는 막이 갖추어야 할 조건은 다음과 같다.

• 한국신재생에너지학회:학술대회논문집
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• 2007.11a
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• pp.79-79
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• 2007

• Proceedings of the Membrane Society of Korea Conference
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• 1998.10a
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• pp.103-105
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• 1998

Asymmetric polymeric membranes prepared by the phase transition technique usually have either a top layer consisting of closely packed nodules or pores dispersed throughout the membrane surfaces. In this study, we present AFM image of a polysulfone membrane which show a clear evidence for the nodular structure and porous structure resulted from different phase separation mechanisms; spinodal decomposition and nucleation and growth. The surface morphology obtained by SEM and AFM was also compared.

• Membrane Journal
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• v.14 no.3
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• pp.218-229
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• 2004

We prepared monodispersed calcium alginate microspheres by controlling various conditions of emulsification procedure using a lab-scale batch type membrane emulsification system equipped with SPG (Shirasu porous glass) tubular membranes. We determined the effects of process parameters of membrane emulsification (ratio of dispersed phase to continuous phase, alginate concentration, emulsifier concentration, type and concentration of stabilizer, transmembrane pressure, concentration of crosslinking agent, stirring speed and membrane pore size) on the mean size and size distribution of alginate microspheres. The increase of the ratio of dispersed phase to continuous phase, transmembrane pressure and alginate concentration led to the increase in the mean size of alginate microspheres. On the contrary, the increase in emulsifier concentration, stirring speed of the continuous phase and concentration of the crosslinking agent caused the reduction of the mean size of microspheres. Through controlling these parameters, monodisperse alginate microspheres with about $6{\mu}{\textrm{m}}$ of the mean size and 1.1 of the size distribution value were finally prepared in case of the using SPC membrane with the pore size of $2.9{\mu}{\textrm{m}}$.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.17 no.3
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• pp.95-101
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• 2007

The synthesis of NaA zeolite membrane on a porous alumina support from clear solution by using hydrothermal reaction was investigated. Effects of reaction temperature, reaction time and seeding for transformation of zeolite A membrane and powder which are produced in the reactor were monitored through X-ray diffraction (XRD) analysis and scanning electron microscopy (SEM). The transformation process of producing Zeolite A membrane starts from the formation of the compact and continuous membrane on the surface of porous support from clear solution. The large Zeolite A poly-crystal was then farmed through the dissolution process. Finally, the process was advanced from sodalite to amorphous. In case of powder, sodalite is formed in the early stage of reaction because of surrounding space difference between membrane and powder crystal. Discrete surrounding space of powder crystal makes easy to transform to sodalite. From Zeolite A to amorphous through transformed product was rapidly advanced at high temperature while the membrane with somewhat low coverage was obtained at low temperature. A compact and continuous zeolite A membrane was synthesized at $120^{\circ}C$ in 12-hour period.

• Proceedings of the Korean Ceranic Society Conference
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• 2003.10a
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• pp.175.2-175
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• 2003

• Proceedings of the Membrane Society of Korea Conference
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• 2000.11a
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• pp.134-135
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• 2000

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