• Membrane Journal
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• v.9 no.1
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• pp.36-42
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• 1999

Permeation behavior of the semiconductor rinsing wastewater contammg Si particles was examined by ultrafiltration using the polyolefin tubular membrane. Flux decline with time was due to the growth of Si cake deposited on the membrane surface and the pore plugging by Si particles. Cake filtration from the cross flow application is compared to the combination of pore blocking and cake filtration from the dead-end application. The cake resistance is 3.16 x $10^{12}$ -4.34 X $\times$$10^{12}$ $m^{-1}$ for the cross flow and 6.6 x $\times$$10^{12}$ -12.19 X $\times$$10^{12}$ $\times$$m^{-1}$for the dead-end flow, respectively. At the initial stage of operation, permeation flux of cross flow type was 1.7 time higher than that of the dead end flow type. Permeation flux of cross flow was about 42 e 1m2 hr and the rejection rate of Si particles was about 96 %. The average particle size of Si particle in the permeate was 20 nm.

• Proceedings of the Materials Research Society of Korea Conference
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• 2011.10a
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• pp.30.2-30.2
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• 2011

나노 채널 구조는 반응 물질의 빠른 확산 경로를 제공하고, 넓은 반응 활성화 면적을 가지므로, 센서, 촉매, 전지 등의 다양한 기능성 전기 화학 소자용 고효율 전극 구조로서 관심을 받고 있다. 최근 양극 산화법을 이용하여, 자가 배열된 나노 채널 구조의 주석 산화물을 형성시키는 연구가 진행되고 있다. 그러나, 기재위에 도금된 주석 박막이 양극 산화에 의해 산화물로 변화하는 과정에서 내부 균열 및 표면 기공의 막힘 현상이 관찰되고, 기재 위 주석의 산화가 완료되는 시점에서는 기재의 산화 및 산소 발생에 의한 기계적 충격 등으로 인해 산화물이 기재로부터 탈리되는 문제가 발생하여, 그 응용 연구가 크게 제한되어 있는 실정이다. 본 연구에서는 다공성 주석 산화물 합성 시의 구조적 결함이 나타나는 이유에 대해 체계적으로 분석하고, 이를 바탕으로 결함이 없는 나노 채널 주석 산화물을 제조하는 방법을 제시하였다. 또한, 주석 산화물 박막을 기능성 전기화학 소자용 전극 활물질, 특히 리튬 전지용 음극재료로 사용하기 위한 효과적인 전극 제조 방법에 대해 논의하고, 그에 따라 제조된 전극의 충방전 용량, 사이클링 안정성 등을 제시하였다.

• Proceeding of EDISON Challenge
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• 2016.03a
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• pp.135-139
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• 2016

본 연구에서는 동역학적 격자기반 대정준 Monte Carlo (Kinetic Lattice Grand Canonical Monte Carlo, KLGCMC) 모의실험 방법을 이용하여 모델 이온채널 내에서 KCl과 HCl의 이온 전류를 시간의 함수로 구하였다. KLGCMC 모의실험 계산 결과로부터 이온채널의 양이온 선택성이 더 큰 것을 확인 할 수 있었다. 또한 모의실험 결과를 통해 각 이온의 확산계수가 전류에 미치는 영향을 확인 할 수 있었다. $H^+$ 이온은 농도가 매우 작음에도 확산계수가 커 전체 전류에 큰 영향을 미쳤다. 반면에 확산계수가 작은 $K^+$ 이온은 이온채널 안에서 쉽게 흐르지 못하고 정체 되며, $H^+$ 이온의 전류흐름을 방해하는 것을 확인 할 수 있었고, 이로 인해 이온전류의 패턴이 시간에 따라 변화함을 알 수 있었다.

• Polymer(Korea)
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• v.26 no.2
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• pp.160-167
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• 2002

We synthesized HPP-g-GMA copolymer using pre-irradiation method by E-beam and aminated HPP-g-GMA using amination reaction. Degree of grafting increased with increasing GMA monomer concentration and showed the maximum value of 130% at 1.46 M of GMA. The degree of amination increased with increasing the degree of grafting. When the degree of grafting was 100%, degree of amination showed the maximum value of 37.4%. The ion exchange capacity of aminated HPP-g-GMA was about 3.78 meq/g, and it showed remarkable adsorption ability of hollow fiber ion exchanger. Through the BET analysis, the surface area of aminated HPP-g-GMA was 54.83 $\m^2/g$ and the mean pore size was $26\AA$. These showed the decrease of surface area and the slight increase of the mean pore size. SEM results show that the thickness of fiber increased after the step of reaction and there pore blocking phenomena was not observed. The aminated HPP-g-GMA was synthesized successfully and found to be suitable for the adsorption and separation of anion.

• Membrane Journal
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• v.9 no.2
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• pp.107-113
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• 1999

Alcohol concentration via pervaporation process was performed by using commercial PDMS(polydimethylsiloxane) composite membrane and plasma treated PP(polypropylene) membranes. Effects of operating parameters of pcrvaporation process were examined. With the increase of butanol concentration in the feed, flux and selectivity increased due to the greater affinity of butanol with PDMS than that of water. As the operating temperature increased, free volume as well as the solubilities and diffusivities of alcohol and water increased to result in the greater flux and less selectivity of the membrane. As solubility parameter difference between alcohol and PDMS membrane decreased, high flux and good selectivity were obtained. When PP membrane was plasma treated with methanol, it has 6 times greater flux than PDMS membrane with equivalent separation factor. With the increase of plasma treatment time, flux and selectivity were enhanced. However, excess treatment time caused pore blocking to result in the flux decrease.

• Membrane Journal
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• v.8 no.2
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• pp.102-108
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• 1998

Permeation behavior of the semiconductor rinsing wastewater containing Si particles was examined by ultrafiltration using the polysulfone plate membrane. The permeation flux was gradually decreased with time. It was due to the growth of cake deposited on the membrane surface and the pore plugging by Si particles. Permeation flux of cross flow type was 1.4 times higher than that of the dead end flow type. Nitrogen back flushing which is the removing method of membrane fouling was superior to the water sweeping. With nitrogen back flushing, the decrease of permeation flux due to the fouling was recovered about 85 % to the initial flux in the flat plate membrane system. The rejection rate of Si particles was about 90 % and the size of Si particle in the permeate was about 70 nm.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.39 no.8
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• pp.633-643
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• 2015

In this study, we develop a highly efficient conical-air diffuser that generates fine bubble. By inserting a sufficient number of aerotropic microorganisms with dissolved oxygen from an air diffuser and minimizing the air-channel blockages within the air diffuser, we expect to improve the efficiency and durability of the decomposition process for organic waste. To upgrade the conventional air diffuser, we perform experiments and numerical analysis to develop a conical-type that generates fine bubble, and which is free from nozzle blockage. We complement the air-diffuser design by numerically analyzing the internal air-flow pattern within the diffuser. Then, by applying the diffuser to a mockup bioreactor, we experimentally and numerically study the bubble behavior observed in the diffuser and the 2-phase fluid flow in the bioreactor. The results obtained include statistics of the cord length and increased velocity, and we investigate the mechanisms of the fluid-flow characteristics including bubble clouds. Throughout the study, we systemize the design procedures for the design of efficient air diffusers, and we visualize the fluid-flow patterns caused by bubble generation within the mockup bioreactor. These results will provide a meaningful basis for further study as well as the detection of oxygen transfer and fluid-flow characteristics in real-scale bio-reactors using sets of air diffusers.

• Korean Chemical Engineering Research
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• v.48 no.1
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• pp.121-127
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• 2010

This study is to optimize the enzyme(lipase) activity for biodiesel production. The ion-exchanged non-woven fabrics(EtA, DEA-EtA non-woven fabric) containing ethanolamine, diethylamine groups are used by radiation induced grafted polymerization onto a non-woven fabric for more effective immobilization of lipase. Since the porous hollow fiber membranes are showed the low throughputibehe non-woven fabric membranes are used for biodiesel production. The physical charateristics of enzyme immobilized and the enzyme activity to EtA and DEA-EtA non-woven fabrics are studied. The EtA non-woven fabrics are quite similar to DEA-EtA non-woven fabric for the amount of enzyme immobilized(EtA non-woven fabric:15.69 mg/g, DEA-EtA non-woven fabric:14.45 mg/g) but DEA-EtA non-woven fabrics have shown the lower permeabiliquite the organic solvent than the EtA non-woven fabrics(EtA non-woven fabric:$3.50mol/h{\cdot}kg$, DEA-EtA non-woven fabric:$0.38mol/h{\cdot}kg$). Optimum characteristics of ehe non-woven fabric membranes and the limilaractivity are also investigated for the effective biodiesel production.