• 한국세라믹학회지
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• 제32권1호
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• pp.63-70
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• 1995

A crack-free ceramic composite membrane with micropores has been synthesized by the pressurized sol-gel coating technique using the mixed Al2O3-SiO2 sols. The mixed sols were prepared by mixing nanoparticulate SiO2 and boehmite sols. These sols were more stable at lower pH, but very unstable when their copositions were in the range of 50~75mol% of SiO2 at the same pH. The mixed Al2O3-SiO2 membrane prepared from the mixed sol (0.2mol/$\ell$ of solid content and pH=2) containing 40mol% of SiO2 had the mean pore radius of 0.80nm and the specific surface area of 280$m^2$/g. The nitrogen permeability through the coated Al2O3-SiO2 layer was 42$\times$107mol/$m^2$.s.Pa. It was found that the thermal stability of aluminosilicate membranes, even through similar to that of SiO2 membranes, was much improved in comparison with ${\gamma}$-alumina membranes.

• Membrane and Water Treatment
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• 제4권2호
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• pp.127-142
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• 2013

In order to investigate the significance of "salting-out" and "pore swelling" effects on the nanofiltration of neutral solutes, rejection properties of two NF ceramic and polymeric membranes were studied with single polyethyleneglycol (PEG) solution and mixed PEG/inorganic electrolyte solutions. For both membranes, the rejection rate of PEG was found to decrease significantly in the presence of ions. In the case of the ceramic membrane (rigid pores), this phenomenon was imputed to the sole partial dehydration of PEG molecules induced by the surrounding ions. This assumption was confirmed by the lowering of the PEG rejection rates which followed the Hofmeister series. Experimental data were used to compute the resulting decrease in the Stokes radius of PEG molecules in the presence of the various salts. Concerning the polymeric membrane, the decrease in the rejection rate was found to be systematically higher than for the ceramic membrane. The additional decrease was then ascribed to the swelling of the pores. The experimental data of rejection rates were then used to compute the variation in the mean pore radius in the presence of the various salts. The pore swelling phenomenon due to accumulation of counterions inside pores was supported by electrokinetic charge density measurements.

• Korean Membrane Journal
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• 제6권1호
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• pp.10-15
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• 2004

We developed a water-selective ceramic composite membrane for use as a dehydration membrane reactor for dimethylether (DME) synthesis from methanol. The membranes were modified on the porous stainless steel support by the sol-gel method accompanied by a suction process. The improved membrane modification process was effective in increasing the vapour permselectivity by removal of defects and pinholes. The optimized alumina/silica composite membrane exhibited a water permeance of 1.14${\times}$10$^{-7}$ mol/$m^2$.sec.Pa and a water/methanol selectivity of 8.4 at permeation temperature of 25$0^{\circ}C$. The catalytic reaction for DME synthesis from methanol using the membrane was performed at 23$0^{\circ}C$, and the reaction conversion was compared with that of the conventional fixed-bed reactor. The reaction conversion of the membrane reactor was much higher than that of the conventional fixed-bed reactor. The reaction conversion of the membrane reactor and the conventional fixed-bed reactor was 82.5 and 68.0%, respectively. This improvement of reaction efficiency can last if the water vapour produced in the reaction zone is removed continuously.

• 한국막학회:학술대회논문집
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• 한국막학회 1995년도 추계 총회 및 학술발표회
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• pp.102-105
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• 1995

The membrane separation process is being utilized to save energy in various fields such as the food, biotechnology, chemical, enviromental fields. Especially the use of ceramic membrane among various inorganic membranes is expected to expand to their excellent thermal, chemical and mechanical resistance. In this presentation, we would like to explain our ceramic membrane CEFILT MF for microfiltration and CEFILT UF for ultra-filtration, and the purification of fermentation products as the application example using CEFILT MF.

• Bulletin of the Korean Chemical Society
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• 제18권9호
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• pp.1028-1031
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• 1997

Electrostatic interaction is a very important parameter for the membrane selectivity. In this work, the electrical double layer establishment on the surface of metal oxide material from the Stern-Grahame model has been described. Then, some examples of rejection using micro and mesoporous ceramic membranes have been given. A correlation between the charges of the membrane material and the species to be filtered has been precised. Two rejection mechanisms have to be taken into account the size of the solutes and the electrostatic interactions.

• 한국막학회:학술대회논문집
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• 한국막학회 2004년도 춘계 총회 및 학술발표회
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• pp.144-146
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• 2004

Various polymeric hollow fiber membranes have been prepared and been used widely due to their high surface area per unit volume and high permselectivity. However, the organic materials are only limited to mild operating conditions because of their weak thermal stability and ease of fouling.(omitted)

• Korean Membrane Journal
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• 제7권1호
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• pp.42-50
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• 2005

Among ceramic membranes developed to date, amorphous silica membranes are attractive for gas separation at elevated temperatures. Most of the silica membranes can be formed on a porous support by sol-gel or chemical vapor deposition (CVD) process. To improve gas permselectivity of the membrane, well-controlled pores having desired size and chemical affinity between permeates and membrane become important factors in the preparation of membranes. In this article, we review the literature and introduce our technologies on the microstructure to be solved and pore size control of silica membranes using sol-gel and CVD methods.

• 한국세라믹학회:학술대회논문집
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• 한국세라믹학회 2003년도 추계총회 및 연구발표회 초록집
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• pp.71.1-71
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• 2003

• 멤브레인
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• 제18권2호
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• pp.176-184
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• 2008

본 연구에서 졸-겔 방법에 의하여 나노 기공을 가지는 세라믹막을 제조하여 단일 조성의 헬륨과 질소를 가지고 기체투과 실험을 수행하였다. 기공 크기 $0.1{\mu}m$, 기공율 32%의 평막형 ${\alpha}-Al_2O_3$ 지지체를 제조하였으며, 지지체를 담지하여 코팅하는 방법으로 4nm의 기공 크기를 가지는 ${\gamma}-Al_2O_3$ 중간층을 제조하였다. 실리카 졸은 TEOS의 산 촉매 가수분해와 축중합반응을 통하여 합성하였다. 막은 딥코팅과 소결과정을 거쳐 제조되었다. 졸-겔 법에 의해 합성된 세라믹 막을 통한 헬륨, 질소 투과 실험은 기체의 투과 특성을 파악하기 위하여 시행하였다. 질소에 대한 헬륨의 선택도는 $100{\sim}160$ 정도였으며 헬륨의 투과도는 $303{\sim}363K$의 온도 범위에서 $10^{-7}mol/m^2{\cdot}s{\cdot}Pa$ 정도였다.

• 한국세라믹학회:학술대회논문집
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• 한국세라믹학회 2004년도 추계총회 및 연구발표회 초록집
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• pp.87.1-87.1
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• 2004