• 공업화학
• /
• 제8권3호
• /
• pp.374-381
• /
• 1997

유리를 원료로 주형법에 의해 세라믹막을 제조하고, sodiumate, $S_3$-Al, $S_3$등의 실리콘 화합물을 침적시켜 세라믹-실리콘 복합막을 제조하여 이에 따른 기체 투과특성에 대해 연구하였다. 제조된 세라믹막과 세라믹-sodiumate 복합막은 다공성 구조임을 알수 있었고, 세라믹-$S_3$-Al과 세라믹-$S_3$ 복합막은 실리콘 화합물의 공극도입에 의한 치밀한 공극구조가 확인되었다. 세라믹막과 세라믹-sodiumate막의 경우 온도가 증가함에 따라 투과속도가 감소하고 압력에 따라 선형적으로 투과속도가 증가하였으며, 세라믹-$S_3$-Al과 세라믹-$S_3$ 복합막은 온도가 증가함에 따라 투과속도가 증가하는 경향을 보였으며, 상대적으로 투과속도에 미치는 압력의 영향이 적었다. 투과속도는 세라믹막이 가장 빠르게 나타났고, 세라믹-sodiumate, 세라믹-$S_3$-Al, 세라믹-$S_3$ 복합막 순서였으며, 선택도는 이와 반대 경향을 보였다. 또한 침적을 통한 투과속도를 구하여 실제 복합막의 투과속도와 비교한 결과, $S_3$가 가장 큰 영향이 있음을 확인하였다. 투과 메카니즘의 변화에서 세라믹막과 세라믹-sodiumate 복합막은 온도에 따라 투과기체의 투과도가 감소하는 Knudsen영역의 투과특성을 보였으나, 세라믹닉-$S_3$-Al과 세라믹-$S_3$ 복합막은 이와 반대로 온도에 따라 투과도가 증가하는 activated 확산 메카니즘을 따르는 특성을 보였다.

• 한국막학회:학술대회논문집
• /
• 한국막학회 2004년도 Proceedings of the second conference of aseanian membrane society
• /
• pp.128-131
• /
• 2004

The composite mesoporous ceramic membranes were prepared with ${\gamma}$-alumina and poly (2, 6-dimethyl-l, 4-pyphenylene oxide) (PPO) on the surface of the macroporous $\alpha$-alumina ceramic membranes and the permeation results were compared with those of the $\alpha$-alumina membrane for large-scale applications. In the results of the transport experiments, the ceramic membranes gave high gas permeances mainly due to Knudsen diffusion and surface diffusion as an additional mechanism. And, the polymer modification increased the permeances of the strongly adsorbing gas components. In this study the modifications of alumina ceramic membranes could increase the gas permeation performances especially for the strongly absorbing gas components.

• Membrane and Water Treatment
• /
• 제11권1호
• /
• pp.31-39
• /
• 2020

Anaerobic membrane bioreactor (AnMBR) treatment has been widely studied in recent years because of the potential for production of bio-energy from wastewater and energy-positive operation of wastewater treatment plants. Several AnMBR systems, including those that incorporate ceramic membranes, take advantage of enhanced water permeability and low membrane fouling potentials. Given that differences in the ceramic membranes may influence the results of AnMBR studies, relevant details are discussed in this review, which focuses on the profiles of common ceramic membranes used in AnMBR, treatment and filtration performances of different anaerobic ceramic membrane bioreactors (AnCMBRs), and the membrane fouling mitigation methods available for effective AnCMBRs operation. The aim of this review is to provide a comprehensive summary of AnCMBR performance, feed wastewater characteristics, operating conditions, and the methods available for effective fouling mitigation.

• 한국세라믹학회지
• /
• 제29권11호
• /
• pp.905-911
• /
• 1992

Model equations for the gas permeation through a ceramic composite membrane were derived for examining the existence of crack, the reproducibility, and the microstructural properties of composite membranes. From the results of analyzing the nitrogen permeability data through alumina-tube supported TiO2 and SiO2 composite membranes, the extent of cracking, and the formation and structure of membrane top-layers were modelled. It was proved that the crack-free and reproducible composite membranes could be easily prepared only by the pore-filled coating within pores of the support in the sol-gel coating process.

• 한국세라믹학회지
• /
• 제44권8호
• /
• pp.424-429
• /
• 2007

Novel conductive $CO_2$ membranes composed of dual phases, molten carbonates and electronic conducting ceramics, were investigated. As the microstructure control of electronic conducting ceramic supports is extremely important to keep the molten carbonates stable in the membranes by a capillary force applied by the pore structure of the supports, we have scrutinized the microstructure of the electronic conducting supports utilizing microscopic images and gas permeability measurement. From the evaluation of the electrical conductivities of the molten carbonates and the electronic conducting ceramic supports, we found that the ionic conductivity of the molten carbonates could determine $CO_2$ flux through the dual phase membranes if the surface exchange rate were relatively high enough.

• Membrane and Water Treatment
• /
• 제8권5호
• /
• pp.499-515
• /
• 2017

The purpose of this study was to investigate membrane fouling caused by microalgal cells in submerged membrane systems consisting of polymeric and ceramic microfiltration membranes. In this study, one polymeric (flat-sheet, pore size: $0.2{\mu}m$) and two ceramic (flat-sheet, pore size: $0.2{\mu}m$ and cylindrical, pore size: $1{\mu}m$) membranes were used. Physical cleaning was performed with water and air to determine the potential for reversible and irreversible membrane fouling. The study results showed that substantial irreversible membrane fouling (after four filtration cycles, irreversible fouling degree 27% (cleaning with water) and 38% (cleaning with air)) occurs in the polymeric membrane. In cleaning studies performed using water and air on ceramic membranes, it was observed that compressed air was more effective (recovery rate: 87-91%) for membrane cleaning. The harvesting performance of the membranes was examined through critical flux experiments. The critical flux values for polymeric membrane with a pore size of $0.20{\mu}m$ and ceramic membranes with a pore size of $0.20{\mu}m$ and $1{\mu}m$ were ${\leq}95L/m^2hour$, ${\leq}70L/m^2hour$ and ${\leq}55L/m^2hour$, respectively. It was determined that critical flux varies depending on the membrane material and the pore size. To obtain more information on membrane fouling caused by microalgal cells, the characterization of the fouled polymeric membrane was performed. This study concluded that ceramic membranes with a pore size of $0.2-1{\mu}m$ in the submerged membrane system could be efficiently used for microalgae harvesting by cleaning the membrane with compressed air at regular intervals.

• 멤브레인
• /
• 제32권6호
• /
• pp.390-400
• /
• 2022

나노여과막(NF)은 식품가공, 제약 등 폐수는 물론 지자체 하수처리시설에서 배출되는 폐수 처리에 있어 훨씬 낮은 압력으로 운용이 가능해 역삼투막(RO)보다 인기가 높다. NF막의 경우 분리 메커니즘은 투과확산 기작과 더불어 RO 박막보다 낮은 가교밀도로 인한 체거름 메커니즘이다. 막 오염은 세라믹 막과 달리 고분자 막의 경우 나노 여과 공정의 고질적인 문제 중 하나이다. 이러한 문제를 해결하기 위해 차아염소산나트륨을 사용한 멤브레인 세척이 이루어진다. 폴리머 멤브레인에 비해 세라믹 멤브레인은 이러한 화합물에 매우 안정적이다. 본 리뷰에서는 NF 프로세스에 의한 폐수 처리의 다양한 유형의 세라믹 막 적용에 대해 논의한다.

• Membrane and Water Treatment
• /
• 제9권4호
• /
• pp.285-292
• /
• 2018

In the following study, Artificial Neural Network (ANN) is used for prediction of permeate flux decline during oily wastewater treatment by hybrid powdered activated carbon-microfiltration (PAC-MF) process using mullite and mullite-alumina ceramic membranes. Permeate flux is predicted as a function of time and PAC concentration. To optimize the networks performance, different transfer functions and different initial weights and biases have been tested. Totally, more than 850,000 different networks are tested for both membranes. The results showed that 10:6 and 9:20 neural networks work best for mullite and mullite-alumina ceramic membranes in PAC-MF process, respectively. These networks provide low mean squared error and high linearity between target and predicted data (high $R^2$ value). Finally, the results present that ANN provide best results ($R^2$ value equal to 0.99999) for prediction of permeation flux decline during oily wastewater treatment in PAC-MF process by ceramic membranes.

• 한국세라믹학회지
• /
• 제35권4호
• /
• pp.355-363
• /
• 1998

The oxygen flux of SDC ($Sm_2O_3\;doped\;CeO_2$) solid electrolyte membranes with electronic and oxygen ion-ic conductivities has been investigated as a basic research in order to develop the conversion process of na-tural gas to syngas using the ceramic membrane reactor. Tube type membranes(1 mm thickness) were fa-bricated by slip casting of SDC powders prepared by the oxalate coprecipitaion method. Dense oxygen per-meation membranes(0.1 mm thickness) could be synthesized via sintering at $1450^{\circ}C$ for 2h and their re-lative density was over 95% The oxygen flux through SDC membranes doped 20mol% $Sm_15$ was about $1.13{\times}10^{-5}\;mol/m_2{\cdot}sec$ at low temperature around $800^{\circ}C$. In addition the SDC membranes showed a good thermaal stability for a long period of service.

• 한국세라믹학회지
• /
• 제29권12호
• /
• pp.970-980
• /
• 1992

${\gamma}-alumina$ membranes were prepared by sol-gel dip coating or pressurized coating of boehmite sols on slipcasted ${\gamma}-alumina$ support tubes. The particle size of sols synthesized via the modified Yoldas-method could be controlled below 5 mn according to the mole ratio of nitric acid/aluminumtri-sec-butoxide (0.07~1.0). The reproducible crack-free composite membranes were produced by the 2nd dip coating or the pressurized coating technique using very stable sols with the particle size of 45 nm. Nitrogen gas permeability through the top-layer in the composite membrane was about $70~55{\times}10^{-7}\;mol/m^2{\cdot}s{\cdot}Pa$. The thermal stability of the top layer was proved to be good enough upto the heat-treatment temperature of $500^{\circ}C$.