• 한국세라믹학회지
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• 제29권2호
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• pp.107-118
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• 1992

Alumina supports for TiO2 ultrafiltration membrane coating were prepared by presintering disk-type preforms at 140$0^{\circ}C$. These supports showed uniform microstructures which had the apparent porosity of 40%, the pore size distribution in the range of 0.1~0.5${\mu}{\textrm}{m}$, and the water flux of 1400ι/$m^2$.h at the pressure difference of 10 atm. The optimum pH and concentration of the TiO2 sol for coating were 0.8 and 1.0 wt%, respectively, and sol particles were identified as rutile forms of 20 nm size. Crack-free alumina-supported rutile TiO2 membranes could be prepared through well controlled drying and heating the gel layer coated by the sol-gel dipping. The pore size of the TiO2 membranes heat-treated at 50$0^{\circ}C$ for 2 hrs was 30~80$\AA$, and their thickness varied from 1.1 to 3.8 ${\mu}{\textrm}{m}$ in accordence with the dipping time (4~40 min). The flux of water through this composite membrane at 10 atm was found to be in the range from 800 to 1100ι/$m^2$.hr depending on the dipping time (10~40 min). The membrane thickness increased linearly with the square root of the dipping time and the slope was 0.62 ${\mu}{\textrm}{m}$/{{{{ SQRT { min} }}.

• 멤브레인
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• 제27권4호
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• pp.328-335
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• 2017

메조포러스 공극구조를 갖는 광촉매 멤브레인은 다양한 환경기술에 적용될 수 있다. 본 연구에서는 $TiO_2$ 층을 형성시킨 광촉매 반응기용 세라믹 멤브레인을 개발하고 이를 염색용액 처리에 적용하였다. 높은 공극률과 균질성을 지닌 $TiO_2$ 광촉매층을 그라프트 공중합체를 사용하여 제조하였다. 멤브레인은 광촉매 반응기와 멤브레인 여과를 결합시킨 하이브리드 광촉매 반응기에 성공적으로 적용하였다. 실험결과 정렬된 구조의 $TiO_2$ 층이 $Al_2O_3$ 지지체에 형성되었다. $TiO_2$ 층 형성 후 제조된 세라믹 분리막의 순수 투과도는 형성된 광촉매 층 저항으로 감소하였다. 정렬된 구조의 $TiO_2$ 층은 UV 결합 시 5시간 안에 완벽한 염색용액 분해를 달성시킬 수 있었다. 광촉매 멤브레인의 염색용액 분해는 Langmuir-Hinshelwood 흡착 모델로 잘 설명할 수 있었다. 또한 $TiO_2$ 층이 고정화된 세라믹 멤브레인의 model Congo Red에 대한 1차 속도상수는 $Al_2O_3$ 지지체 단독인 경우에 비해 약 6배 정도 큰 값을 나타내었다(0.0081 vs. $0.0013min^{-1}$).

• 한국세라믹학회지
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• 제56권2호
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• pp.197-204
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• 2019

An electrochemical oxygen permeating membrane (OPM) is fabricated using Zr_0.895Sc_0.095Ce_0.005Gd_0.005O_2-δ (ScCeGdZ) as the solid electrolyte and aLa_0.7Sr_0.3MnO₃-bScCeGdZ composite (LZab, electrode) as the electrode. The crystal phase of the electrode and the microstructure of the membrane is investigated with X-ray diffraction and scanning electron microscopy. The electrochemical resistance of the membrane is examined using 2-p ac impedance spectroscopy, and LZ55 shows the lowest electrode resistance among LZ82, LZ55 and LZ37. The oxygen permeation is studied with an oxygen permeation cell with a zirconia oxygen sensor. The oxygen flux of the OPM with LZ55 is nearly consistent with the theoretical value calculated from Faraday's Law below a critical current. However, it becomes saturated above the critical current due to the limit of the oxygen ionic conduction of the OPM. The OPM with LZ55 has a very high oxygen permeation flux of ~ 3.5 × 10^-6 mol/㎠s in I = 1.4 A/㎠.

• Journal of Electrochemical Science and Technology
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• 제14권1호
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• pp.85-95
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• 2023

In recent years, solid-state Li metal batteries (SSLBs) have attracted significant attention as the next-generation batteries with high energy and power densities. However, uncontrolled dendrite growth and the resulting pulverization of Li during repeated plating/stripping processes must be addressed for practical applications. Herein, we report a plastic-crystal-based polymer/ceramic composite solid electrolyte (PCCE) to resolve these issues. To fabricate the one-side ceramic-incorporated PCCE (CI-PCCE) film, a mixed precursor solution comprising plastic-crystal-based polymer (succinonitrile, SN) with garnet-structured ceramic (Li₇La₃Zr₂O₁₂, LLZO) particles was infused into a thin cellulose membrane, which was used as a mechanical framework, and subsequently solidified by using UV-irradiation. The CI-PCCE exhibited good flexibility and a high room-temperature ionic conductivity of over 10^-3 S cm^-1. The Li symmetric cell assembled with CI-PCCE provided enhanced durability against Li dendrite penetration through the solid electrolyte (SE) layer than those with LLZO-free PCCEs and exhibited long-term cycling stability (over 200 h) for Li plating/stripping. The enhanced Li⁺ transference number and lower interfacial resistance of CI-PCCE indicate that the ceramic-polymer composite layer in contact with the Li anode enabled the uniform distribution of Li⁺ flux at the interface between the Li metal and CI-PCCE, thereby promoting uniform Li plating/stripping. Consequently, the Li//LiFePO₄ (LFP) full cell constructed with CI-PCCE demonstrated superior rate capability (~120 mAh g^-1 at 2 C) and stable cycle performance (80% after 100 cycles) than those with ceramic-free PCCE.

• 공업화학
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• 제8권3호
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• pp.374-381
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• 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.

• 한국세라믹학회지
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• 제42권2호
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• pp.77-80
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• 2005

A series of proton conductive composite membranes based on poly(vinyl alcohol) and phosphosilicate gels powders were successfully prepared. The proton conductivity of these composite was attributed to the phosphosilicate gel, which derived from tetraethoxysilane and phosphoric acid by sol-gel process at a molar ratio of P/Si = 1.5. The proton conductivity increased with increasing both the content of phosphosilicate gel and relative humidity. Temperature dependence of conductivity showed a Vogel-Tamman-Fulcher type behavior, indicating that proton was transferred through a liquidlike phase formed in micropores of phosphosilicate gel. The high conductivity of 0.065 S/cm with a membrane containing 60 wt$\%$ of the gel was obtained at $60^{\circ}C$ at $90\%$ relative humidity.

• Membrane and Water Treatment
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• 제15권1호
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• pp.21-29
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• 2024

1H,1H,2H,2H-perfluorodecytriethoxysilane (C₁₆H₁₉F₁₇O₃Si) be successfully applied to the hydrophobic modification of Al₂O₃ tubular ceramic membrane. Taking the concentration of modification solution, modification time, and modification temperature as factors, orthogonal experiments were designed to study the hydrophobicity of the composite membranes. The experiments showed that the modification time had the greatest impact on the experimental results, followed by the modification temperature, and the modification solution concentration had the smallest impact. Concentration of the modified solution 0.012 mol·L^-1, modification temperature 30 ℃ and modification time 24 h were considered optimal hydrophobic modification conditions. And the pure water flux reached 274.80 kg·m^-2·h^-1 at 0.1MPa before hydrophobic modification, whereas the modified membrane completely blocked liquid water permeation at pressures less than 0.1MPa. Air gap membrane distillation experiments were conducted for NaCl (2wt%) solution, and the maximum flux reached 4.20 kg·m^-2·h^-1, while the retention rate remained above 99.8%. Given the scarcity of freshwater resources in coastal areas, the article proposed a system for seawater desalination using air conditioning waste heat, and conducted preliminary research on its freshwater production performance using Aspen Plus. Finally, the proposed system achieved a freshwater production capacity of 0.61 kg·m^-2·h^-1.

• 한국화재소방학회논문지
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• 제30권1호
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• pp.17-23
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• 2016

막구조물은 코팅된 직물을 주재료로 하는 구조로 연성을 가진 막을 사용하여 외부하중에 대해 안정된 형태를 유지하는 구조물을 말한다. 막에 의한 구조시스템은 대공간 시공이 가능하고 가벼우며 빛을 투과할 수 있는 등 자원 및 관리비용 절감 면에서 많은 이점을 가지고 있어 다양한 용도의 구조물에 적용되며 그 사용용도가 점차 확대되고 있는 실정이다. 하지만 막구조 건축물 및 막재가 다양해짐에도 불구하고 화재안전을 고려한 막재의 성능에 대한 기준은 미비한 실정이며 다양한 용도에 적합한 난연성능이 우수한 막재의 개발이 요구되고 있다. 따라서 본 연구에서는 시판되는 건축용 막재인 PTFE, PVDF와 PVF, ETFE 필름 막재의 방염 및 난연성능 시험 등을 통해 건축용 막재의 난연특성을 확인하였다.

• 한국세라믹학회지
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• 제51권5호
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• pp.477-480
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• 2014

An $Al_2O_3$-CuO-ZnO (ACZ) precursor powder was synthesized by a facial sol-gel process using a nonionic surfactant span 80 as the chelating agent to improve the surface area and morphology. When creating a hydrogen membrane, several kinds of properties are required, such as easy dissociation of hydrogen molecules, fast hydrogen diffusion, high hydrogen solubility, and resistance to hydrogen embrittlement. ACZ-Ni composite membranes (cermet) were prepared with this precursor and pure Ni powder via the hot press sintering (HPS) method. The ACZ powder was characterized by XRD, BET, and FE-SEM. Hydrogen permeation experiments were performed by Sievert's type of hydrogen permeation membrane equipment. The hydrogen permeability of ACZ/Ni 10 wt% and ACZ/Ni 20 wt% was obtained as 7.2 and $10molm^{-2}s^{-1}$ at RT, respectively. These values of the corresponding membranes were slightly increased with increasing pressures.

• 한국수소및신에너지학회논문집
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• 제21권4호
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• pp.264-270
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• 2010

Recently, the most promising methods for high purity hydrogen production are membranes separation such as polymer, metal, ceramic and composites. It is well known that Pd and Pd-alloys membranes have excellent properties for hydrogen separation. However, it has hydrogen embrittlement and high cost for practical applications. Therefore, most scientists have studied new materials instead of Pd and Pd-alloys. On the other hand, TiN powders are great in resistance to acids and chemically stable under high operating temperature. In order to get specimens for hydrogen permeation, the TiN powders synthesized were consolidated together with Co, Ni powders by hot press sintering (HPS). During the consolidation of powders at HPS, heating rate was 10 K/min and the pressure was 10 MPa. It was characterized by XRD, SEM. Also, we estimated the hydrogen permeability by Sievert's type hydrogen permeation membrane equipment.