• Title/Summary/Keyword: alumina membrane

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Development of control technique of nano-sized pattern for electroplating (나노급 도금공정을 위한 미세패턴 제어기술의 개발)

  • Lee, Jae-Hong;Lee, Byoung-Wook;Lee, Kyung-Ho;Kim, Chang-Kyo
    • Proceedings of the KIEE Conference
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    • 2004.07c
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    • pp.1576-1578
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    • 2004
  • The alumina membrane with nano sized pore was prepared from aluminum by anodic oxidation to apply for storage equipment, gas sensor and stamper. The pore size and cell size of the pores are controlled by anodic oxidation voltage. The alumina thickness was controlled by etching process using 0.2M $H_3PO_4$. The thickness of alumina on Si wafer was very accurately controlled by anodic oxidation time. Nickel with nano-sized grain was electroplated on the Au layer on silicon wafer. The fabricated pores on alumina membrane was the thickness of $7{\sim}10{\mu}m$ with straight nano-sized pore of 307${\sim}$120nm. The alumina by the etching process shows smooth surface. The size of Ni grain was 130nm and 250nm for 10mA/$cm^2$and 20mA/$cm^2$of electroplating currents, respectively.

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Reclamation of Waste Lubricating Oil Using Ceramic Micro/Ultrafiltration Composite Membrances (세라믹 정밀/한외여과 복합막을 이용한 폐윤활유 정제)

  • 김계태;현상훈
    • Journal of the Korean Ceramic Society
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    • v.37 no.5
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    • pp.403-409
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    • 2000
  • The permeation characteristics and reclamation efficiency of waste lubricating oil were studied as a function of the types of ceramic composite membranes and the membrane separation process variables. The oil permeability of the TiO2 composite membrane(pore size 0.015 $\mu\textrm{m}$) was directly proportional to the crossflow velocity(0.22∼0.9 m/s) and temperature(150$^{\circ}C$∼200$^{\circ}C$). In the batch concentration process, as the concentration factor increased, both the permeability and the ash content of the permeate decreased. The average ash contents of the total permeate through the A6 alumina membrane(average pore size 0.8$\mu\textrm{m}$), Z1/A6 and Z1/A4(pore size 0.23$\mu\textrm{m}$)/A7(pore size 6$\mu\textrm{m}$) zirconia composite membrances(average pore size 0.07$\mu\textrm{m}$) were about 0.063 wt%, 0.045wt% and 0.08wt% in the region of 1∼2 concentration factor, respectively. The ash content of the mixed permeate through the A6 alumina and zirconia composite membrane was about 0.06 wt% and it can be also reduced to 0.06 wt% in the Z1/A6 membrane and below 0.003 wt% in the TiO2/Z1/A6 membrane. It was concluded that the treated oil obtained from the multi-step membrane separation process could be used as reclaimed lubricating oil as well as reclained fuel oil.

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Advanced Water Treatment of High Turbidity Source by Hybrid Process of Photocatalyst and Alumina Microfiltration: Effect of Organic Matters at Nitrogen Back-flushing (광촉매 및 알루미나 정밀여과 혼성공정에 의한 고탁도 원수의 고도정수처리: 질소 역세척시 유기물의 영향)

  • Park, Jin Yong;Sim, Sung Bo
    • Membrane Journal
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    • v.22 no.6
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    • pp.441-449
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    • 2012
  • Effect of humic acid (HA) with periodic nitrogen back-flushing was investigated in hybrid process of alumina microfiltration and photocatalyst for drinking water treatment. It was compared and investigated with the previous results of microfiltration water back-flushing or ultrafiltration nitrogen back-flushing in viewpoints of membrane fouling resistance ($R_f$), permeate flux (J), and total permeate volume ($V_T$). As results, the trends of membrane fouling were different depending on nitrogen or water back-flushing, and depending on ultrafiltration or microfiltration made with the same material. Also, the nitrogen back-flushing using microfiltration was more effective membrane fouling inhibition than ultrafiltration, and the nitrogen back-flushing was more effective than water back-flushing using the same microfiltration membrane. Turbidity treatment efficiencies were almost constant independent of HA concentration, but HA treatment efficiency was the maximum at HA 10 mg/L. From this results, it was shown that the treated water HA quality increased as increasing HA concentration, but HA could be removed the most effectively by photocatalyst beads adsorption and photo-oxidation at HA 10 mg/L.

Gas Permeation Characteristics of Microporous Alumina Membrane Prepared by Anodic oxidation (양극산화에 의한 다공성 알루미나 막의 제조 및 기체투과 특성)

  • Shim, Won;Lee, Chang-Woo;Hahm, Yeong-Min
    • Applied Chemistry for Engineering
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    • v.10 no.2
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    • pp.212-217
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    • 1999
  • Porous alumina membrane with asymmetrical structure was prepared by anodic oxidation under constant DC current mode in aqueous solution of sulfuric acid. In order to produce membrane with improved properties, the aluminium plate was pre-treated with thermal oxidation, chemical polishing and electrochemical polishing before anodic oxidation. The thickness and pore diameter of the membrane were controlled by current density and charge density, respectively. The upper layer of 20 nm under of pore diameter was produced under very low current density while the lower layer of 36 nm pore diameter was produced under higher current density. The thickness of the membrane was about $80{\sim}90{\mu}m$ and that of the upper layer was $6{\mu}m$. We found that the mechanism of gas permeation through the membrane depended on Knudsen diffusion.

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Advanced Water Treatment of High Turbidity Source by Hybrid Process of Photocatalyst and Ceramic Microfiltration: Effect of Water Back-flushing Period (광촉매 및 세라믹 정밀여과 혼성공정에 의한 고탁도 원수의 고도정수처리: 물역세척 주기의 영향)

  • Park, Jin Yong;Park, Sung Woo
    • Membrane Journal
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    • v.22 no.4
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    • pp.243-250
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    • 2012
  • The effect of water back-flushing period (filtration time, FT) was investigated in hybrid process of alumina microfiltration and photocatalyst for advanced drinking water treatment in this study, and compared with the previous studies with carbon microfiltration or alumina ultrafiltration membranes. The FT was changed in the range of 2~10 min with fixed 10 sec of BT. Then, the FT effects on resistance of membrane fouling ($R_f$), permeate flux (J) and total permeate volume ($V_T$) were observed during total filtration time of 180 min. As decreasing FT, $R_f$ decreased and J increased as decreasing FT, which was same with the previous results with carbon microfiltration or alumina ultrafiltration membranes. The treatment efficiency of turbidity was high beyond 98.1%, and the effect of FT was not shown on treatment efficiency of turbidity, which was same with the previous result of carbon microfiltration. The treatment efficiency of organic matters was the highest value of 89.6 % at FT 8 min, which was a little higher than those of the previous results, and the effect of FT was not shown on treatment efficiency of organic matters.

Preparation of Asymmetric Ceramic Membrane by Coating-Pyrolysis Process (도포-열분해법을 이용한 비대칭 세라믹 분리막 제조)

  • Ryu, Hyun-Wook;Kim, Byung-Hoon
    • Journal of the Korean Ceramic Society
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    • v.39 no.12
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    • pp.1153-1157
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    • 2002
  • The fabrication of a three-layered asymmetric ceramic membrane was performed by slip casting of the porous alumina support and dip coating of the alumina intermediate layer using high purity ${\alpha}-Al_2O_3$ powders that have different particle size, followed by screen printing-pyrolysis of the $Tio_2$ layer as an ultrafilteration membrane using Ti-naphthenate solution. The bending strength, porosity and mean pore size of the alumina support were 231 kg/$cm^2$s, 30.26% and 0.19 ${mu}m$, respectively. The thickness of the intermediate layer was 30 ${mu}m$ and the mean pore size of that was 0.063 ${mu}m$. Also, the top layer was 0.5 ${mu}m$ thick and micropores with about 20 nm size were formed uniformly.

The Effect of Porous Support and Intermediate Layer on the Silica-zirconia Membranes for Gas Permeation Performance (실리카-지르코니아 분리막 성능에 대한 다공성 지지체와 중간층의 영향)

  • Lee, Hye Ryeon;Seo, Bongkuk
    • Membrane Journal
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    • v.25 no.1
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    • pp.15-26
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    • 2015
  • In this study, porous metal (O.D. = 10 mm, length = 10 mm, 316 L SUS, Mott Corp.) and ${\alpha}$-alumina tube (O.D. = 10 mm, length = 50 mm, Pall, German) support was modified with suspension sols, which were consisted of $3{\sim}4{\mu}m$ and 150 nm size of ${\alpha}$-alumina particle in the water or silica-zirconia colloidal sol. The porous support was fabricated by dip coating method for 5 seconds with suspension of alumina particles. After drying at $100^{\circ}C$ for 1 h, it was calcined at $550^{\circ}C$ for 30 min. It was repeated several times in order to decrease big pore on support. The surface roughness and largest pore size on the porous support was decreased by increasing coating times with $3{\sim}4{\mu}m$ size of ${\alpha}$-alumina particle and alumina coating with 150 nm size of ${\alpha}$-alumina particle served as further smoothening the surface and decreasing the pore size of the substrate. And the silica-zirconia membranes were successfully prepared on the modified porous metal and ${\alpha}$-alumina supports, and showed hydrogen permeance in the range of $1.8-8.4{\times}10^{-4}mol{\cdot}m^{-2}{\cdot}s^{-1}{\cdot}Pa^{-1}$ and $3.3-5.0{\times}10^{-5}mol{\cdot}m^{-2}{\cdot}s^{-1}{\cdot}Pa^{-1}$, respectively.

The Preparation and the Gas Permeation Characteristics of the Soluble Polyimides (용해성 폴리이미드의 제조 및 기체투과특성)

  • Chun, Kyoung-Yong;Kim, Han-Sung;Han, Hak-Soo;Joe, Yung-il
    • Applied Chemistry for Engineering
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    • v.9 no.2
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    • pp.306-310
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    • 1998
  • The soluble polyimides(PMDA/diamine/dianhydride) were prepared and investigated. After coating the prepared PMDA/diamine/dianhydride solution into the commercial tubular alumina ceramic membranes, gas permeation characteristics was investigated. $T_g{\prime}s$ of the polyimides were in the range of $337{\sim}358^{\circ}C$ and thermal stability was good. The polymer was soluble in NMP, DMAc, DMSO, THF, and m-cresol. The adhesion between the alumina membrane and the soluble polyimide was excellent. The soluble polyimide/alumina membranes containing 6FDA showed the highest permeability among others. The permeability of nitrogen of PMDA/1,3PDA/6FDA-alumina membrane was about $7.6{\times}10^{-7}(mol/m^2{\cdot}Pa{\cdot}s)$ in the gas permeation experiments. The ideal separation factor of $O_2/N_2$ and $H_2/N_2$ in PMDA/1,3PDA/6FDA-alumina membrane were 6.19, and 70.0, respectively.

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Fast Fabrication of Nanoporous Anodic Alumina Membrane by Hard Anodization (하드애노디제이션에 의한 나노다공질 양극산화 알루미나 멤브레인의 제조)

  • Ha, Yoon-Cheol;Jeong, Dae-Yeong
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2009.06a
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    • pp.429-429
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    • 2009
  • Nanoporous anodic alumina membranes (NAAM) with high-density through-hole pores fabricated by hard anodization of aluminum in 0.3 M oxalic acid under the applied voltage of 40 (mild anodization), 80, 100, 120 and 140 V were investigated. The current-time responses monitored using a PC-controlled anodization cell and the corresponding pore structures attainable from field-enhanced scanning electron microscopy (FE-SEM) were analyzed in order to establish the optimum fabrication process. The nanoporous structure can be produced for all the voltage conditions, while the stabilized through-hole pore formation seems to occur at 40, 80 and 140 V. The growth rate under 140 V hard anodization was over 30 times higher than under 40 V mild anodization (1.5 um/hr).

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