• Environmental Engineering Research
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• 제25권2호
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• pp.258-265
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• 2020

Heavy metal removal by using porous mineral adsorbents bears a great potential to decontaminate sludge compost, and natural zeolite (NZ), artificial zeolite (AZ), and expanded perlite (EP) seem to be possible candidates for this purpose. A composting experiment was conducted to compare the efficiency of those adsorbents for removal of iron (Fe), manganese (Mn), chromium (Cr), copper (Cu), zinc (Zn), nickel (Ni), and lead (Pb) from sewage sludge compost with no adsorbent amendment. For this purpose, 10 g of NZ and AZ and 5 g of EP was filled in a small bag made from non-biodegradable synthetic textile and was separately mixed in composting piles. The bags were separated from compost samples at the end of the experiment. AZ and NZ exhibited different reduction potentials depending on the type of heavy metal. AZ significantly reduced Cr (43.7%), Mn (35.8%), and Fe (29.9%), while NZ more efficiently reduced Cu (24.5%), Ni (22.2%), Zn (22.1%), and Pb (21.2%). The removal efficiency of EP was smaller than both AZ and NZ. The results of this simultaneous composting and metal removing study suggest that AZ and NZ can efficiently bind metal during composting process.

• 대한기계학회논문집B
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• 제25권4호
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• pp.572-582
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• 2001

A method of metal-hydride thermal conversion that is an alternative to the traditional method is proposed and investigated. The unit heat pump consists of reactors of two different metal-hydrides are distributed inside parallel channels filled with porous media. The channels are blown through with a heat-transfer agent. Thermal conversion develops as a set of successive heat waves. By a numerical-modeling method it is shown that the maximum thermal effect is attained in synchronous motion of the heat wave and the heat source (or sink) that accompanies the phase transition in the succession of unit metal-hydride pumps. The results are presented in a form convenient for prediction of the thermal and energy efficiency of the proposed thermal-conversion method in real devices.

• Current Applied Physics
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• 제18권11호
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• pp.1388-1392
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• 2018

Metal thin films are used widely to solve the vibration problem. However, damping mechanism is still not clear, which limits the further improvement of the damping properties for film and the development of multi-functional damping coating. In this paper, Damping microscopic mechanism of porous metal films was investigated at both macroscopically and microscopically mixed levels. Molecular dynamics simulation method was used to model and simulate the loading-unloading numerical experiment on the micro-pore and vacancy model to get the stress-strain curve and the microstructure diagram of different defects. And damping factor was calculated by the stress-strain curve. The results show that dislocations and new vacancies appear in the micro-pores when metal film is stretched. The energetic consumption from the motion of dislocation is the main reason for the damping properties of materials. Micro-mechanism of damping properties is discussed with the results of in-situ experiment.

• 한국세라믹학회지
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• 제33권5호
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• pp.572-582
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• 1996

전류밀도, 70mA/cm2와 전류인가시간, 5초, 10초 조건의 양극반응으로 다공성 실리콘을 제작하여 800~110$0^{\circ}C$에서 열산화시킨 후 AI 전극을 증착시켜 만든 MOS(Metal Oxide Semiconductor) 구조의 C-V(Capacilance-Voltage) 특성을 조사하였다. 800, 90$0^{\circ}C$의 저온과 20~30분 이내의 단시간 산화에서는 산화막의 유전상수가 보통의 열산화막보다 크게 나타나고, 산화온도가 110$0^{\circ}C$의 고온과 60분 이상의 장시간 산화의 경우에는 3.9에 근접한 값을 갖는다. 이는 다공성 실리콘 산화막내에 존재하는 산화되지 않은 silicon들에 의한 효과와 표면적 증가에 의한 정전용량의 증가 효과가 복합적으로 작용하는 것이 그 원인이라 생각된다.

• 공업화학
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• 제22권3호
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• pp.332-335
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• 2011

친환경 재료에 대한 관심이 급증함에 따라 재료의 구조적 기능성 및 투수성을 동시에 갖는 다공성 콘크리트의 활용이 증가되고 있다. 본 연구에서는 다공성 콘크리트에 제올라이트를 혼합하여 다양한 활용도를 갖는 다기능형 옥석 제품의 수질정화 능력을 평가하여 친환경제품으로서의 적합성을 검토하였다. 흐름이 없는 시험용 수조에서 시간에 따른 오염도 제거율은 T-N (70.6%), T-P (67.0%), BOD (57.7%), TOC (50.6%) 순으로 우수한 수질정화 특성을 보였다. 또한 유입 및 유출이 가능한 비점오염원에서 시간에 따른 유출부에서의 수질오염도 및 중금속 농도의 제거율은 Zn (99.9%), Pb (90.0%), BOD (69.2%), COD (33.5%) 순으로 흐름이 없는 경우에서의 오염도 제거율보다 수질정화 특성이 우수한 것으로 나타났다. 따라서 다공성 콘크리트 시설물을 실제 하천 등에 시공했을 시에 우수한 오염도 제거율을 바탕으로 친환경제품으로 적합함을 확인할 수 있었다.

• Korean Chemical Engineering Research
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• 제61권1호
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• pp.1-7
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• 2023

가스 분리 기술은 혼합 가스로부터 신재생에너지 자원 및 환경 오염 물질과 관련된 수소(H₂) 및 이산화탄소(CO₂)와 같은 주요 가스를 효과적으로 추출할 수 있기 때문에 매우 유용하다. 에너지 소비를 줄이기 위한 가스 분리 기술로서 분리막 공정과 흡착 공정이 널리 사용되고 있는데, 두 공정 모두 분리막과 흡착제의 역할을 하는 다공성 물질이 필요하다. 특히 다공성 물질의 한 종류인 금속-유기물 골격체(Metal-organic frameworks, MOFs)는 가스 흡착 및 분리를 목적으로 발전되었다. 그런데 MOF 구조의 수가 지속적으로 증가하고 있지만 시행착오 실험을 통해 우수한 MOF 기반의 분리막과 흡착제를 발견하는데 효율적이지 않다. 따라서 수소와 이산화탄소를 분리할 수 있는 고성능 다공성 물질의 발견을 가속화하기 위해 고속전산스크리닝(High-throughput computational screening) 기술이 등장하였고 현재까지 활용되고 있다. 본 리뷰에서는 다공성 물질에 대한 중요한 연구와 수소와 이산화탄소의 가스 분리에 초점을 맞춘 고속 전산스크리닝 기술을 소개한다.

• 한국세라믹학회지
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• 제30권6호
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• pp.485-491
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• 1993

Porous glass in the ZrO2.SiO2 system containning up to 30mol% zirconia were prepared by the sol-gel method from metal alkoxides and their pore characteristics with reaction parameters were investigated. The gels were made by hydrolyzing and condensation of the mixed metla alkoxides and were converted into the porous glass by heating up to $700^{\circ}C$. As a results, the mean pore radius became larger with increasing contents of HCl, H2O and hydrolysis temperature, and an alcohol with a large molecular weight for making the porous glass. In the case of 20ZrO2.80SiO2 porous glass with heated at $700^{\circ}C$, HCl and H2O content was 0.3mol and 4mol, the specific surface area was 284$m^2$/g, average mean pore radius was about 19.4$\AA$, porosity was 22.55% and pore characteristics depended on heating temperature.

• 센서학회지
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• 제15권6호
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• pp.457-461
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• 2006

To use the porous silicon as gas sensors, we made the MOPS structure from the porous silicon with Al evaporation and investigated the sensing characteristic of ethanol. When the MOPS structure is in contact with ethanol gas, the maximum peak of PL changes and it return to original intensity without contact. The MOPS structure had response time 0.78s and recovery time 4.13s when it is in contact with ethanol, which satisfied the required sensor standards. Further complimentary researches, however, are required to investigate the contact mechanism between MOPS structure and ethanol and to solve the surface contamination problem.

• 한국분말재료학회지
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• 제12권2호
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• pp.151-158
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• 2005

Porous graphite was synthesized by removal of template in HF after pyrolysis of pyrolyzed fuel oil (PFO) at $900^{\circ}C$ using the template of Co or Ni intercalated magadiite. Porous graphite had a plate structure like template, and d-spacing value of about 0.7 nm. The extent of crystallization of porous graphite was dependent on the contents of Co or Ni intercalated in interlayer. It can be explained that the metal such as Co and Ni acts as a promotion catalyst for graphite formation. Porous graphite shows the surface area of $328\sim477 m^2/g$.

• 한국대기환경학회:학술대회논문집
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• 한국대기환경학회 2005년도 추계학술대회 논문집
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• pp.491-493
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• 2005