• 한국산학기술학회논문지
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• 제15권7호
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• pp.4698-4706
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• 2014

본 연구에서는 디메틸에테르(dimethyl ether) 생산 공정에 포함된 이산화탄소 제거공정에서 이산화탄소 제거 방법으로 복합막(composite membrane)을 사용하는 공정에 대해 공정구성과 모사를 수행하였다. 복합막은 (주)에어레인에서 제조한 PEI-PDMS(polyetherimide-polydimethyl siloxane) 복합막을 대상으로 하였으며 복합막 공정을 모델링하기 위해서 상용성 화학공정 모사기인 Invensys 사의 PRO/II with PROVISION 9.2를 사용하였다. 그리고 복합막 공정을 모사하기 위해 필요한 각 순수성분들의 투과도 상수는 (주)에어레인에서 수행한 실험 데이터를 회귀분석 하여 새롭게 결정 하였다. 결국 실험을 통해 얻은 투과도 상수와 상용성 화학공정 모사기를 활용하여 이산화탄소를 제거하기 위한 복합막 공정을 구성하고 제거에 필요한 분리막 면적과 Utility 비용을 도출하였다.

• 한국환경보건학회지
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• 제26권4호
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• pp.45-48
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• 2000

Reverse osmosis filtration(RO) system and ultrafiltration(UF) system are principally use for domestic home drinking water treatment systems. The object of this study is to make a comparison between two systems in terms of theirs abilities to remove RNA coilphage QB as an indicator of pathogenic enteroviruses. The virus removal ratio of RO system was 99.999%, which was higher than EPA virus treatment guideline(99.99%). In the course of filtration, removal ratios of sediment filter, pre-carbon filter, reverse osmosis membrane and post-carbon filter were 75.000%, 93.208%, 99.997% and 99.999%, repectively. In case of UF system, virus removal ratio was 99.708%. Removal ratios of sediment filter, pre-carbon filter, post-carbon filter and ultrafiltration membration membrane were 71.038%, 91.530%, 98.283% and 99.708%, respecively, in UF steps. Therefore, RO system is more effective than UF system in virus removal.

• 한국태양에너지학회:학술대회논문집
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• 한국태양에너지학회 2012년도 춘계학술발표대회 논문집
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• pp.406-409
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• 2012

Recently, enormous research efforts have been focused on the development of non-precious catalysts to replace Pt for electrocatalytic oxygen reduction reaction (ORR), and to reduce the cost of proton exchange membrane fuel cells (PEMFCs). In recent years, heteroatom (N, B, and P) doped carbon nanostructures have been received enormous importance as a non-precious electrode materials for oxygen reduction. Doping of foreign atom into carbon is able to modify electronic properties of carbon materials. In this study, nitrogen and boron doped carbon nanostructures were synthesized by using a facile and cost-effective thermal annealing route and prepared nanostructures were used as a non-precious electrocatalysts for the ORR in alkaline electrolyte. The nitrogen doped carbon nanocapsules (NCNCs) exhibited higher activity than that of a commercial Pt/C catalyst, excellent stability and resistance to methanol oxidation. The boron-doped carbon nanostructure (BC) prepared at $900^{\circ}C$ showed higher ORR activity than BCs prepared lower temperature (800, $700^{\circ}C$). The heteroatom doped carbon nanomaterials could be promising candidates as a metal-free catalysts for ORR in the PEMFCs.

• 멤브레인
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• 제22권6호
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• pp.415-423
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• 2012

탄소섬유 한외여과막 및 광촉매 혼성 수처리를 위해 관형 여과막 외부와 원통형 막 모듈 내부 사이 공간에 광촉매를 충전하였다. 광촉매는 PP (polypropylene) 구에 이산화티타늄 분말을 플라즈마 화학증착 공정으로 코팅한 것이다. 휴믹산과 카올린 모사용액을 대상으로 막오염을 최소화하기 위해 10분 주기로 10초 동안 물 역세척을 시행하였다. 기존 결과와 동일하게 휴믹산을 10 mg/L부터 2 mg/L로 변화시킴에 따라, 막오염에 의한 저항 ($R_f$)이 감소하여 2 mg/L에서 최대 총여과부피 ($V_T$)를 얻었다. 탁도와 휴믹산의 처리효율은 각각 97.1%와 74.2% 이상으로 휴믹산 농도의 영향을 받지 않았다. 그러나 기존 결과에서는 휴믹산의 농도가 증가할수록 휴믹산의 처리효율이 다소 증가하는 경향을 나타냈다.

• 멤브레인
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• 제33권6호
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• pp.305-314
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• 2023

화학 반응의 수율 향상을 위해 부산물을 제거하는 다양한 방법이 연구되고 있다. 특히 산업적으로 중요한 반응에서 주로 부산물로 물이 생성되기 때문에 넓은 범위의 온도에서 안정적으로 물을 분리하는 기술이 필요하다. 흡수제의 사용, 탈수 반응의 도입 등 다양한 방법이 제안되었으나 추가적인 에너지 및 시간 소요, 전환율의 지속 가능성 등의 문제로 한계를 가지고 있다. 그에 반해 운전 및 설치가 용이하고, 낮은 유지비용 등의 장점을 가지고 있는 분리막 기술은 다양한 촉매 반응에 도입되었을 때 안정적으로 부산물을 제거할 수 있어 반응의 효율을 향상시킬 수 있는 좋은 방안이다. 따라서 본 총설에서는 분리막을 이용한 부산물 제거 및 이를 통한 효과에 대해 논의하였다.

• 멤브레인
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• 제23권6호
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• pp.460-468
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• 2013

가압식 MF공정의 전처리공정으로 침전지가 없는 혼화/응집공정에서 적정응집제 투입농도선정 및 유기물 제거성능을 평가하였다. 전처리 공정에서 생성된 플럭이 가압펌프의 임펠러에 의해 해체됨을 확인하였으며 원수탁도가 10 NTU 이하로 유입이 될 때, 혼화/응집조와 펌프후단에서 플럭형성을 위한 최적응집제 투입량은 4 mg/L (as PACl 17%)이었다. 이때의 DOC 제거율은 평균 43%이었으며, 응집제투입량을 계속적으로 증가시켜 8 mg/L (as PACl 17%)로 투입을 하였을 때, DOC 제거율은 평균 48%를 나타내어 제거율은 크게 개선되지 않았다. 전처리가 없는 PVDF 가압식 MF공정의 TMP는 0.54 bar에서 운영이 되었으며, 혼화/응집 전처리 공정을 적용하여 운영 시 TMP는 0.41 bar로 안정적인 운영이 가능하였다.

• Carbon letters
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• 제24권
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• pp.82-89
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• 2017

In this study, composite PAN-based ACNFs embedded with MgO and $MnO_2$ were prepared by the electrospinning method. The resultant pristine ACNFs, ACNF/MgO and $ACNF/MnO_2$ were characterized in terms of their morphological changes, SSA, crystallinity and functional group with FESEM-EDX, the BET method, XRD and FTIR analysis, respectively. Results from this study showed that the SSA of the ACNF/MgO composite ($1893m^2g^{-1}$) is significantly higher than that of the pristine ACNFs and $ACNF/MnO_2$ which is 478 and $430m^2g^{-1}$, respectively. FTIR analysis showed peaks of 476 and $547cm^{-1}$, indicating the presence of MgO and $MnO_2$, respectively. The FESEM micrographs analysis showed a smooth but coarser structure in all the ACNFs. Meanwhile, the ACNF/MgO has the smallest fiber diameter ($314.38{\pm}62.42nm$) compared to other ACNFs. The presence of MgO and $MnO_2$ inside the ACNFs was also confirmed with EDX analysis as well as XRD. The adsorption capacities of each ACNF toward $CH_4$ were tested with the volumetric adsorption method in which the ACNF/MgO exhibited the highest $CH_4$ adsorption up to $2.39mmol\;g^{-1}$. Meanwhile, all the ACNF samples followed the pseudo-second order kinetic model with a $R^2$ up to 0.9996.

• 상하수도학회지
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• 제20권1호
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• pp.27-34
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• 2006

This study was conducted to evaluate the performance of a membrane bioreactor filled with high concentration of powdered activated carbon (HCPAC-MBR) to reduce DBPs at the drinking water treatment. The pilot system was installed after the rapid sand filtration process whose plant was the conventional treatment process. The removal efficiencies of DBPs were measured during pilot operation period of 2 years. HAA and THM removal rates could be maintained around 80~90% without any troubles and then tremendous reduction of HAA and THM reactivity were observed more than 52%. The average removal rate of HAA formation potential (FP) and THM formation potential (FP) were 70.5% and 67.6% respectively. It is clear that the PAC membrane bioreactor is highly applicable for advanced water treatment to control DBPs.

• Applied Microscopy
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• 제44권2호
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• pp.68-73
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• 2014

With wide use of nano-materials, it is increasingly important to address their potential toxicity to mammalian cells. However, toxic effects of these materials have been mainly assessed by the cell survival assays. Considering that mitochondrial morphology and quality are highly sensitive to the condition of the cells, and the impairment of mitochondrial function greatly affect the survival of cells, here we tested the impact of multi-walled carbon nanotubes (MWNT) on the survival, mitochondrial morphology, and their membrane potential in HeLa cells. Interestingly, although MWNT did not induce cell death until 24 hours as assessed by pyknotic cell assay, mitochondrial length was elongated and the mitochondrial membrane potential was significantly reduced by exposure of HeLa cells to MWNT. These results suggest that MWNT exposure is potentially harmful to the cell, and the mechanism how MWNT alters mitochondrial quality should be further explored to assess the safety of MWNT use.

• 상하수도학회지
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• 제21권2호
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• pp.195-201
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• 2007

A submerged flat-sheet membrane separation system integrated with PAC (powdered activated carbon) was used in this research in order to investigate the effects of PAC on the efficiencies of operation and treatment and to evaluate the performance of the system. The experiments were carried out under operating conditions of a filtration rate of 0.38 m/d, water temperature of $20-28^{\circ}C$, and PAC dose of 0 g/L (Run-A) and 20 g/L (Run-B). The influent concentrations of TOC (total organic carbon), $NH_4{^+}-N$ (ammonia nitrogen) and $UV_{254}$ (UV absorbance at 254 nm) were 2.48 mg/L, 1.4 mg/L and 2.53 1/m, respectively. TOC removal of 43.2 and 73.6%, ammonia nitrogen removal of 4.9 and 15.9%, and $UV_{254}$ removal of 20.6 and 31.6% were obtained for Run-A and Run-B, respectively. During an experimental period of 33 days, no change was found in TMP (Run-B), but the TMP in Run-A increased by 5 kPa after 29 days. This research showed that the filtrate quality and the performance efficiency were enhanced when PAC was introduced into the filtration system.