• Bulletin of the Korean Chemical Society
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• 제24권9호
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• pp.1333-1338
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• 2003

Hollow Fiber flow field-flow fractionation (HF-FlFFF) has been tested in polyacrylonitrile (PAN) membrane channel in order to compare it with polysulfone (PSf) membrane channel. It has been experimentally shown that the separation time of 0.05-0.304 ${mu}m$ polystyrene latex (PSL) standards in PAN membrane channel is shorter than that in PSf channel by approximately 65%. The optimized separation condition in PAN membrane is ${\dot V}_{out}/{\dot V}_{rad}=1.4/0.12\;mL/min$, which is equal to the condition in PSf membrane channel. In addition both the resolution ($R_s$) and plate height (H) in PAN membrane channel are better than that in PSf membrane channel. The membrane radius was obtained by back calculation with retention time. It shows that the PSf membrane is expanded by swelling and pressure, but the PAN membrane doesn't expand by swelling and pressure.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2010년도 추계학술대회 초록집
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• pp.129.2-129.2
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• 2010

As a part of the government renewable energy policy, KOWEPO is constructing 300MW IGCC plant in Taean. IGCC plant consists of gasification block, air separation unit and power block, which performance test is separately conducted. Overall performance test for IGCC plant is peformed to comply with ASME PTC 46. Major factors affected on the overall efficiency for IGCC plant are external conditions, each block performance(gasification, ASU, power block), water/steam integration and air integration. Performance parameters of IGCC plant are cold gas efficiency, oxygen consumption, sensible heat recovery of syngas cooler for gasification block and purity of oxygen, flow amount of oxygen and nitrogen, power consumption for air separation unit and steam/water integration among the each block. The gas turbine capacity applied to the IGCC plant is 20 percent higher than NGCC gas turbine due to the low caloric heating value of syngas, therefor it is possible to utilize air integration between gas turbine and air separation unit to improve overall efficiency of the IGCC plant and there is a little impact on the ambient condition. It is very important to optimize the air integration design with consideration to the optimized integration ratio and the reliable operation. Optimized steam/water integration between power block and gasification block can improve overall efficiency of IGCC plant where the optimized heat recovery from gasification block should be considered. Finally, It is possibile to achieve the target efficiency above 42 percent(HHV, Net) for 300MW Taean IGCC plant by optimized design and integration.

• Bulletin of the Korean Chemical Society
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• 제25권9호
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• pp.1336-1340
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• 2004

The same kind of chiral stationary phase with a commercialized chiral column was used to make preparative chiral columns and was applied to resolve racemic N-acetyl-1-naphthylethylamide (3) by preparative liquid chromatography. An improved chromatographic condition to resolve racemic 3 on the CSP was examined by changing flow rate and kind of the mobile phase and the sample injection volume. The optimized separation conditions were applied to resolve racemic 1,1'-Binaphthyl-2,2'-diamine(4).

• 센서학회지
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• 제29권2호
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• pp.89-92
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• 2020

Polytetrafluoroethylene (PTFE) fibers are widely used in the textile industry, filter media, membrane distillation, electronic appliances, and construction. In this study, PTFE-polyethylene oxide (PEO) fibrous membranes were fabricated by emulsion electrospinning; subsequently, pure PTFE nanofibers were obtained via sintering. PTFE-PEO electrospinning solutions were prepared using different weight ratios to determine the optimized condition. As the ratio of the PEO increased, the fiber structure improved. Scanning electron microscopy and Fourier-transform infrared spectroscopy observations indicate that PEO is removed and PTFE fused gradually to form bonds among them during sintering. The obtained pristine PTFE membrane demonstrated hydrophobicity at 143.6° water contact angle and oleophilicity at 0° oil contact angle, which is known to be utilized for oil/water separation. A simple separation experiment was performed to remove oil droplets from water. The PTFE membrane exhibited good chemical stability and a high surface-area-to-volume nanofiber ratio. These excellent properties suggest that it is applicable to oil/water separation in harsh chemical environments.

• Bulletin of the Korean Chemical Society
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• 제33권5호
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• pp.1509-1516
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• 2012

Nano-assisted inclusion separation of alkali metals from basic solutions was reported by inclusion-facilitated emulsion liquid membrane process. The novelty of this study is application of nano-baskets of calixarene in the selective and efficient separation of alkali metals as both the carrier and the surfactant. For this aim, four derivatives of $p-tert-calix$[4]arene bearing different sulfonamide moieties were synthesized and their inclusion-extraction parameters were optimized including the calixarene scaffold $\mathbf{3}$ (4 wt %) as the carrier/demulsifier, the commercial kerosene as diluent in membrane, sulphonic acid (0.2 M) and ammonium carbonate (0.4 M) as the strip and the feed phases, the phase and the treat ratios of 0.8 and 0.3, mixing speed (300 rpm), and initial solute concentration (100 mg/L). The selectivity of membrane over more than ten interfering cations was examined and the results reveled that under the optimized operating condition, the degree of inclusion-extraction of alkali metals was as high as 98-99%.

• Bulletin of the Korean Chemical Society
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• 제24권9호
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• pp.1339-1344
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• 2003

Flow field-flow fractionation (FlFFF) is a technology to separate the molecules by size in an open channel. Molecules with different size have different diffusivities and are located vertically in different positions when passing through an open channel. In this study, hollow fiber membranes instead of conventional rectangular channels have been used as materials for the open channel and this change would decrease the cost of manufacturing. FlFFF is a useful technique to characterize the biopolymeric materials. Retention time, diffusion coefficients and Stokes radius of analysis can be calculated from the related simple equations. Hollow-fiber flow field-flow fractionation (HF-FlFFF) has been used for the characterization and separation of protein mixture in a phosphate buffer solution and has demonstrated the potential to be developed into a disposable FlFFF channel. The important indexes for the analytical separation are selectivity, resolution and plate height. The optimized separation condition for protein mixture of Ovalbumin, Alcohol dehydrogenase, Apoferritin and Thyroglobulin is ${\dot V}_{out}/{\dot V}_{rad}=0.65/0.85\;mL/min$.

• Mass Spectrometry Letters
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• 제4권4호
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• pp.87-90
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• 2013

Isotope amount ratios of lead in a bronze sample have been successfully determined using multicollector inductively coupled plasma mass spectrometry (MC-ICP-MS). Matrix separation conditions were tested and optimized using ion exchange chromatography with anion-exchange resin, AG1-X8, and sequential elution of the 0.5 M HBr and 7 M $HNO_3$ to separate lead from very high contents of copper and tin in bronze matrix. Mercury was also removed efficiently in the optimized separation condition. The instrumental isotope fractionation of lead in the MC-ICP-MS measurement was corrected by the external standard sample bracketing method using an external standard, NIST SRM 981 lead common isotope ratio standard followed by correction of procedure blank to obtain reliable isotope ratios of lead. The isotope ratios, $^{206}Pb/^{204}Pb$, $^{207}Pb/^{204}Pb$, $^{208}Pb/^{204}Pb$, and $^{208}Pb/^{206}Pb$, of lead were determined as $18.0802{\pm}0.0114$, $15.5799{\pm}0.0099$, $38.0853{\pm}0.0241$, and $2.1065{\pm}0.0004$, respectively, and the determined isotope ratios showed good agreement with the reference values of an international comparison for the same sample within the stated uncertainties

• 한국환경과학회지
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• 제31권1호
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• pp.1-8
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• 2022

In this study, solid-liquid separation conditions for coagulation and sedimentation experiments using inorganic coagulant (aluminum sulfate and Poly-Aluminum Chloride (PAC)) were optimized with brine wastewater discharged by the epoxy-resin process. When the turbidity and suspended solid (SS) concentration in raw wastewater were 74 NTU and 4.1 mg/L, respectively, their values decreased the lowest in a coagulant dosage of 135.0 - 270.0 mg Al³⁺/L. The epoxy resin was re-dispersed in the upper part of wastewater treated above 405.0 mg Al³⁺/L. The removal efficiencies of turbidity and SS via dosing with aluminum sulfate and PAC were evaluated at initial turbidity and SS of 74 - 630 NTU and 4.1 - 38.5 mg/L, respectively. They increased most in the range from 135.0 - 270.0 mg Al³⁺/L. The solid-liquid separation condition was quantitatively compared to the correlation of SS removal efficiency between the coagulant dosage and SS concentration based on the concentration of aluminum ions. The empirical formula, R = be^aD, shows the relationship between SS removal efficiency (R) and coagulant dosage (D) at 38.5 mg/L; it produced high correlation coefficients (r²) of 0.9871 for aluminum sulfate and 0.9751 for PAC.

• 청정기술
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• 제10권2호
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• pp.89-100
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• 2004

도장부스 수조 내에 부유되는 도장 슬러지의 효율적인 분리를 위한 수조 형상 및 skimmer 설치에 대한 설계를 최적화하였다. VOF 모델을 사용하여 수조 내 도장 슬러지-물-공기 혼합물의 유동형태에 대한 해석을 수행하였고, 해석된 결과를 바탕으로, 수조 내 물로부터 효과적인 슬러지 분리를 위한 도장 부스 수조 내 흡입관, 격판 및 슬러지 유입구의 설치에 대한 최적 설계 기준을 제시하였다. 더 나아가, skimmer 가 수조 내 물에 잠기는 설치조건에 대한 최적화를 통하여 슬러지 흡입 시 공기 혼입 및 압력손실을 최소화 하였다.

• Bulletin of the Korean Chemical Society
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• 제33권10호
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• pp.3387-3390
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• 2012

In this research work the potentialities of microemulsion bulk liquid membrane for the selective transport of L-tryptophan (L-Trp) and L-tyrosine (L-Tyr) are investigated at 298.15 K. Reversed micelle formed by sodium bis(2-ethylhexyl)sulfosuccinate (AOT) in dichloroethane, was used as mobile carrier to transport amino acids between a source and a receiving aqueous phase. The effects of pH, surfactant concentration and initial amino acid concentration on the extraction efficiency and transfer rate of the amino acids were studied. It is verified that for a mixture of two amino acids, L-Trp can be extracted selectively by using this type of the bulk liquid membrane with optimized condition.