• Clean Technology
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• v.15 no.2
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• pp.69-74
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• 2009

A high-dose ion-implanted photoresist (HDIPR) was stripped off from the surface of a semiconductor wafer by using a mixture of supercritical carbon dioxide and a co-solvent. The additional ultrasonication improved the stripping efficiency remarkably and thus reduced the stripping time by supplying physical force to the substrate. We investigated the effect of co-solvents, co-solvent concentration, and stripping temperature and pressure on the stripping efficiency. The wafer surfaces before and after stripping were analyzed by scanning electron microscopy and by an energy dispersive X-ray spectrometer. The HDIPR could be stripped off completely in 3 min with 10%(w/w) acetone/sc$C0_2$ mixture at 27.6 MPa and 343 K.

• Clean Technology
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• v.13 no.4
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• pp.274-280
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• 2007

A liquid-liquid solvent extraction process was developed in this study to recover Fe and Ni from heavily concentrated aqueous ferric chloride solution, in an effort to substitute the conventional iron reduction method. Solvent composition and extraction conditions were first developed from the laboratory experiments, and the pilot system was designed and built for commercialization. Stage numbers for extraction and stripping were determined from pilot plant runs, and other operation data were obtained for mass production.

• Applied Chemistry for Engineering
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• v.25 no.4
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• pp.357-362
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• 2014

To prepare diketopyrrolopyrrole (DPP) red 254 pigment with high shield and bright color, DPP red 254 crude previously synthesized was treated at various thermal-treat temperature, addition derivative and ball-milling. The properties of samples were measured by the means of FT-IR, UV-Vis spectroscopy, TEM, PSA, BET surface area analyzer, viscometer and spectrophotometer. It was found that solvent thermal-treatment of the sample prepared after ball-milling as nano-scale was very effective method in pigmentation process.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2011.05a
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• pp.108-109
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• 2011

유기태양전지를 제작 시에 요구되는 것 중 하나는 active layer의 thermal annealing이다. Thermal thermal annealing 없이는 P3HT의 self-organization이 잘 이뤄지지 않아 비정질의 모습을 보인다. 또한 low band-gap이나 열에 취약한 물질을 사용 시에 태양전지 효율이 낮아지게 된다. 이 점을 착안하여 Active layer에 사용되는 유기용매의 solvent vapor pressure 차이를 이용하여 co-solvent가 되도록 mixing하여, co-solvent로 poly(3-hexylthiopene)(P3HT):[6,6] - phenyl $C_{61}$-butyric acid methyl ester (PCBM)를 blending 하여 active layer로 사용하였으며, 유기태양전지 디바이스 제작 결과 thermal thermal annealing 없이 2.8%까지 도달하였다. X-Ray Diffraction(XRD)과 Atomic Force Microscopy(AFM)를 통하여 P3HT의 결정화가 이루어 졌음을 확인하고 이를 통해 active layer의 thermal annealing이 없이도 P3HT의 self-organization이 이뤄짐을 알 수 있었다.

• Macromolecular Research
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• v.8 no.2
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• pp.80-88
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• 2000

Biodegradable microspheres were prepared with poly(L-lactide-co-glycolide) (PLGA, 75 : 25 by mole ratio) by an oil/oil solvent evaporation method for the sustained release of anti-AIDS virus agent, AZT The microspheres of relatively narrow size distribution (7.6$\pm$ 3.8 ㎛) were obtained by controlling the fabrication conditions. The shape of microspheres prepared was smooth and spherical. The efficiency of AZT loading into the PLGA microsphere was over 93% compared to that below 15% for microspheres by a conventional water/oil/water method. The effects of Preparation conditions on the morphology and in vitro AZT release pattern were investigated. in vitro release studies showed that different release pattern and release rates could be achieved by simply modifying factors in the fabrication conditions such as the type and amount of surfactant, initial amount of loaded drug, the temperature of solvent evaporation, and so on. PLCA microspheres prepared by 5% of initial drug loading, 1.0% (w/w) of surfactant concentration, and 25$\^{C}$ of solvent evaporation temperature were free from initial burst effect and a near-zero order sustained release was observed. Possible mechanisms of the near-zero order sustained release for our system have been proposed.

• Nuclear Engineering and Technology
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• v.52 no.1
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• pp.109-114
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• 2020

This work presents the results of laboratory scale tests of the CARBOFLUOREX (CARBOnate FLUORide EXtraction) process - a novel technology for the recovery of U and Pu from the solid fluorides residue (fluorination ash) of Fluoride Volatility Method (FVM) reprocessing of spent nuclear fuel (SNF). To study the oxidative leaching of U from the fluorination ash (FA) by Na₂CO₃ or Na₂CO₃-H₂O₂ solutions followed by solvent extraction by methyltrioctylammonium carbonate in toluene and purification of U from the fission products (FPs) impurities we used a surrogate of FA consisting of UF₄ or UO₂F₂, and FPs fluorides with stable isotopes of Ce, Zr, Sr, Ba, Cs, Fe, Cr, Ni, La, Nd, Pr, Sm. Purification factors of U from impurities at the solvent extraction refining stage reached the values of 10⁴-10⁵, and up to 10⁶ upon the completion of the processing cycle. Obtained results showed a high efficiency of the CARBOFLUOREX process for recovery and separating of U from FPs contained in FA, which allows completing of the FVM cycle with recovery of U and Pu from hardly processed FA.

• Korean Journal of Metals and Materials
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• v.48 no.1
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• pp.62-70
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• 2010

Leaching and solvent extraction experiments have been performed to develop a hydrometallurgical process for the recovery of nickel and cobalt from nickel laterite ore with high magnesium content. Most of the nickel and magnesium in the laterite ore dissolved at leaching conditions of $80^{\circ}C$ and 100 g/L sulfuric acid concentration. while half of the cobalt and iron were leached at the same conditions. Solvent extraction experiments were carried out with D2EHPA and saponifed D2EHPA from a synthetic solution containing Ni, Co, and Mg. The extraction percentage of Co, Mg. and Ni by D2EHPA was very low in a pH range of 4.4 to 7.3. while the extraction percentage sharply increased by using saponified D2EHPA. The stripping percentage of the metals from the saponified D2EHPA increased with sulfuric acid concentration and reached 99.9% at 1 M $H_2SO_4$ solution.

• Biotechnology and Bioprocess Engineering:BBE
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• v.6 no.6
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• pp.426-432
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• 2001

Perstractive fermentation is a good way to increase the productivity of bioreactors. Us-ing Propionibacteria as the model system, the feasibility of using supported emulsion liquid mem-brane(SELM) fro perstractive fermentation is assessed in this study. Five industrial solvents were considered as the solvent for perparing the SELM. The more polar a solvent, is the higher the par-tition coefficeint However, toxicity of a solvent also increases with its polarity. CO-1055(indus-trial decanol/octanol blend)has the highest partition coefficient toward propionic acid among the solvents that has no molecular toxicity toward Propionibacteria, A preliminary extraction study was conducted using tetradecane as solvent in a hydrophobic hollow fiber contactor. The results confirmed that SELM eliminates the equilibrium limitation of conventional liquid-liquid extrac-tion and allows the use of a non-toxic solvent with low partition coefficient.

• Korean Chemical Engineering Research
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• v.47 no.3
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• pp.380-385
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• 2009

The absorption rate of carbon dioxide with 2-amino-2-methyl-1-propanol(AMP) was measured in such non-aqueous solvents as methanol, ethanol, n-propanol, n-butanol, ethylene glycol, propylene glycol, and propylene carbonate, and in water at 298 K and 101.3 kPa using a semi-batch stirred tank with a plane gas-liquid interface. The overall reaction rate constant, obtained under the condition of fast reaction regime, from the measured rate of absorption was used to get the elementary reaction rate constants in complicated reactions represented by reaction mechanism of carbamate formation and the order of overall reaction of $CO_2$ with amine. The correlation between the elementary reaction rate constant and the solubility parameter of the solvent was also presented.

• Proceedings of the Korean Radioactive Waste Society Conference
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• 2003.11a
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• pp.650-654
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• 2003

A major problem of nuclear energy is the production of radioactive wastes. Needs for more environmentally favorable method to decontaminate radioactive contaminants make the use of liqui $d^ercritical $CO_2$ as a solvent medium. In removing radioactive metallic contaminants under $CO_2$ solvent, two methods - use of chelating ligands and that of water in $CO_2$ emulsion-are possible. In the chelating ligand method, a combination of ligands that can make synergistic effects seems important. We discuss about the properties of microemulsion formed by F-AOT and that by non-ionic surfactant. By adding acid in water core, decontamination of metallic parts, soils were possible. The rate of metal surface dissolution to the microemulsion solution was measured by QCM. The possibility of recovering the surfactants after use is also mentioned.ed.