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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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Journal DOI :
The Korean Society of Clean Technology
Editor in Chief :
Volume & Issues
Volume 13, Issue 4 - Dec 2007
Volume 13, Issue 3 - Sep 2007
Volume 13, Issue 2 - Jun 2007
Volume 13, Issue 1 - Mar 2007
Selecting the target year
Phase Behavior of Simvastatin Drug in Mixtures of Dimethyl Ether and Supercritical Carbon Dioxide
Shin, Eun-Kyoung ; Oh, Dong-Joon ; Lee, Byung-Chul ;
Clean Technology, volume 13, issue 4, 2007, Pages 237~243
Phase behavior of the ternary systems of water-insoluble simvastatin drug, which is well known to be effective drugs for hypercholesterolemia therapy, in solvent mixtures of dimethyl ether (DME) and supercritical carbon dioxide was investigated to present a guideline of establishing operating conditions in the particle formation of the drugs by a supercritical anti-solvent recrystallization process utilizing DME as a solvent and carbon dioxide as an anti-solvent. The solubilities of simvastatin in the mixtures of DME and carbon dioxide were determined as functions of temperature, pressure and solvent composition by measuring the cloud points of the ternary mixtures at various conditions using a high-pressure phase equilibrium apparatus equipped with a variable-volume view cell. The solubility of the drug increased as the DME composition in solution and the system pressure increases at a fixed temperature. A lower solubility of the drug was obtained at a higher temperature.
Diffusion rate of C. I. Disperse Yellow 54 Dye in PTT and PET Textiles in the Presence of Supercritical Carbon Dioxide
Ihm, Bang-Hyun ; Choi, Jun-Hyuck ; Shim, Jae-Jin ;
Clean Technology, volume 13, issue 4, 2007, Pages 244~250
Sorption of C. I. Disperse Yellow 54 dye in poly(trimethylene terephthalate) (PTT) and poly (ethylene terephthalate) (PET) textile fibers were measured at various pressures, temperatures, and times in the presence of supercritical carbon dioxide and thereby the diffusivities of the dye in the fibers were calculated. The diffusivity of dye in the polymeric fibers was very low, only in the order of
, but increased with increasing temperature at constant pressure and with increasing pressure at constant temperature. The diffusivity in PTT fibers were about 1.5 to 3 times as large as that in PET fibers. As the fiber was very thin, the dye distribution in the fiber was almost uniform everywhere inside the fiber.
Depolymerization of Polycarbonate Using Glycolysis/Methanolysis Hybrid Process
Kim, D.P. ; Kim, B.K. ; Cho, Y.M. ; Kim, B.S. ; Han, M. ;
Clean Technology, volume 13, issue 4, 2007, Pages 251~256
Several studies regarding depolymerization of polycarbonate waste to get the essential monomer, bisphenol A, have been reported in recent years. However, those methods have some environmental safety problems of using highly toxic organic solvents as well as product separation problem due to the use of alkali catalyst. In this study, we proposed the combination of glycolysis and methanolysis to depolymerize the polycarbonate waste. Glycolysis reaction reached at the reaction equilibrium after about 180 minat 473.15K and dissolution of the polycarbonate was found to be a rate controlling step of the reaction. The yield of BPA was improved with the aid of combination of glycolysis and methanolysis. The methanolysis was carried out at a temperature range of
and MeOH/PC molar ratio
. The yield of BPA had a maximum at 1.0 MeOH/PC molar ratio and increased with the reaction temperature.
Reclamation of High Purity Organic Solvents from Waste Photoresist Stripper
Kim, Dae-Jin ; Oh, Han-Sang ; Kim, Jae-Kyeong ; Park, Myeong-Jun ; Lee, Moon-Yong ; Koo, Kee-Kahb ;
Clean Technology, volume 13, issue 4, 2007, Pages 257~265
As a basic study for the development of pilot-scale distillation process of waste photoresist strippers from semiconductor industry, lab-scale experiments for the recovery of NMP (N-methy1-pyrrolidione) and BDG (Butyldiglycol) from waste photoresist strippers have been made using a spinning band vacuum distillation column. Purities of NMP and BDG obtained from the present experiments were higher than 99.5%. Furthermore, water content was less than 1000 ppm, color grade(APHA) less than 50, most metal contents except sodium less than 1 ppb. Those results indicate that NMP and BDG reclamed by distillation satisfy the their specifications required for the formulation of new photoresist strippers. Recovery rate of NMP and BDG was 96 and 53%, respectively, for type A, and 93 and 57%, respectively, for type B waste PR stripper solution.
The Adsorption of COS with a Modified-Activated Carbon for Ultra-Cleanup of Coal Gas
Lee, You-Jin ; Park, No-Kuk ; Lee, Tae-Jin ;
Clean Technology, volume 13, issue 4, 2007, Pages 266~273
The adsorption properties of the activated carbon-based adsorbents were studied to remove COS emitted from
catalytic reduction process on the integrated gasification combined cycle (IGCC) system in this work. Transition metal supported catalysts and mixed metal oxide catalysts were used for the
catalytic reduction. The mechanism of COS produced from the
reduction and the COS concentration s according to the reaction temperature were investigated. In this study, an activated carbon and a modified activated carbon doped with KOH were used to remove the very low concentration of COS effectively. The adsorption rate and the breakthrough time of COS were measured by a thermo gravity analyzer (TGA, Cahn Balance) and a fixed bed flow reactor equipped with GC-pulsed flammable photometric detector (PFPD), respectively. It was confirmed that the COS breakthrough time of the activated carbon doped with KOH was longer than that of an activated carbon. In conclusion, the modified-activated carbon having a high surface area showed a high adsorption rate of COS produced from the
Separation of Iron and Nickel from Heavily Concentrated Aqueous Ferric Chloride Solution by Liquid-liquid Extraction
Park, Moo-Ryong ; Kim, Young-Wook ; Park, Jae-Ho ; Park, Chin-Ho ;
Clean Technology, volume 13, issue 4, 2007, Pages 274~280
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.
A Study on the Release Characteristics of VOCs from Heat Recovery Ventilation System
Kwak, Kyung-Min ; Bai, Cheol-Ho ; Kim, Jee-Yong ; Chu, Euy-Sung ;
Clean Technology, volume 13, issue 4, 2007, Pages 281~286
VOCs from the heat recovery ventilation system (total heat exchanger) are measured in this study. Two different types of element (L and M type) from heat recovery ventilating system are tested to study the intial release characteristics of VOCs under KS cooling and heating standard conditions. VOCs are measured for the various flow rates and different operating times. Considering errors in the test method and the measuring instrument, the tested heat recovery ventilating systems was found to release 6 major VOCs, such as acetic acid, 2-butanone (MEK), 2-(methylthio )ethylamine, toluene, styrene, and x-acids (Ion 57). The concentrations of released VOCs are not quite much affected by operating conditions. The results show much larger VOCs concentrations in the cooling mode than in the heating mode, due to the high operating temperatures.
Hydrogen Production by Auto-thermal Reforming of Ethanol over
(M = Mn, Fe, Co, Ni, Cu) Catalysts
Youn, Min-Hye ; Seo, Jeong-Gil ; Cho, Kyung-Min ; Park, Sun-Young ; Kim, Pil ; Song, In-Kyu ;
Clean Technology, volume 13, issue 4, 2007, Pages 287~292
] (M = Mn, Fe, Co, Ni, Cu) catalysts supported on commercial alumina (
) were prepared by an impregnation method, and were applied to the hydrogen production by auto-thermal reforming of ethanol. It was revealed that each catalyst retained its own metallic phase and product distribution strongly depended on the identity of active metal. Among the catalysts prepared,
showed the best catalytic performance in the auto-thermal reforming of ethanol. However, the reaction mechanisms over these two catalysts were different. Ni/Al_2O_3 catalyst showed 100% ethanol conversion at
, but it exhibited a rapid decrease in hydrogen selectivity. Although
catalyst showed an excellent performance in hydrogen selectivity, on the other hand, no significant improvement in hydrogen yield was observed due to the low ethanol conversion over the catalyst.
Design Factors of Membrane Electrode Assembly for Direct Methanol Fuel Cells.
Cho, Jae-Hyung ; Hwang, Sang-Youp ; Kim, Soo-Kil ; Ahn, Dong-June ; Lim, Tae-Hoon ; Ha, Heung-Yong ;
Clean Technology, volume 13, issue 4, 2007, Pages 293~299
Direct coating of catalyst layer on the
membrane has been optimized in the process of fabrication of membrane electrode assembly (MEA) to enhance the performance of direct methanol fuel cell (DMFC). In this method, the contact resistance at the interface of the catalyst layer and the membrane was found to be low. The effect of catalyst loading, thickness of membrane and the gas diffusion layer (GDL) with or without the presence of micro-porous layer (MPL) on the performance of the MEA was also investigated. The MEA fabricated by the above-mentioned method exhibited a performance of
, respectively, with the catalysts loading of
A Study on the Combustion Characteristics of Diffusion Flame with the Fuel Injection Condition
Lee, Sung-No ; An, Jin-Geun ;
Clean Technology, volume 13, issue 4, 2007, Pages 300~307
The combustion characteristics of diffusion flame formed in the wake of a cylindrical stabilizer with varying fuel injection angle were studied. This study was performed by measuring the flame stability limits, lengths and temperatures of recirculation zones of flames, turbulence intensity in the wake of stabilizer, and concentration distribution of combustion gas, and by taking photographs of flames. The flame stability limits are dependent on fuel injection angle and main air velocity. The length and temperature of recirculation zone are dependent on fuel injection angle. As the length of the recirculation zone is decreased, the flame shows more stable behavior. The temperature of recirculation zone has a maximum value at the condition of theoretical mixture. The flame stability is enhanced when the temperature in the recirculation zone decreases. The turbulence intensity in the wake of stabilizer is independent of the fuel injection angle, but it is affected by stabilizer itself and main air flow condition. If the stabilization characteristics of flame is good, the concentration of
is high, but the concentration of
is low at the boundary of recirculation zone. The combustion characteristics of diffusion flame can be controlled by changing the fuel injection angles. The appropriate fuel injection angle should be selected to get high combustion efficiency, high load power, low environmental pollution, and clean combustion condition of fuel.