• Environmental Engineering Research
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• v.22 no.1
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• pp.19-30
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• 2017

Direct catalysis of vapors from vacuum pyrolysis of biomass was performed on MCM-41 to investigate the effects of operating parameters including catalyzing temperature, catalyzing bed height and system pressure on the organic yields. Optimization of organic phase yield was further conducted by employing response surface methodology. The statistical analysis showed that operating parameters have significant effects on the organic phase yield. The organic phase yield first increases and then decreases as catalyzing temperature and catalyzing bed height increase, and decreases as system pressure increases. The optimal conditions for the maximum organic phase yield were obtained at catalyzing temperature of $502.7^{\circ}C$, catalyzing bed height of 2.74 cm and system pressure of 6.83 kPa, the organic phase yield amounts to 15.84% which is quite close to the predicted value 16.19%. The H/C, O/C molar ratios (dry basis), density, pH value, kinematic viscosity and high heat value of the organic phase obtained at optimal conditions were 1.287, 0.174, $0.98g/cm^3$, 5.12, $5.87mm^2/s$ and 33.08 MJ/kg, respectively. Organic product compositions were examined using gas chromatography/mass spectrometry and the analysis showed that the content of oxygenated aromatics in organic phase had decreased and hydrocarbons had increased, and the hydrocarbons in organic phase were mainly aliphatic hydrocarbons. Besides, thermo-gravimetric analysis of the MCM-41 zeolite was conducted within air atmosphere and the results showed that when the catalyst continuously works over 100 min, the index of physicochemical properties of bio-oil decreases gradually from 1.15 to 0.45, suggesting that the refined bio-oil significantly deteriorates. Meanwhile, the coke deposition of catalyst increases from 4.97% to 14.81%, which suggests that the catalytic activity significantly decreases till the catalyst completely looses its activity.

• Nuclear Engineering and Technology
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• v.51 no.3
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• pp.761-768
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• 2019

Understanding the phenomena of formation of single drops is necessary to understand the hydrodynamics in solvent extraction equipment which are used for separation of nuclear materials. In this work, the phenomena of aqueous phase and organic phase drop formation at submerged nozzles are compared by conducting experiments with 30%TBP (v/v) in dodecane as the organic phase and nitric acid as the aqueous phase. Two different nozzles and three different nitric acid concentrations are used. For each nozzle and nitric acid concentration, velocity of the dispersed phase is varied. Drops of aqueous phase formed at downward oriented nozzles submerged in organic phase are observed to be smaller than the drops of organic phase formed at upward oriented nozzles submerged in aqueous phase. Correlations to estimate drop diameter are proposed.

• Microbiology and Biotechnology Letters
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• v.20 no.1
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• pp.61-67
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• 1992

The synthesis of N-benzyloxycarbonyl-L-aspartyl-L-phenylalanine methyl ester(ZAPM), a precursor of aspartame, from N-benzyloxycarbonyl-L-aspartic acid(Z-Asp) and L-phenylalanine methyl ester hydrochloride(L-PM-HCl) was investigated in ethylacetate-MES buffer two-phase system using thermolysin. In organic two-phase system, the degree of spontaneous hydrolysis of L-PM. HCl was significantly reduced with increasing the volume ratio of organic to aqueous phase. Stability of thermolysin in organic two-phase system was found to be higher than that in MES buffer solution. More than 90% of initial enzyme activity was maintained after 10 days of incubation in case that the volume of organic phase was equal to that of buffer phase, while the half life of thermolysin was about 2 days in aqueous buffer solution. The results of partitioning of substrates and product in organic two-phase system showed that the difference in partition coefficients between substrates and product was maximum at pH 5.5. The optimal pH for 2-APM synthesis in organic two-phase system was found to be 5.5-5.8, which is consistent with the value expected from the partition experiments. As the concentration of substrates was increased the conversion yield of Z-APM was increased with concomitant reduction of L-PMqHC1 hydrolysis. In case that the concentration of L-PM-HCl and Z-Asp were 160 mM and 80 mM respectively, the conversion yield of Z-APM reached 90% after 28 hrs of reaction. The yield obtained at different volume ratio of organic phase compares well with the predicted equilibrium constant in biphasic system.

• 한국정보디스플레이학회:학술대회논문집
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• 2007.08b
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• pp.1600-1602
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• 2007

TPS (Temperature Programmed Sublimation) technology is known to research for the plane evaporation of the organic film.[5] Using TPS technology, the plane source evaporation of NPB organic film has been studied for the first time. The NPB organic film consists of nano scale film phase and bulk phase on a substrate. The 400 ${\AA}$ in film phase thickness of NPB sublimates at the $175^{\circ}$ of the Ta made metal plate. It was proved that the sublimation temperature of the organic film has much lower than that of the organic powder. ($130^{\circ}$ is lower for Alq3 and $90^{\circ}$ is lower for NPB.)

• Journal of Microbiology and Biotechnology
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• v.7 no.5
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• pp.345-351
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• 1997

An aqueous/organic two-phase reaction system was applied to the production of catechol using immobilized resting cells of Pseudomonas putida CY 400. Water/ethyl ether system was used because of high partition coefficient of catechol and thus to reduce the product inhibition and degradation. Among the tested immobilization carriers, polyacrylamide gel gave the highest catechol productivity. The immobilization seemed to protect the cells against solvent toxicity. From the simulation of reaction conditions based on two-phase models, it was found that there was an optimum acetate concentration at fixed benzoate and cell concentrations for the catechol productivity. A lower phase volume ratio (lower fraction of organic phase) gave a higher productivity. However, the substrate conversion was low at low phase volume ratio.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1997.10a
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• pp.515-518
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• 1997

Resident time of the centrifugal extractor for organic phase extraction using a height controlled separator weir and a divert plate is the important factor that affects significantly the chemical material extraction and the productivity in the chemical and mechanical processes. In this paper, it describes the design of the device for extraction of an organic phase from radioactive wastes, and considers phase separating weir and divert disk, both being designed to be adjustable in their positions, for effectively separating an organic phase. A height-adjustable separating weir unit used for separating the organic phase from the aqueous phase using a phase separating weir and designed to control the height of the separating weir as desired so as to allow the weir to be positioned at a boundary layer between two separated phases. The centrifugal extractor controls satisfactorily the mixed reaction time of two phases within the separator regardless of the variations of the mixing ratio of the two phases and the rotating speed of the extractor, is designed to be adjustable in its position in the vertical direction, thus allowing the user to appropriately select the mixed reaction time of the two phases within the extractor as desired. From development of a centrifugal extractor, it can effectively recover such usable elements, and preferably reducing the output quantity of radioactive wastes.

• ALGAE
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• v.21 no.2
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• pp.253-259
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• 2006

Organic substances are released from phytoplankton cells during all phases of growth. The type and amounts of organic substance excreted and the effects of nutrient limitation are often highly species-specific. Dinoflagellate, Cochlodinium polykrikoides grown in batch culture produced an exopolysaccharide. Exopolysaccharide and intracellular polysaccharide concentrations increased as C. polykrikoides cultures progressed from exponential phase, through stationary phase, to declining phase. In the exponential phase, the concentration of exopolysaccharide was relatively low, but in the stationary phase, it showed a rapid increase which seemed to coincide with the depletion of nitrate from the medium. Of the 20 amino acids analyzed, proline dominated in the organic matter of all cultures ranging from 48.2 to 79.9 nmol L–1, and constituting the 20-90% of total amino acids, and followed by histamine varying from 0.7 to 47.5 nmol L–1. Leucine and cysteine were also abundant in the stationary phase. The release rates of exopolysaccharide and intracellualr polysaccharide were higher the end of stationary phase than in the exponential phase. Exopolysaccharide concentration per cell was more than two times higher during the end of stationary phase than that in exponential phase. C. polykrikoides produced extracellular polysaccharide at a rate of 47.04 pg cell–1 day–1.

• Food Science and Biotechnology
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• v.14 no.1
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• pp.131-136
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• 2005

The selective extraction behavior of lactoferrin (Lf) from whey protein mixture was examined using reverse micelles formed by the cationic surfactant, cetyldimethylammonium bromide (CDAB). The major whey proteins, including ${\beta}$-lactoglobulin, ${\alpha}$-lactalbumin and bovine serum albumin, were solubilized from aqueous phase to organic phase while Lf was recovered in the aqueous phase. The solubilization behaviors of the proteins were manipulated by the process parameters such as the pH and salt concentration of the aqueous phase and the surfactant concentration in the organic phase. Efficient forward extraction was achieved with sodium borate buffer (50 mM, pH 9) containing 50 mM KCl and organic phase containing 100 mM CDAB. Based on SDS-PAGE and densitometry, about 96% of the initial Lf remained in the aqueous phase after forward extraction. The dialyzed Lf fully maintained its bacteriostatic activity against E. coli O157:H7.

• Membrane and Water Treatment
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• v.5 no.3
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• pp.171-182
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• 2014

Organic compounds are adsorbed on RO/NF membranes, and the adsorption may influence the rejection of organic compounds by the membranes. Because almost RO/NF membranes are composite membranes, the results obtained by adsorption experiment with using membrane pieces are unable to avoid the influence by the support membrane. In this work, the interaction between membrane polymer and organic solutes was examined by an inverse HPLC methodology. Poly (m-phenylenetrimesoylate), the constituent of skin layer of RO/NF membranes, was coated on silica gel particles and used as a stationary phase for HPLC. When water was used as a mobile phase, almost hydrophilic aliphatic compounds were not effectively adsorbed on the stationary phase, although hydrophobic compounds were slightly adsorbed. The results indicated that the hydrophilic aliphatic compounds are useful probe solutes to examine the molecular sieving effect of a membrane. When water was used as a mobile phase, the aromatic compounds were strongly retained, and therefore $CH_3CN/H_2O$ (30/70) was used as a mobile phase. It was revealed that the adsorption of aromatic compounds was controlled by stacking between solute and polymer and was hindered by non-planar structure and substituents.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.6 no.1
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• pp.55-66
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• 1996

This study was conducted to evaluate breakthrough characteristics of respirator cartridge using multi-organic vapors, including carbon tetrachloride, trichloroethylene, and toluene. The organic vapors were used as single phase, binary system, and ternary system. The results are summarized as follows. 1. Organic vapors studied were 1,000 ppm, 750 ppm, 500 ppm and 250 ppm in single phase. Carbon tetrachloride having the highest molecular weight showed the breakthrough first, and breakthrough sequency by organic vapor was dependent on its molecular weight. The 10% breakthrough times at 1,000 ppm of organic vapor were 97 minutes for carbon tetrachloride, 129 minutes for trichloroethylene and 135 minutes for toluene. 2. When concentrations of organic vapors were at levels of the Threshold Limit Values, the lives of the respirator cartridges were 122 hours in carbon tetrachloride, 18 hours in trichloroethylene and 28 hours in toluene. 3. In the binary system at a total concentration of 1,000 ppm with carbon tetrachloride and trichloroethylene, breakthrough times ranged from 104 minutes to 125 minutes, which were longer than 97 minutes in a single phase (1,000 ppm) for carbon tetrachloride, but shorter than breakthrough times for TCE and Toluene. 4. Breakthrough times in the binary system with carbon tetrachloride and toluene were 131~132 minutes. 5. Breakthrough times in the ternary system with carbon tetrachloride, toluene, and trichloroethyl ene were $120{\pm}8$ minutes, which were longer than 97 minutes in the single phase (1,000 ppm) for carbon tetrachloride, equal to 129 minutes for trichloroethylene, and shorter than 135 minutes for toluene. Those were almost similar to $124{\pm}9$ minutes of breakthrough times in the binary systems.