• Korean Chemical Engineering Research
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• v.57 no.4
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• pp.484-491
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• 2019

An efficient propylene/propane separation technology is needed to obtain high-purity propylene, which is a raw material for polypropylene synthesis. Since conventional cryogenic distillation is an energy-intensive process due to the similar physicochemical properties of propylene and propane, adsorptive separation has gained considerable interest. In this study, we have computationally investigated the changes in adsorption separation performances by arbitrarily controlling the adsorption strength of open metal sites in two different types of metal-organic frameworks (MOFs). Through the evaluation of adsorptive separation performances in terms of working capacity, selectivity, and Adsorption Figure of Merit (AFM), we have suggested proper density and strength of adsorption sites as well as appropriate temperature condition to obtain optimal propylene/propane adsorptive separation performances.

• Journal of the Korean Applied Science and Technology
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• v.25 no.2
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• pp.252-256
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• 2008

We investigated phase separation by adding different concentrations of MTBE, to the mixtures of naphtha, ethanol and water. The phase separation temperatures of the Naphtha-Ethanol-Water solutions have dropped when the concentration of MTBE increases more. When adding IPA and IBA to the solutions of Gasoline-Ethanol and Gasoline base-Ethanol individually, IBA shows lower temperatures of phase separation than IPA, and it shows synergistic effect when mixtures of IPA and IBA is applied.

• Bulletin of the Korean Chemical Society
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• v.22 no.5
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• pp.503-506
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• 2001

Separation of lithium isotopes was investigated by chemical ion exchange with a hydrous manganese(IV) oxide ion exchanger using an elution chromatography. The capacity of manganese(IV) oxide ion exchanger was 0.5 meq/g. One molar CH3COO Na solution was used as an eluent. The heavier isotope of lithium was enriched in the solution phase, while the lighter isotope was enriched in the ion exchanger phase. The separation factor was calculated according to the method of Glueckauf from the elution curve and isotopic assays. The single stage separation factor of lithium isotope pair fractionation was 1.021.

• Proceedings of the Membrane Society of Korea Conference
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• 2005.05a
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• pp.131-135
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• 2005

• Bulletin of the Korean Chemical Society
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• v.27 no.1
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• pp.71-76
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• 2006

Porous polymer monolithic columns were prepared by the direct free radical copolymerization of methacrylic acid and ethylene glycol dimethacrylate within the confines of a chromatographic column in the presence of toluene-dodecanol as a porogenic solvent. The separation characteristics of the monolithic columns were tested by a homologous series of xanthine derivatives, theophylline and caffeine. The effects of the polymerization mixture composition and polymerization condition, mobile phase composition, flow rate and temperature on the retention times and separation efficiencies were investigated. The results showed that the selection of correct porogenic solvents and appropriate polymerization conditions are crucial for the preparation of the monolithic stationary phases. The separation efficiency was only extremely weakly dependent on flow rate and temperatures. Hydrogen-bonding interaction played an important role in the retention and separation. Compared with conventional particle columns, the monolithic column exhibited good stability, ease of regeneration, high separation efficiency and fast analysis.

• Journal of Radiation Industry
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• v.17 no.4
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• pp.543-549
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• 2023

Thallium-201 (²⁰¹Tl) is a medical radioisotope which emits gamma rays when it decays and used in myocardial perfusion scans in single-photon emission tomography due to its similar properties to potassium. Currently, the Korea Institute of Radiological & Medical Sciences is the only institution producing ²⁰¹Tl in Korea, and optimization of ²⁰¹Tl production research is necessary to meet supply compared to domestic demand. To this end, technical analysis of plating target production and chemical separation methods essential for ²⁰¹Tl production research is conducted. It deals with the process of generating and separating ²⁰¹Tl radioisotope and target production, It can be generated through a nuclear reaction such as ^natHg(p,xn)²⁰¹Tl, ²⁰¹Hg(p,n)²⁰¹Tl, ^natPb(p,xn)²⁰¹Bi → ²⁰¹Pb → ²⁰¹Tl, ²⁰⁵Tl(p,5n)²⁰¹Pb → ²⁰¹Tl, and considering impure nuclide generated simultaneously with the use of proton beam energy of 35 MeV or less, it is intended to be produced using the ²⁰³Tl(p,3n)²⁰¹Pb→²⁰¹Tl nuclear reaction. In particular, the chemical separation of Tl is a very important element, and the chemical separation methods that can separate it is broadly divided into four types, including solid phase extraction, liquid-liquid, electrochemical, and ion exchange membrane separation. Some chemical separations require additional separation steps, such as methods using selective adsorption. Therefore, this technical report describes four chemical separation methods and seeks to separate high-purity ²⁰¹Tl using a method without additional separation steps

• Proceedings of the Membrane Society of Korea Conference
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• 1996.03a
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• pp.69-90
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• 1996

In the chemical industry, in the pharmaceutical industry, and in a number of other industries separation processes are necessary to separate and purify products and raw materials [1,2]. Separation processes are also widely used in other applications such as in recycling valuable materials from waste streams. Unit operations for separation processes can be classified in phase separation techniques and component separation techniques based on the nature of the feed mixtures to be separated. The former techniques are used for the separation of heterogeneous mixtures, in which the feed is already present in two or more separated phases on a micro-scale. The latter are suitable for the separation of homogeneous mixtures such as gaseous mixtures and mixtures of completely miscible liquids. tn these cases the separation into individual components is generally achieved by utilizing the differences in physico-chemical properties of components, and is much more difficult compared to phase separation techniques. Separation processes such as distillation, evaporation, liquid-liquid extraction, and crystallization belong to this class.

• Macromolecular Research
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• v.11 no.3
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• pp.157-162
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• 2003

6FDA-based polyimides were prepared from the thermal imidization reaction of 6FDA with diamines of BAPAF, DAP, and DABA having a polar group of hydroxyL or carboxyl. Properties of the dense polyimide membranes were characterized and their gas permeation properties for H$_2$, $CO_2$, $O_2$, $N_2$, and CH$_4$ were investigated. Permeabilities, diffusion coefficients and diffusivity selectivities of polar group-containing polyimide membranes including 6FDA-BAPAF, 6FDA-DAP, and 6FDA-DABA polymer for the gases did not change largely. The separation properties of 6FDA-TrMPD polyimide membrane used as a reference polymer were compared with those of the polyimide membranes mentioned above. It was found that the polyimides of 6FDA-BAPAF, 6FDA-DAP, and 6FDA-DABA, which were soluble in alcohol or/and 2-methoxyethanol, could be applicable to the preparation of a dense composite membrane by dip-coating method.

• Korean Membrane Journal
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• v.8 no.1
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• pp.31-35
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• 2006

Pervaporation of water/2,2,2-trifluoroethanol (TFEA) mixtures was performed using a NaY zeolite membrane which was prepared by a hydrothermal synthesis. Pervaporation with a zeolite membrane is one of the economic separation technologies for liquid mixtures including organic/water solutions. The effects of a TFEA feed concentration and a temperature were studied on the permeation flux and the separation factor. Not only the water flux increased significantly with the increase of the operating temperature, but also the TFEA flux through the NaY zeolite membrane rapidly increased with the increase of the temperature at the feed concentration below 0.8 mole fraction of TFEA.

• Bulletin of the Korean Chemical Society
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• v.23 no.11
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• pp.1677-1679
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• 2002