• Journal of Radiation Protection and Research
• /
• v.8 no.1
• /
• pp.15-25
• /
• 1983

The sequential separation of Ru-103, Cs-137 and Ce-144 was carried out by organic cation exchanger, Amberite CG-120, and inorganic ion exchangers, silica gel and montmorillonite. The optimum conditions of Ru-103, Cs-137 and Ce-144 on Amberite CG-120 are 0.01M-, 0.01M- and 0.1IM- hydrochloric acid for the adsorption, and 3M-, 3M- and 5M-hydrochloric acid for the desorption, respectively. The optimum conditions of Ru-103, Cs-137 and Ce-144 on silica gel are pH 8, pH 8 and pH 8 for the adsorption. and 3M-, 1M- and 1M-hydrochloric acid for the desorption. respectively. The optimum conditions of Ru-103, Cs-137 and Ce-144 on montmorillonite are pH 8, 0.01M-hydrochloric acid and pH 4 for the adsorption, and 1M-, 5M- and 3M-hydrochloric acid for the desorption. respectively. The adsorption which occurs at lower ionic strength and the differences in desorption ionic strength are utilized for the separation of tracer mixture in continuous experiments. The individual separation of Ru-103, Cs-137 and Ce-144 can be carried out more efficiently with montmorillonite than with silica gel and Amberite CG-120.

• Analytical Science and Technology
• /
• v.37 no.2
• /
• pp.123-129
• /
• 2024

We present a rapid method for the determination of Cs, Sr, and Ba, heat generators found in highly active liquid wastes, by gas-pressurized extraction chromatography (GPEC) using a column containing a cation-exchange resin. GPEC is a microscale column chromatographic technique that uses a constant flow rate of solvent (0.07 mL/min) with pressurized nitrogen gas supplied through a valve. In particular, because this method uses a small sample volume (a few hundred microliters), it produces less chemical waste and allows for faster separation compared to traditional column chromatography. In this study, we evaluated the separation of Cs, Sr, and Ba using GPEC. The eluate from the column (GPEC or conventional column chromatography) was quantitatively analyzed using inductively coupled plasma-mass spectrometry to measure the column recovery and precision. The column reproducibility of the proposed GPEC system (RSDs of recoveries) ranged from 2.7 to 4.1 %, and the column recoveries for the three elements ranged from 72 to 98% when aqueous HCl was used as the eluent. The GPEC results are slightly different in efficiency and separation resolution compared to those of conventional column chromatography because of the differences in the eluent flow rate as well as the internal diameter and length of the column. However, the two methods had similar recoveries for Cs and Sr, and the precision of GPEC was improved by two-fold. Remarkably, the solvent volume required for GPEC analysis was five times lower than that of the conventional method, and the total analysis time was 11 times shorter.

• Proceedings of the Membrane Society of Korea Conference
• /
• 2000.11a
• /
• pp.71-74
• /
• 2000

• Journal of the Korean Chemical Society
• /
• v.5 no.1
• /
• pp.29-32
• /
• 1961

Two methods for the determination of Cesium-137 in various foods(ashes) were compared. The one comprises two steps, the first being the separation of alkalies as cobaltinitrites or perchlorates by the radiochemical method, and the second being the measurement of photopeak area due to the presence of Cs-137 by the use of scintillation spectrometer. The other method is the direct subjection of ash samples to the spectrometry without the radiochemical separation. The combined contribution of K-40 and Rb-87 to the spectrum was not found on account of the difference in energies of these nuclides. These two methods gave, a good agreement in the determination of Cs-137 in 50-100g ash samples of vegetables or cereals under investigation.

• Korean Chemical Engineering Research
• /
• v.43 no.6
• /
• pp.722-727
• /
• 2005

Dow99Ca350 (Dowex monosphere 99Ca/350 separation resin), MFG-220, and Finex CS-10GC are ion-exchange resins, and primarily used to separate sugars, and all of these resins have poly styrene DVB backbone, and sulfonyl group. These resins are already used to separate sugars continuously at sugar industry at constant temperature. These resins are used in experiments for understanding temperature effect on retention or adsorption behavior. Using Dow99Ca350, swelling test, porosity test, pulse test, and frontal analysis at various temperatures were performed. In the cases of MFG-220, and Finex CS-10GC, the effect of temperature variation was verified by pulse test. The experimental results are shown that Dow99Ca350, MFG-220, and Finex CS-10GC, which are commercial resins for sugar separation, are stable to temperature variation because the maximum change of retention time of fructose, and glucose are 1.76, and 3.37％ respectively.

• Bulletin of the Korean Chemical Society
• /
• v.4 no.2
• /
• pp.87-91
• /
• 1983

Molecular dynamic method has been applied to a single polymer chain immersed in a solvent. The interactions for the pairs, of two solvent molecules (SS), of a chain element and a solvent molecules (CS), and of two non-neighbor chain elements (CC) are given by the Lennard-Jones potential, and the interaction between two bonded chain elements is given by a harmonic potential. We changed the CS interaction parameter ${\varepsilon}_{CS}$ to 0.5, 1.0 and 2.0 times of the SS interaction ${\varepsilon}_{SS}$. We calculated the pair correlation functions for the SS, CS, and CC pairs, end-to-end distance and radius of gyration with the varying ${\varepsilon}_{CS}$ parameters. The results showed that a phase separation occurs between the polymer and solvent in the 0.5 system where ${\varepsilon}_{CS}$ = 0.5 {\varepsilon}_{SS}$. The autocorrelation functions for end-to-end distance and radius of gyration were also calculated.

• Proceedings of the Korean Radioactive Waste Society Conference
• /
• 2017.05a
• /
• pp.275-276
• /
• 2017

• Proceedings of the Korea Society of Poultry Science Conference
• /
• 2004.11a
• /
• pp.26-27
• /
• 2004

This study was conducted to evaluate the value of chicken keel cartilage as a source of mucopoly-saccharide-protein containing chondroitin sulfate (CS) and to find the optimum extraction conditions. The hot water extraction and alcalase hydrolysis methods were performed for extraction mucopolysaccharide in lyophilized chicken keel cartilage. The most efficient condition was hydrolysis with 2 % alcalase in 10 volumes of distilled water for 120 min. The yield of hydrolysate and CS content were 75.87 % and 25.61 %, respectively. For further separation of CS from hydrolysate by alcalase, ethanol precipitation was performed. The yield of ethanol precipitate and its CS content were 21.41 % and 46.31 %, respectively.

• Korean Journal of Chemical Engineering
• /
• v.35 no.12
• /
• pp.2336-2347
• /
• 2018

The azeotrope of methyl acetate methanol and water was isolated using extractive distillation with water as entrainer. The pressure-swing extractive distillation (PSED) process and vapor side-stream distillation column (VSDC) with the rectifier process were designed to separate the methyl acetate, methanol and water mixture. It was revealed that the VSDC with the rectifier process had a reduction in energy consumption than the PSED process. Four control schemes of the two process were investigated: Double temperature control scheme (CS1), $Q_R/F$ feedforward control of reboiler duty scheme for PESD (CS2), $Q_R/F$ feedback control scheme for VSDC (CS3), the feedback control scheme of sensitive plate temperature of side-drawing distillation column to dominate the compressor shaft speed (CS4). Feed flow and composition disturbance were used to evaluate the dynamic performance. As a result, CS4 is a preferable choice for separation of methyl acetate-methanol-water mixture. A control scheme combining the operating parameters of dynamic equipment with the control indicators of static equipment was proposed in this paper. It means using the sensitive plate temperature of side-drawing column to control the compressor shaft speed. This is a new control scheme for extractive distillation.

• Nuclear Engineering and Technology
• /
• v.33 no.2
• /
• pp.231-240
• /
• 2001

When it is assumed that PWR, CANDU and DUPIC spent fuels are disposed of in deep geological repository, consequent annual individual doses are calculated, and it is shown that doses meet the regulatory limit. From these results, the hazardous radionuclides applicable to partitioning and transmutation are selected. These selected radionuclides such as Tc-99, Ⅰ-129, Cs-135 and Np-237 are then reviewed in terms of partitioning and transmutation. Separation of I-129, Np-237 and Tc-99 from spent fuels is considered desirable, and transmutation of these radionuclides results in remarkable hazard reduction. However, it is concluded that separation and transmutation of Cs-135 may be ineffective although it is classified into a hazardous radionuclide.