• Analytical Science and Technology
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• v.11 no.6
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• pp.421-428
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• 1998

A method has been studied to separate Zr from various fission products in PWR spent nuclear fuels. A solution containing metal ions in place of radioactive fission products was prepared. The Zr was separated with 5 M HCl followed by eluting metal ions such as Ce, Nd, Cs, Rb, Ba, Sr, Ru, Rh, Pd, Ag and Cd with 12 M HCl on Dowex $1{\times}8$, anion exchange resin. The recovery of Zr was more than 95%. The purification of Zr was carried out on anion exchange resin, Dowex $1{\times}8$, in 5 M HCl in order to remove Mo causing isobaric effect during mass spectrometry. The method was applied to separate Zr from a spent PWR fuel. From mass spectrometric measurement, the purified Zr portion was not showed the isobars from other elements such as Mo and Sr.

• Journal of Hydrogen and New Energy
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• v.33 no.3
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• pp.209-218
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• 2022

Recently, research on the development of anion exchange membranes (AEMs) has received considerable attention from the scientific community around the world. Here, we fabricated a series of AEMs with branched structures with different alkyl spacers and conducted comparative evaluations. The introduction of these branched structures is an attempt to overcome the low ionic conductivity and stability problems that AEMs are currently facing. To this end, branched polymers with different spacer lengths were synthesized and properties of each membrane prepared according to the branched structure were compared. The chemical structure of the polymer was investigated by proton nuclear magnetic resonance, Fourier transform infrared, and gel permeation chromatography, and the thermal properties were investigated using thermogravimetric analysis. The branched anion exchange membrane with (CH₂)₃ and (CH₂)₆ spacers exhibited ionic conductivities of 8.9 mS cm^-1 and 22 mS cm^-1 at 90℃, respectively. This means that the length of the spacer affects the ionic conductivity. Therefore, this study showing the effect of the spacer length on the ionic conductivity of the membrane in the polymer structure constituting the ion exchange membrane is judged to be very useful for future application studies of AEM fuel cells.

• Membrane Journal
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• v.27 no.1
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• pp.84-91
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• 2017

In this study, heterogeneous ion exchange membranes were prepared by mixing cation or anion exchange resins and commercial polyvinylidene fluoride (PVDF) for MCDI process. The mixing ratios of PVDF and ion exchange resins were 1 : 1, 1.4 : 1, 2 : 1, and 3 : 1. We characterized SEM, water content, ion exchange capacity, methanol permeability, and ion conductivity. In the viewpoint of membrane characterization, the blending ratio of 2 : 1 showed the best. For the blending ratio of 2 : 1, heterogeneous cation exchange membrane showed the water content 34%, ion exchange capacity 1.54 meq/g, ion conductivity 0.019 S/cm, and methanol permeability $2.28{\times}10^{-7}{\sim}8.86{\times}10^{-7}cm^2/s$ while In the case of heterogeneous anion exchange membrane, the result showed 37%, 2.18 meq/g, and 0.034 S/cm and $1.46{\times}10^{-7}{\sim}8.66{\times}10^{-7}cm^2/s$.

• Polymer(Korea)
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• v.26 no.2
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• pp.153-159
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• 2002

In order to remove $NO_3;^-$ ion from ground-water, fibrous ion -exchangers, APP-g-GMA, were synthesized by GMA grafting onto PP trunk polymer with E-beam accelerator for pre-irradiation. Their degrees of grafting and amination yield increased up to $60^{\circ}C$ and showed maximum values as 133%, 88%, respectively. And their swelling ratio and ion exchange capacity at the maximum values are 86%, 2.5 meq/g, respectively which was higher than commercial ion-exchangers such as IMAC HP555 and Amberlite IRA 400. Optimum adsorption condition of $NO_3;^-$ ion was measured at pH 5~6 and -Cl form of APP-g-GMA containing trimethylammonium group showed the highest adsorption capacity.

• Polymer(Korea)
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• v.25 no.4
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• pp.451-459
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• 2001

Fabric ion-exchanger, aminated PP-g-styrene was synthesized with styrene monomer onto PP staple fiber by pre-irradiational grafting with E-beam and subsequent chloromethylation and amination. Degree of grafting was increased with increasing the styrene monomer concentration and the highest degree of grafting was obtained 118% at a monomer concentration of 80% styrene. Optimum condition of Mohr's salt and sulphuric acid were 1.0 ${\times}\;10^{-3}$ M and 0.1 M. Amount of amination was increased with increasing degree of grafting. Swelling ratio of aminated PP-g styrene was higher than that of trunk polymer. Ion-exchange capacity was 6.7 meq/g, which was three times greater than commercial ion-exchanger. Optimum condition of baron ion adsorption was pH 4 and amount of adsorption were increased with increasing the amount of amination.

• Journal of Korean Society of Water and Wastewater
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• v.27 no.1
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• pp.121-128
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• 2013

The concern for dissolved phosphate in water/wastewater has been increasing because of the risk for eutrophication. A variety of conventional and advanced technologies were applied to meet the enforced new regulation of phosphate around the world. However, there still remained a lot of challenge because most introduced/developed method, for example, biological and physic-chemical treatment is not easy to satisfy the new regulation of phosphate in water. In order to meet the new regulation, the application of ion exchanger has been tried which showed that the removal efficiency for phosphate was strongly determined by in the presence of the competing ion, especially sulfate. As results, a new class of ion exchanger governed by ligand exchange was developed and investigated to increase the selectivity for phosphate. The current study using organic/inorganic anion exchanger developed with Lewis acid-base interaction confirms the selectivity for phosphate over sulfate. According to isotherm test and column test, the value of the maximum phosphate uptake (Q) showed 64 mg/g as $po{_4}^{3-}$ and the breakthrough for phosphate occurs after 1000 min and completely finishes at 2500 min, respectively.

• KSBB Journal
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• v.8 no.4
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• pp.307-312
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• 1993

A fructosyltransferase from Aureobasidium pullulans was immobilized onto a polystyrene-type anionic ion-exchange resin and the production of fructo-oligosaccharides was Investigated by the immobilized enzyme. The optimum pH and the temperature of immobilized enzyme were found to be pH 5.0, $55^{\circ}C$ respectively. The thermal stability of the enzyme was greatly enhanced after immobilization. The reaction profiles of the immobilized enzyme was almost identical to those of the free cells and the soluble enzyme. The immobilized enzymes were stable up to 20 cycles without loss of initial activity in a repeated-batch operation $50^{\circ}C$.

• Applied Chemistry for Engineering
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• v.17 no.6
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• pp.653-657
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• 2006

The adsorption properties for $NO_{2}$ by hybrid ion exchange fiber with resins were investigated. The adsorption of $NO_{2}$ was increased with increasing of adsorption time and the initial concentration. At the initial $NO_{2}$ concentration of 900 ppm, approximately 40% of initial $NO_{2}$ was adsorbed around 20 min. And the adsorption of $NO_{2}$ was decreased with increasing of flow rate from 20 to 40 L/min. The maximum adsorbed amount of initial $NO_{2}$ was 45% at the flow rate of 10 L/min. The amount of adsorption was increased with increasing the water content.

• Korean Chemical Engineering Research
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• v.49 no.6
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• pp.840-845
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• 2011

Degradation products of agarose are biologically active and thus used as an ingredient in pharmaceuticals or functional cosmetics. Furthermore, it has been strongly considered as a substrate for bio-ethanol fermentation. Recently, we isolated new agarase-producing microorganism, Pseudoalteromonas sp. from south sea of Korea. In this study, we aimed to separate and purify the agarase from culture broth of this strain. Separation of agarase was performed by ion- exchange chromatography on DEAE-Sepharose resin. Equilibrium pH and volume ratio of resin to the amount of protein were optimized for the efficient adsorption of protein. 410 ${\mu}g$ of protein was completely adsorbed to 3 mL of resin at pH 7.5. The total amount of eluted protein increased as NaCl concentration increased to 400 mM at isocratic elution. Agarase was separated by linear gradient elution of NaCl (0~1,000 mM). Three major protein peaks were observed and the presence or absence of agarase in these eluted proteins was measured by Lugol's staining technique. Only six eluted protein fractions showed strong agarase activity.

• Analytical Science and Technology
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• v.12 no.2
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• pp.99-104
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• 1999

A stepwise gradient elution with two wavelengths detection was performed for the separation and determination of some anions in saline water. The eight anions such as iodate, bromate, nitrite, bromide, nitrate, chromate, iodide and thiocyanate were successfully separated using AS-7 column and sodium chloride/sodium phosphate buffer solution as an eluant within 40 min. The separation behaviors of anions were studied at various sodium chloride concentrations. The peak shapes of anions of bromate, nitrite, bromide and nitrate gradually broadened as the concentration of sodium chloride increased until 1.0 M in the sample solutions. However, no effect was observed in the peak shapes of chromate, iodide and thiocynate. A good linearity was obtained at the range of ppm(mg/L). The detection limit was proved to be $10-720{\mu}g/L$ for the eight anions with $50{\mu}L$ injection volume. This method was applied to the determination of $Br^-$, ${NO_3}^-$ and $I^-$ in sea water.