• Journal of Korean Society of Forest Science
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• v.79 no.3
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• pp.285-289
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• 1990

Soil N mineralization and nitrification can be measured conveniently using mixed bed (cation and anion) exchange resin bags. However, appropriate use of these resin bags requires pretreatment to avoid colorimetric interference and standardize N ion adsorption. Three pretreatments were evaluated : control (untreated), 2 M NaCl with a distilled water rinse, and 4 M NaCl. The 4 M NaCl treatment was effective at removing background levels of $NH_4{^+}$ and $NO_3{^-}$, but adsorbed low amounts (about 40%) of inorganic N from standard solutions. Untreated resin bags adsorbed a constant, higher amount of $NO_3{^-}$ (60%), but did not remove background levels of $NH_4{^+}$. The 2 M NaCl treatment followed by a distilled water rinse performed best : it removed background $NH_4{^+}$ and adsorbed a constant amount of both $NH_4{^+}$ (70%) and $NO_3{^-}$ (60%). Because the ion exchange resin is fairly expensive, we also tested if the resin bags could be reused. Resin bags were either loaded with $NH_4{^+}$ and $NO_3{^-}$ in the laboratory or incubated in soil in the field, desorbed with the 2 M NaCl treatment, and then loaded with standard $NH_4{^+}$ and $NO_3{^-}$ solutions. Lab loaded resin bags adsorbed about 60% of inorganic N then loaded with 2.5 or $5.0mgN\;1^{-1}$ and 70% when loaded at 10 or $20mgN\;1^{-1}$, whereas reused field incubated bags showed the opposite adsorption efficiency. These results demonstrate that resin bags can give reproducible results, but care must be taken to evaluate the effect of pretreatment and potential for reuse.

• Applied Chemistry for Engineering
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• v.23 no.1
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• pp.86-92
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• 2012

A characteristic study of chlorine dioxide generation by the electrolysis system was performed after chlorite ($ClO_2^-$) is adsorbed from sodium chlorite by a polymer ion exchange resin. A strongly basic anion exchange resin was used and a Ti plate coated with Ru and Ir was used as an electrode. Various parameters such as reaction stirring velocity, reaction temperature, chlorine dioxide product concentration, ion exchange resin content and product maker type for the adsorption quantity in the chlorite adsorption of ion exchange resin were investigated and found the ion exchange resin with the maximum adsorption quantity. A generation trend of chlorine dioxide was observed by the electrolysis system and optimum conditions on the desired value were found using response surface design of DOE (Design of Experiments). The strongly basic anion exchange resin with the maximum adsorption quantity was SAR-20 (TRILITE Gel type II) and the adsorption quantity was around 110 mg/IER (g). Observed generation optimum conditions of chlorine dioxide were constant-current (electrode area base; $A/dm^2$) and flow rate of $N_2$ gas (4.7 L/min) at the desired value of sterilization (900~1000 ppm, 1 h).

• Nuclear Engineering and Technology
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• v.55 no.10
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• pp.3617-3627
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• 2023

This study presents a method to solidify spent ion-exchange resin (IER) in a metakaolin-based geopolymer and shows results of mechanical strength, immersion, leaching, irradiation, and thermal cycling tests for waste acceptance criteria (WAC) to repository. The geopolymer waste form with 20 wt% of simulated spent IER met the WAC in South Korea (ROK), and the leaching tests of various sized-waste forms up to 15.0 × 30.0 cm and waste loadings up to 20 wt% for 1-5 d and 1-90 d achieved a leachability index, L_i > 6. In a leaching test for 5 d, the cumulative fraction leached (CFL) for Cs, which leached the most, was linearly correlated with the square root of leaching time for all waste forms, and L_i increased as the size of the waste form increased. The CFL was also correlated with elapsed time in the 90 d leaching test. The correlations among CFL, time, and volume-to-surface area ratio of waste forms used to estimate the L_i of Cs of a 200-L sized geopolymer with 15 wt% IER showed the L_i values as 14.73 (5 d) and 17.71 (90 d), respectively, indicating that the large-sized geopolymer waste form met the WAC.

• Membrane Journal
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• v.26 no.2
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• pp.97-107
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• 2016

This study was carried out to prepare a heterogeneous cation exchange membrane by mixing polyvinylidene fluoride (PVDF), commercial cation exchange resin and sulfonated poly(phenylene oxide)(SPPO) in order to propose an optimum condition for the preparation, and to compare its properties with commercial membrane. Study results show that the ion exchange capacity and electrical resistance were outstanding when the ratio of polymer matrix was less than 30% comparing between PVDF-IER, PVDF-SPPO and PVDF-SPPO-IER. The tensile strength was confirmed that seemed a hard look was five times greater compared to the commercial heterogeneous membrane, despite the weak durability of PVDF resin. Therefore, when chemical and mechanical properties are considered, the optimum mixing ratio between PVDF, IER and SPPO was 30 : 70, at which electric resistance was measured as $3{\sim}5{\Omega}{\cdot}cm^2$, ion exchange capacity as 0.6~1.0 meq/g, while mechanical strength was in a range of $12{\sim}15kgf/cm^2$.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.2 no.3
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• pp.165-174
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• 2004

In order to simultaneously vitrify the ion exchange resin(IER) and combustible dry active waste(DAW) generated from Korean nuclear power plants, a vitrification pilot test was conducted using an induction cold crucible melter(CCM) . The energy necessary for startup of the glass using a Ti-ring was evaluated as about 290 kWh. The power supplied from a high frequency generator to melt the glass properly was ranged from 160 to 190 kW without any interruption. When the mixture of the IER and DAW was fed into the CCM, the concentration of CO was lowered up to 1/40 compared to feeding the IER solely. It may be caused by the DAW which can produce about 1.8 times higher heat compared to the IER. When the swelling phenomenon occurred in the glass melt, the concentration of $NO_2$, oxidizing gas, was higher than NO, reducing gas. Total feed amounts of the IER and DAW were 368 and 751 kg, respectively. And then, about 74 of volume reduction factor was achieved.

• Journal of the Korean Ceramic Society
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• v.38 no.9
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• pp.839-845
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• 2001

In order to vitrify the Ion-Exchange Resin(IER), Dry Active Waste(DAW), and borate concentrate generated from the commercial nuclear facilities, the glass formulation study based on the their compositions was performed. Two glasses named as RG-1 and DG-1 were formulated as the candidate glasses for the vitrification of hte IER and DAW, respectively. A glass named as MG-1 was also formulated as a candidate glass for the vitrification of the mixed wastes containing the IER, DAW, and borate concentrate. The process parameters, product qualities, and economics were evaluated for the candidate glasses and confirmed experimentally for the some properties. The glass viscosity and electrical conductivity as the process parameters were in the desired ranges. the product qualities such as glass density, chemical durability, phase stability, etc. were satisfactory. In case of vitrifying the wastes using our developed glass formulation study, the volume reduction factors for the IER, DAW and mixed wastes were evaluated as 21, 89 and 75, respectively.

• Journal of Radiation Protection and Research
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• v.29 no.1
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• pp.33-39
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• 2004

In order to vitrify the W1 waste (ion-exchange resin(IER), zeolite, and dry active waste(DAW)) generated from Korean Nuclear Power Plants, a glass formulation development based on waste compositions and production rates was performed. A aluminoborosilicate glass, AG8W1, was formulated to vitrify the W1 waste in an induction cold crucible melter(CCM). The processability, product performance, and economics of the candidate glass were calculated using a computer code and were measured experimentally in the laboratory and CCM. The glass viscosity and electrical conductivity as the process parameters were in the desired ranges. Start-up and maintaining glass melt of the candidate glass were favorable in the CCM. The product quality of the glass such as chemical durability, phase stability, etc. was satisfactory. The vitrification process using the candidate glass was also evaluated to be operated as economically as possible.