• Title/Summary/Keyword: Mixed-bed ion exchange

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The Effects of Resin Ratio and Bed Depth on the Performance of Mixed-bed Ion Exchange at Ultralow Solution

  • Yoon, Tae-Kyung;Lee, Gang-Choon;Noh, Byeong-Il
    • Journal of Environmental Science International
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    • v.18 no.6
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    • pp.595-601
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    • 2009
  • The effects of the cation-to-anion resin ratio and bed depth on ion exchange performance of mixed-bed were studied at ultralow solution concentration. Breakthrough curves were experimentally obtained for NaCI solution as functions of resin ratio and bed depth. The bed depth affects the pattern of the sodium breakthrough curve but not the chloride breakthrough curve in beds because of the selectivity difference. Resin selectivity determines the shape of breakthrough curves, Some sodium and chloride breakthrough curves crossed at a point as a function of resin ratio. The lower cation-to-anion resin ratio showed the higher effluent concentration or treated volume of the crossover point regardless of the total resin weight.

Iron hydrolysis and lithium uptake on mixed-bed ion exchange resin at alkaline pH

  • Olga Y. Palazhchenko;Jane P. Ferguson;William G. Cook
    • Nuclear Engineering and Technology
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    • v.55 no.10
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    • pp.3665-3676
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    • 2023
  • The use of ion exchange resins to remove ionic impurities from solution is prevalent in industrial process systems, including in the primary heat transport system (PHTS) purification circuit of nuclear power plants. Despite its extensive use in the nuclear industry, our general understanding of ion exchange cannot fully explain the complex chemistry in ion exchange beds, particularly when operated at or near their saturation limit. This work investigates the behaviour of mixed-bed ion exchange resin, saturated with species representative of corrosion products in a CANDU (Canadian Deuterium Uranium) reactor PHTS, particularly with respect to iron chemistry in the resin bed and the removal of lithium ions from solution. Experiments were performed under deaerated conditions, analogous to normal PHTS operation. The results show interesting iron chemistry, suggesting the hydrolysis of cation resin bound ferrous species and the subsequent formation of either a solid hydrolysis product or the soluble, anionic Fe(OH)3-.

Equilibrium Property of Ion Exchange Resin for Silica Removal at Ultralow Concentration (초저이온농도에서 이온교환수지에 의한 실리카제거 평형특성)

  • Yoon, Tae-Kyung;Lee, Gang-Choon;Noh, Byeong-Il
    • Journal of Environmental Science International
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    • v.16 no.8
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    • pp.907-912
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    • 2007
  • Ion exchange resin was used to remove silica ion at ultralow concentration. The effects of temperature, type of ion exchange resin and single/mixed-resin systems on removal efficiency were estimated. As temperature increased, the slope of concentration profile became stiff, and the equilibrium concentration was higher. In the single resin system, the removal of silica was continued up to 400 min, but the silica concentration was recovered to initial concentration after 400 min due to the effect of dissolved $CO_2$. In the mixed-resin system it took about 600 min to reach equilibrium. Because of faster cation exchange reaction than anion exchange reaction, the effect of $CO_2$ could be removed. Based on the experimental results carried out in the mixed-resin system, the selectivity coefficients of silica ion for each ion exchange resin were calculated at some specific temperatures. The temperature dependency of the selectivity coefficient was expressed by the equation of Kraus-Raridon type.

The Mixed-Bed Ion Exchange Performance and Temperature Effects at Ultra-Low Concentrations - 2.Temperature Effects - (초저이온 농도범위에서 혼합층 이온교환능과 온도의 영향 - 2. 온도의 영향 -)

  • Yoon, Tae Kyung;Noh, Byeong Il;Lee, Chang Won;Moon, Byung Hyun;Lee, Gang Choon;Jo, Myung Chan
    • Applied Chemistry for Engineering
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    • v.10 no.2
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    • pp.206-211
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    • 1999
  • Mixed-bed ion exchange performance was studied experimentally with variations of cation to anion resin ratio, resin weight and temperature at ultralow sodium chloride solution concentrations of less than $1.0{\times}10^{-4}M$. Analyzing the effluent concentration histories the performance test was examined as a function of tested solution volume for a laboratory-scale continuous flow column until both the cation and anion-exchange resins were exhausted. Initial leakage was observed for both cation and anion breakthrough curves, but serious at cation breakthrough curve because of low selectivity coefficient. The slope of breakthrough curve was affected by selectivity coefficient and temperature. The slope of anion breakthrough curve was steep because of the large selectivity coefficient, and ion exchange rates increased as temperature increased. The temperature effect decreased as the total volume was increased or as the resins were exhausted.

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Continuous Ion Exchange Characteristics of Ni, Co and Ag Ions in Acidic-Oxidizing Conditions (산성-산화성 분위기에서 니켈(Ni), 코발트(Co) 및 은(Ag) 이온의 연속식 이온교환 특성)

  • Kim, Young H.;Yang, Hyun S.;Kim, Woong K.
    • Applied Chemistry for Engineering
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    • v.10 no.2
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    • pp.218-224
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    • 1999
  • Continuous ion exchange characteristics of the synthetic coolant contained Ni, Co and Ag ions of low concentration in acidic-oxidizing conditions have been studied to suggest the guideline for the optimum operation of mixed-bed demincralizer during the shutdown period of a pressurized water reactor (PWR). In the effect of the form of cation resins on the removal capacity of metal ions, the performance of a $H^+$-form resin was about 6% higher than that of a $Li^+$-form resin. Mixed-bed of cation and anion resins in comparison with nonmixed-bed of them, had no affected on the removal capacity of metal ions but very slightly increased the slope of breakthrough curves of metal ions. In the effect related to acidic-oxidizing conditions of the coolant, the addition of boric acid very slightly decreased the slope of breakthrough curves of metal ions, while the addition of hydrogen peroxide slightly decreased the removal capacity of metal ions.

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A study on breakthrough characteristics of ion exchange bed with H- and ETAH-form resins for cation exchange in NH3 and ETA solution including trace NaCl (미량의 NaCl을 포함하는 NH3 및 ETA 용액에서 H 및 ETAH 형 수지에 대한 이온교환 파과 특성 연구)

  • Ahn, Hyun-Kyoung;Kim, Youn-Su;Park, Byung-Gi;Rhee, In-Hyoung
    • Journal of Korean Society of Water and Wastewater
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    • v.35 no.6
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    • pp.533-544
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    • 2021
  • Ion exchange (IX) performance on the exchanger bed is essentially evaluated for the generation of ultrapure water in electronics and chemical industries and for the corrosion control in nuclear power plants. The breakthrough characteristics of IX bed with multi-component were investigated with both cation- and mixed-IX beds of H- and ETAH-form for four kinds of cation exchange resins by using the combined solution of ethanolamine (ETA) and ammonia (NH3) at trace NaCl. Unlike major components (ETAH+ and NH4+ ), the phenomena of breakthrough and overshooting at bed outlet were not observed by Na+ over the test period (> 3 times theoretical exchange capacity of IX bed). The breakthrough from H-form resin bed was sequentially reached by ETAH+ and NH4+, while the overshooting was observed for ETAH+ at the breakthrough of NH4+. NH4+ was 51.5% higher than ETAH+ in terms of the relative selectivity determined with the width of breakthrough zone. At the increased concentration of Na+ at bed inlet, the selectivity and the overshooting were decreased and increased, respectively. Na+ leakage was higher from ETAH-form resin bed and was not identical for four kinds of cation-exchange resins, which may be reduced by improving the intrinsic property of IX resin.

Ion Exchange Modeling in ETA and NH$_3$ Aqueous Solutions (ETA 및 암모니아 수용액에서 이온교환 모델링)

  • 안현경;김상대;이인형
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.4 no.3
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    • pp.307-311
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    • 2003
  • The test did for the determine the optimized ratio of cation to anion in mixed ion exchange demineralizers. Binary, ternary, quaternary, and quinary cation and anion adsorption was performed to develop a comprehensive experimental data set from small-volume batch tests to obtain the selectivity coefficients of many cations and anions. The quantitative run time might be estimated by such ion exchange models as semi-empirical mass action and surface complexation models. The demineralizer can be used longer by increasing the ratios of cation to anion exchange resins in the bed.

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A STUDY ON ADSORPTION AND DESORPTION BEHAVIORS OF 14C FROM A MIXED BED RESIN

  • Park, Seung-Chul;Cho, Hang-Rae;Lee, Ji-Hoon;Yang, Ho-Yeon;Yang, O-Bong
    • Nuclear Engineering and Technology
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    • v.46 no.6
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    • pp.847-856
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    • 2014
  • Spent resin waste containing a high concentration of $^{14}C$ radionuclide cannot be disposed of directly. A fundamental study on selective $^{14}C$ stripping, especially from the IRN-150 mixed bed resin, was carried out. In single ion-exchange equilibrium isotherm experiments, the ion adsorption capacity of the fresh resin for non-radioactive $HCO_3{^-}$ ion, as the chemical form of $^{14}C$, was evaluated as 11mg-C/g-resin. Adsorption affinity of anions to the resin was derived in order of $NO_3{^-}$ > $HCO_3{^-}{\geq}H_2PO_4{^-}$. Thus the competitive adsorption affinity of $NO_3{^-}$ ion in binary systems appeared far higher than that of $HCO_3{^-}$ or $H_2PO_4{^-}$, and the selective desorption of $HCO_3{^-}$ from the resin was very effective. On one hand, the affinity of $Co^{2+}$ and $Cs^+$ for the resin remained relatively higher than that of other cations in the same stripping solution. Desorption of $Cs^+$ was minimized when the summation of the metal ions in the spent resin and the other cations in solution was near saturation and the pH value was maintained above 4.5. Among the various solutions tested, from the view-point of the simple second waste process, $NH_4H_2PO_4$ solution was preferable for the stripping of $^{14}C$ from the spent resin.

Selective Adsorption Properties of Nitrate ion in Sulfate and Nitrate Solution by Bead and Fibrous Hybrid Ion Exchange Bed (비드와 섬유 혼성이온교환 베드를 이용한 황산이온과 질산이온 혼합용액에서 질산이온의 선택 흡착 특성)

  • 황택성;박명규
    • Polymer(Korea)
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    • v.27 no.1
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    • pp.69-74
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    • 2003
  • In this study, we have investigated the adsorption properties for nitrate ion in ground water using mixed resin type hybrid ion exchange (HIXF) and fiber type ion exchanger. Their swelling ratio (4.45 g/g) and ion exchange capacities (2.45 meq/g) were higer than the swelling ratio of IEC and IXF. Adsorption yield increased for nitrate $NO_3^-$ and sulfate $SO_4^{2-}$ ions were optimal at the concentration ratios of nitrate and sulfate below 1.0 and the adsorption yields were 100% and 20%, respectively. On the other hand it was shown that the degree of adsorpted for nitrate to pH 3, but it was little changed in the other pH range. We found that the selective adsorption capacity for nitrate was the optimal the mixing ratios of resin and fibrous ion exchanger of below 0.5.