• Environmental Engineering Research
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• v.7 no.3
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• pp.149-157
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• 2002

• Environmental Engineering Research
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• v.7 no.2
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• pp.103-111
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• 2002

• Polymer(Korea)
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• v.26 no.1
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• pp.121-127
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• 2002

We investigated uranium adsorption and adsorption process characteristics in brine water, changing column bed height packed with amidoximated polypropylene-g- acrylonitrile (AOPP-g-AN) fibrous ion-exchanger. Swelling ratios of AOPP-g-AN in fibrous ion-exchanger were 8.54g/g $H_2O_2$ and 8.87 g/g for $H_2O_2$ solvent respectively. Ion exchange capacity increased with degree of graft and showed the maximum, 3.99 meq/g at 100% degree of graft. In batch process, uranium adsorption had reached an initial equilibrium in 10 min with the adsorption rate of 9.5 mg/min. Finial adsorption capacity was 3.95 meq/g, and pH effect could not be observed. In continuous process, adsorption capacity depended on various packing ratios and showed the maximum, 3.92 meq/g at L/D=1. In L/D<2, breakthrough curve was shown two step by channeling flow and ununiform adsorption. Breakthrough time and adsorption capacity were 26 min and 3.63 meq/g, respectively, in brine water adsorption. When compared with actual brine water and model solution, there was no significant difference of adsorption characteristics.

• Proceedings of the Korean Radioactive Waste Society Conference
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• 2003.11a
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• pp.73-77
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• 2003

In order to predict the dynamic behaviors of uranium and cobalt in a fixed bed at various influent pH values of liquid waste, the adsorption system was regarded as multi-component adsorption between each ionic species in a solution. Langmuir isotherm parameters of each species were extracted by incorporating equilibrium data with the solution chemistry of uranium and cobalt using IAST. Prediction results were in good agreement with the experimental data, except for a high concentration and pH. Although there was some limitations in predicting the cobalt adsorption, this method may be useful in analyzing a complex adsorption system where various kinds of ionic species exist in a solution.

• Advances in environmental research
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• v.4 no.2
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• pp.135-142
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• 2015

In this study, we evaluated the adsorption/desorption of uranium (U) in pure soil environment using continuous column reactor. We additionally investigated the adsorption/desorption mechanism of U on vivianite surface in molecular scale using quantum calculation. We observed that below $0.1{\mu}M$ of U was detected after 20 d from U injection ($1{\mu}M$) in adsorption test. However, all of absorbed U was detached from vivianite surface in 24 h by injection of CARB solution ($1.44{\times}10^{-2}M\;NaHCO_3$ and $2.8{\times}10^{-3}M\;Na_2CO_3$). Based on exchange energy calculation, we found that $UO_2(CO_3)_2{^{2-}}$ and $UO_2(CO_3)_3{^{4-}}$ species have higher repulsive energy than $UO_2(OH)_2$ species. The results obtained from this study could be applied to predict the behavior of uranium in contaminated and remediation sites.

• Journal of environmental and Sanitary engineering
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• v.22 no.3
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• pp.77-87
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• 2007

The ion exchange resins have been synthesized from chlormethyl styrene - 1,4 - divinylbenzene(DVB) with 1%, 3%, and 5%-crosslinking and macro cyclic ligand of OenNen-$H_4$ by copolymerization method and the adsorption characteristics of uranium(VI), iron(II) and samarium(III) metallic ions have been investigated in various experimental conditions. The synthesis of these resins was confirmed by content of chlorine, element analysis, and IR-spectrum. The effects of pH, time, dielectric constant of solvent and crosslink on adsorption of metallic ions were investigated. The uranium ion was showed fast adsorption on the resins above pH 3. The optimum equilibrium time for adsorption of metallic ions was about two hours. The adsorption selectivity determined in ethanol was in increasing order uranium ${UO_2}^{2+}>Fe^{2+}>Sm^{3+}$ ion. The adsorption was in order of 1%, 3%, and 5% crosslink resin and adsorption of resin decreased in proportion to order of dielectric constant of solvent.

• Journal of environmental and Sanitary engineering
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• v.20 no.3 s.57
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• pp.27-35
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• 2005

The ion exchange resins have been synthesized from chlormethyl styrene - 1,4 -divinyl-benzene(DVB) with $1\%,\;4\%,\;and\;10\%$-crosslinking and macrocyclic ligand of cryptand type by copolymerization method and the adsorption characteristics of uranium(VI), calcium(II) and lutetium(III) metallic ions have been investigated in various experimental conditions. The synthesis of these resins was confirmed by content of chlorine, element analysis, and IR-spectrum. The effects of pH, time, dielectric constant of solvent and crosslink on adsorption of metallic ions were investigated. The uranium ion was showed fast adsorption on the resins above pH 3. The optimum equilibrium time for adsorption of metallic ions was about two hours. The adsorption selectivity determined in ethanol was in increasing order uranium $(UO_2^{2+})>calcium(Ca^{2+})>lutetium(Lu^{3+})$ ion. The adsorption was order of $1\%,\;4\%,\;and\;10\%$ crosslink resin and adsorption of resin decreased in proportion to order of dielectric constant of solvents.

• Journal of Korean Society of Environmental Engineers
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• v.22 no.5
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• pp.827-835
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• 2000

Adsorption characteristics of uranium on activated carbon whose surface is modified with $HNO_3$ and/or NaOH were investigated. Na-OAC, which was the activated carbon treated with both $HNO_3$ and NaOH. showed higher adsorption capacity than OAC, which was treated with $HNO_3$, as well as Na-AC, which was treated with only NaOH. This can be explained based on the surface functional groups increased by surface modification of activated carbon and the change of solution pH as adsorption proceeds. From these experimental results, it is thought that the pH of uranium solution and surface functional groups on the activated carbon surface are the governing factors in the uranium adsorption system.

• Proceedings of the Korean Radioactive Waste Society Conference
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• 2004.06a
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• pp.119-120
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• 2004

A study on the selective adsorption of uranium(VI) from a high concentration of chemical salts has tern peformed to investigate the uranium removal mechanisms and the application conditions of the electrosorption technique using the activated carbon fiber(ACF) as a good conductive electrosorption adsorbent. Electrosorption test were carried out using an electrochemical cell.(omitted)

• Carbon letters
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• v.4 no.2
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• pp.64-68
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• 2003

A study on the electrosorption of uranium ions onto a porous activated carbon fiber (ACF) was performed to treat uraniumcontaining lagoon sludge. The result of the continuous flow-through cell electrosorption experiments showed that the applied negative potential increased the adsorption kinetics and capacity in comparison to the open-circuit potential (OCP) adsorption for uranium ions. Effective U(VI) removal is accomplished when a negative potential is applied to the activated carbon fiber (ACF) electrode. For a feed concentration of 100 mg/L, the concentration of U(VI) in the cell effluent is reduced to less than 1 mg/L. The selective removal of uranium ions from electrolyte was possible by the electrosorption process.