Improvement of radioactive liquid waste treatment efficiency by sequential cationic and anionic ion exchangers

Abstract

Liquid radioactive / Waste treatment / Ion exchange / Radionuclides / Complexant / Cesium removalSummary. Various types of liquid radioactive wastes are released from different nuclear activities. The treatment efficiencies of these wastes depend highly on the physical and chemical composition of each waste such as pH, TDS and electrical conductivity. The treatment efficiency of some radionuclides with different valency states (such as 134 Cs, 65 Zn, 60 Co and 152+154 Eu) was tested based on the absorption capacity of cationic exchanger (KY-2) functionlized with polystyrene sulphonic group. The competitive adsorption on cationic exchanger was investigated by mono radionuclide and multi radionuclides wastes. The influence of the presence of various anionic complexants in the rad-waste on the adsorption capacity and hence the treatment efficiency was quantitatively studied using weakly base aminated anionic exchanger (AN-31). The enhancement in decontamination factor of each radionuclide is mostly attributed to the high adsorption capacity of the cationic resin in addition to the complexation capability of the radionuclide with the different complexant existed in the waste solution. The complex formation improved the decontamination factor through indirect adsorption of the anionic species on the subsequent anionic exchanger during the treatment process. The results showed that the removal percentages are around 50% for 134 Cs, 60 Co, 65 Zn and 152,154 Eu, without complexant compound. Significant enhancements of the removal percentages > 85% were obtained for 60 Co, 65 Zn and 152,154 Eu, respectively, on addition of manganese sulphate while maximum removal percentage (75.3 ± 0.7%) is obtained for 134 Cs when using 0.1 M citric acid as a complexing agent.

Preparation and characterization of aluminum silicotitanate: ion exchange behavior for some lanthanides and iron

“…So the sorption of the cations by AST 1, AST 6 and AST 20 is a mixed process involving ion exchange and physical adsorption. Similar results have been reported by several authors . It was found that the order of selectivity of the investigated cations under the same conditions has the following sequence: Eu(III) > La(III) > Fe(III) following the decrease in the hydrated ionic radii …”

“…Thus these findings cannot be explained only in terms of electrostatic interactions between the hydrated cations and the anionic sites in the exchanger. It may therefore be concluded that K d cannot be understood by a purely columbic interaction, but may also be closely related to the ionic potential of the cations . So the sorption of the cations by AST 1, AST 6 and AST 20 is a mixed process involving ion exchange and physical adsorption.…”

“…It may therefore be concluded that K d cannot be understood by a purely columbic interaction, but may also be closely related to the ionic potential of the cations. 16,24 So the sorption of the cations by AST wileyonlinelibrary.com/jctb 1, AST 6 and AST 20 is a mixed process involving ion exchange and physical adsorption. Similar results have been reported by several authors.…”

Liquid Radioactive Wastes Treatment: A Review

“…Pb-Fe based adsorbents were synthesized to remove Mo from the high-level radioactive liquid waste by Dodbiba et al [37]. The preparation was conducted by adding sodium hydroxide in mixture of 1 mol/L lead nitrate and 1 mol/L ferric nitrate aqueous solutions.…”

Radiochemistry

“…During use ion-exchange resins will become increasingly contaminated with, amongst other isotopes, carbon-14; a new quantitative method has been reported 190 to determine its distribution between organic and inorganic fractions. The adsorption behaviour of many radioisotopes on cationic and anionic ion exchangers has been reviewed 191 and the biosorption of americium-241 by Saccharomyces cerevisiae 192 and Rhizopus arrhizus 193 investigated (there's no accounting for taste! ).…”