New solutions to the problem of handling long-lived radionuclides

Egorov, N.N.; Zakharov, M. A.; Lazarev, L. N.; Lyubtsev, R.I.; Nikiforov, A. S.; Strakhov, M. V.; Filippov, E.A.

doi:10.1007/bf01121088

Cited by 3 publications

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“…Crown ethers have attracted considerable attention as Potential extractants for cesium from nuclear-waste solutions [1][2][3][4][5][6][7][8]. Among the simple crown ethers examined, alkylated derivatives of benzo-21-crown-7 and dibenzo-21-crown-7 appear most promising, either by themselves in solvents modified with fluorinated [8] or other [5,9,10] alcohols or in synergistic combination with cation exchangers [11], Selectivity ratios for cesium vs. sodium exceed 10^, though even this impressive selectivity may prove to be inadequate for treatment of high-salt wastes such as those stored at the Hanford site in the United States.…”

Section: Introductionmentioning

confidence: 99%

Applicability of a Calixarene-Crown Compound for the Removal of Cesium from Alkaline Tank Waste

et al. 1997

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Radioactive waste / Solvent extraction / Crown ether / Calixarene / Cesium / Macrocycle SummaryIn terms of extractive strength and selectivity over sodium, calix[4]arene-bis-(2,3-naphtho-crown-6) exhibits superior properties in comparison with simple crown ethers for separating cesium from an alkaline Solution simulating a Hanford tank supematant waste. The calixarene was studied at O.Ol M in four diluents. In two cases a cesium distribution coefficient near unity was obtained. Successive water washes sufficed to Strip the loaded solvents. In addition, selectivity ratios for cesium over sodium exceeded 10" for all of the diluents. By contrast, bis-(tert-butylbenzo)-21-crown-7 gave distribution coefficients an average of 200 times lower under identical conditions; its selectivity ratio for cesium over sodium was at best 200 in one of the four diluents tried. Although Cs/Na selectivity in the case of the calixarene is so high as to make Na^ ion extraction inconsequential, Cs/K selectivity lay in the lower ränge 122-935. Owing to the relatively high concentration of K^ ion in the waste, strong competition due to K^ ion extraction resulting in high loading of the calixarene was observed to limit the effectiveness of cesium extraction and Stripping. For both the calixarene and crown ether, extraction strength correlates with the empirical solvent polarity Parameters DP* and E-r.

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