The Universal Solvent Extraction (Unex) Process. I. Development of the Unex Process Solvent for the Separation of Cesium, Strontium, and the Actinides From Acidic Radioactive Waste

Potentiometric Response Characteristics of Membrane-BasedCs+-Selective Electrodes Containing Ionophore-Functionalized Polymeric Microspheres

“…This has resulted in the development of several Cs + -selective extractants that contain pendant ethylene glycol functionalities [25]. Moreover, in its polymerized form, poly(ethylene glycol) has been used as a carrier in the universal (solvent) extraction (UNEX) process, which removes cesium and strontium isotopes from radioactive waste [26].…”

Preliminary evaluation of solvent-extraction and/or ion-exchange process for meeting AAA program multi-tier systems recovery and purification goals.

“…A solvent extraction process that allows extraction of Cs and Sr along with actinides (plus lanthanides) from acidic waste solutions has been developed [Law et al 2001;Romanovskiy et al 2001]; this process has been termed the UNEX process (for universal solvent extraction). The UNEX process solvent consists of chlorinated cobalt dicarbollide for the extraction of Cs, polyethylene glycol for the extraction of Sr, and diphenyl-N,N-dibutylcarbamoyl phosphine oxide for the extraction of actinides; the preferred diluent is phenyltrifluoromethyl sulfone.…”

N,N,N’,N’-Tetrabutyl-1,10-phenanthroline- 2,9-dicarboxamide as Very Effective Extraction Agent for Trivalent Europium and Americium

“…29 However, in Russia, nitrobenzene derivatives (e.g., 3-nitro-α,α,α-trifluorotoluene, also denoted by F-3) have been successfully utilized as diluents for cobalt dicarbollide processes. 28 Recently, diamides of 1,10-phenanthroline-2,9-dicarboxylic acid have been proposed as selective extractants for trivalent americium and curium. The mixture of N,N,N'N'-tetraoctyl-1,10-phenanthroline-2,9-dicarboxamide and Br-cosan effectively extracts americium with a separation factor (SF Am/Eu ) over forty.…”

“…FS-13). 28,29 It is necessary to emphasize that the FS-13 diluent was developed for the UNEX process as an alternative organic diluent to the highly polar nitrobenzene. Finally, FS-13 has the advantage of low viscosity and good solubility of metal solvates as well as the UNEX extractants.…”

“…[18][19][20] Besides, some of these functionalized calixarenes have been applied for the isolation of carrier-free 90 Y from 90 Sr. 21 The dicarbollylcobaltate anion 22 and some of its halogen derivatives have been employed often for the solvent extraction of various metal cations (e. g., Cs + , Sr 2+ , Ba 2+ , Eu 3+ , and Am 3+ ) from aqueous solutions into a polar organic phase, both under laboratory conditions for theoretical or analytical purposes, [23][24][25][26][27] and on the technological scale for the separation of some high-activity isotopes in the reprocessing of spent nuclear fuel and acidic radioactive waste. 28,29 Furthermore, a process involving chlorinated cobalt dicarbollide, polyethylene glycol, and diphenyl-N,N-dibutylcarbamoylmethyl phosphine oxide, also called UNEX, has been suggested for the simultaneous recovery of cesium, strontium, lanthanides, and actinides from highly acidic media into phenyltrifluoromethyl sulfone (abbrev. FS-13).…”