Solvent extraction mechanism of pertechnetate with tetraphenylarsonium chloride

Molecular recognition of pertechnetate and perrhenate

“…Solvent extraction and ion exchange are two of the most efficient methods reported to date for effecting the separation and removal of 99 TcO 4 À and ReO 4 À from aqueous media. 34 Species that have been used for this purpose include neutral extractants, such as tributylphosphate, and cationic agents, such as cation-bound forms of crown ethers, 35 ferrocenium cations, 36 and tetraorgano-ammonium, -phosphonium and -arsonium 37 salts, as well tetraphenyltetrazolium 38 salts and Primene JMT (a primary ammonium-based anion exchanger). 39 Neutral extractants are preferably used for the removal of Tc(VII) from acidic solutions, while charged extractants dominate the extraction on the alkaline-side, an observation that reflects the fact that formation of the pertechnetate anion increases with increasing pH.…”

A Novel Approach to the Oxidation Potential of the Tc(VII)/Tc(IV) Couple in Hydrochloric Acid Medium through the Reduction of TCO- 4 by Fe2+ Ion

“…The pH value at constant ionic strength influences also slightly the D values (a protonation reaction of TPAC1 with TPAC1 · H + formation takes place in the aqueous phase [7]). Thus, measured D are accurate in the range of 30 to 0.01 obtained with TPAC1 0.002 M in 1.0 M HCl and with chloride concentration about 1.34 M. During solvent extraction, both aqueous and organic phases are mixed together by vortex apparatus during two minutes (equilibrium achievement was checked) and separated by centrifugation at a speed of 2000 revolutions a minute during two minutes at 293 K. D is determined from the counting of each phase.…”

“…The chloride concentration ranged from 1.00 to 1.34 M (due to the presence of HCl and of iron chloride) ; for [H + ] lower than 1.0 M, it was adjusted to 1.00 M by sodium chloride solution (NaCl, RP Normapur). Ionic strengths, 7, ranged from 1.00 to 1.66 M. Selective TcCXr solvent extraction was performed with 0.001 or 0.002 M tetraphenylarsonium chloride (C 6 H 5 ) 4 AsCl (TPAC1 97%, Aldrich) in chloroform (HCC1 3 , Labosi) [7]. In the following, these solutions will just be designated as "TPAC1" with the corresponding concentrations.…”

Highly Efficient and Selective Recovery of Technetium with a Novel MTPN Resin: A Remarkable Outcome of Bulky Cation–Bulky Anion Interactions

“…To this end, various techniques have been developed for the separation of technetium; the most preferred ones are liquid–liquid extraction, − ion exchange/sorption, − and extraction chromatography . In nuclear spent fuel reprocessing, liquid–liquid (solvent) extraction is routinely used at the commercial scale, for example, in the PUREX process .…”