Extraction of moderate oxidation state technetium species between 30 % tri-n-butyl phosphate and H2SO4/HNO3

Abstract

The extraction of technetium species at oxidation state lower than +7 has been examined in sulfuric and sulfuric/nitric acid solutions using UV–Vis spectroscopy and optically transparent thin layer cell (RVC-OTTLE). Soluble Tc(III), TcO2+ and [Tc2O2]3+ species with absorption bands at 420–450, 400, and 502 nm, respectively, were detected as products of pertechnetates electroreduction. The distribution ratios of 99Tc with lower than +VII oxidation state ionic species between 4 M H2SO4 and 30 % TBP/kerosene were found and are significantly lower than for TcO4− in the same solution.

Extraction of pertechnetates from HNO3 solutions into ionic liquids

“…The distribution ratio of TcO 4 – , D Tc , has been determined for aqueous solutions in contact with organic systems, e.g. derivatives of ammonium chlorides in toluene [ 2 ], TBP in kerosine/dodecane [ 3 – 6 ], crown ether in m-xylene [ 7 ], tetraphenylphosphonium in chloroform/nitrobenzene [ 8 ], acetohydroxamic acid(AHA)/TBP [ 9 ] or tricaptylmethyl ammonium salt (Aliquat-336) [ 10 ]. Summary of the extraction properties of various extracting agents has been presented by Schwochau [ 11 ] and Spitsyn et al [ 12 ].…”

Redox interactions of technetium with neptunium in acid solutions

“…Technetium with oxidation states other than + 7, which are referred to as “reduced Tc” hereafter, were generated by the methods described previously [ 15 ]. The experiments were carried out by using a home made electrochemical thin layer cell with a reticulated vitreous carbon (RVC, thickness 2 mm, 100 ppi porosity, supplied by ERG Aerospace Corporation), a gold foil and an Ag/AgCl in 3 M NaCl as a working-, counter- and reference electrode, respectively.…”

“…The spectroscopic properties of main Tc(IV) species present in aqueous solutions, i.e. TcO 2+ and Tc(III/IV)-polymers [ 15 – 17 ].…”

Structural Investigation of Technetium Dibutylphosphate Species Using X-ray Absorption Fine Structure Spectroscopy

“…During this step, the behavior of Tc is poorly understood. In nitric acid, the heptavalent Tc may be reduced to lower valences (most likely IV) by various reducing agents. – Previous studies have shown that Tc­(IV) species are not extractable by TBP, but Tc­(IV) can form kinetically stable complexes with DBP that can be extracted . Solvent extraction studies have shown that a TcO 2+ oxocation complex with the formula TcO­(DBP·HDBP) 2 was extracted, but no structural data were reported.…”