Authors:K. Shang, Y. Yang, J. Guo, W. Lu, F. Liu and W. Wang
The extraction of cobalt by Winsor II microemulsion system was studied. In the bis (2-ethylhexyl) sulfosuccinate sodium salt
(AOT)/n-pentanol/n-heptane/NaCl system, AOT was used as a anionic surfactant to form microemulsion in n-heptane, n-pentanol was injected in the microemulsion as a cosurfactant. Co(II) was found to be extracted into the microemulsion phase
due to ion pair formation such as Co2+(R–SO3−)Cl. The influence of different parameters such as the volume ratio of aqueous phase to microemulsion, surfactant concentration,
pH of the feed solutions, cosurfactant concentration as well as temperature on the extraction yield (E%) were investigated. The results showed that it was possible to extract 95% of cobalt by the AOT Winsor II microemulsion.
NH). Our laboratory studies its extraction process in conformity with the particularly restricting specifications.
The first step consists to neutralize the piperidine salt of the crude synthesis solutions by soda addition. A demixing
Influence of ionic liquids (ILs) addition (1–50 wt%) on extraction efficiency of actinides by diphenyl(dibutyl)carbamoylmethylphosphine
oxide (Ph2Bu2) from 3 M HNO3 has been studied. Am(III) distribution ratios in two-phase systems 0.1 M Ph2Bu2 in either DCE or CHCl3–3 M HNO3 depending on the nature of additional ionic liquids: imidazolium-based ILs: [C4mim][PF6], [C4mim][BF4] and phosphonium-based ILs: PPF6, PBF4 and PCl were determined. The highest value of Am(III) extraction ratio change (1040) was found on addition of PPF6 to Ph2Bu2 in CHCl3. Extraction of Pu(IV) and U(VI) by 0.001 M Ph2Bu2 in the presence of [C4mim][PF6] in DCE, CHCl3 or meta-nitrobenzotrifluoride (NBTF) have been investigated. The greatest enhancement of extraction efficiency was observed using
CHCl3, the least polar studied solvent. Using a mixture of conventional solvent and ionic liquid as a solvent for extractant enables
one to increase distribution ratios and reduce viscosity of organic phase as compared with ionic liquid viscosity. The marked
increase of Am(III), Pu(IV) and U(VI) extraction extent by Ph2Bu2 on addition of ionic liquids to the extent of 10 wt% permit one essentially to diminish amounts considerably more expensive
carbamoylmethylphosphine oxide(the general name is CMPO) used in TRUEX process.
Authors:Ahmed Abdel-Khalek, M. Ali, Radwa Ashour and A. Abdel-Magied
Liquid–liquid extraction of U (VI) from concentrated phosphoric acid by using (2-ethyl hexyl) phosphonic acid, mono (2-ethyl
hexyl) ester (PC88A) and di-butyl butyl phosphonate (DBBP) has been investigated. The effect of different factors affecting
the extraction process (PC88A concentration, DBBP concentration, shaking time, aqueous/organic phase ratio, phosphoric acid
concentration and effect of diluents) have been investigated. The obtained data of temperature on the extraction showed that
the enthalpy change is −17.15 kJ mol−1. Uranium was extracted from the strip liquor by using di (2-ethylhexyl) phosphoric acid and tri-octyl phosphine oxide mixture
and finally converted to a high purity UO3 product using precipitation with hydrogen peroxide and heat treatment at 365 °C.
Authors:W. Wang, Y. Yang, H. Zhao, Q. Guo, W. Lu and Y. Lu
The extraction of europium to a W/O microemulsion with an anionic surfactant was studied. In the sodium oleate (NaOL)/pentanol/heptane/NaCl
system, the influence of aqueous-microemulsion ratio, concentration of NaOL, extraction temperature, concentration of cosurfactant,
pH and salting-out agent on the extraction yield were investigated. Europium was probably extracted into the microemulsion
phase in the form of Eu(OL)2Cl, and the extraction yield (E%) was above 99% when R = 8. The enthalpy and entropy of Eu(III) extraction were calculated to be −12.18 kJ/mol and −61.41 J/(mol K), respectively.
The back-extraction is conducted by hydrochloric acid (0.8 mol/L), which provided better back-extraction yields (95.15%).
N,N,N′,N′-tetraoctyldiglycolamide (TODGA) was synthesized and characterized with elemental analysis, infrared spectrometry and nuclear
magnetic resonance spectrometry. The synthesized TODGA was applied for the extraction and separation of Zr(IV) and Hf(IV)
from nitric acid solutions. The performed studies include the effects of TODGA, nitric acid, nitrate ion, hydrogen ion, and
metal ion concentrations as well as time and temperature. TODGA shows effective extraction of Zr(IV) and Hf(IV) from HNO3 ≥ 3 M. However, the maximum separation factor (DZr/DHf) obtained using TODGA is 2.8.
Authors:E. Makrlík, J. Budka, P. Vaňura and P. Selucký
From extraction experiments and γ-activity measurements, the extraction constants corresponding to the general equilibrium
Eu3+(aq) + 3 A−(nb) + L(nb) ⇔ EuL3+(nb) + A−(nb) taking place in the two-phase water–nitrobenzene system (
; L = tetrakis(2-ethoxyethoxy)-tetra-p-tert-butylcalixarene (1), tetraethyl p-tert-butylcalixarene tetraacetate (2), p-tert-butylcalixarene-tetrakis(N,N-diethylacetamide) (3), hexaethyl p-tert-butylcalixarene hexaacetate (4), p-tert-butylcalixarene-hexakis(N,N-diethylacetamide) (5); aq = aqueous phase, nb = nitrobenzene phase) were evaluated. Further, the stability constants of the EuL3+ complexes in nitrobenzene saturated with water were calculated; they were found to increase in the series of 2 < 4 < 1 < 5 < 3.
Extraction of microamounts of cesium by a nitrobenzene solution of hydrogen dicarbollylcobaltate (H+B−) in the presence of polypropylene glycol PPG 425 (L) has been investigated. The equilibrium data have been explained assuming
that the complex species HL+ and CsL+ (L = PPG 425) are extracted into the organic phase. The values of extraction and stability constants of the cationic complex
species in nitrobenzene saturated with water have been determined.
Authors:Yanxia Geng, Zhan Li, Duoqiang Pan and Wangsuo Wu
For the selective extraction of Am(III) and Eu(III), quadridentate divalent phenolic Schiff bases-bis-salicylaldehyde ethylenediamine
(H2salen) was investigated as a kind of extractant. The influences of alkaline cation, inorganic anion, ionic strength, pH and
the concentration of H2salen on the distribution ratio of Am(III) and Eu(III) were investigated in detail. As a result, Am(III) and Eu(III) made
anionic 1:1 complexes with the ligand (H2salen) and could be extracted into nitrobenzene as ion-pairs with a suitable monovalent counter anion in the aqueous solution,
the extracted species were possibly of the type Am(H2salen) Eu(salen)Cl and Eu(H2salen)Cl3, respectively. The extractability of Eu(III) was significantly stronger than that of Am(III) and the maximum separation factor,
SF(Am/Eu), was 96 at pH 4.0. The results indicated that H2salen had good selectivity for Am(III) and Eu(III).
Solvent extraction of microamounts of cesium by a nitrobenzene solution of hydrogen dicarbollylcobaltate (H+B−) in the presence of dodecaethylene glycol (DDEG, L) has been investigated. The equilibrium data have been explained assuming
that the species HL+, H2L2+, CsL+ and CsHL2+ (L = DDEG) are extracted into the organic phase. The values of extraction and stability constants of the complex species
in nitrobenzene saturated with water have been determined.