Documents disponibles écrits par cet auteur

Extraction of tetra-oxo anions into a hydrophobic, ionic liquid-based solvent without concomitant ion exchange / Dominique C. Stepinski in Industrial & engineering chemistry research, Vol. 49 N° 12 (Juin 2010) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 49 N° 12 (Juin 2010) . - pp. 5863–5868 Titre : Extraction of tetra-oxo anions into a hydrophobic, ionic liquid-based solvent without concomitant ion exchange Type de document : texte imprimé Auteurs : Dominique C. Stepinski, Auteur ; George F. Vandegrift, Auteur ; Ilya A. Shkrob, Auteur Année de publication : 2010 Article en page(s) : pp. 5863–5868 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Ionic  liquids  Tetra-oxo  anions Résumé : Hydrophobic ionic liquids (IL) have the potential to simplify certain separations by serving as both an extraction solvent and an electrolyte for subsequent electrochemical reductions. While IL-based solvents are known to be efficient media for metal ion extraction, separations employing these solvents are frequently complicated by the loss of constituent IL ions to the aqueous phase, resulting in deteriorating performance. In this study, we have examined the extraction of pertechnetate and related tetra-oxo anions from aqueous solutions into IL-based solvents incorporating tetraalkylphosphonium bis[(trifluoromethyl)sulfonyl]imide and a crown ether. In contrast to various previously studied IL-based cation extraction systems, facile anion extraction without significant transfer of the IL ions to the aqueous phase has been observed. In addition, the solvents exhibit high distribution ratios (100−500 for pertechnetate), significant electrical conductivity (>100 μS/cm), and a wide (∼4 V) electrochemical window. The results suggest that these solvents may provide the basis for improved approaches to the extraction and recovery of a variety of anions. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie1000345 [article] Extraction of tetra-oxo anions into a hydrophobic, ionic liquid-based solvent without concomitant ion exchange [texte imprimé] / Dominique C. Stepinski, Auteur ; George F. Vandegrift, Auteur ; Ilya A. Shkrob, Auteur . - 2010 . - pp. 5863–5868. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 49 N° 12 (Juin 2010) . - pp. 5863–5868 Mots-clés : Ionic  liquids  Tetra-oxo  anions Résumé : Hydrophobic ionic liquids (IL) have the potential to simplify certain separations by serving as both an extraction solvent and an electrolyte for subsequent electrochemical reductions. While IL-based solvents are known to be efficient media for metal ion extraction, separations employing these solvents are frequently complicated by the loss of constituent IL ions to the aqueous phase, resulting in deteriorating performance. In this study, we have examined the extraction of pertechnetate and related tetra-oxo anions from aqueous solutions into IL-based solvents incorporating tetraalkylphosphonium bis[(trifluoromethyl)sulfonyl]imide and a crown ether. In contrast to various previously studied IL-based cation extraction systems, facile anion extraction without significant transfer of the IL ions to the aqueous phase has been observed. In addition, the solvents exhibit high distribution ratios (100−500 for pertechnetate), significant electrical conductivity (>100 μS/cm), and a wide (∼4 V) electrochemical window. The results suggest that these solvents may provide the basis for improved approaches to the extraction and recovery of a variety of anions. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie1000345

Study of the interaction between HDEHP and CMPO and its effect on the extraction of selected lanthanides / Peter Tkac in Industrial & engineering chemistry research, Vol.51 N° 31 (Août 2012) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol.51 N° 31 (Août 2012) . - pp. 10433-10444 Titre : Study of the interaction between HDEHP and CMPO and its effect on the extraction of selected lanthanides Type de document : texte imprimé Auteurs : Peter Tkac, Auteur ; George F. Vandegrift, Auteur ; Gregg J. Lumetta, Auteur Année de publication : 2012 Article en page(s) : pp. 10433-10444 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Lanthanides Résumé : Separation of the trivalent actinides from the trivalent lanthanides relevant to used nuclear fuel reprocessing remains still a challenging task. One of the options currently being investigated is the combination of two extraction processes, TRUEX and TALSPEAK. However, the two extractants used in the individual processes, when combined, result in a system with complex extraction behavior. To better understand the interactions in this combined extraction system, FT-IR spectroscopy was used in combination with small-scale solvent extraction tests. The data indicate that in the presence of CMPO, HDEHP dimer cleaves and interacts with CMPO through hydrogen bonding between POH and phosphoryl group of CMPO. The formation of a new HDEHP-CMPO adduct (log β = 3.4) at [HDEHP] > [CMPO] significantly lowers the concentration of free CMPO available for complexation with metal. The distribution ratios of Eu(III) decrease significantly with increasing nitric acid concentration and point to the acidic properties of this mixed extractant. The data presented suggest that several species containing HDEHP-CMPO adduct, HDEHP, and nitrate are formed upon extraction of Eu(III) by the mixture of HDEHP and CMPO. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie300326d [article] Study of the interaction between HDEHP and CMPO and its effect on the extraction of selected lanthanides [texte imprimé] / Peter Tkac, Auteur ; George F. Vandegrift, Auteur ; Gregg J. Lumetta, Auteur . - 2012 . - pp. 10433-10444. Industrial chemistry Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol.51 N° 31 (Août 2012) . - pp. 10433-10444 Mots-clés : Lanthanides Résumé : Separation of the trivalent actinides from the trivalent lanthanides relevant to used nuclear fuel reprocessing remains still a challenging task. One of the options currently being investigated is the combination of two extraction processes, TRUEX and TALSPEAK. However, the two extractants used in the individual processes, when combined, result in a system with complex extraction behavior. To better understand the interactions in this combined extraction system, FT-IR spectroscopy was used in combination with small-scale solvent extraction tests. The data indicate that in the presence of CMPO, HDEHP dimer cleaves and interacts with CMPO through hydrogen bonding between POH and phosphoryl group of CMPO. The formation of a new HDEHP-CMPO adduct (log β = 3.4) at [HDEHP] > [CMPO] significantly lowers the concentration of free CMPO available for complexation with metal. The distribution ratios of Eu(III) decrease significantly with increasing nitric acid concentration and point to the acidic properties of this mixed extractant. The data presented suggest that several species containing HDEHP-CMPO adduct, HDEHP, and nitrate are formed upon extraction of Eu(III) by the mixture of HDEHP and CMPO. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie300326d