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Three-liquid-phase extraction and separation of Ti(IV), Fe(III), and Mg(II) / Keng Xie in Industrial & engineering chemistry research, Vol. 50 N° 10 (Mai 2011) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 50 N° 10 (Mai 2011) . - pp. 6362-6368 Titre : Three-liquid-phase extraction and separation of Ti(IV), Fe(III), and Mg(II) Type de document : texte imprimé Auteurs : Keng Xie, Auteur ; Kun Huang, Auteur ; Lin Xu, Auteur Année de publication : 2011 Article en page(s) : pp. 6362-6368 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Liquid  phase Résumé : Three-liquid-phase extraction has been considered to be a promising method for isolation and separation of multicomponents. Selective extraction-separation of Ti(IV), Fe(III), and Mg(II) in the three-liquid-phase system containing trialkylphosphine oxide (TRPO), poly(ethylene glycol) with an average molecular mass of 2000 (PEG 2000), and (NH4)2SO4 was achieved by adding a water-soluble complexing agent, ethylenediaminetetraacetic acid (EDTA). The simple and environmentally benign complexing method was proved to be an effective strategy for enhancing the selectivity of the PEG-2000-rich middle phase for Fe(III) without reducing the affinity of the TRPO-rich top phase to Ti(IV). The related chemistry was detailed, and effects of some important parameters such as the aqueous phase pH, EDTA amount, mixing time, and temperature were examined. It revealed that Ti(IV) and Fe(III) could be enriched respectively into the TRPO-rich top phase and the PEG-2000-rich middle phase through optimization of the aqueous pH and the EDTA amount. Ti(IV) was extracted into the top phase with a slow kinetics and a positive enthalpy change (ΔH), whereas Fe(III) was rapidly transferred to the middle phase as Fe(III)-EDTA complexes formed by an exothermic reaction. Mg(II) tended to remain in the bottom phase. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24158932 [article] Three-liquid-phase extraction and separation of Ti(IV), Fe(III), and Mg(II) [texte imprimé] / Keng Xie, Auteur ; Kun Huang, Auteur ; Lin Xu, Auteur . - 2011 . - pp. 6362-6368. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 50 N° 10 (Mai 2011) . - pp. 6362-6368 Mots-clés : Liquid  phase Résumé : Three-liquid-phase extraction has been considered to be a promising method for isolation and separation of multicomponents. Selective extraction-separation of Ti(IV), Fe(III), and Mg(II) in the three-liquid-phase system containing trialkylphosphine oxide (TRPO), poly(ethylene glycol) with an average molecular mass of 2000 (PEG 2000), and (NH4)2SO4 was achieved by adding a water-soluble complexing agent, ethylenediaminetetraacetic acid (EDTA). The simple and environmentally benign complexing method was proved to be an effective strategy for enhancing the selectivity of the PEG-2000-rich middle phase for Fe(III) without reducing the affinity of the TRPO-rich top phase to Ti(IV). The related chemistry was detailed, and effects of some important parameters such as the aqueous phase pH, EDTA amount, mixing time, and temperature were examined. It revealed that Ti(IV) and Fe(III) could be enriched respectively into the TRPO-rich top phase and the PEG-2000-rich middle phase through optimization of the aqueous pH and the EDTA amount. Ti(IV) was extracted into the top phase with a slow kinetics and a positive enthalpy change (ΔH), whereas Fe(III) was rapidly transferred to the middle phase as Fe(III)-EDTA complexes formed by an exothermic reaction. Mg(II) tended to remain in the bottom phase. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24158932

Three - liquid - phase extraction / Keng Xie in Industrial & engineering chemistry research, Vol. 50 N° 22 (Novembre 2011) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 50 N° 22 (Novembre 2011) . - pp. 12767-12773 Titre : Three - liquid - phase extraction : a new approach for simultaneous enrichment and separation of Cr(III) and Cr(VI) Type de document : texte imprimé Auteurs : Keng Xie, Auteur ; Kun Huang, Auteur ; Liangrong Yang, Auteur Année de publication : 2012 Article en page(s) : pp. 12767-12773 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Liquid  phase Résumé : A novel and simple three-liquid-phase extraction (TLPE) approach was developed for the simultaneous removal and separation of Cr(III) and Cr(VI) from aqueous solutions. The proposed three-liquid-phase system (TLPS) consists of di(2-ethylhexyl)phosphoric acid (D2EHPA), poly(ethylene glycol) (PEG) with a molecularweight of 2000, and (NH4)2SO4. The effects of various factors including the aqueous solution pH, amounts of (NH4)2SO4 and PEG, initial chromium amount, D2EHPA concentration, phase-mixing time, and diluent on the three-phase partitioning behavior of Cr(III) and Cr(VI) were evaluated. The distribution behavior of the two oxidation states of chromium was found to be highly pH-dependent. Cr(III) preferred the D2EHPA-rich top phase through a cation-exchange reaction, whereas Cr(VI) was enriched in the PEG-rich middle phase through ion-pair formation. By appropriate selection of the extraction conditions, nearly all of the Cr(III) was extracted into the D2EHPA top phase, and more than 90% of the Cr(VI) was transferred into the PEG-rich middle phase within 5 min. The present work highlights the possibility of using the TLPE approach for the extraction and separation of two different oxidation states of metal ions, such as Cr(III) and Cr(VI), in a single extraction step. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24745751 [article] Three - liquid - phase extraction : a new approach for simultaneous enrichment and separation of Cr(III) and Cr(VI) [texte imprimé] / Keng Xie, Auteur ; Kun Huang, Auteur ; Liangrong Yang, Auteur . - 2012 . - pp. 12767-12773. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 50 N° 22 (Novembre 2011) . - pp. 12767-12773 Mots-clés : Liquid  phase Résumé : A novel and simple three-liquid-phase extraction (TLPE) approach was developed for the simultaneous removal and separation of Cr(III) and Cr(VI) from aqueous solutions. The proposed three-liquid-phase system (TLPS) consists of di(2-ethylhexyl)phosphoric acid (D2EHPA), poly(ethylene glycol) (PEG) with a molecularweight of 2000, and (NH4)2SO4. The effects of various factors including the aqueous solution pH, amounts of (NH4)2SO4 and PEG, initial chromium amount, D2EHPA concentration, phase-mixing time, and diluent on the three-phase partitioning behavior of Cr(III) and Cr(VI) were evaluated. The distribution behavior of the two oxidation states of chromium was found to be highly pH-dependent. Cr(III) preferred the D2EHPA-rich top phase through a cation-exchange reaction, whereas Cr(VI) was enriched in the PEG-rich middle phase through ion-pair formation. By appropriate selection of the extraction conditions, nearly all of the Cr(III) was extracted into the D2EHPA top phase, and more than 90% of the Cr(VI) was transferred into the PEG-rich middle phase within 5 min. The present work highlights the possibility of using the TLPE approach for the extraction and separation of two different oxidation states of metal ions, such as Cr(III) and Cr(VI), in a single extraction step. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24745751