Ion-Transfer Current-Scan Polarographic Studies of Metal Extractants with Ascending Water Electrode: Manganese(H)-1,10-Phenanthroline and Related Ligand Systems

Doe, Hidekazu; Freiser, Henry

doi:10.2116/analsci.7.303

Cited by 24 publications

(7 citation statements)

References 18 publications

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“…Wendt et al 104,105 studied the transfer of Fe, Ni, and Zn assisted by bidentate nitrogen bases, such as phenanthroline and bipyridine. Similar studies were carried out by Wang et al 107 and by Doe and Freiser, 119,120 who also studied the transfer of cadmium assisted by diphenylthiocarbazone, a weak monobasic acid. 95 Solomon et al l2l studied terpyridine as an extractant for transition metals.…”

Section: Facilitated Ion Transfersupporting

confidence: 54%

Charge Transfer across Liquid—Liquid Interfaces

Girault¹

1993

Modern Aspects of Electrochemistry

108

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Section: Facilitated Ion Transfersupporting

confidence: 54%

Charge Transfer across Liquid—Liquid Interfaces

Girault¹

1993

Modern Aspects of Electrochemistry

108

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“…6.9 As a part of the series of studies concerning the metal complexes of the 1,10-phenanthrolines (Phen)'ol', we recently examined a current-scan polarographic wave from ion-transfer processes of Mn2+-Phen complexes from a dichloroethane (DCE) to an aqueous phase ("metal wave"). 12 The Mn2+ wave was controlled not only by diffusion of Phen in the DCE phase, but also kinetically by an interfacial formation of 1:1 Mn2+-Phen complexes.…”

mentioning

confidence: 99%

Ion-Transfer Current-Scan Polarographic Studies of Metal Extractants with Ascending Water Electrode: Transfer of Divalent Metal Ion Complexes of Phenanthrolines across a Liquid-Liquid Interface

Doe

Freiser

1991

ANAL. SCI.

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The transfer mechanism of Nit, Cot, Zn2+ and Cd2+ ions from an aqueous to a dichloroethane (DCE) solution of phenanthroline derivatives (Phen) was studied.Included were 1,10-phenanthroline (phen), 4,7-dimethyl-1,10-phenanthroline (4,7-DMP), 4,7-diphenyl-1,10-phenanthroline (4,7-DPP) and 2,9-dimethyl-1,10-phenanthroline (2,9-DMP). The investigation was carried out by current-scan polarography at the ascending water electrode (AWE). Some polarographic waves were observed that can be attributed to the slow formation of 1:1 M2+-Phen complexes. In some cases, as with the Ni2+-Phen systems and the Cot+-4,7-DPP system, no wave was observed, because the complexation rates are too slow. All of the Cd2+-Phen and all of the Zn2+-Phen systems, except for the Zn2+-4,7-DPP system which exhibits a kinetic wave, yielded diffusion-controlled waves. Furthermore, a number of these systems appear to be affected by significant interfacial adsorption of the M2+-Phen complexes. KeywordsCurrent-scan polarography, ascending water electrode, ion transfer, divalent metal-phenanthroline complex ion Electrochemical studies at the interface of two immiscible electrolyte solutions (ITIES) have resulted in much important information characterizing the liquid-liquid mass-transfer process 15, including those involved in solvent extraction.6.9As a part of the series of studies concerning the metal complexes of the 1,10-phenanthrolines (Phen)'ol', we recently examined a current-scan polarographic wave from ion-transfer processes of Mn2+-Phen complexes from a dichloroethane (DCE) to an aqueous phase ("metal wave").12 The Mn2+ wave was controlled not only by diffusion of Phen in the DCE phase, but also kinetically by an interfacial formation of 1:1 Mn2+-Phen complexes.Furthermore, three Phen were required to transfer one Mn2+. For these reasons, characterization of the metal wave was very complicated. Nevertheless, a theory was proposed in a previous paper12 which satisfactorily explained these waves. In this study, other divalent transition metals were examined in order to characterize the kinetics at the interface and to check the applicability of the theory. ExperimentalThe electrolytic cell and the electrochemical pro. cedures were the same as those reported previously. The aqueous phase always contained 0.16 M Na2SO4 and 0.01 M acetate buffer to give an ionic strength was 0.5 M. The organic supporting electrolyte solution was 0.01 M tetraheptylammonium tetraphenylborate (THA+, TPB-). The electrode potential, E (mV), was referred to the half wave potential of the transfer of tetraethylammonium cation (TEA+) from an aqueous to a 1,2-dichloroethane (DCE) solution. All reagent grade chemicals were employed without further purification. Results and DiscussionIn accord with our earlier paper12, the following steps are involved in ion transfer:

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“…In most systems reversible characteristics were observed. [15][16][17][18][19][20][21] Exceptionally, an irreversible nature was observed in such systems where successive complex formation in org occurred after an electrochemical ion transfer from w to org [22][23][24] , or where complex formation of the metal ion with a ligand is accompanied by a slow dehydration process. 25 In order to elucidate the irreversible nature of the UO 2 2+ transfer in the presence of BDPPM, the drop time (t d ) of AEDE was measured under polarographic conditions.…”

Section: Resultsmentioning

confidence: 99%