Author
G.F. Vandegrift
Bio: G.F. Vandegrift is an academic researcher from Argonne National Laboratory. The author has contributed to research in topics: Dodecane & Nitric acid. The author has an hindex of 5, co-authored 5 publications receiving 195 citations.
Papers
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TL;DR: Gibb's isotherm curves were run for a series of dialkyl phosphoric, phosphonic, and phosphinic acids, most in dodecane against 1 M HNO3 at 25°C as discussed by the authors.
90 citations
TL;DR: In this paper, a consistant and revealing mechanism of extraction of calcium ion from di(2-ethylhexyl)phosphoric acid (DEHP) was proposed, in which a structured layer of water at the interface impedes the progress of the ion from the bulk aqueous phase to the interface.
63 citations
TL;DR: In this paper, Gibbs' absorption curves for tridodecylmethylammonium and trioctylmethylammmonium salts in o-xylene vs an aqueous phase which was 2M in the corresponding acid were performed at 25°C and the effect on interfacial activity from changing dodecyl to octyl groups was experimentally imperceptable.
19 citations
13 citations
TL;DR: In this article, the authors investigated the pertechnetate extraction kinetics in the system trioctylmethylammonium nitrate (TOMAN) or tridodecyl methylamethylamiumnitrate (TDMAN) in o-xylene/aqueous nitric acid and showed that mass transfer across the interface is rate limiting.
Abstract: The extraction kinetics of pertechnetate (TcO/sub 4//sup -/) in the system trioctylmethylammonium nitrate (TOMAN) or tridodecylmethylammonium nitrate (TDMAN) in o-xylene/aqueous nitric acid has been investigated. Procedures for the synthesis and purification of the TOMAN and TDMAN were developed. The kinetics were performed by stirring the two phases while maintaining a quiescent and constant area interface. Interfacial mass transfer coefficients were measured as a function of concentration of the quaternary ammonium salt, nitric acid, lithium nitrate, and stirring rates. The results of the kinetic experiments show that mass transfer across the interface is rate limiting. Aggregation data were obtained for TOMAN in o-xylene at 25/sup 0/C. An extraction mechanism is proposed and discussed in terms of aggregation. Both quaternary ammonium salts follow the same kinetic behavior. 9 figures, 1 table.
11 citations
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TL;DR: In this article, the authors measured the permeability coefficients of some metal species through selected supported liquid membranes (SLM) over extended periods of time, in the presence and absence of osmotic pressure gradients.
163 citations
TL;DR: In this paper, the authors considered biphasic systems consisting of an aqueous electrolyte solution containing a metal cation which, according to the nature and composition of the electrolyte, can exist either as a free (hydrated) ion or as neutral, positively or negatively charged complex species.
Abstract: I. EXTRACTING REAGENTS In the present review, dealing with the kinetics of solvent extraction of metal species, we will consider biphasic systems consisting of: 1. An aqueous electrolyte solution containing a metal cation which, according to the nature and composition of the electrolyte, can exist either as a free (hydrated) ion or as neutral, positively or negatively charged complex species 2. An organic phase which is a solution, in a water-immiscible organic diluent, of an organic molecule called extractant; only organic diluent not exhibiting appreciable extraction properties by themselves will be considered; the extractant will instead be a molecule capable of reacting with the aqueous metal species, transferring them into the organic phase; this reactivity is conferred to the extractant by the presence of a functional group which has binding properties with respect to the metal species; the only purpose of the diluent will then be that of dissolving the extractant and possibly to improve its physica...
152 citations
106 citations
TL;DR: Gibb's isotherm curves were run for a series of dialkyl phosphoric, phosphonic, and phosphinic acids, most in dodecane against 1 M HNO3 at 25°C as discussed by the authors.
90 citations
TL;DR: In this paper, a theoretical study on the liquid−liquid interfacial behavior of the species involved in the extraction of Cs+ by a calix[4]arene-crown6 ionophore (L):
Abstract: We report a theoretical study on the liquid−liquid interfacial behavior of the species involved in the extraction of Cs+ by a calix[4]arene-crown6 ionophore (L): the free Cs+ Pic- and Cs+ Cl- salts, the LCs+ and LCs+ Pic- complexes, and uncomplexed L. Based on molecular dynamics simulations, we calculated the free energies changes for migration from the interface into the aqueous and the organic phases, respectively. For free L and for the LCs+ complex, with or without Pic- counterion, an energy minimum is found close to the interface, on the chloroform side, showing that these species behave as surfactants. This contrasts with the uncomplexed Cs+, which diffuses spontaneously from the interface to water and displays no energy minimum. A remarkable counterion effect is found with Pic- which displays a high affinity for the interface, while Cl- prefers the bulk aqueous phase. The questions of ion extraction by ionophores, counterions, concentration and synergistic effects in assisted cation transfer throu...
86 citations