The binding of strontium and europium by an aquatic fulvic acid—ion exchange distribution and ultrafiltration studies

Nordén, Maria; Ephhraim, James H.; Allard, Bert

doi:10.1016/0039-9140(93)80221-c

Cited by 16 publications

(7 citation statements)

References 14 publications

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“…Results show that the latter were systematically lower or equal to blank values ( 0.1 ppm). Even if the passage of small amounts of low molecular weight FA through the ultrafiltration membrane was previously described (Nordén et al, 1993) of the REE present in solution were recovered in the ultrafiltrates, demonstrating that no REE was adsorbed on the membranes nor on the walls of the cell devices used.…”

Section: ([Shulphqwdo Vhwxs Ghvfulswlrqmentioning

confidence: 89%

Rare earth elements complexation with humic acid

et al. 2007

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The binding of rare earth elements (REE) to humic acid (HA) was studied by combining ultrafiltration and Inductively Coupled Plasma Mass Spectrometry techniques. REEHA complexation experiments were performed at various pH conditions (ranging from 2 to 10.5) using a standard batch equilibration method. Results show that the amount of REE bound to HA strongly increases with increasing pH. Moreover, a Middle-REE (MREE) downward concavity is evidenced by REE distribution patterns at acidic pH. Modelling of the experimental data using Humic Ion Binding Model VI provided a set of log KMA values (i.e., the REEHA complexation constants specific to Model VI) for the entire REE series. The log KMA pattern obtained displays a MREE downward concavity. Log KMA values range from 2.42 to 2.79. These binding constants are in good agreement with the few existing datasets quantifying the binding of REE with humic substances but quite different from a recently published study which evidence a lanthanide contraction effect (i.e., continuous increase of the constant from La to Lu). The MREE downward concavity displayed by REEHA complexation pattern determined in this study compares well with results from REEfulvic acid (FA) and REEacetic acid complexation studies. This similarity in the REE complexation pattern suggests that carboxylic groups are the main binding sites of REE in HA. This conclusion is further illustrated by a detailed review of published studies for natural, organic-rich, river- and ground-waters which show no evidence of a lanthanide contraction effect in REE pattern. Finally, application of Model VI using the new, experimentally determined log KMA values to World Average River Water confirms earlier suggestions that REE occur predominantly as organic complexes (= 60%) in the pH range between 55.5 and 78.5 (i.e., in circumneutral pH waters). The only significant difference as compared to earlier model predictions made using estimated log KMA values is that the experimentally determined log KMA values predict a significantly higher amount of Light-REE bound to organic matter under alkaline pH conditions

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Section: ([Shulphqwdo Vhwxs Ghvfulswlrqmentioning

confidence: 89%

Rare earth elements complexation with humic acid

et al. 2007

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“…In the literature, a large number of studies on the interaction of various humic and fulvic acids with trivalent actinides [11][12][13][14][15][16][17][18][19][20][21][22] and lanthanides [22][23][24][25][26][27][28][29][30][31][32][33][34][35][36] which are frequently used as chemical analogs are available. However, all of these studies are limited to room temperature conditions.…”

Section: Introductionmentioning

confidence: 99%

Fulvic acid complexation of Eu(iii) and Cm(iii) at elevated temperatures studied by time-resolved laser fluorescence spectroscopy

et al. 2014

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The interaction of Eu(III) and Cm(III) with three different aquatic fulvic acids (FA) was studied as a function of the temperature (T = 20-80 °C) in 0.1 M NaCl solution by time-resolved laser fluorescence spectroscopy. The speciation of both trivalent metal ions was determined by peak deconvolution of the recorded fluorescence spectra. For each studied metal ion-FA system only one complexed species is formed under the given experimental conditions. The stability constants at 20, 40, 60 and 80 °C (log β'(T)) were determined according to the charge neutralization model. The log β' (20 °C) for the different FAs show similar values (log β(20 °C) = 5.60-6.29). The stability constants increase continuously with increasing temperature by approximately 0.3-1.0 orders of magnitude. The reaction enthalpies and entropies are derived from the integrated Van't Hoff equation. The results show that all investigated complexation reactions are endothermic and entropy-driven.

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“…In case that the equilibrium among all the species of cadmium present establishes more rapidly than the species are being separated by the electrophoresis, the boundary between the labelled ( 109 Cd) and unlabelled solutions moves in one direction only, with the valocity defined by Eq. (1). Then the presence of the negatively charged complexes must be considered and Eq.…”

Section: Resultsmentioning

confidence: 99%

“…Among the experimental methods used for this purpose, membrane separations and ion exchange predominate (see e.g. [1]). Electrophoresis has only seldom been used in this connection [2,3], although it enables not only to analyze the extent of the complexation but also to characterize the complexes formed by their mean electrophoretic mobility.…”

Section: Introductionmentioning

confidence: 99%

Applications of Electrophoresis to the Study of the Complexation of Cadmium with Humic Substances Using ¹⁰⁹Cd as Radiotracer

Beneš¹,

Mizera²

1996

Radiochimica Acta

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The free-liquid electrophoresis combined with radiotracer method was used for the analysis of bonding of cadmium with humic substances in aqueous solutions. It has been shown that the method enables the determination of the abundance and/or mean electrophoretic mobility of cadmium húmate complexes and can bring new possibilities into the study of cadmium bonding with humic substances. The abundances and negative mobilities (charges) of cadmium complexes with two industrial humâtes and 3 molecular size fractions of one of the humâtes increased from pH 4 to pH 8 and with increasing molecular weight of the fraction.

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The binding of strontium and europium by an aquatic fulvic acid—ion exchange distribution and ultrafiltration studies

Cited by 16 publications

References 14 publications

Rare earth elements complexation with humic acid

Rare earth elements complexation with humic acid

Fulvic acid complexation of Eu(iii) and Cm(iii) at elevated temperatures studied by time-resolved laser fluorescence spectroscopy

Applications of Electrophoresis to the Study of the Complexation of Cadmium with Humic Substances Using ¹⁰⁹Cd as Radiotracer

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The binding of strontium and europium by an aquatic fulvic acid—ion exchange distribution and ultrafiltration studies

Cited by 16 publications

References 14 publications

Rare earth elements complexation with humic acid

Rare earth elements complexation with humic acid

Fulvic acid complexation of Eu(iii) and Cm(iii) at elevated temperatures studied by time-resolved laser fluorescence spectroscopy

Applications of Electrophoresis to the Study of the Complexation of Cadmium with Humic Substances Using 109Cd as Radiotracer

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Applications of Electrophoresis to the Study of the Complexation of Cadmium with Humic Substances Using ¹⁰⁹Cd as Radiotracer