The Influence of Iron (II) and (III) on the Kinetics of Goethite Dissolution by EDTA

Ballesteros, María C.; Rueda, Elsa H.; Blesa, Miguel A.

doi:10.1006/jcis.1997.5360

Cited by 17 publications

(9 citation statements)

References 18 publications

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“…This agrees with previous investigations that demonstrated the rate of dissolution reaches an apparent maximum at high adsorbed EDTA concentrations (Rubio and Matijevic 1979;Chang and Matijevic 1983;Ballesteros et al 1998). …”

Section: Dependence Of Dissolution Rate On Edta Concentrationsupporting

confidence: 82%

Corrosion of Metal Inclusions In Bulk Vitrification Waste Packages

Bacon¹,

Pierce²,

Wellman³

et al. 2006

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SummaryThe primary purpose of the work reported here is to analyze the potential effect of the release of technetium (Tc) from metal inclusions in bulk vitrification (BV) waste packages once they are placed in the Integrated Disposal Facility (IDF). As part of the strategy for immobilizing waste from the underground tanks at Hanford, selected wastes will be immobilized using BV. During analyses of the glass produced in engineering-scale tests, metal inclusions were found in the glass product. This report contains the results from experiments designed to quantify the corrosion rates of metal inclusions found in the glass product from Test ES-32B (AMEC 2005) and simulations designed to compare the rate of Tc release from the metal inclusions to the release of Tc from glass produced with the BV process. Due to the probability of oxidizing conditions surrounding the waste packages in the IDF, in the simulations the Tc in the metal inclusions and the glass is conservatively assumed to be released congruently as soluble TcO 4 -. The experimental results and modeling calculations (Bacon and McGrail 2005) show that the metal corrosion rate will, under all conceivable conditions at the IDF, be dominated by the presence of the passivating layer and corrosion products on the metal particles. As a result, the release of Tc from the metal particles at the surfaces of fractures in the glass releases at a rate similar to the Tc present as a soluble salt (McGrail et al. 2003;Pierce et al. 2005). The release of the remaining Tc in the metal is controlled by the dissolution of the glass matrix.The dissolution kinetics of iron [Fe(0)] was quantified under conditions of constant dissolved O 2 [O 2 (aq)] and in solutions that minimized the formation of a passive film on the metal surface. These tests were performed to determine the forward reaction rate for the metal inclusions in the BV glass. Single-pass flow through (SPFT) tests were conducted over the pH(23°C) range from 7.0 to 12.0 and temperature range from 23°C to 90°C. The presence of EDTA minimized the formation of a passive film and Fe-bearing secondary phase(s) during testing allowing us to determine the forward dissolution rate. These results indicate that the corrosion of Fe(0) is relatively insensitive to pH and temperature and the forward rate is 3 to 4 orders of magnitude higher than when a passive film and corrosion products are present. Tests conducted with Amasteel (a low carbon steel non-radioactive surrogate) and ES-32B metal indicated that the forward dissolution rates for both metals were similar, if not identical. In other words, the presence of P and 99 Tc in the ES-32B metal appeared to have little effect on the forward dissolution rate. These results indicate that the corrosion rate of the ES-32B metal at repository relevant conditions was not significantly less than the surrogate metal. Because the effects of temperature (E a = 15 ±5 kJ/mol at pH(23°C) = 9.0 based on Fe release from ES-32B metal) and solution pH (η = -0.13 ±0.02 at 70°C based on Fe releas...

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Section: Dependence Of Dissolution Rate On Edta Concentrationsupporting

confidence: 82%

Corrosion of Metal Inclusions In Bulk Vitrification Waste Packages

Bacon¹,

Pierce²,

Wellman³

et al. 2006

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“…The importance of ligand-adsorption on the metal oxide/ solution interface has been addressed (Zhang et al 1985;Amirbahman et al 1997;Dos Santos Afonso et al 1990;Carbonaro et al 2008) and the importance of stability constants (Slemnik and Milošev 2006;Milošev 2002;Milosev and Strehblow 2000) highlighted. Synergistic effects of different complexing agents and metal ions have been observed in several of these studies (Amirbahman et al 1997;Ballesteros et al 1998;Carbonaro et al 2008;Dos Santos Afonso et al 1990).…”

Section: Introductionmentioning

confidence: 92%

“…Complexation-induced metal release has previously been investigated for 316L massive materials (Herting et al 2006(Herting et al , 2008aOkazaki and Gotoh 2005;Cieslik et al 2009;Slemnik and Milošev 2006;Milošev 2002;Milosev and Strehblow 2000;Kocijan et al 2003) and for iron and chromium compounds (Zhang et al 1985;Amirbahman et al 1997;Ballesteros et al 1998;Dos Santos Afonso et al 1990;Carbonaro et al 2008;Schwertmann 1991) using similar complexing agents in different solutions (e.g., citric acid or citrate) as used in this study. The importance of ligand-adsorption on the metal oxide/ solution interface has been addressed (Zhang et al 1985;Amirbahman et al 1997;Dos Santos Afonso et al 1990;Carbonaro et al 2008) and the importance of stability constants (Slemnik and Milošev 2006;Milošev 2002;Milosev and Strehblow 2000) highlighted.…”

Section: Introductionmentioning

confidence: 95%

Complexation- and ligand-induced metal release from 316L particles: importance of particle size and crystallographic structure

Hedberg

Liu

et al. 2011

Biometals

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Iron, chromium, nickel, and manganese released from gas-atomized AISI 316L stainless steel powders (sized <45 and <4 μm) were investigated in artificial lysosomal fluid (ALF, pH 4.5) and in solutions of its individual inorganic and organic components to determine its most aggressive component, elucidate synergistic effects, and assess release mechanisms, in dependence of surface changes using atomic absorption spectroscopy, Raman, XPS, and voltammetry. Complexation is the main reason for metal release from 316L particles immersed in ALF. Iron was mainly released, while manganese was preferentially released as a consequence of the reduction of manganese oxide on the surface. These processes resulted in highly complexing media in a partial oxidation of trivalent chromium to hexavalent chromium on the surface. The extent of metal release was partially controlled by surface properties (e.g., availability of elements on the surface and structure of the outermost surface) and partially by the complexation capacity of the different metals with the complexing agents of the different media. In general, compared to the coarse powder (<45 μm), the fine (<4 μm) powder displayed significantly higher released amounts of metals per surface area, increased with increased solution complexation capacity, while less amounts of metals were released into non-complexing solutions. Due to the ferritic structure of lower solubility for nickel of the fine powder, more nickel was released into all solutions compared with the coarser powder.

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“…In addition, adsorbed Fe(II) may strongly affect the Fe(III) dissolution rate of iron oxide minerals in the presence of organic anions (Stumm and Sulzberger, 1992;Ballesteros et al, 1998), and may catalyze 0016-7037/$ -see front matter Ó 2007 Elsevier Ltd. All rights reserved. doi:10.1016All rights reserved.…”

Section: Introductionmentioning

confidence: 99%