Complexation of carbonate species at the goethite surface: Implications for adsorption of metal ions in natural waters

Geen, Alexander van; Robertson, A.; Leckie, James O.

doi:10.1016/0016-7037(94)90286-0

Cited by 229 publications

(177 citation statements)

References 34 publications

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“…Ferric nitrate was combined with concentrated sodium hydroxide in the absence of CO 2 . An effort was made to keep CO 2 out of the product during initial synthesis but not during the dialysis purification stage; CO 2 adsorbed during product synthesis can significantly impact the zero point of charge of the product (Vangeen et al, 1994). Sodium hydroxide was slowly pumped into the ferric nitrate solution over a period of several hours until a pH of 12 was reached during continuous stirring.…”

Section: Synthesis Of Iron (Hydr)oxide-coated Sandsmentioning

confidence: 99%

Influence of Uranyl Speciation and Iron Oxides on Uranium Biogeochemical Redox Reactions

Stewart

Amos

Nico

et al. 2011

Geomicrobiology Journal

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Uranium is a pollutant of concern to both human and ecosystem health. Uranium's redox state often dictates its partitioning between the aqueous-and solid-phases, and thus controls its dissolved concentration and, coupled with groundwater flow, its migration within the environment. In anaerobic environments, the more oxidized and mobile form of uranium (UO 2 2+ and associated species) may be reduced, directly or indirectly, by microorganisms to U(IV) with subsequent precipitation of UO 2 . However, various factors within soils and sediments may limit biological reduction of U(VI), inclusive of alterations in U(VI) speciation and competitive electron acceptors. Here we elucidate the impact of U(VI) speciation on the extent and rate of reduction with specific emphasis on speciation changes induced by dissolved Ca, and we examine the impact of Fe(III) (hydr)oxides (ferrihydrite, goethite and hematite) varying in free energies of formation on U reduction. The amount of uranium removed from solution during 100 h of incubation with S. putrefaciens was 77% with no Ca or ferrihydrite present but only 24% (with ferrihydrite) and 14% (no ferrihydrite) were removed for systems with 0.8 mM Ca.Imparting an important criterion on uranium reduction, goethite and hematite decrease the dissolved concentration of calcium through adsorption and thus tend to diminish the effect of calcium on uranium reduction. Dissimilatory reduction of Fe(III) and U(VI) can proceed through different enzyme pathways, even within a single organism, thus providing a potential second means by which Fe(III) bearing minerals may impact U(VI) reduction. We quantify rate coefficients for simultaneous dissimilatory reduction of Fe(III) and U(VI) in systems varying in Ca concentration (0 to 0.8 mM), and using a mathematical construct implemented with the reactive transport code MIN3P, we reveal the predominant influence of uranyl speciation, 2 specifically the formation of uranyl-calcium-carbonato complexes, and ferrihydrite on the rate and extent of uranium reduction in complex geochemical systems.3

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Section: Synthesis Of Iron (Hydr)oxide-coated Sandsmentioning

confidence: 99%

Influence of Uranyl Speciation and Iron Oxides on Uranium Biogeochemical Redox Reactions

Stewart

Amos

Nico

et al. 2011

Geomicrobiology Journal

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“…Relatively few measurements have been made for carbon-14 adsorption on natural materials. Most studies have been conducted on calcite or mixtures of calcite and sands (Martin 1996;Garnier 1985;Mozeto, Fritz, and Reardon 1984) and ferric oxyhydroxides (Zachara et al 1987;van Geen et al 1994). While anion adsorption on ferric oxyhydroxides has shown to be important, the total volume of work on oxides is limited.…”

Section: Adsorptionmentioning

confidence: 99%

Transport Models for Radioactive Carbon Dioxide at RWMC

Hull¹,

Hohorst²

2001

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“…They stated that these ions adsorb competitively on the same A1 sites, but not necessarily by the same mechanisms. Competitive adsorption also has been observed between CrO42-and dissolved CO2(g ) on amorphous Fe hydroxide (Zachara et al 1987) and on goethite (Van Geen et al 1994). In addition to surface adsorption, carbonate can also form discrete solid phases with A1 such as dawsonite [NaAI(CO3)(OH)2].…”

Section: Introductionmentioning

confidence: 99%

In Situ Infrared Speciation of Adsorbed Carbonate on Aluminum and Iron Oxides

Suarez

1997

Clays and clay miner.

257

176

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Abstract--Surface adsorption mechanisms of dissolved inorganic carbon species on soil minerals are not well understood. Traditional infrared (IR) study of adsorbed species of inorganic carbon using air-dried samples may not reveal true species in the solid/water interface in suspension. The ptu'pose of this study was to obtain information on interracial carbonate speciation between solid and aqueous phases. The interaction of bicarbonate and carbonate ions with X-ray amorphous (am) A1 and Fe oxides, gibbsite (~/-AI(OH)3 ) and goethite (a-FeOOH) was examined by electrophoresis and in situ attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy. The presence of carbonate lowered the electrophoretic mobility and decreased the point of zero charge (PZC) of all minerals, implying specific adsorption. Inner-sphere complexation of bicarbonate and carbonate was supported by a lowering in the anion symmetry due to the interaction with A1 and Fe oxide surfaces. Only complexed monodentate carbonate was identified in am-Al(OH)3/aqueous solution at pH 4.1-7.8 when the solid was reacted with either NanCO 3 or Na2CO 3 solutions. Am-AI(OH)3 was transformed to a crystalline sodium aluminum hydroxy carbonate, dawsonite [NaAl(CO3)(OH)2], and bayerite (ct-AI(OH)3) after reacting with 1.0 M Na2CO3 for 24 h. Gibbsite adsorbed much less carbonate than am-AI(OH)3 such that adsorbed carbonate on gibbsite gave weak IR absorption. It is probable that monodentate carbonate is also the complexed species on gibbsite. Evidence suggesting the presence of both surface complexed bicarbonate and carbonate species in the interfacial region of am-Fe(OH)3 in suspension and the dependence of their relative distribution on solution pH is shown. Only monodentate carbonate was found in the interracial region of goethite in 1.0 M NaHCO3. A ligand exchange reaction was proposed to describe the interaction of bicarbonate and carbonate with the surface functional groups of A1 and Fe oxides.

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Complexation of carbonate species at the goethite surface: Implications for adsorption of metal ions in natural waters

Cited by 229 publications

References 34 publications

Influence of Uranyl Speciation and Iron Oxides on Uranium Biogeochemical Redox Reactions

Influence of Uranyl Speciation and Iron Oxides on Uranium Biogeochemical Redox Reactions

Transport Models for Radioactive Carbon Dioxide at RWMC

In Situ Infrared Speciation of Adsorbed Carbonate on Aluminum and Iron Oxides

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