Rate laws of steady-state and non-steady-state ligand-controlled dissolution of goethite

Photodissolution of lepidocrocite (γ-FeOOH) in the presence of desferrioxamine B and aerobactin

“…3 and 4 in the electronic annex). Subsequent to the fast initial dissolution of lepidocrocite observed during the first 45 min, probably associated with a release of kinetically labile iron from the surface Eggleston, 1998, 2000;Eggleston et al, 2004;Reichard et al, 2007), dissolution was generally linear. The only case where non-linear dissolution was observed at longer time scales was in the presence of aerobactin at high dissolved iron concentrations at low pH (65).…”

Evidence for ligand hydrolysis and Fe(III) reduction in the dissolution of goethite by desferrioxamine-B

“…These include organic ligands called siderophores that have high affinity and specificity for Fe(III) and therefore can solubilize iron from minerals. The dissolution of Fe(III) bearing minerals in the presence of siderophores has been the subject of numerous recent studies (e.g., Reichard et al, 2005Reichard et al, , 2007Wolff-Boenisch and Traina, 2007;Haack et al, 2008;Borer et al, 2009b). These multidentate ligands often contain several a-hydroxycarboxylate, catecholate, and/or hydroxamate moities that chelate to metals (Kiss and Farkas, 1998;Hersman et al, 2000;Kraemer, 2004;Dhungana and Crumbliss, 2005;Sandy and Butler, 2009 The focus of this study is the reaction of a trihydroxamate siderophore, desferrioxamine-B (DFOB), with the Fe(III) bearing soil mineral, goethite (a-FeOOH), in the absence of visible light.…”

Roles of Siderophores, Oxalate, and Ascorbate in Mobilization of Iron from Hematite by the Aerobic Bacterium Pseudomonas mendocina

“…The model is described simply here as follows for amorphous Fe(OH) 3 and has been described in detail by Kraemer (26): Fe(OH) 3 (39), suggests that [FeL] could in principle easily be micromolar or higher and could support vigorous bacterial growth. However, the trishydroxamate siderophores that have been studied most to date adsorb only weakly to Fe(III) (hydr)oxide minerals, likely due to steric constraints, although charge repulsion may also play a role for positively charged siderophores, such as desferrioxamine B (DFO-B) (6,26,41,42). Therefore, it has been proposed that siderophores act primarily in conjunction with other molecules, such as simple plant-derived carboxylic acids or reductants, which interact more strongly with mineral surfaces and release Fe directly through ligand-promoted and/or reductive mechanisms (52).…”