COLL 461 |
| Siderophores are biogenic ligands which promote iron oxide dissolution in a surface controlled process. The adsorption of bio-surfactants can influence the physico-chemical properties of interfaces and therefore surface controlled processes. We investigated the influence of adsorbed synthetic and biogenic surfactants on the surface properties, the adsorption of ligands and the promoted dissolution of goethite (α-FeOOH) and boehmite (γ-AlOOH) in the presence of siderophores and other ligands. Surfactants adsorption on goethite reversed the surface charge even at low concentrations. The adsorption of different ligands in the presence of surfactant revealed that hydrophobic interactions contributing to ligand adsorption are more important than electrostatic interactions. The dissolution rates at low surfactant concentrations were increased, but they were not linearly related to the adsorbed ligands as predicted by the ligand-promoted dissolution law. These results provide evidence that the adsorption of surfactants on mineral surfaces has an important effect on siderophore-promoted dissolution. |
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Environmental Interfaces
8:30 AM-12:40 PM, Wednesday, 13 September 2006 Sir Francis Drake -- Empire Room, Oral
Division of Colloid & Surface Chemistry |