BeskrivelseKnowledge of the possible mechanisms that control lateral structures in biomembranes is crucial for understanding how Modeling the environmental impact of pollutants requires a molecular level understanding of how i) toxic ions interact with soil mineral and ii) structural defects affect the uptake properties. Iron minerals like goethite (α- FeOOH) and lepidocrocite (β-FeOOH) are some of the most important sorption sites in the environment for heavy metal ions and toxic anions e.g., arsenate and selenate.
Solid-state NMR spectroscopy (SSNMR) is poised to obtain such information, but the magnetic properties of iron are generally thought to prevent SSNMR studies. I will illustrate how SSNMR is not only feasible, but also how paramagnetic shifts can be used for identification of binding sites on iron oxy hydroxide surfaces and for characterization of the local magnetic environment in jarosite samples, a text book example of a 2D Heisenberg anti-ferromagnet. The acid mine drainage minerals alunite and jarosite are isostructural both containing high concentrations (10-30 %) of structural defects, which affect their uptake properties and for jarosite, the magnetic properties. A new model for charge compensation of defects is obtained based on the molecular level information obtained from SSNMR experiments.
|Periode||15. maj 2007|
|Begivenhedstitel||Understanding sorption and defect sites in materials: Implication for pollutant binding|