SIZE-DEPENDENT REACTIONS BETWEEN Fe(II) AND GOETHITE

摘要

The biogeochemical cycling of iron is closely linked to contaminant transformations in anaerobic subsurface environments. Microbial reduction of Fe(III) oxides produces significant levels of dissolved Fe(II) at the surface of Fe(III) oxides. Numerous studies have shown that Fe(II) in the presence of mineral surfaces can reduce a wide variety of organic and inorganic compounds (e.g., 1). In addition to the potential reduction of contaminants by Fe(II), it has also been shown that Fe(II) sorbed to Fe(III) oxides can reduce the underlying structural Fe(III) via interfacial electron transfer. We are interested in the effect of particle size, particularly in the nanoscale range, on both contaminant reduction by Fe(II) and electron transfer between sorbed Fe(II) and structural Fe(III). The prevalence of nanoscale iron oxides in natural environments, coupled with recent reports of enhanced reactivity of nanoparticles necessitates a better understanding of Fe(II) reactions with these small particles3,4. Here we present results for the interaction of Fe(II) with goethite particles of varying size using 57Fe M?ssbauer spectroscopy.