Despite the high natural abundance of iron-organic matter (Fe-OM)  coprecipitates, only few studies have attempted to determine their reactivity and characterize their chemical and physical properties. In this study, we synthesized ferrihydrite-OM coprecipitates by hydrolysis or oxidation. We then characterized the morphology, structure, and reactivity of these coprecipitates. X-ray diffractometry analysis indicated that coprecipitated OM did not change the crystal structure of ferrihydrite. Electrophoretic mobility measurements showed that the addition of OM resulted in more negatively charged particles compared to pure ferrihydrite. Scanning transmission X-ray microscopy analysis indicated that Fe and C are evenly distributed within particles and that carboxylic-C may play an important role in complexation with Fe oxides. The crystal size decreased as a function of increased OM based on pair distribution function analysis and X-ray absorption spectroscopy . Our results indicate that both the ferrihydrite morphology and reactivity are strongly influenced when coprecipitated with soil organic matter.

Structure and reactivity of ferrihydrite-organic matter coprecipitates

245th National Meeting (2013)

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.