The formation of poorly crystalline Fe-oxyhydroxide phases in aquatic systems, soils, and sediments typically occurs in the presence of natural organic matter (NOM) such as humic and fulvic acids. Carboxyl and phenol functional groups are abundant in NOM and known to interfere with the polymerization of Fe(III) and impact ferrihydrite formation. This study of synthetic ferrihydrite using X-ray total scattering examines how the number and position of the phenol groups in hydroxybenzoic acids affect the size and structure of the ferrihydrite precipitate. We show that hydroxybenzoic acids decreased the coherent scattering domain size of the ferrihydrite and increased apparent strain in the order 4-hydroxybenzoic acid~2,4-dihydroxybenzoic acid<<3,4-dihydroxybenzoic acid. Developing a deeper understanding of the effects of organic solution constituents on the structure of ferrihydrite is important in order to predict the nanomineral's biogeochemical reactivity in the environment.

Total X-ray scattering study of the effect of benzoic acids on the structure of ferrihydrite

243rd National Meeting (2012)

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