FTIR spectral components of schwertmannite

• Fourier transform infrared (FTIR) spectral components of three dominant groups of sulfate species in synthetic schwertmannite (Fe8O8(OH)6-x(SO4)x*nH2O) are presented. These components were extracted by multivariate curve resolution analysis of spectra obtained from N2(g)-dry samples initially reacted in aqueous solutions (pH 3-9) at room temperature. Each component contains complex sets of bands that correspond to mixtures of similar species. We tentatively assign these components to sulfate ions that are hydrogen- (components I and III) and iron-bonded (component I) to schwertmannite. Another component (II) is assigned to protonated sulfate species. Heating experiments to 130 degrees C moreover confirmed this possibility for component II. The spectral components extracted from this study can be used to identify dominant sulfate species in FTIR spectra of naturally occurring schwertmannite samples.

Publikations- och innehållstyp

ref (ämneskategori)

art (ämneskategori)