title: Structural incorporation of As5+ into hematite.
abstract: Hematite (α-Fe2O3) is one of the most common iron oxides and a sink for the toxic metalloid arsenic. Arsenic can be immobilized by adsorption to the hematite surface; however, the incorporation of As in hematite was never seriously considered. In our study we present evidence that, besides adsorption, the incorporation of As into the hematite crystals can be of great relevance for As immobilization. With the coupling of nanoresolution techniques and X-ray absorption spectroscopy the presence of As (up to 1.9 wt %) within the hematite crystals could be demonstrated. The incorporated As(5+) displays a short-range order similar to angelellite-like clusters, epitaxially intergrown with hematite. Angelellite (Fe4As2O11), a triclinic iron arsenate with structural relations to hematite, can epitaxially intergrow along the (210) plane with the (0001) plane of hematite. This structural composite of hematite and angelellite-like clusters represents a new immobilization mechanism and potentially long-lasting storage facility for As(5+) by iron oxides.
authors.affiliation: Institute of Geosciences, Friedrich-Schiller-University Jena, 07745 Jena, Germany. Ralph.Bolanz@uni-jena.de
authors.forename: Ralph M
authors.initials: RM
authors.lastname: Bolanz
authors.forename: Mária
authors.initials: M
authors.lastname: Wierzbicka-Wieczorek
authors.forename: Mária
authors.initials: M
authors.lastname: Čaplovičová
authors.forename: Peter
authors.initials: P
authors.lastname: Uhlík
authors.forename: Jörg
authors.initials: J
authors.lastname: Göttlicher
authors.forename: Ralph
authors.initials: R
authors.lastname: Steininger
authors.forename: Juraj
authors.initials: J
authors.lastname: Majzlan
mesh_terms: D001151:Arsenic / Q000737:chemistry*; D004785:Environmental Pollutants / Q000737:chemistry*; D005290:Ferric Compounds / Q000737:chemistry*; D046529:Microscopy, Electron, Transmission; D056928:X-Ray Absorption Spectroscopy
chemical_list: D004785:Environmental Pollutants; D005290:Ferric Compounds; C000499:ferric oxide; C092844:ferric oxyhydroxide; D001151:Arsenic