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Goethite and Hematite Nucleation and Growth from Ferrihydrite: Effects of Oxyanion Surface Complexes.
Namayandeh, Alireza; Zhang, Wei; Watson, Steven K; Borkiewicz, Olaf J; Bompoti, Nefeli M; Chrysochoou, Maria; Penn, R Lee; Michel, F Marc.
Afiliación
  • Namayandeh A; Department of Geosciences, Virginia Tech, Blacksburg, Virginia 24061, United States.
  • Zhang W; Department of Earth System Science, Stanford University, Stanford, California 94305, United States.
  • Watson SK; Department of Diagnostic and Biological Sciences, University of Minnesota, Minneapolis, Minnesota 55455, United States.
  • Borkiewicz OJ; Department of Geosciences, Virginia Tech, Blacksburg, Virginia 24061, United States.
  • Bompoti NM; Advanced Photon Source, Argonne National Laboratory, Lemont, Illinois 60439, United States.
  • Chrysochoou M; Department of Civil and Environmental Engineering, University of Massachusetts, Dartmouth, Massachusetts 02747, United States.
  • Penn RL; Department of Civil and Environmental Engineering, University of Connecticut, Storrs, Connecticut 06269, United States.
  • Michel FM; Department of Civil and Environmental Engineering, University of Connecticut, Storrs, Connecticut 06269, United States.
Environ Sci Technol ; 58(13): 5952-5962, 2024 Apr 02.
Article en En | MEDLINE | ID: mdl-38506754
ABSTRACT
The presence of oxyanions, such as nitrate (NO3-) and phosphate (PO43-), regulates the nucleation and growth of goethite (Gt) and hematite (Hm) during the transformation of ferrihydrite (Fh). Our previous studies showed that oxyanion surface complexes control the rate and pathway of Fh transformation to Gt and Hm. However, how oxyanion surface complexes control the mechanism of Gt and Hm nucleation and growth during the Fh transformation is still unclear. We used synchrotron scattering methods and cryogenic transmission electron microscopy to investigate the effects of NO3- outer-sphere complexes and PO43- inner-sphere complexes on the mechanism of Gt and Hm formation from Fh. Our TEM results indicated that Gt particles form through a two-step model in which Fh particles first transform to Gt nanoparticles and then crystallographically align and grow to larger particles by oriented attachment (OA). In contrast, for the formation of Hm, imaging shows that Fh particles first aggregate and then transform to Hm through interface nucleation. This is consistent with our X-ray scattering results, which demonstrate that NO3- outer-sphere and PO43- inner-sphere complexes promote the formation of Gt and Hm, respectively. These results have implications for understanding the coupled interactions of oxyanions and iron oxy-hydroxides in Earth-surface environments.
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Texto completo: 1 Colección: 01-internacional Banco de datos: MEDLINE Asunto principal: Compuestos Férricos / Compuestos de Hierro Idioma: En Revista: Environ Sci Technol Año: 2024 Tipo del documento: Article País de afiliación: Estados Unidos

Texto completo: 1 Colección: 01-internacional Banco de datos: MEDLINE Asunto principal: Compuestos Férricos / Compuestos de Hierro Idioma: En Revista: Environ Sci Technol Año: 2024 Tipo del documento: Article País de afiliación: Estados Unidos