Preferential adsorption of selenium oxyanions onto {1 1 0} and {0 1 2} nano-hematite facets

Amanda W. Lounsbury, Ranran Wang, Desiree L. Plata, Nicholas Billmyer, Christopher Muhich, Kiyoshi Kanie, Tadao Sugimoto, Derek Peak, Julie B. Zimmerman

Research output: Contribution to journalArticle

5 Citations (Scopus)

Abstract

As the commercial use of nano metal oxides, including iron oxides, becomes more prevalent, there is a need to understand functionality as it relates to the inherent properties of the nanomaterial. Many applications of nanomaterials rely on adsorption, ranging from catalysis to aqueous remediation. In this paper, adsorption of selenium (Se), an aqueous contaminant, is used as a model sorbate to elucidate the relationships of structure, property, and (adsorptive) function of nano-hematite (nα-Fe2O3). As such, six nα-Fe2O3 particles were synthesized controlling for size, shape and surface area without capping agents. Sorbent characteristics of the six particles were then assessed for their impact on selenite (HSeO3 ) and selenate (SeO4 2−) adsorption capacity and mechanism. Mechanism was assessed using in-situ attenuated total reflectance-Fourier transform infrared (ATR-FTIR) spectroscopy and extended X-ray absorption fine edge spectroscopy (EXAFS). Regression analyses were then performed to determine which characteristics best describe adsorption capacity and binding mechanisms of Se on nα-Fe2O3. The results demonstrate that crystal surface structure, specifically presence of the {0 1 2} facet promotes adsorption of Se and the presence of {0 1 2} facets promotes SeO4 2− sorption to a greater extent than HSeO3 . The data further indicates that {1 1 0} facets bind HSeO3 with binuclear complexes while {0 1 2} facets bind HSeO3 via mononuclear inner-sphere complexes. Specific nα-Fe2O3 facets also likely direct the ratio of inner to outer-sphere complexes in SeO4 2− adsorption.

Original languageEnglish
Pages (from-to)465-474
Number of pages10
JournalJournal of Colloid And Interface Science
Volume537
DOIs
Publication statusPublished - 2019 Mar 1

Keywords

  • Adsorption
  • Hematite (α-FeO)
  • Nanoparticle
  • Selenium (Se)

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Biomaterials
  • Surfaces, Coatings and Films
  • Colloid and Surface Chemistry

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  • Cite this

    Lounsbury, A. W., Wang, R., Plata, D. L., Billmyer, N., Muhich, C., Kanie, K., Sugimoto, T., Peak, D., & Zimmerman, J. B. (2019). Preferential adsorption of selenium oxyanions onto {1 1 0} and {0 1 2} nano-hematite facets. Journal of Colloid And Interface Science, 537, 465-474. https://doi.org/10.1016/j.jcis.2018.11.018