Journal of Physical Chemistry C
Journal of Physical Chemistry C
5 years ago

Quantum Chemical Investigation of the Selenite Incorporation into the Calcite (101̅4) Surface

Quantum Chemical Investigation of the Selenite Incorporation into the Calcite (101̅4) Surface
Frank Heberling, Horst Geckeis, Bernd Schimmelpfennig, Robert Polly
Selenium is a common pollutant in soils and aquifers. The radioisotope 79Se, an abundant fission product of 235U, is of particular concern in the context of nuclear waste disposal safety due to its long half life and its expected high mobility in the multibarrier system around potential nuclear waste disposal sites. Oxidized selenium species are relatively soluble and show only weak adsorption at common mineral surfaces. However, a possible sorption mechanism for selenium in the geosphere is the structural incorporation of selenium(IV) (selenite, SeO32–) into calcite (CaCO3). We carried out a detailed quantum chemical study of the incorporation of SeO32– into the calcite surface and the subsurface layers. As the main result, we present the structural changes upon incorporation of selenite (SeO3–2) into the dry and hydrated calcite (1014) surface. These results are complemented by energetic considerations and, in turn, used to estimate the thermodynamic partition coefficient D for SeO3–2 incorporation into the surface and subsurface layers. The results corroborate the recently proposed entrapment model for selenium(IV) coprecipitation with calcite and show that equilibrium incorporation of selenite into calcite may occur in the surface layer but is practically impossible in subsurface layers or the bulk.

Publisher URL: http://dx.doi.org/10.1021/acs.jpcc.7b03499

DOI: 10.1021/acs.jpcc.7b03499

You might also like
Discover & Discuss Important Research

Keeping up-to-date with research can feel impossible, with papers being published faster than you'll ever be able to read them. That's where Researcher comes in: we're simplifying discovery and making important discussions happen. With over 19,000 sources, including peer-reviewed journals, preprints, blogs, universities, podcasts and Live events across 10 research areas, you'll never miss what's important to you. It's like social media, but better. Oh, and we should mention - it's free.

  • Download from Google Play
  • Download from App Store
  • Download from AppInChina

Researcher displays publicly available abstracts and doesn’t host any full article content. If the content is open access, we will direct clicks from the abstracts to the publisher website and display the PDF copy on our platform. Clicks to view the full text will be directed to the publisher website, where only users with subscriptions or access through their institution are able to view the full article.