Molecular Dynamics Modeling of Ion Adsorption to the Basal Surfaces of Kaolinite

Journal Article · Sat Apr 14 00:00:00 EDT 2007 · Journal of Physical Chemistry. C

DOI:https://doi.org/10.1021/jp065687+· OSTI ID:1426982

Vasconcelos, Igor F. ^[1]; Bunker, Bruce A. ^[1]; Cygan, Randall T. ^[2]

---

1. Univ. of Notre Dame, IN (United States). Dept. of Physics
2. Sandia National Lab. (SNL-NM), Albuquerque, NM (United States). Geochemistry Dept.

In this paper, molecular dynamics simulation is used to study the mechanisms involved in the adsorption of various ions to the basal surfaces of kaolinite. Analysis of simulation data indicates that cations and anions adsorb preferably on the siloxane and gibbsite surfaces of kaolinite, respectively. Strong inner-sphere adsorption of chlorine at aluminum vacancies on the gibbsite surface and the occurrence of chlorine-driven inner-sphere adsorption of cesium and sodium on the gibbsite surface for high ionic strengths are observed. Cesium ions form strong inner-sphere complexes at ditrigonal cavities on the siloxane surface. Outer-sphere cesium is highly mobile and only weak adsorption may occur. A small amount of sodium adsorbs on the siloxane surface as inner-sphere complexes at less clearly defined sites. Like cesium, sodium only forms very weak outer-sphere complexes on this surface. Inner-sphere complexes of cadmium and lead do not occur on either surface. Finally, relatively strong outer-sphere cadmium and lead complexes are present on the siloxane surface at ditrigonal cavities.

• Research Organization: Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Univ. of Notre Dame, IN (United States)
• Sponsoring Organization: USDOE National Nuclear Security Administration (NNSA); USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
• Grant/Contract Number: AC04-94AL85000
• OSTI ID: 1426982
• Alternate ID(s): OSTI ID: 1007646
• Report Number(s): SAND2007--0734J; 524414
• Journal Information: Journal of Physical Chemistry. C, Journal Name: Journal of Physical Chemistry. C Journal Issue: 18 Vol. 111; ISSN 1932-7447
• Publisher: American Chemical Society
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY