Ab initio study of dissolution and precipitation reactions from the edge, kink, and terrace sites of quartz as a function of pH

Shikha Nangia, Barbara J. Garrison

Research output: Contribution to journalArticle

25 Citations (Scopus)

Abstract

In this study, the fundamental concept of mineral surface roughness and the role it plays on the dissolution and precipitation processes using ab initio density functional theory calculations, have been investigated. To understand the topological contribution to the dissolution and precipitation rates of quartz, a systematic study was designed to determine the reaction mechanisms and barrier heights of the forward reaction of hydrolysis of-Si(OH)3 group from underlying edge, kink, and terrace sites. The edge and kink sites are topological features on mineral surfaces that are bound to the bulk with fewer Si-O-Si bridge bonds than a terrace site, a factor that can be significant in the dissolution process. In this work, the local arrangement of atoms on the underlying sites is included by systematically increasing the Si-O-Si bridging to represent the edge, kink, and terrace sites under ambient conditions in the neutral, deprotonated, and protonated states. Nine reaction profiles were studied using the M05-2X density functional with 6-31 + G(d,p) basis set. The results show that hydrolysis of the-Si(OH)3 group and the back reactions are not too sensitive to the underlying edge, kink, and terrace site. The barrier height data also explain the experimentally observed dissolution rate over the entire pH range, especially the tremendously high dissolution rate below pH 2.

Original languageEnglish (US)
Pages (from-to)831-843
Number of pages13
JournalMolecular Physics
Volume107
Issue number8-12
DOIs
StatePublished - Jan 2009
Externally publishedYes

Fingerprint

Quartz
Minerals
dissolving
Dissolution
Hydrolysis
quartz
hydrolysis
minerals
Density functional theory
surface roughness
Surface roughness
density functional theory
Atoms
profiles
atoms

Keywords

  • Ab initio
  • Dissolution
  • Precipitation
  • Surface roughness
  • Topography

ASJC Scopus subject areas

  • Biophysics
  • Molecular Biology
  • Physical and Theoretical Chemistry
  • Condensed Matter Physics

Cite this

Ab initio study of dissolution and precipitation reactions from the edge, kink, and terrace sites of quartz as a function of pH. / Nangia, Shikha; Garrison, Barbara J.

In: Molecular Physics, Vol. 107, No. 8-12, 01.2009, p. 831-843.

Research output: Contribution to journalArticle

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