Surface evolution of dissolving minerals investigated with a kinetic Ising model

Molecular-level mechanisms of quartz dissolution under neutral and alkaline conditions in the presence of electrolytes

“…Many researchers have investigated the mechanisms of quartz dissolution in the presence of electrolytes (e.g., Bandstra and Brantley, 2008;Berger et al, 1994;Bickmore et al, 2008;Criscenti and Sverjensky, 2002;Dove, 1999;Dove and Nix, 1997;Dove and Colin, 2005;Gratz and Bird, 1993;House, 1994;Karlsson et al, 2001;Kitamura et al, 1999;Sahai and Sverjensky, 1997;Strandh et al, 1997;Wallace et al, 2010). Their results suggest hydrolysis of the Si-O br bond is affected strongly by the presence of the electrolytes.…”

Defining reactive sites on hydrated mineral surfaces: Rhombohedral carbonate minerals

“…Furthermore, the presence of surface irregularities (e.g., steps, kinks and dislocations), chemical micro-heterogeneities, and multi-domain crystal surfaces, difficult to characterize experimentally, add to the complexity of multi-site models, so that the physical-chemical significance of the derived model parameters and their application to natural systems is seriously questioned (Lü tzenkirchen, 1997). It follows that simpler models are expected to remain predominant in the quantitative modeling of equilibrium adsorption phenomena (Lü tzenkirchen, 2002) and kinetic dissolution processes (Bandstra and Brantley, 2008).…”

Reaction pathways for quartz dissolution determined by statistical and graphical analysis of macroscopic experimental data

“…Furthermore, although it is widely accepted that oxide dissolution rates vary with the degree of surface charging arising from Brønsted acid-base reactions involving surface functional groups (Stumm et al, 1983Schindler and Stumm, 1987;Wieland et al, 1988;Casey et al, 1990;Stumm, 1992;Dove, 1994;e.g., Casey and Ludwig, 1996;Stumm, 1997;Brantley, 2004;Mielczarski and Pokrovskii, 2006), it is notoriously difficult to determine the speciation of individual types of functional groups on complex surfaces (Rustad, 2001(Rustad, , 2005Rustad et al, 2003;Bickmore et al, 2004Bickmore et al, , 2006bRustad and Felmy, 2005;Rustad and Casey, 2006). These practical problems have led some researchers to propose dissolution models related more to classical crystal growth theory than TST (Lasaga and Luttge, 2001, 2003, 2004a,b, 2005Lü ttge et al, 2003;Dove et al, 2005;Lü ttge, 2006;Dove and Han, 2007;Bandstra and Brantley, 2008;Zhang and Lü ttge, 2008). These approaches emphasize the influence of microscopic features of the mineral-solution interface such as surface topography and the Gibbs free energy required to open etch pits, and ignore the influence of molecular-scale details such as surface speciation.…”

“…Third, quartz dissolution rates are likely controlled almost solely by the ease with which siloxane (>Si-O-Si<) bridging bonds are broken and formed. Fourth, even though quartz dissolution is dominated by different processes (e.g., step propagation from dislocation or impurity defects, or from homogeneously nucleated surface vacancies) at a microscopic scale under different saturation states (Dove et al, 2005;Dove and Han, 2007), Bandstra and Brantley (2008) have noted that quartz dissolution rate vs. free energy of reaction curves do not exhibit an inflection point, which may mean that there is a single, rate-limiting step controlling the reaction. In other words, it appears that the energy involved in breaking or forming bonds in siloxane groups is similar regardless of defects in the structure or composition of quartz.…”