Dissolution of insulating oxide materials at the molecular scale

Abstract

Our understanding of mineral and glass dissolution has advanced from simple thermodynamic treatments to models that emphasize adsorbate structures. This evolution was driven by the idea that the best understanding is built at the molecular level. Now, it is clear that the molecular questions cannot be answered uniquely with dissolution experiments. At the surface it is unclear which functional groups are present, how they are arranged, and how they interact with each other and with solutes as the key bonds are activated. An alternative approach has developed whereby reactions are studied with nanometre-sized aqueous oxide ions that serve as models for the more complicated oxide interface. For these ions, establishing the structure is not a research problem in itself, and bond ruptures and dissociations can be followed with much confidence. We review the field from bulk-dissolution kinetics to the new isotope-exchange experiments in large oxide ions.

The mechanism of borosilicate glass corrosion revisited

“…In this regard, we note that the model is basically derived from the notion of a coupled dissolution-reprecipitation mechanism that has been proposed by Putnis (2002, see also references therein) as an important mechanism for the re-equilibration of minerals in fluids. Conventionally, these re-equilibration reactions have been described by solid-state mechanisms involving volume diffusion (e.g., Casey et al, 1993;Brantley, 2008;Ohlin et al, 2010). Nevertheless, further evidence for a coupled dissolution-reprecipitation mechanism has subsequently been reported from numerous experimental studies on many more solid-fluid systems (Putnis and Putnis, 2007;Putnis et al, 2009;Hellmann et al, 2012;Putnis, 2014).…”

Cooperation between bound waters and hydroxyls in controlling isotope-exchange rates

“…The extent to which they apply to polymeric structures remains unclear and only experiments on model systems and simulation can establish the relevance (Casey and Swaddle, 2003;Casey and Rustad, 2007;Spiccia and Casey, 2007;Wang et al, 2007;Casey et al, 2009;Ohlin et al, 2010;Swaddle, 2010). It appears that the general trends in water-exchange rates across the Periodic Table are not fundamentally disrupted for larger, and even nanometer-size, ions, with the exception of the changes in pH dependencies.…”

“…7. Selected values of the rate coefficient for exchange of a bound and bulk water (here denoted k 298, which corresponds to k 298 0 for complexes [1] and [2] discussed in the text) compared with the corresponding experimental DH à values for water exchange rates from fully protonated aqueous complexes and nanometer-size aqueous clusters (adapted from Richens (2005b) and Ohlin et al (2010)). The large gray triangle symbols correspond to the data presented here.…”

Enhanced ice nucleation efficiency of microcline immersed in dilute NH<sub>3</sub> and NH<sub>4</sub><sup>+</sup>-containing solutions

“…The presence of additional external cations in a salt solution introduces competition in the cation exchange. The hydrated size of the externally introduced cations, the stability of surface complexes and the pH of the solution are factors that govern the cation-exchange selectivity of the aluminosilicate 240 surface (Garrels and Howard, 1959;Petrović et al, 1976;Auerbach et al, 2003;Ohlin et al, 2010;Belchinskaya et al, 2013). ] has reached a value of 1, with the exception of (NH4)2SO4 solutions.…”