Structural evolution of glass surface during alteration: Application to nuclear waste glasses

Structure and composition of the surface layer of Zr-containing fiberglass materials

“…The glass fiber was found to consist of a rigid silicon-zirconium framework with sodium silicates filling the framework voids. The embedding of Zr in three-dimensional network of silicon-oxygen tetrahedrons was confirmed by the 29 Si and 23 Na NMR data. We suppose that the silicon-zirconium framework is forming at glass preparation when cooling down to 1000-1200°C.…”

“…The types of oxygen environment of silicon differing in symmetry (denoted as Q (n) , n = 0, 1, 2, 3, 4) were identified based on the magnitude of the isotropic shift in the MAS NMR spectra. The 23 Na MAS NMR spectra were obtained at a pulse with duration of 1 μs; the delay between pulses was 0.5 s, the number of scans was 5000. As an external standard, we used a 0.1 M aqueous solution of NaCl.…”

“…Among the numerous works devoted to the glass structure, most part was focused on studying the glass bulk, and we found only a few works devoted to the structure and composition of the surface layers of Zr-Si glasses (layers with a depth of 10-20 nm) [22,23]. Henderson and co-workers stated that the composition of the surface layers of glass should strongly depend on pretreatment procedures [24].…”

Impact of iron chelators on short-term dissolution of basaltic glass

“…These short and long-term dissolution kinetics were investigated with respect to parameters such as temperature and pH (Pierce et al, 2008) and glass elemental composition http://dx.doi.org/10.1016/j.gca.2015.04.025 0016-7037/Ó 2015 Elsevier Ltd. All rights reserved. , and they have been coupled to studies of the alteration gel (Rebiscoul et al, 2005;Jollivet et al, 2008;Gin et al, 2015;Hellmann et al, 2015) or of secondary phases (Pelegrin et al, 2010). These experiments were performed in pure water, water enriched in elements from the glass (Luckscheiter and Nesovic, 2004;Thien et al, 2012) and in salt solutions (Godon et al, 1988;Abdelouas et al, 1993).…”

Mineral-Aqueous Solution Interfaces and Their Impact on the Environment

“…At under-saturated conditions, the surface evolution is fast, with clays forming an outer layer 500 nm thick after 7 days, and an underlying gel layer 200 nm thick . In contrast, during leaching at near-saturated conditions, there is no detectable evolution of surface morphology after 7 days (Pèlegrin et al, 2010) . …”