Feedbacks and non-linearity of silicate glass alteration in hyperalkaline solution studied by in operando fluid-cell Raman spectroscopy

The Replacement of Celestine (SrSO4) by Strontianite (SrCO3) in Aqueous Solution Studied In Situ and in Real Time Using Fluid-Cell Raman Spectroscopy

“…An increase in SO 4 2− in the interfacial solution due to transport limitations could thus dramatically decrease the dissolution rate of celestine (chemical affinity approaches zero), while strontianite continues to precipitate, eventually producing self-organized chemical waves. The exact feedback mechanism is not yet understood, but it is noted that temporal chemical oscillations in reacting solutions have also been observed during the dissolution of dolomites and the reprecipitation of a Mg carbonate phase via atomic force microscopy and regular solution sampling [42] and, more recently, during the corrosion of a silicate glass via fluid-cell Raman spectroscopy [20].…”

“…This is because fluid-cell Raman spectroscopy allows us to study the replacement reaction in real time by continuously analysing the solution or, more sophisticatedly, by imaging the solid-liquid interface where the reaction takes place and while the replacement process is running. Using home-made heated fluid cells, our group has applied, for the first time, fluid-cell Raman spectroscopy to in situ study the corrosion of silica glasses in aqueous solutions with a spatial resolution of a few micrometres [17][18][19][20]. These experiments have given new, intriguing, and partly paradigm-breaking mechanistic insights in the glass corrosion process.…”